Universe Today

I can remember when Perseverance was launched, travelled out into the Solar System and landed on Mars in February 2021.  In all the time since it arrived, having clocked up 1000 days of exploration, it has collected 23 samples from different geological areas within the Jezero Crater. The area was once home to an ancient lake and if there is anywhere on Mars to find evidence of ancient (fossilised) life, it is here. 

The date was 30 July 2020 when a gigantic Atlas V-541 rocket roared off the launchpad from Cape Canaveral in Florida. On board was the Perseverance rover, on its way to Mars. It arrived around 7 months later, entered the Martian atmosphere and successfully landed using a complex sequence of parachutes, retrorockets and for the first time, a sky crane to lower it from a hovering platform. Its chief purpose on Mars was to explore the geology, climate and atmospheric conditions as a precursor to human exploration. 

A United Launch Alliance Atlas V rocket with NASA’s Mars 2020 Perseverance rover onboard launches from Space Launch Complex 41 at Cape Canaveral Air Force Station, Thursday, July 30, 2020, from NASA’s Kennedy Space Center in Florida. The Perseverance rover is part of NASA’s Mars Exploration Program, a long-term effort of robotic exploration of the Red Planet. Photo Credit: (NASA/Joel Kowsky)

The landing site, the Jezero Crater, was chosen because previous orbital studies revealed clear evidence of an ancient lake that once filled the crater. It is thought that water is a key ingredient to the evolution of life so if there had been a body of water, then there is a greater chance of life evolving. Studying the rocks here is like taking a flick through the history books as it preserves signs of ancient life and also ancient environmental conditions. 

The crater had been formed, like the majority of other craters in the Solar System from some form of impact event. In the case of Jezero it was an asteroid impact around 4 billion years ago. On its arrival at the crater the floor was soon discovered to be made of igneous rock, formed from a huge underground chamber of magma and bought to the surface through volcanic activity. Since then, other types of rock from sand and mud were found providing evidence of the presence of water in Mars’ distant past. 

Jezero Crater on Mars. Credit: NASA/JPL-Caltech/ASU

By the time Perseverance had hit the 1000 day anniversary of its exploration of the red planet it had collected the rock samples, safely packaged them up ready for collection and by and large, completed its exploration of the ancient lake bed. One sample in particular which has been called ‘Lefroy Bay’ has been found to contain fine grained silica. This material is commonly found on Earth and known to preserve fossils. Another of the samples contains phosphate which, on Earth is most definitely associated with biological processes. Both of these contain carbon which can be used to study the environmental conditions from when the rock formed. 

Jezero crater is a big place, 45 kilometres across so deciding on where to collect the samples was challenging. When a target site had been identified, Perseverance would first use its abrasion tool to wear away the surface and then use the onboard instruments such as PIXL, the Planetary Instrument for X-ray Lithochemistry. The instruments on board have the ability to detect both microscopic, fossil-like structures and also to identify chemical changes left behind by ancient microbes. Alas to date, whilst Perseverance has achieved an amazing amount, the detection of signs of life have alluded the rover. 

Source : NASA’s Perseverance Rover Deciphers Ancient History of Martian Lake

The post Perseverance Wraps Up Over 1,000 Days on Mars. Still Going Strong appeared first on Universe Today.

Back in the year 2000, Epsilon Eridani b was discovered. It is a Jupiter-like exoplanet 10.5 light years away but it has taken decades of observations to learn more about the planet. One thing that remains a mystery is it’s orbit which, until recently has been unknown. There has never been a direct image of the planet either, so now, it’s the turn of JWST to see what it can do. 

The concept of exoplanets has been around for a few decades now but the first confirmed discovery occurred in 1992. Astronomers at the Arecibo Observatory discovered a number of Earth-mass planets orbiting around the pulsar PSR B1257+12. Since then, over 5,000 planets have been discovered around other star systems. Astronomers use a number of Studying them once they have been confirmed requires more direct study.

The Arecibo Radio Telescope Credit: UCF

One such exoplanet is known as Epsilon Eridani b which also goes by the name AEgir. Exoplanets are named after their host star (in this case Epsilon Eridani) and the letter ‘b’ designates that it was the first exoplanet discovered around that star. The next to be discovered would be ‘c’ and so on although in the case of Epsilon Eridani it is the only planet. It is thought to orbit around the star at a distance of 3.5 astronomical units (where 1 AU is the average distance between the Sun and Earth) and takes about 7.6 years to complete one orbit.  

One area of exoplanet study that has been lacking over recent years is the study of the surface and atmospheric conditions, in particular a study into their potential habitability. Cold exoplanets seem to have received the least study due to their faint appearance in the mid-infrared wavelength. Due to the properties of these cold planets, direct imaging techniques are required and must employ high contrast processes.  To date, no instrument has been capable of delivering. 

The crux of the challenge is that the cold exoplanets have no intrinsic energy source and only re-use the radiation from the host star. Their luminosity is based upon their size and distance from host star but usually the radiation is at the same wavelength as the emission from the star. To address this challenge, a paper has been published in ‘Astronomy & Astrophysics’ journal by a team led by C. Tschudi from the Institute for Particle Physics and Astrophysics in Switzerland.

The paper provides an insight into high contrast observations of Epsilon Eridani taken in 20198 and 2020 using the VLT (Very Large Telescope). Using the SPHERE instrument (Spectro-Polarimetric High-contrast Exoplanet Research) as part of the ongoing RefPlanets programme, the team were able to use polarising technology to search for signals from the planet. 

In mid-August 2010 ESO Photo Ambassador Yuri Beletsky snapped this amazing photo at ESO’s Paranal Observatory. A group of astronomers were observing the centre of the Milky Way using the laser guide star facility at Yepun, one of the four Unit Telescopes of the Very Large Telescope (VLT). Yepun’s laser beam crosses the majestic southern sky and creates an artificial star at an altitude of 90 km high in the Earth’s mesosphere. The Laser Guide Star (LGS) is part of the VLT’s adaptive optics system and is used as a reference to correct the blurring effect of the atmosphere on images. The colour of the laser is precisely tuned to energise a layer of sodium atoms found in one of the upper layers of the atmosphere — one can recognise the familiar colour of sodium street lamps in the colour of the laser. This layer of sodium atoms is thought to be a leftover from meteorites entering the Earth’s atmosphere. When excited by the light from the laser, the atoms start glowing, forming a small bright spot that can be used as an artificial reference star for the adaptive optics. Using this technique, astronomers can obtain sharper observations. For example, when looking towards the centre of our Milky Way, researchers can better monitor the galactic core, where a central supermassive black hole, surrounded by closely orbiting stars, is swallowing gas and dust. The photo, which was chosen as Astronomy Picture of the Day for 6 September 2010 and Wikimedia Picture of the Year 2010, was taken with a wide-angle lens and covers about 180 degrees of the sky.   This image is available as a mounted image in the ESOshop.   #L

Unfortunately the team were unable to successfully detect Epsilon Eridani b despite a total exposure time of 38.5 hours spread over 12 nights. This was however, useful at understanding the limitations of the instrumentation. What next then? Well it looks like we have to wait for a next generation of infrared sensitive instruments to peer deeper into the system. The James Webb telescope is a fine example of such a device and, once it turns its sights onto Epsilon Eridani maybe the mysteries will finally be resolved.

Source : SPHERE RefPlanets: Search for ? Eridani b and warm dust

The post Astronomers Try to Directly Observe Epsilon Eridani b. No Luck. Maybe Webb Can Find it? appeared first on Universe Today.

Primordial Black Holes (PBHs) have recently received much attention in the physics community. One of the primary reasons is the potential link to dark matter. In effect, if PBHs can be proven to exist, there’s a very good chance that they are what dark matter, the invisible thing that makes up 85% of the universe’s mass, is made of. If proven, that would surely be a Nobel-level discovery in astrophysics. 

But to prove it, someone has to find them first. So far, PBHs exist only in theory. But we’re getting closer to proving they do exist, and a new paper from Marcos Flores of the Sorbonne and Alexander Kusenko of UCLA traces some ideas on how we might be able to finally find PBHs and thereby prove or disprove their connection to dark matter.

Drs. Flores and Kusenko focus on understanding PBH formation theories and then extrapolate how those formations might be detectable, even with modern equipment. A typical black hole, which we know exists, forms when supermassive stars collapse under their own weight.

Fraser discusses PBHs.

PBHs were formed before any stars of such size were available to collapse, so they must be formed using a different mechanism. The paper details a theorized PBH formation process that involves a detailed mathematical look at particle asymmetry and how that fits in with other models of particle physics. But how can astronomers see those formations?

One way is by watching a loss of angular momentum. Astronomers can observe “halos” of particles early on in the universe. In many cases, they are spinning rapidly. However, if their spin slows dramatically, it may indicate that a PBH was forming in the vicinity, sapping some of the energy from that angular momentum by pulling the particles towards themselves.

Another way is by watching a new favorite mechanism of astronomers everywhere – gravitational waves. It’s not completely clear whether the formation of PBHs can cause gravitational waves. Still, the paper discusses some frameworks that can potentially lead to a theory of whether they do. 

Fraser discusses how hard it is to find PBHs with Dr. Celeste Keith.

Supersymmetry provides one of those frameworks. In some cases, the early universe operating under the principles of supersymmetry could form a PBH that would form a gravitational wave that the next generation of gravitational wave detectors could potentially detect. In particular, it would involve what the paper calls a “poltergeist mechanism” resulting from space-time perturbations in certain theories. 

A final way to detect these PBHs is to watch for gravitational lenses. Some experiments like the Optical Gravitational Lensing Experiment (OGLE) and the Hyper Suprime-Cam (HSC) of the Subaru telescope have noticed gravitational microlensing where there is no known massive object to cause such lensing. PBHs, which would be effectively invisible to those telescopes, could offer one explanation, though other explanations must be ruled out first.

Other theories offer other opportunities for PBH detection, including watching the interaction of “Q-balls” or theoretical large “blobs” of matter. If enough of these are collected together, they could potentially form a PBH. 

Ultimately, there are more questions than answers surrounding these mysterious objects. If they do exist, they could answer plenty of them. However, more data is needed to prove that beyond any reasonable doubt. Experimentalists are already pushing forward as quickly as they can to develop new and better detectors that can help in the hunt for PBHs. If they do exist, it’s only a matter of time before we find them.

Learn More:
Flores & Kusenko – New ideas on the formation and astrophysical detection of primordial black holes
UT – The Universe Could Be Filled With Ultralight Black Holes That Can’t Die
UT – If We Could Find Them, Primordial Black Holes Would Explain a Lot About the Universe
UT – Neutron Stars Could be Capturing Primordial Black Holes

Lead Image:
Illustration of colliding black holes.
Credit – Caltech / R. Hurt (IPAC)

The post Some Clever Ways to Search for Primordial Black Holes appeared first on Universe Today.

We already know that water has existed on the surface of Mars but for how long? Curiosity has been searching for evidence for the long term presence of water on Mars and now, a team of researchers think they have found it. The rover has been exploring the Gale Crater and found it contains high concentrations of Manganese. The mineral doesn’t form easily on Mars so the team think it may have formed as deposits in an ancient lake. It is interesting too that life on Earth helps the formation of Manganese so its presence on Mars is a mystery.

The Mars Curiosity Rover was launched in November 2011. It arrived on 6 August 2012 in the Gale Crater region of Mars. It’s purpose was to explore the geology of the area, climatic conditions and the potential for habitability for future explorers.  We have seen stunning images from the surface of Mars thanks to Curiosity and our understanding of Mars both past and present has been improved as a result of its work. 

New simulations are helping inform the Curiosity rover’s ongoing sampling campaign. Credit:NASA/JPL-Caltech/MSSS

A paper published in the Journal of Geophysical Research : Planets has reported on findings using the ChemCam instrument on board Curiosity. The paper’s lead author Patrick Gasda from the Los Alamos National Laboratory’s Space Science and Application group announced the findings of high levels of manganese in rocks from the base of the crater. It is thought that the Gale Crater is an ancient lake so this poses interesting questions as to its origin. 

On Earth, biological processes are fundamental to the formation of materials like manganese oxide with photosynthesis producing atmospheric oxygen. There are also microbes that act as a catalyst to the oxidisation of manganese. The problem is that there is no such sign other life on Mars so the process that led to the formation of oxygen in the ancient Martian atmosphere is unclear. If we cannot understand the formation of oxygen, then we struggle to understand how manganese oxide might form. Perhaps something relating to large bodies of surface water could be responsible. 

The ChemCam instrument on Curiosity uses a laser to generate small amounts of plasma on the surface of Martian rocks. Light is then collected to enable the composition of the rock to be identified. The team studied sand, silts and muds, the former being more porous than the latter. The majority of the manganese found in the sands is thought to have been the result of ground water percolation. On Earth the manganese is oxidised by atmospheric oxygen in a process that is accelerated by microbes. 

We still don’t have all the answers but but the study has revealed yet again, to an environment that was once suitable for life. That environment seems similar to many places on Earth that also display rich manganese deposits. 

Source : New findings point to an Earth-like environment on ancient Marsh

The post These Rocks Formed in an Ancient Lake on Mars appeared first on Universe Today.

“A dream come true.”
“I never expected this!”
“The most amazing light show I’ve ever seen in my life!”
“Once in a lifetime!”
“No doubt, this weekend will be remembered as ‘that weekend.’”

That’s how people described their views of the Aurora borealis this weekend, which put on a breathtaking celestial show around the world, and at lower latitudes than usual. This allowed hundreds of millions of people to see the northern lights for the first time in their lives. People as far south as Arizona and Florida in the US and France, Germany and Poland in Europe got the views of their life as a series of intense solar storms – the most powerful in more than 20 years – impacted Earth’s atmosphere starting Friday and through the weekend.

As we reported on Friday, a giant Earth-facing sunspot group named AR3664 hurled at least six coronal mass ejections our way, triggering a dazzling display of breathtaking celestial shows over several nights. NOAA’s Space Weather Prediction Center issued a geomagnetic storm watch in anticipation of G4 or G5 events; G5 is the highest rating on NOAA’s space weather scale. This means not only was there a spectacular sky show, but some electrical grid systems could have experienced blackouts; however, there was no widespread reports of any problems or damage to electrical grids.

“Watches at this level are very rare,” the SWPC said in an advisory on Saturday.

Let’s take a look at the incredible views of our readers and friends, many shared on Universe Today’s Flickr page. Our lead image comes from Julien Looten, who took this photo at the cliffs of Étretat in northern France. Looten said, “These auroras began to be visible around 10:30 PM, even before nightfall… From then on, they were visible to the naked eye until dawn… Without interruption…”

A spectacular light show over North Cascades National Park, Washington state, USA. Credit: Patrick Vallely. Used by permission. A 360° panorama of the May 10/11, 2024 great aurora display, as seen in southern Alberta, Canada. This is a stitch of 20 segments, each 13-second exposures, with “very odd vertical blue and magenta rays.” Credit: Alan Dyer/AmazingSky.com A unique orange and red aurora seen over Vancouver Island, British Columbia, Canada. Credit: Karla Thompson.

No doubt this weekend will be remembered as 'that weekend'. Here's my rushed, ordinary photos of an extraordinary event.
Taken locally in Cheshire during the 'spike' at 03:00 Saturday. Zero colour enhancement in post processing. The greens were JUST visible with the naked eye: pic.twitter.com/Z9uQA4fFaW

— Andy Saunders – Apollo Remastered (@AndySaunders_1) May 12, 2024 Ohio’s Aurora 05-10-2024, captured in front of John Chumack’s observatory domes at JBSPO in Yellow Springs, Ohio. Canon 6DDSLR 16mm F2.8 lens, ISO 1250, 10 second exposure. Credit: John Chumack, galacticimages.com. Used by permission.

"Once in a Lifetime" – The Needles, Isle of Wight, UK
Credit @chadpowellphoto pic.twitter.com/NAoi6k9h9E

— Chad Powell (@chadpowellphoto) May 12, 2024 “Bonkers” aurora display in Tucson, Arizona, USA. Credit: Robert Sparks. Used by permission.

8 hrs, 2 camera batteries, 500 photos & a full memory card later, we're home after our epic aurora hunt. Just a magical, magnificent night. Aurora filling the sky at one point, green curtains/ red/pink rays & beams, reflected in the reservoir we were parked next to up nr Shap… pic.twitter.com/0iApnjZ05H

— Stuart Atkinson (@mars_stu) May 11, 2024 Aurora over Raisting Earth Station near near Raisting, Bavaria, Germany. “We experienced three waves of incredibly strong Aurora, especially for our rather Southern latitude. During the second wave we saw individual pulsating filaments dancing over our heads. What a breathtaking experience!” Credit: Simeon Schmauß, used by permission. The aurora as seen in the Rocky Mountains west of Denver on May10-11, 2024, taken with an iPhone. Credit: Carolyn Collins Petersen.

I asked a complete stranger to take my photo during the stunning aurora show. I did the same for her.
Seeing the aurora from our location was incredible. We will treasure the memory of our shared experience.
10.05.24 Bedfordshire UK #aurora #auroraUK #StormHour #ThePhotoHour pic.twitter.com/vWwAjSQK2I

— Dawn (@DawnSunrise1) May 12, 2024 This colorful auroral display was visible from Bishopmill, Scotland, UK on May 10, 2024. “It was capped by several beautiful coronae, the holy grail for many aurora photographers. At times, the colours were clearly visible to the unaided eye.” Credit: Alan Tough. Used by permission.

The sky opened over Bear Lake, Utah pic.twitter.com/zW3nSRafZa

— Riding with Robots (@ridingrobots) May 11, 2024 Aurora on May 10/11 2024, taken from Ottawa, Canada with an iPhone 14 Pro Max. Credit: Andrew Symes. Used by permission. Aurora Borealis on May 10, 2024 From British Columbia, Canada. Credit: Debra Ceravolo. Used by permission. “The moment when the Great Aurora of 2024 went from looking average to exploding and filling the entire sky. Until that moment, it looked cool, but nothing I hadn’t seen from this location before. The curious part was it was in the western sky instead of the north when I normally see it. But in this moment, the entirity of the visible sky lit up in the most amazing light show I’ve ever seen in my life. Credit: Dark Arts Astrophotography. Used by permission. Unique view of the KP9 aurora on May 11, 2024 at Owen Sound, Ontario, Canada. Credit: Northern Lights Graffiti. Used by permission

The amount of insane beauty that’s on my memory cards right now is almost overwhelming. Aurora chasing may be my new addiction.

I also will likely release a shot or two in print, so if you want a memento from this event make sure you’re on my email list! pic.twitter.com/OjrthGlqJB

— Andrew McCarthy (@AJamesMcCarthy) May 12, 2024 Aurora and the Moon seen over central Minnesota, USA. Credit: Nancy Atkinson

The post What a Weekend! Spectacular Aurora Photos from Around the World appeared first on Universe Today.

In February 2022, SpaceX and entrepreneur/philanthropist Jared Isaacman (commander of the Inspiration4 mission) announced they were launching a new program to “rapidly advance human spaceflight capabilities” while supporting important charitable and humanitarian causes here on Earth. It’s called the Polaris Program. In a recent press release, SpaceX revealed the spacesuits its Polaris astronauts will be wearing (up top) and described the research crews will conduct during the program’s three human spaceflight missions – the first of which is scheduled to launch this summer!

These missions will build on the company’s experience with NASA’s Commercial Crew Delivery (CCD) program, where NASA certified SpaceX’s Crew Dragon vehicle to transport crews to the International Space Station (ISS). According to the company’s press statement, the new suits are an evolution of the Intravehicular Activity (IVA) suit currently used by Dragon crews. This included the crew of the Demo-2 mission, which validated the flight system and was the first crewed mission to take off from U.S. soil since the retirement of the Space Shuttle in 2011.

It was also the suit worn by the Inspiration4 crew as they became the first flight to be crewed entirely by private citizens. These latest are known as the Extravehicular Activity Space Suit, which has several new features. Per the company’s press statement, “Developed with mobility in mind, SpaceX teams incorporated new materials, fabrication processes, and novel joint designs to provide greater flexibility to astronauts in pressurized scenarios while retaining comfort for unpressurized scenarios.”

The suit also has redundancy features, such as additional seals and pressure valves to help ensure the suit remains pressurized during EVAs. The new 3D-printed helmet incorporates a new visor that reduces glare and features a camera and a new Heads-Up Display (HUD) that monitors conditions inside the suit. These suits will make their debut during the first of three Polaris missions – Polaris Dawn – scheduled to take place this summer (at the earliest). This mission will be commanded by Isaacman and will see a Crew Dragon launched from Launch Complex 39A atop a Falcon 9 rocket. The crew will spend five days in orbit and attempt to reach the highest Earth orbit ever flown.

During their time in space, the Polaris Dawn crew will conduct the first commercial spacewalk (and the first EVA where four astronauts were in space simultaneously) and be the first to test the Starlink laser-based communication system in space. The crew will also conduct scientific research in collaboration with the Translational Research Institute for Space Health (TRISH), BioServe Space Technologies, Space Technologies Lab, Weill Cornell Medicine, the Johns Hopkins University Applied Physics Laboratory (JHUAPL), the Pacific Northwest National Laboratory, and the U.S. Air Force Academy.

These efforts are designed to advance our understanding of human health during long-duration spaceflights, with applications for health here on Earth. According to the company website, these research activities will include:

• Using ultrasound to monitor, detect, and quantify venous gas emboli (VGE), contributing to studies on human prevalence to decompression sickness;
• Gathering data on the radiation environment to better understand how space radiation affects human biological systems;
• Providing biological samples towards multi-omics analyses for a long-term Biobank; and
• Research related to Spaceflight Associated Neuro-Ocular Syndrome (SANS), which is a key risk to human health in long-duration spaceflight.

Polaris Dawn will be followed up by a second mission (Polaris II, the date of which is TBD) that will attempt to build upon these objectives. The third mission (Polaris III) will be the first human spaceflight involving the Starship and Super Heavy launch vehicle. But as is made clear in the company’s statement, the suits are intended to fulfill SpaceX’s long-term goals:

“While Polaris Dawn will be the first time the SpaceX EVA suit is used in low-Earth orbit, the suit’s ultimate destiny lies much farther from our home planet. Building a base on the Moon and a city on Mars will require the development of a scalable design for the millions of spacesuits required to help make life multiplanetary.”

Further Reading: SpaceX, Polaris Program

The post SpaceX Shows Off Its New Extravehicular Activity Suit appeared first on Universe Today.

Within the last five years, astronomers have discovered a new type of astronomical phenomenon that exists on vast scales – larger than whole galaxies. They’re called ORCs (odd radio circles), and they look like giant rings of radio waves expanding outwards like a shockwave. Until now, ORCs had never been observed in any wavelength other than radio, but according to a new paper released on April 30 2024, astronomers have captured X-rays associated with an ORC for the first time.

The discovery offers some new clues as to what might be behind the creation of an ORC.

While many astronomical events, like supernova explosions, can leave behind circular remnants, ORCs seem to require a different explanation.

“The power needed to produce such an expansive radio emission is very strong,” said Esra Bulbul, lead author of the new paper. “Some simulations can reproduce their shapes but not their intensity. No simulations explain how to create ORCs.”

ORCs can be a challenge to study, in part because they are usually only visible in radio wavelengths. They haven’t previously been associated with X-ray or infrared emissions, nor has there been any sign of them in optical wavelengths. Sometimes, ORCs surround a visible galaxy, but not always (eight have been discovered to date around known elliptical galaxies).

Using ESA’s XMM-Newton telescope, Bulbul and her team observed one of the nearest known ORCs, an object called the Cloverleaf, and found a striking X-ray component to the object.

“This is the first time anyone has seen X-ray emission associated with an ORC,” said Bulbul. “It was the missing key to unlock the secret of the Cloverleaf’s formation.”

This image of the first ORC (odd radio circle) ever discovered, aptly dubbed ORC-1, overlays radio observations from South Africa’s MeerKAT telescope in green atop an optical and infrared map from the international DES (Dark Energy Survey) project. J. English (U. Manitoba)/EMU/MeerKAT/DES (CTIO)

X-rays of the Cloverleaf show gas that has been heated and excited by some process. In this case, the X-ray emissions reveal two groups of galaxies (totaling about a dozen galaxies altogether) that have begun to merge inside the Cloverleaf, heating the gas to 15 million degrees Fahrenheit.

The chaotic galaxy mergers are interesting, but they can’t explain the Cloverleaf by themselves. Galaxies mergers happen all over the universe, while ORCs are a rare phenomenon. There’s something unique going on to create something like the Cloverleaf.

“Mergers make up the backbone of structure formation, but there’s something special in this system that rockets the radio emission,” Bulbul said. “We can’t tell right now what it is, so we need more and deeper data from both radio and X-ray telescopes.”

That doesn’t mean astronomers don’t have any guesses.

“One fascinating idea for the powerful radio signal is that the resident supermassive black holes went through episodes of extreme activity in the past, and relic electrons from that ancient activity were reaccelerated by this merging event,” said Kim Weaver, NASA project scientist for XMM-Newton.

In other words, ORCs like the Cloverleaf might require a two-part origin story – powerful emissions from active supermassive black holes, followed by galaxy merger shockwaves that give those emissions a second kick.

Learn More:

E. Bulbul et. al. “The galaxy group merger origin of the Cloverleaf odd radio circle system.” Astronomy and Astrophysics.

“X-ray Satellite XMM-Newton Sees ‘Space Clover’ in a New Light.” NASA.

The post Do Clashing Galaxies Create Odd Radio Circles? appeared first on Universe Today.

Supermassive black holes are central to the dynamics and evolution of galaxies. They play a role in galactic formation, stellar production, and possibly even the clustering of dark matter. Almost every galaxy has a supermassive black hole, which can make up a small fraction of a galaxy’s mass in nearby galaxies. While we know a great deal about these gravitational monsters, one question that has lingered is just how supermassive black holes gained mass so quickly.

Most of what we know about early black holes comes from quasars. These occur when supermassive black holes are in an extremely active phase, consuming prodigious amounts of matter and emitting intense light that can be seen across the Universe. Observations from the James Webb Space Telescope (JWST) and other observatories have observed quasars as far back as 13 billion years ago, meaning that they were already large and active just a few hundred million years after the big bang. But these brilliant beacons also pose an observational challenge. Early quasars are so bright they vastly outshine their host galaxy, making it difficult to observe the environments of early quasars. But a new study in The Astrophysical Journal has used a spectral trick to see these distant galactic hosts.

The team gathered JWST data on six distant quasars known to be about 13 billion light-years away. Since the quasars were observed at a range of wavelengths, the team then compared the light to model quasars and was able to categorize which wavelengths likely came from the compact source of the quasar, and which from the more diffuse galaxy surrounding it. By filtering out the quasar light, they obtained the first images of the distant galaxies that are home to these ancient quasars.

Since the brightness of each light source is related to its mass, the team could compare the mass of a quasar to the mass of its host galaxy. The result was surprising. In these early galaxies, the mass of the supermassive black hole is about 10% of that of the galaxy. This is much larger than the mass ratio seen in local galaxies, where supermassive black holes can comprise just a tenth of a percent of a galaxy’s mass. This likely means that early supermassive black holes grew extremely quickly, and could have even been the seeds of their galaxies. The observations go against the idea that early galaxies formed first and that their black holes formed later.

Astronomers still don’t know just how supermassive black holes formed so quickly in the early Universe, but it’s now clear that they did. In answering one question about the evolution of supermassive black holes, the team has raised several other questions.

Reference: Yue, Minghao, et al. “EIGER. V. Characterizing the Host Galaxies of Luminous Quasars at z ? 6.” The Astrophysical Journal 966.2 (2024): 176.

The post Supermassive Black Holes Got Started From Massive Cosmic Seeds appeared first on Universe Today.

Tonight and the rest of the weekend could be your best chance ever to see the aurora.

The Sun has been extremely active lately as it heads towards solar maximum. A giant Earth-facing sunspot group named AR3664 has been visible, and according to Spaceweather.com, the first of an unbelievable SIX coronal mass ejections were hurled our way from that active region, and is now hitting our planet’s magnetic field.

Solar experts predict that people in the US as far south as Alabama and Northern California could be treated to seeing the northern lights during this weekend. For those of you in northern Europe, you could also be in for some aurora excitement. Check the Space Weather Prediction Center’s 30-minute Aurora Forecast for the latest information.

If the weather conditions are right in your area, you might hit the aurora jackpot.  See a map with predictions, below.

A map from the Space Weather Prediction Center shows the aurora forecast for the U.S. on May 11, 2024. Credit: Space Weather Prediction Center

“If you happen to be in an area where it’s dark and cloud free and relatively unpolluted by light, you may get to see a fairly impressive aurora display, and that’s really the gift from space weather, is the aurora,” said Rob Steenburgh, from NOAA’s (National Oceanic and Atmospheric Administration) Space Weather Prediction Center (SWPC), during a briefing on Friday.

A map from the Space Weather Prediction Center shows the aurora forecast for the northern hemisphere on May 10, 2024. Credit: Space Weather Prediction Center

According to SWPC, the impact from the geomagnetic storm reached Earth-based magnetometers on May 10th at 1645 UT. More CMEs are following close behind and their arrival could extend the storm into the weekend.

While these solar storms could provide stunning views of auroras, there is also the potential for disruption to communications systems, power grids and satellite operations.

The Sun is super active right now! ?? ? ?

The video below shows a series of flares that erupted over the past seven days… not counting another X-class flare that happened this morning! pic.twitter.com/O5jwUBmMDT

— NASA Sun & Space (@NASASun) May 10, 2024

As we reported earlier this week, the Sun released three X-class solar flares — the strongest class of flares — in short succession. Solar flares are explosions on the Sun that release powerful bursts of energy and radiation coming from the magnetic energy associated with the sunspots. The more sunspots, the greater potential for flares.

NASA’s Solar Dynamics Observatory captured these images of the solar flares — as seen in the bright flashes in the upper right — on May 5 and May 6, 2024. The image shows a subset of extreme ultraviolet light that highlights the extremely hot material in flares and which is colorized in teal. Credit: NASA/SDO

The sunspot group AR3664 is so large, it is visible to the naked eye — but you MUST be wearing special eye-wear (got any of your eclipse glasses left from April 8?) or use special solar filters for telescopes or binoculars. AR3664 is enormous, about 10 times the size of Earth.

How to see the Northern Lights

The aurora is an incredible sight. Your best shot to see it is to be in a dark area.

“Get away from city lights into a dark, rural surrounding and look north,” said the National Weather Service in St. Louis, Missouri on X (Twitter). “Aside from some clouds associated with a passing front, much of the time looks mostly clear.”

Check the weather forecast in your region for cloud cover. But if you don’t have any luck tonight, check again Saturday or Sunday night. With multiple CMEs, the storm was expected to last through the weekend.

Good luck!

The post If You’ve Never Seen An Aurora Before, This Might Be Your Chance! appeared first on Universe Today.

The Moon’s polar regions are home to permanently shadowed craters. In those craters is ancient ice, and establishing a presence on the Moon means those water ice deposits are a valuable resource. Astronauts will likely use solar energy to work in these craters and harvest water, but the Sun never shines there.

What’s the solution? According to one team of researchers, a solar collector perched on the crater’s rim.

There’s abundant solar energy on the Moon. But not all the time and not everywhere. At the bottom of the deepest craters closest to the poles, there’s no Sun.

Researchers from the Texas A&M Department of Aerospace Engineering are anticipating future missions to the Moon’s permanently shadowed craters to harvest water resources. They’re working with NASA’s Langley Research Centre on reflectors that can be mounted on a crater rim. When paired with a receiver somewhere inside the crater, solar power can be delivered where it’s needed.

Dr. Darren Hartl is an associate professor of aerospace engineering at Texas A&M University. He’s leading a team of researchers working on solar reflectors. “If you perch a reflector on the rim of a crater, and you have a collector at the center of the crater that receives light from the sun, you are able to harness the solar energy,” said Hartl. “So, in a way, you’re bending light from the sun down into the crater.”

Though they’re still in the early stages of their research, computer models show that a parabolic reflector transmits the optimal amount of light to crater bottoms. Parabola designs are common in different types of things like telescopes, microphones, and car headlights. There are also solar parabolic reflectors at work here on Earth.

This is the Eurodish, a parabolic solar collector. The collector is mounted to the dish itself, but on the Moon, the collector would be in the crater where power is needed. Image Credit: Schlaich Bergermann und Partner and released into the Public Domain at http://wire0.ises.org/wire/independents/imagelibrary.nsf

Parabolic dishes are common on Earth. Here, we can make them any size we want and build them wherever we need to. But the whole endeavour is different on the Moon. Every pound we launch into space is expensive. Their goal is a reflector small enough to be transported to the Moon and large enough to harness enough energy.

The researchers are working with self-morphing material that was developed by Hartl and other engineers at Texas A&M. Self-morphing materials are based on natural materials that turn matter into complex surfaces. They can change shape in response to their environments. These include muscles, tendons, and plant tissue.

“During space missions, astronauts may need to deploy a large parabolic reflector from a relatively small and light landing system. That’s where we come in,” said Hartl. “We are looking at using shape memory materials that will change the shape of the reflector in response to system temperature changes.”

Dr. Hartl specializes in advanced multifunction materials. At Texas A&M, his team focuses on projects ranging from “… self-folding origami-based structures to self-regulating morphing radiators for spacecraft to advanced actuators for avian-inspired aircraft,” according to his bio. He also has over a decade of experience working with self-morphing structures and Shape Memory Alloys (SMA.)

One of the difficulties of operating on the Moon is the wild temperature swings between night and day. At the equator, the temperature can reach 121 Celsius (250 F), far hotter than anywhere on Earth. But at night, the temperature drops precipitously to -133 C (-208 F.) The permanent shadows in the Moon’s deep polar craters foster temperatures as low as -250 C (-415 F.)

Hartl has experience developing materials for these pronounced swings in temperature. He leads the Multifunctional Materials and Aerospace Structures Optimization (M2AESTRO) Lab at Texas A&M. “Our proposed solutions incorporate shape-shifting metals that adjust their own heat rejection based on how hot or cold they are, so it solves the problem for us,” Hartl said in 2019.

This video explains some of what they’re working on at M2AESTRO, though it’s a few years old.

The Moon is the next frontier for human habitation. Astronauts will live and work there, and water is a vital resource. Not just for drinking, but it can also be split into oxygen for respiration and hydrogen for fuel. Scientists aren’t certain how much water ice there is, but there’s enough to be useful.

Extracting and managing that resource will be critical for the success of Artemis and other lunar exploration efforts. Doing it effectively will require advanced solutions designed specifically for the lunar environment. Self-morphing materials could play an important role.

The post Lighting Up the Moon’s Permanently Shadowed Craters appeared first on Universe Today.

Humanity got its first look at the other side of the Moon in 1959 when the USSR’s Luna 3 probe captured our first images of the Lunar far side. The pictures were shocking, pointing out a pronounced difference between the Moon’s different sides. Now China is sending another lander to the far side.

This time, it’ll bring back a sample from this long-unseen domain that could explain the puzzling difference.

Chang’e-6 (CE-6) launched on May 3rd and is headed for the second largest impact crater in the Solar System: the South Pole Aitken (SPA) basin. It’ll land at Apollo Basin, a sub-basin inside the much larger SPA basin.

China has placed a lander on the far side of the Moon before (Chang’e 4.) They also placed a lander on the near side of the Moon and brought back samples (Chang’e 5.) But CE-6 will be the first sample ever returned from the Lunar far side. It’s the latest mission in the Chinese Lunar Exploration Program (CLEP.)

This graphic outlines China’s Lunar Exploration Program. Image Credit: CASC

A new paper published in Earth and Planetary Science Letters outlines the significance of the CE-6 landing site and the samples it’ll return to Earth. It’s titled “Long-lasting farside volcanism in the Apollo basin: Chang’e-6 landing site.” The lead author is Dr. Yuqi Qian from the Department of Earth Sciences at The University of Hong Kong.

When the USSR’s Luna 3 probe gave us our first look at the lunar far side, it didn’t take scientists long to realize how different it is from the near side. The near side of the Moon is marked by vast basaltic lava plains called lunar mares. Mares cover about 31% of the lunar near side.

But the far side is much different. Lunar mares cover only about 2% of the lunar far side. Instead, it’s dominated by densely-cratered highlands. This is known as the lunar dichotomy. The difference likely stems from a deposit of heat-producing elements under the near side that created the lunar mares. Scientists have also proposed that a long-gone companion moon slammed into the far side, creating the highlands.

This global map of the Moon, as seen from the Clementine mission, shows the differences between the lunar near side and far side. The familiar near side is marked by dark lunar mares. The far side has very few of them. This is known as the lunar dichotomy. Credit: NASA.

“A major lunar scientific question is the cause of the paucity of farside mare basalts,” Qian and his colleagues write in their paper. “The Chang’e-6 (CE-6) mission, the first sample-return mission to the lunar farside, is targeted to land in the southern Apollo basin, sampling farside mare basalts with critical insights into early lunar evolution.” 

CE-6 samples from the far side can start to answer the questions about the differences between the two sides. In preparation for receiving the samples, Qian and his colleagues studied the Apollo Basin’s volcanism. Their work revealed diverse and puzzling volcanism.

Their research shows that the Apollo basin experienced volcanic activities lasting from the Nectarian (~4.05 billion years ago) to the Eratosthenian Period (~1.79 billion years ago). However, since the far side’s crust is much thicker, it influenced the volcanic activity. In regions like the Oppenheimer Crater, where the crust has intermediate thickness, lava dikes stall beneath the crater floor. Lava spreads laterally and forms a sill and floor-fractured crater.

These two images give context to the CE-6 landing site. The left image shows where Apollo is inside the SPA. The right image shows some of the features in the Apollo crater, with the landing zone in a white rectangle. Image Credit: Qian et al. 2024.

Some regions, like the inner floor of the Apollo crater, have thin crusts. Here, lava dikes erupted directly and formed extensive lava flows. But where the crust is thickest, in the highland regions, there’s no evidence that dikes there ever reach the surface.

“This fundamental finding indicates that the crustal thickness discrepancy between near side and far side may be the primary cause of lunar asymmetrical volcanism,” said Dr. Qian. “This can be tested by the returned Chang’e-6 samples.”

They’ve chosen Apollo Crater’s Southern Mare partly because it contains at least two historic eruptions from two different times. Each one has a different Titanium content. The earlier one occurred ~3.34 billion years ago and has a low Titanium content (3.2% by weight.) The later one occurred ~3.07 billion years ago and has a higher Titanium content (6.2% by weight.)

This figure from the study shows the prime location for collecting samples according to the authors. This region would provide samples from the older, low-Ti basalts, the younger high-Ti basalts, and also overlying impact ejecta from the Chaffee S crater. Image Credit: Qian et al. 2024.

The titanium content in the rock is relevant because of petrogenesis, the origin and formation of rocks. Scientists think that high-Ti and low-Ti lunar basalts form when different geological layers of the Moon melted. “CE-6 samples returned from the unique geological setting will provide significant petrogenetic information to address further the paucity of farside mare basalts and the lunar nearside-farside dichotomy,” the authors write.

The authors suggest that CE-6 collect samples from the edge of the later eruption with the higher Titanium content. That sample will have higher scientific value because it’ll actually sample three things at once: Newer high-Ti basalt, underlying low-Ti basalt, and other materials unrelated to the mares that were transported by impact events. “Diverse sample sources would provide important insights into solving a series of lunar scientific questions hidden in the Apollo basin,” said Professor Joseph Michalski, a co-author of the paper also from the University of Hong Kong.

“The result of our research is a great contribution to the Chang’e-6 lunar mission. It sets a geological framework for completely understanding the soon-returned Chang’e-6 samples and will be a key reference for the upcoming sample analysis for Chinese scientists,” said Professor Guochun Zhao, Chair Professor of HKU Department of Earth Sciences and the co-author of the paper.

Chang’e 6 will deliver up to 2 kg (4.4 lbs) of lunar material. It should arrive on Earth around June 25th.

“These returned samples could help to answer questions about the evolution of high-Ti and low-Ti basalts, the influence of crustal thickness on lunar volcanism, and the most fundamental unsolved question of lunar science: What is the cause of the pronounced lunar nearside-farside asymmetry?” the authors conclude.

The post Here’s Where China’s Sample Return Mission is Headed appeared first on Universe Today.

Exoplanets are a fascinating astronomy topic, especially the so-called “Hot Jupiters”. They’re overheated massive worlds often found orbiting very close to their stars—hence the name. Extreme gravitational interactions can tug them right into their stars over millions of years. However, some hot Jupiters appear to be spiraling in faster than gravity can explain.

WASP-12b is a good example of one of these rapidly spiraling hot Jupiters. In about three million years, thanks to orbital decay, it will become one with its yellow dwarf host star. Both are part of a triple-star system containing two red dwarf stars. The hot Jupiter orbits the dwarf in just over one Earth day at a distance of about 3.5 million kilometers. That’s well within the orbit of Mercury around the Sun. Thanks to that orbit and gravitational influence, one side of the planet always faces the star. That heats only one side and puts the surface temperature at about 2,200 C. Eventually heat flows to the opposite side, which stirs up strong winds in the upper atmosphere. The planet doesn’t reflect much light, and astronomers have described it as a pitch-black world.

As if all that isn’t odd enough, the gravitational pull of the nearby star distorts this hot Jupiter into an egglike shape. It’s also stripping the planet’s atmosphere away. So, it’s no wonder astronomers described WASP-12b as a doomed planet.

Artist’s impression of WASP-12b, a Hot Jupiter deformed by its close orbit to its star. Credit: NASA What’s Tugging on Hot Jupiters?

According to conventional theory, a hot Jupiter planet like WASP-12b should create strong gravitational tidal waves between themselves and their parent stars. Those waves transfer energy, which tugs at the planet. That pulls the planet right into the star. Such a fiery death is definitely in WASP-12b’s future. But, there’s just one problem: it’s getting sucked in faster than gravitational tidal waves can explain. What’s happening?

A team of scientists at Durham University in England studied WASP-12b and they’ve come up with an interesting idea. What if this hot Jupiter’s fate is determined by magnetic fields? That’s what Durham’s Craig Duguid proposed in a recently published paper. Duguid’s team thinks the strong magnetic fields inside some stars can dissipate the tidal waves generated by orbiting hot Jupiters.

Artist’s concept of the exoplanet WASP-12b, parent star devouring its hot Jupiter planet. Artwork Credit: NASA, ESA, and G. Bacon (STScI)

How this works isn’t completely confirmed yet, but here’s the basic idea. Inwardly propagating internal gravity waves (IGWs) (such as those from the nearby hot Jupiter) move through a star. They eventually run into the star’s magnetic interior. If that magnetic field is strong enough, it transforms them into magnetic waves. They move back outward and eventually dissipate. In the process, however, that dissipation causes a huge energy drain. The result is still the same as with gravitational tidal waves: the hot Jupiter loses energy and plows into its parent star. And, it could explain why some hot Jupiters spiral into their stars more quickly than expected.

Exploring the Magnetic Mechanism Idea

In the paper, Duguid and his team used models of stars with convective cores—such as F-type stars with masses between 1.2 to 1.6 solar masses. Astronomers suspect these experience weak tidal dissipation. The team used the known properties of these stars’ interiors, along with estimates of their magnetic fields. For these stars, a convective core is the dynamo that generates the magnetic field. Although it’s classified as a type-G star, WASP-12 fits into the study, thanks to its near-solar mass and radius.

So, is it just gravitational tidal waves pulling the planet in, or could the proposed magnetic field action be at work? Duguid and colleagues concluded that the magnetic field idea is very possible. They write, “Our main result is that this previously unexplored source of efficient tidal dissipation can operate in stars within this mass range for significant fractions of their lifetimes. This tidal dissipation mechanism appears to be consistent with the observed inspiral of WASP-12b and more generally could play an important role in the orbital evolution of hot Jupiters—and to lower-mass ultra-short-period planets—orbiting F-type stars.”

Need More Data about Hot Jupiters

It’s an interesting result. There are a great many hot Jupiters in the exoplanet archives, simply because they are the easiest exoplanets to observe. Some of them are spiraling in faster than expected. This leads the authors to suggest that additional studies of similar-type stars and their hot Jupiters could confirm the magnetic mechanism. In addition, future observations could help astronomers also understand the tidal wave theory and help place some constraints on the types of stars where it would operate.

For More Information

Scientists Explain Why Some Exoplanets are Spiraling Towards Their Stars
An Efficient Tidal Dissipation Mechanism via Stellar Magnetic Fields

The post Why Hot Jupiters Spiral into Their Stars appeared first on Universe Today.

The Large and Small Magellanic Clouds are well known satellite galaxies of the Milky Way but there are more. It is surrounded by at least 61 within 1.4 million light years (for context the Andromeda Galaxy is 2.5 million light years away) but there are likely to be more. A team of astronomers have been hunting for more companions using the Subaru telescope and so far, have searched just 3% of the sky. To everyone’s surprise they have found nine previously undiscovered satellite galaxies, far more than expected. 

Data from Gaia (the satellite collecting accurate position information of astronomical objects) suggests that most of the satellite galaxies orbiting our own are newcomers! Even the Large and Small Magellanic Clouds are now known to be newcomers. Whether any of these will fall into orbit around the Milky Way is as yet unknown, largely because we do not have an accurate measure for the mass of our home Galaxy.

The recent search hopes to expand our understanding of this corner of the Universe with the first detailed search for companion dwarf galaxies. The paper from lead author Daisuke Homma and team from the National Astronomical Observatory of Japan reports on the findings of their survey using the Subaru Telescope. 

Based on Mauna Kea in Hawaii The Subaru Telescope is an 8.2m diameter telescope located at the Mauna Kea Observatory in Hawaii. Until 2005 it was the largest single mirror telescope in the world with a gigantic 8.2 metre mirror. In all telescopes, larger mirrors collect more light bringing with it the ability to see fainter objects and finer levels of detail. A number of telescopes have now surpassed Subaru’s massive light collecting power but multi-mirror telescopes are becoming more popular. 

As the cornerstone of the study is a drive to understand dark matter distribution. The concept of the Universe being dominated by cold dark matter nicely describes the large scale model of the cosmos. It struggles however, to describe the structure in the local Universe predicting hundreds of satellite galaxies to the Milky Way. Until recently, we only knew of a handful of satellite galaxies contradicting the model in a quandary known as the missing satellites problem. The team from Japan hopes their work will help provide clues to understand this problem.

The paper reports that the previous data obtained before 2018 of an area of sky covering 676 degrees2 revealed three candidate satellite galaxies; Vir I, Cet III and Boo IV. Data released over the three years that followed covering 1,140 degrees2 revealed two additional candidates; Sext II and Vir III. Unexpectedly, the model suggests there should be  3.9 ± 0.9 satellite galaxies within 10 pc within the virial radius of the Milky Way (based on the density distribution of the Milky Way). Instead the team found more, nine to be precise! It seemed then that the missing satellite problem was no worse than expected, indeed there were too many galaxies!

The team acknowledged that their research was based on statistically small numbers and several assumptions had been made based on an isotropic distribution of satellites. To progress this further, there will need to be follow up studies of stars in the satellite galaxies and high resolution imaging.

Source : Final Results of Search for New Milky Way Satellites in the Hyper Suprime-Cam Subaru Strategic Program Survey: Discovery of Two More Candidates

The post Does the Milky Way Have Too Many Satellite Galaxies? appeared first on Universe Today.

There’s something poetic about humanity’s attempt to detect other civilizations somewhere in the Milky Way’s expanse. There’s also something futile about it. But we’re not going to stop. There’s little doubt about that.

One group of scientists thinks that we may already have detected technosignatures from a technological civilization’s Dyson Spheres, but the detection is hidden in our vast troves of astronomical data.

A Dyson Sphere is a hypothetical engineering project that only highly advanced civilizations could build. In this sense, ‘advance’ means the kind of almost unimaginable technological prowess that would allow a civilization to build a structure around an entire star. These Dyson Spheres would allow a civilization to harness all of a star’s energy.

A Civilization could only build something so massive and complex if they had reached Level II in the Kardashev Scale. Dyson Spheres could be a technosignature, and a team of researchers from Sweden, India, the UK, and the USA developed a way to search for Dyson Sphere technosignatures they’re calling Project Hephaistos. (Hephaistos was the Greek god of fire and metallurgy.)

They’re publishing their results in the Monthly Notices of the Royal Academy of Sciences. The research is titled “Project Hephaistos – II. Dyson sphere candidates from Gaia DR3, 2MASS, and WISE.” The lead author is Matías Suazo, a PhD student in the Department of Physics and Astronomy at Uppsala University in Sweden. This is the second paper presenting Project Hephaistos. The first one is here.

“In this study, we present a comprehensive search for partial Dyson spheres by analyzing optical and
infrared observations from Gaia, 2MASS, and WISE,” the authors write. These are large-scale astronomical surveys designed for different purposes. Each one of them generated an enormous amount of data from individual stars. “This second paper examines the Gaia DR3, 2MASS, and WISE photometry of ~5 million sources to build a catalogue of potential Dyson spheres,” they explain.

A Type II civilization is one that can directly harvest the energy of its star using a Dyson Sphere or something similar. Credit: Fraser Cain (with Midjourney)

Combing through all of that data is an arduous task. In this work, the team of researchers developed a special data pipeline to work its way through the combined data of all three surveys. They point out that they’re searching for partially-completed spheres, which would emit excess infrared radiation. “This structure would emit waste heat in the form of mid-infrared radiation that, in addition to the level of completion of the structure, would depend on its effective temperature,” Suazo and his colleagues write.

The problem is, they’re not the only objects to do so. Many natural objects do, too, like circumstellar dust rings and nebulae. Background galaxies can also emit excess infrared radiation and create false positives. It’s the pipeline’s job to filter them out. “A specialized pipeline has been developed to identify potential Dyson sphere candidates focusing on detecting sources that display anomalous infrared excesses that cannot be attributed to any known natural source of such radiation,” the researchers explain.

This flowchart shows what the pipeline looks like.

This flowchart from the research illustrates the pipeline the team developed to find Dyson Sphere candidates. Each step in the pipeline filters our objects that don’t match the expected emissions from Dyson Spheres. Image Credit: Suazo et al. 2024.

The pipeline is just the first step. The team subjects the list of candidates to further scrutiny based on factors like H-alpha emissions, optical variability, and astrometry.

368 sources survived the last cut. Of those, 328 were rejected as blends, 29 were rejected as irregulars, and 4 were rejected as nebulars. That left only 7 potential Dyson Spheres out of about 5 million initial objects, and the researchers are confident that those 7 are legitimate. “All sources are clear mid-infrared emitters with no clear contaminators or signatures that indicate an obvious mid-infrared origin,” they explain.

This pie chart shows the breakdown of the 368 sources that made it through the filter. Only 7 objects out of millions are labelled Dyson Sphere candidates. Image Credit: Suazo et al. 2024.

These are the seven strongest candidates, but the researchers know they’re still just candidates. There could be other reasons why the seven are emitting excess infrared. “The presence of warm debris disks surrounding our candidates remains a plausible explanation for the infrared excess of our sources,” they explain.

But their candidates seem to be M-type (red dwarf) stars, and debris disks around M-dwarfs are very rare. However, it gets complicated because some research suggests that debris disks around M-dwarfs form differently and present differently. One type of debris disk called Extreme Debris Disks (EDD) can explain some of the luminosity the team sees around their candidates. “But these sources have never been observed in connection with M dwarfs,” Suazo and his co-authors write.

That leaves the team with three questions: “Are our candidates strange young stars whose flux does not vary with time? Are these stars’ M-dwarf debris disks with an extreme fractional luminosity? Or something completely different?”

This figure from the research shows the seven candidates plotted on a colour-magnitude diagram. It indicates that all seven are M-dwarfs. Image Credit: Suazo et al. 2024.

“After analyzing the optical/NIR/MIR photometry of ~5 x 106 sources, we found 7 apparent M dwarfs exhibiting an infrared excess of unclear nature that is compatible with our Dyson sphere models,” the researchers write in their conclusion. There are natural explanations for the excess infrared coming from these 7, “But none of them clearly explains such a phenomenon in the candidates, especially given that all are M dwarfs.”

The researchers say that follow-up optical spectroscopy would help understand these 7 sources better. A better understanding of the H-alpha emissions is especially valuable since they can also come from young disks. “In particular, analyzing the spectral region around H-alpha can help us ultimately discard or verify the presence of young disks,” the researchers write.

“Additional analyses are definitely necessary to unveil the true nature of these sources,” they conclude.

The post Astronomers are on the Hunt for Dyson Spheres appeared first on Universe Today.

Astrobiology is the field of science that studies the origins, evolution, distribution, and future of life in the Universe. In practice, this means sending robotic missions beyond Earth to analyze the atmospheres, surfaces, and chemistry of extraterrestrial worlds. At present, all of our astrobiology missions are focused on Mars, as it is considered the most Earth-like environment beyond our planet. While several missions will be destined for the outer Solar System to investigate “Ocean Worlds” for evidence of life (Europa, Ganymede, Titan, and Enceladus), our efforts to find life beyond Earth will remain predominantly on Mars.

If and when these efforts succeed, it will have drastic implications for future missions to Mars. Not only will great care need to be taken to protect Martian life from contamination by Earth organisms, but precautions must be taken to prevent the same from happening to Earth (aka. Planetary Protection). In a recent study, a team from the University of New South Wales (UNSW) in Sydney, Australia, recommends that legal or normative frameworks be adopted now to ensure that future missions do not threaten sites where evidence of life (past or present) might be found.

The study was led by Clare Fletcher, a Ph.D. student with the Australian Centre for Astrobiology (ACA) and Earth and Sustainability Science Research Centre at UNSW. She was joined by Professor Martin Van Kranendonk, a researcher with the ACA and the head of the School of Earth and Planetary Sciences at Curtin University, and Professor Carol Oliver of the School of Biological, Earth & Environmental Sciences at UNSW. Their research paper, “Exogeoconservation of Mars,” appeared on April 21st in Space Policy.

The search for life on Mars can be traced to the late 19th and early 20th centuries when Percival Lowell made extensive observations from his observatory in Flagstaff, Arizona. Inspired by Schiaparelli’s illustrations of the Martian surface (which featured linear features he called “canali”), Lowell recorded what he also believed were canals and spent many years searching for other indications of infrastructure and an advanced civilization. During the ensuing decades, observatories worldwide observed Mars closely, looking for indications of life and similarities with Earth.

However, it was not until the Space Age that the first robotic probes flew past Mars, gathering data directly from its atmosphere and taking close-up images of the surface. These revealed a planet with a thin atmosphere composed predominantly of carbon dioxide and a frigid surface that did not appear hospitable to life. However, it was the Viking 1 and 2 missions, which landed on Mars in 1976, that forever dispelled the myth of a Martian civilization. But as Fletcher told Universe Today via email, the possibility of extant life has not been completely abandoned:

“It’s my personal belief that it is unlikely we will find evidence of extant (current) life on Mars, as opposed to evidence of past life on Mars. If we were to find extant life on Mars that could be proven to be endemic to Mars and not contamination from Earth, some think it might be found underground in lava tubes, for example, and some think the ice caps or any possible source of liquid water might be suitable places.”

Ironically, it was the same missions that discredited the notion of there being life on Mars that revealed evidence that water once flowed on its surface. Thanks to the many orbiter, lander, and rover missions sent to Mars since the turn of the century, scientists theorize that this period coincided with the Noachian Era (ca. 4.1 – 3.7 billion years ago). According to the most recent fossilized evidence, it was also during this period that life first appeared on Earth (in the form of single-celled bacteria).

Artist’s impression of Mars during the Noachian Era. Credit: Ittiz/Wikipedia Commons

Our current astrobiology efforts on behalf of NASA and other space agencies are focused on Mars precisely for this reason: to determine if life emerged on Mars billions of years ago and whether or not it co-evolved with life on Earth. This includes the proposed Mars Sample Return (MSR) mission that will retrieve the drill samples obtained by the Perseverance rover in the Jezero Crater and return them to Earth for analysis. In addition, NASA and China plan to send crewed missions to Mars by 2040 and 2033 (respectively), including astrobiology studies.

These activities could threaten the very abodes where evidence of past life could be found or (worse) still exists. “Human activities might threaten sites like this in part due to possible microbial contamination,” said Fletcher. “Evidence of life (past and extant) also has greater scientific value when in its palaeoenvironmental context, so any human activities that might damage the evidence of life and/or its surrounding environmental context pose a risk. This could be something innocuous, like debris falling in the wrong spot, or something more serious, like driving over possibly significant outcrops with a rover.”

Conservation measures must be developed and implemented before additional missions are sent to Mars. Given humanity’s impact on Earth’s natural environment and our attempts to mitigate this through conservation efforts. In particular, there have been numerous cases where scientific studies were conducted without regard for the heritage value of the site and where damage was done because of a lack of proper measures. These lessons, says Fletcher, could inform future scientific efforts on Mars:

“It’s important that we learn from what has been considered “damaging” on Earth and take this into consideration when exploring Mars. If a site is damaged beyond being able to be studied in the future, then we limit what can actually be learned from a site. When considering Mars missions cost billions of dollars and are to meet specific scientific goals, limiting the information being learned from a site is incredibly detrimental. My recommendations are that of my paper: interdisciplinary cooperation, drawing on experience and knowledge from Earth, creating norms and a code of practice (part of my PhD work), and working towards creating legislation for these issues.”

Artist’s rendition of NASA’s Dragonfly on the surface of Titan. Credit: NASA/Johns Hopkins APL/Steve Gribben

The need for exogeoconservation is paramount at this juncture. In addition to Mars, multiple astrobiology missions will travel to the outer Solar System this decade to search for evidence of life on icy moons like Europa, Ganymede, Titan, and Enceladus. This includes the ESA’s JUpiter ICy moons Explorer (JUICE) mission, currently en route to Ganymede, and NASA’s Europa Clipper and Dragonfly missions that will launch for Europa and Titan in October 2024 and 2028 (respectively). Therefore, the ability to search for extant or past life without damaging its natural environment is an ethical and scientific necessity.

“I hope this paper is very much a starting point for anyone working in Mars science and exploration, as well as anyone thinking about space policy and exogeoconservation,” said Fletcher. “My goal was to start drawing attention to these issues, and that way start a generation of researchers and practitioners focused on exogeoconservation of Mars.”

Further Reading: Space Policy

The post We Need to Consider Conservation Efforts on Mars appeared first on Universe Today.

When astrophysicists observe the cosmos, they see different types of black holes. They range from gargantuan supermassive black holes with billions of solar masses to difficult-to-find intermediate-mass black holes (IMBHs) all the way down to smaller stellar-mass black holes.

But there may be another class of these objects: primordial black holes (PBHs) that formed in the very early Universe. If they exist, the Nancy Grace Roman Space Telescope should be able to spot them.

Stellar-mass black holes form when massive stars explode as supernovae. SMBHs grow over time by merging with other black holes. How IMBHs form is still unclear, but it could involve mergers between stellar-mass black holes or multiple stellar collisions in dense star clusters.

Primordial black holes, if they exist, didn’t have any of these mechanisms available to them.

“If we find them, it will shake up the field of theoretical physics.”

William DeRocco, postdoctoral researcher, University of California Santa Cruz. Artist’s impression of merging binary black holes. When they merge, they emit gravitational waves that observatories like LIGO can detect. Image Credit: LIGO/A. Simonnet.

Nobody knows if primordial black holes exist. They’re theoretical. No physical process we know of can form them. But the early Universe was much different.

New research published in Physical Review D shows how the upcoming Nancy Grace Roman Telescope could detect these primordial Earth-mass objects. It’s titled “Revealing terrestrial-mass primordial black holes with the Nancy Grace Roman Space Telescope.” The lead author is William DeRocco, a postdoctoral researcher at the University of California Santa Cruz.

via GIPHY

“Detecting a population of Earth-mass primordial black holes would be an incredible step for both astronomy and particle physics because these objects can’t be formed by any known physical process,” lead author DeRocco said. “If we find them, it will shake up the field of theoretical physics.”

In the modern Universe, only stars with at least eight stellar masses can become black holes. Less massive stars will become neutron stars or white dwarfs. (The Sun will become a white dwarf.)

But things were different in the early Universe. During a period of rapid inflation, space expanded faster than the speed of light. In these unusual conditions, dense areas could have collapsed into PBHs. The scale of these objects is remarkably small. They would be the size of Earth or smaller and have event horizons about as wide as a coin.

PBHs could’ve formed when overdense regions in the inflationary or early radiation-dominated universe collapsed. Image Credit: By Gema White – https://www.slideserve.com/gema/primordial-black-hole-formation-in-an-axion-like-curvaton-model slide 19. Cropped to remove all elements of original authorship.Based on Kawasaki, Masahiro (2013-03-18). “Primordial black hole formation from an axionlike curvaton model.” Physical Review D 87 (6): 063519. DOI:10.1103/PhysRevD.87.063519., Public Domain, https://commons.wikimedia.org/w/index.php?curid=131103715

The least massive of these ones would’ve disappeared due to evaporation. That’s what Stephen Hawking figured out. But some, the ones as massive as Earth, could’ve survived.

<Click on image for larger version> Stephen Hawking came up with the idea of black hole evaporation. He theorized that black holes slowly shrink as radiation escapes. The slow leak of what’s now known as Hawking radiation would, over time, cause the black hole to simply evaporate. This infographic shows the estimated lifetimes and event horizon –– the point past which infalling objects can’t escape a black hole’s gravitational grip –– diameters for black holes of various small masses. Image Credit: NASA’s Goddard Space Flight Center

Even though they’re theoretical, there are some evidential hints of their presence. Those hints come from gravitational microlensing.

Two efforts have used microlensing to study objects in the Universe. One is OGLE, the Optical Gravitational Lensing Experiment. Another is MOA, Microlensing Observations in Astrophysics. OGLE found 17 isolated Earth-mass objects in space.

Planet OGLE-2012-BLG-0950Lb was detected through gravitational microlensing, a phenomenon that acts as Nature’s magnifying glass. CREDIT: LCO/D. BENNETT

These objects could be PBHs, or they could be rogue planets. Unfortunately, it’s very difficult to differentiate on an individual basis. But since theory predicts the masses and the abundance of rogue planets, that could provide a way for the Roman Telescope to tell them apart from PBHs.

“There’s no way to tell between Earth-mass black holes and rogue planets on a case-by-case basis,” DeRocco said. “Roman will be extremely powerful in differentiating between the two statistically.”

In their research, the authors explain it more fully. “The key point is that though PBH and FFP events cannot be discriminated on an event-by-event basis, the two populations can be distinguished by the statistical distribution of their event durations.” Scientists think that Roman will find 10 times as many objects in this mass range than ground-based efforts like OGLE and MOA.

Artist’s impression of the Nancy Grace Roman Space Telescope, named after NASA’s first Chief of Astronomy. When launched later this decade, the telescope should make a significant contribution to the study of FFPs and will hopefully detect PBHs. Credits: NASA

Finding primordial black holes would create a big upheaval.

“It would affect everything from galaxy formation to the universe’s dark matter content to cosmic history,” said Kailash Sahu, an astronomer at the Space Telescope Science Institute in Baltimore. Sahu wasn’t involved in the research but understands the impact the results would have. “Confirming their identities will be hard work and astronomers will need a lot of convincing, but it would be well worth it.”

If the Roman Space Telescope can find the black holes and confirm them, it could be a defining moment in astronomical history. The discovery would be strong evidence in favour of a period of rapid inflation in the early Universe, an epoch that so far is unproven. Physicists think there must have been a period like this as it helps explain so much else about the Universe.

More excitingly, these primordial black holes could comprise a percentage of dark matter. A small percentage, but a massive improvement over our current understanding of what dark matter is. Scientists keep looking for things like WIMPs (Weakly Interacting Massive Particles) and other particles that could be dark matter, but they never find them.

“The nature of dark matter remains one of the most pressing open questions in fundamental physics. While multiple lines of compelling evidence indicate its existence, its microphysical nature remains unknown,” the authors explain.

The elegant thing about the Roman and PBHs is that it won’t require a special effort to find them. The Roman will already search for planets. “Roman’s Galactic Bulge Time Domain Survey is expected
to observe hundreds of low-mass microlensing events, enabling a robust statistical characterization
of this population,” the authors write in their paper.

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Each space telescope we launch is a new window into some aspect of the Universe. The Nancy Grace Roman Space Telescope sure will be. “Though its Galactic Bulge Time Domain Survey targets bound and unbound exoplanets, we have shown that it will have unprecedented sensitivity to physics beyond the Standard Model as well,” DeRocco and his co-researchers write in their paper. That’s because it can “probe the fraction of dark matter composed of primordial black holes,” they write.

“This is an exciting example of something extra scientists could do with data Roman is already going to get as it searches for planets,” Sahu said. “And the results are interesting whether or not scientists find evidence that Earth-mass black holes exist. It would strengthen our understanding of the universe in either case.”

And who doesn’t want a stronger understanding of the Universe?

The post Roman Space Telescope Will Be Hunting For Primordial Black Holes appeared first on Universe Today.

Even though Venus and Earth are so-called sister planets, they’re as different as heaven and hell. Earth is a natural paradise where life has persevered under its azure skies despite multiple mass extinctions. On the other hand, Venus is a blistering planet with clouds of sulphuric acid and atmospheric pressure strong enough to squash a human being.

But the sister thing won’t go away because both worlds are about the same mass and radius and are rocky planets next to one another in the inner Solar System. Why are they so different? What do the differences tell us about our search for life?

The international astronomical community recognizes that understanding planetary habitability is a critical part of space science and astrobiology. Without a stronger understanding of terrestrial planets and their atmospheres, whether habitable or not, we won’t really know what we’re seeing when we examine a distant exoplanet. If we find an exoplanet that exhibits some signs of life, we’ll never visit it, never study it up close, and never be able to sample its atmosphere.

Artist’s impression of the exoplanet Ross 128 b orbiting its red dwarf star. Potentially habitable rocky worlds like this one are beyond our physical reach. Image Credit: ESO/M. Kornmesser. Public Domain

That shifts the scientific focus to the terrestrial planets in our own Solar System. Not because they appear to be habitable but because a complete model of terrestrial planets can’t be complete without including ones that are near-literal hellholes, like sister Venus.

A recent research perspective in Nature Astronomy examines how the two planets diverged and what might have driven the divergence. It’s titled “Venus as an anchor point for planetary habitability.” The lead author is Stephen Kane, from the Department of Earth and Planetary Sciences, University of California, Riverside. His co-author is Paul Byrne from the Department of Earth, Environmental, and Planetary Sciences, Washington University in St. Louis.

“A major focus of the planetary science and astrobiology community is understanding planetary habitability, including the myriad factors that control the evolution and sustainability of temperate surface environments such as that of Earth,” Kane and Byrne write. “The few substantial terrestrial planetary atmospheres within the Solar System serve as a critical resource for studying these habitability factors, from which models can be constructed for application to extrasolar planets.”

From their perspective, our Solar System’s twins provide our best opportunity to study how similar planets can have such divergent atmospheres. The more we understand that, the better we can understand how rocky worlds evolve over time and how different conditions benefit or restrict habitability.

This figure from the study presents some of the main, basic differences between Earth and Venus. Image Credit: Kane and Byrne, 2024.

Earth is an exception. With its temperate climate and surface water, it’s been habitable for billions of years, albeit with some climate episodes that severely restricted life. But when we look at Mars, it seems to have been habitable for a period of time and then lost its atmosphere and its surface water. Mars’ situation must be more common than Earth’s.

Artist’s impression of Snowball Earth 650 million years ago during the Marinoan glaciation. Earth has had episodes of extreme climates but is still going strong. Image Credit: University of St. Andrews.

It’s a monumental challenge to understand an exoplanet when we know nothing of its history. We only see it at one epoch of its climate and atmospheric history. But the discovery of thousands of exoplanets is helping. “The discovery of thousands of exoplanets, and the confirmation that terrestrial planets are among the most common types, provides a statistical framework for studying planetary properties and their evolution generally,” the authors write.

A narrow range of properties allows biochemistry to emerge, and those properties may not last. We need to identify these properties and their parameters and build a better understanding of habitability. From this perspective, Venus is a treasure trove of information.

But Venus is a challenge. We can’t see through its dense clouds except with radar, and nobody’s tried landing a spacecraft there since the USSR in the 1980s. Most of those attempts failed, and the ones that survived didn’t last long. Without better data, we can’t understand Venus’ history. The simple answer is that it’s closer to the Sun. But it’s too simple to be helpful.

“The evolutionary pathway of Venus to its current runaway-greenhouse state is a matter of debate, having traditionally been attributed to its closer proximity to the Sun,” Kane and Byrne explain.

We don’t know why Venus is a greenhouse effect. Volcanoes may have played a role. They emit carbon dioxide, and without oceans and tectonic plates, the planet can’t remove the carbon from its atmosphere. Image Credit: NASA/JPL-Caltech/Peter Rubin

But when scientists look closer at Venus and Earth, they find many fundamental differences between them beyond their distances from the Sun. They have different rotation rates, they have differing obliquities, and they have different magnetic fields, to name a few. That means that we can’t measure the precise effect greater solar insolation has on the planet.

This is the authors’ main point. The differences between Earth and Venus make Venus a powerful part of understanding rocky exoplanet habitability. “Venus thus offers us a critical anchor point in the planetary habitability discourse, as its evolutionary story represents an alternate pathway from the Earth-based narrative—even though the origins of both worlds are, presumably, similar,” they write.

The authors point out that the basic requirement for life is surface water. But the bigger question is what factors govern how long surface water can persist. “By this measure, investigations of planetary habitability can then focus on the conditions that allow surface liquid water to be sustained through geological time,” they write.

This figure from the research illustrates some of the factors that can influence surface water and planetary habitability. Image Credit: Kane and Byrne 2024, National Academies Press, Ron Pettengill.

Earth and Venus are on opposite ends of the spectrum of rocky planet habitability. That’s an important lesson we can learn from our own Solar System. For that reason, “…understanding the pathway to a Venus scenario is just as important as understanding the pathway to habitability that characterizes Earth,” the authors write.

The pair of researchers created a list of some of the factors that govern habitability on Earth and Venus.

Most of these factors are self-explanatory. CHNOPS is carbon, hydrogen, nitrogen, oxygen, phosphorous, and sulphur, the life-supporting elements. Redox is the potential for an element or molecule to be reduced or oxidized and made available as chemical energy for life. The fact that there’s a question mark beside for Venus’s redox environment is a major stumbling block. Image Credit: Kane and Byrne, 2024.

There’s so much we don’t know about Venus. How big is its core? Did it ever have water? Some research shows that when the planet lost its water and became totally inhabitable, there was lots of oxygen in its atmosphere. If we saw that same amount of oxygen on a distant exoplanet, we might interpret it as a sign of life. Big mistake. “Venus thus acts as a cautionary tale for interpretations of apparently oxygen-rich atmospheres,” the authors write.

Kane and Byrne’s research perspective is a call to action. It mirrors what recent Decadal Surveys have said. “The recent astronomy and astrophysics, and planetary science and astrobiology decadal surveys both emphasize the need for an improved understanding of planetary habitability as an essential goal within the context of astrobiology,” they write. For the authors, Venus can anchor the effort.

But for it to serve as an anchor, scientists need answers to lots of questions. They need to study its atmosphere more thoroughly at all altitudes. They need to study its interior and determine the nature and size of its core. Critically, they need to get a spacecraft to its surface and examine its geology up close. In short, we need to do at Venus what we’ve done at Mars.

That’s challenging, considering Venus’ hostile environment. But missions are being prepared to explore Venus in more detail. VERITAS, DAVINCI, and EnVision are all Venus missions scheduled for the 2030s. Those missions will start to give scientists the answers we need.

As we learn more about Venus, we also need to learn more about exo-Venuses. “A parallel approach to studying the intrinsic properties of Venus is the statistical analysis of the vast (and still rapidly growing) inventory of terrestrial exoplanets,” the authors write.

This figure from the research represents the Venus zone and the habitable zone as a function of stellar effective temperature and insolation flux received by the planet. The Venus zone is shaded in red, and the habitable zone is in blue. The images on the left show main sequence stars of various effective temperatures. The images of Venus indicate the location of Kepler candidates that lie within the Venus zone, scaled by the size of the planet. The Solar System planets of Venus, Earth and Mars are also shown. Image Credit: Habitable Zone Gallery/Chester Harman; Planets: NASA/JPL. Kane and Byrne, 2024.

We’re living in an age of exoplanet discovery. We’ve discovered over 5,000 confirmed exoplanets, and the tally keeps growing. We’re launching spacecraft to study the most interesting ones more thoroughly. But at some point, things will shift. How many of them do we need to catalogue? Is 10,000 enough? 20,000? 100,000?

It’s all new right now, and the enthusiasm to find more exoplanets, especially rocky ones in habitable zones, is understandable. But eventually, we’ll reach some kind of threshold of diminishing returns. In order to understand them, our effort might be more wisely spent studying Venus and how it evolved so differently.

Just as Kane and Byrne suggest.

The post What Deadly Venus Can Tell Us About Life on Other Worlds appeared first on Universe Today.

The Gum Nebula is an emission nebula almost 1400 light-years away. It’s home to an object known as “God’s Hand” among the faithful. The rest of us call it CG 4.

Many objects in space take on fascinating, ethereal shapes straight out of someone’s psychedelic fantasy. CG4 is definitely ethereal and extraordinary, but it’s also a little more prosaic. It looks like a hand extending into space.

The Dark Energy Camera (DECam) on the NSF’s Víctor M. Blanco 4-meter Telescope captured the image. DECam’s primary job is to survey hundreds of millions of galaxies in its study of dark energy. But it’s also a general-purpose instrument used for other scientific endeavours.

CG 4 is called a cometary globule because of its appearance. But it’s actually a star-forming region. It has a head that’s about 1.5 light-years in diameter and a tail that’s about 8 light-years long. The head is dense and opaque and is lit up by a nearby star. The globule is surrounded by a diffuse red glow, emissions from ionized hydrogen.

This excerpt shows a close-up of CG 4. The hand looks like it’s about to grasp an edge-on spiral galaxy named ESO 257-19 (PGC 21338). But the galaxy is more than a hundred million light-years beyond CG 4. Only a chance alignment makes it seem close. Near the head of the cometary globule are two young stellar objects (YSOs). They’re stars in their early stage of evolution before they become main-sequence stars. Image Credits: Credit: CTIO/NOIRLab/DOE/NSF/AURA
Image Processing: T.A. Rector (University of Alaska Anchorage/NSF’s NOIRLab), D. de Martin & M. Zamani (NSF’s NOIRLab)

There are lots of cometary globules in the Milky Way. They’re a sub-class of objects called Bok globules, after astronomer Bart Bok, who discovered them. Both types of globules are dark nebulae, molecular clouds so dense they block optical light. Astronomers aren’t absolutely certain how cometary globules get their shape.

But they do know what’s happening to them.

The red glow surrounding CG 4 is ionized hydrogen lit up by radiation from nearby hot, massive stars. That same radiation is eroding CG 4 away. Since the globule is denser than its surroundings, it’s resisting diffusion. It still contains enough gas and dust to form several new stars about as massive as the Sun.

In this zoom-in, the hand looks more like the mouth of the Shai-Hulud, reaching out into space to destroy the approaching Sardaukar. Image Credit: CTIO/NOIRLab/DOE/NSF/AURA. Image Processing: T.A. Rector (University of Alaska Anchorage/NSF’s NOIRLab), D. de Martin & M. Zamani (NSF’s NOIRLab)

Even though there are many of these globules in the Milky Way, the majority of them are in the Gum Nebula. Scientists know of 31 other globules in the nebula. This one’s called CG 4 (Cometary Globule 4) because they’re all numbered.

This image shows three of the 32 CGs in the Gum Nebula: CG 30, 31, and 8. Image Credit: By Legacy Surveys / D.Lang (Perimeter Institute) & Meli Thev – Own work, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=143429111

The Gum Nebula is likely the remnant of a huge supernova explosion, and that could be the reason the globules have their unique shape. They may have originally been spherical nebula like the Ring Nebula. But a powerful supernova explosion about one million years ago stretched them into their long, comet-like forms.

The James Webb Space Telescope captured this image of the Southern Ring Nebula, or NGC 3132, with its NIRCAM instrument. Cometary globules could’ve started out as ring-shaped nebulae before being deformed by supernova explosions. Image Credit: By Image: NASA/ESA/CSA/Space Telescope Science Institute. Public Domain

Astronomers also suggest another reason for their shape. Nearby hot, massive stars exert radiation pressure on the globules, and their stellar wind also slams into them. In the Gum Nebula, their tails point away from the Vela Supernova Remnant and the pulsar that sits in its centre. Since the Vela Pulsar is a spinning neutron star, it’s possible that its winds and radiation pressure are shaping CG 4.

Whatever its cause, the Hand of God is a visually intriguing object. If you really want to lose yourself in this amazing nebula, download the TIFF file here.

The post A Nebula that Extends its Hand into Space appeared first on Universe Today.

Earth is naked without its protective barrier. The planet’s magnetic shield surrounds Earth and shelters it from the natural onslaught of cosmic rays. But sometimes, the shield weakens and wavers, allowing cosmic rays to strike the atmosphere, creating a shower of particles that scientists think could wreak havoc on the biosphere.

This has happened many times in our planet’s history, including 41,000 years ago in an event called the Laschamps excursion.

Cosmic rays are high-energy particles, usually protons or atomic nuclei, that travel through space at relativistic speeds. Normally, they’re deflected into space and away from Earth by the planet’s magnetic shield. But the shield is a natural phenomenon and its strength fluctuates, as does its orientation. When that happens, cosmic rays strike the Earth’s atmosphere.

That creates a shower of secondary particles called cosmogenic radionuclides. These isotopes become embedded in sediments and ice cores and even in the structure of living things like trees. There are different types of these isotopes, including ones like Calcium 41 and Carbon 14.

Showers of high-energy particles occur when energetic cosmic rays strike the top of the Earth’s atmosphere. Illustration Credit: Simon Swordy (U. Chicago), NASA.

Some of the isotopes are stable, and some are radioactive. The radioactive ones have half-lives ranging from only 20 minutes (Carbon 11) up to 15.7 million years (Xenon 129.)

When Earth’s shield weakens, more of these isotopes reach the planet’s surface and collect in sediments and ice. By studying these cores and sediments, scientists can determine the magnetic shield’s history. Their observations show that Earth experienced a geomagnetic excursion or reversal 41,000 years ago. It’s called the Laschamps excursion after the Laschamps lava flows in France, where geomagnetic anomalies revealed its occurrence.

Every few hundred thousand years, the Earth’s magnetic poles flip. North becomes South and vice versa. In between those major events are more minor events called excursions. During excursions, the poles shift around for a while without swapping places. The excursions weaken the Earth’s shield and can last from a few thousand to tens of thousands of years. When that happens, more cosmic rays strike the atmosphere, creating more radionuclides that shower down onto Earth.

Scientists often focus on one particular radioactive isotope in paleomagnetic studies. Beryllium 10 has a relatively long half-life of 1.36 million years and tends to accumulate on the soil surface.

Sanja Panovska is a researcher at GFZ Potsdam, Germany, who studies geomagnetism. At the recent European Geosciences Union (EGU) General Assembly 2024, Panovska presented new research on the Laschamps excursion. She found that during the Laschamps excursion, production of Be 10 was twice as high as normal.

To understand the Laschamps excursion more thoroughly, Panovska combined cosmogenic radionuclide and paleomagnetic data to reconstruct the Earth’s magnetic field at the time. She found that when the field decreased in strength, it also shrank. The transition from normal field to reversed field took about 250 years, and it stayed flipped for about 440 years. During the transition, the Earth’s shield weekend to as little as 5% of its normal strength. When it was fully reversed, it was at about 25% of its regular strength. This weakening allowed more Be 10 and other cosmogenic radionuclides to reach Earth’s surface.

Each map shows the intensity of Earth’s geomagnetic field at different snapshots in time, according to Panovska’s reconstructions that are constrained by both paleomagnetic data and records of cosmogenic beryllium-10 radionuclides. DM stands for Dipole Moment, which is a measure of the field’s polarity or separation of positive and negative. Age [ka BP] is the age measures in thousands of years before the present. Image Credit: Sanja Panovska.

These radionuclides do more than collect in sediments and ice. Some of them are radioactive. The weakening of the shield also weakened the ozone layer, letting more UV radiation reach Earth’s surface. The high-altitude atmosphere also cooled, which changed the wind flows. This could’ve caused drastic changes on the Earth’s surface.

For these reasons, the Laschamps event has been linked to the extinction of the Neanderthals, the extinction of Australian megafauna, and even to the appearance of cave art. Those links haven’t withstood scientific scrutiny, but that doesn’t mean that events like the Laschamps event aren’t hazardous. If it occurred now, it would knock out our power grids. The Earth’s equatorial region would light up with aurorae.

“Understanding these extreme events is important for their occurrence in the future, space climate predictions, and assessing the effects on the environment and on the Earth system,” Panovska said.

Scientists are learning that the magnetic shield isn’t static. There are anomalies. One of them is the South Atlantic Anomaly, a region where the magnetic field is weakest near Earth. When satellites pass over this region, they’re exposed to higher levels of ionizing radiation. The anomaly is likely caused by a reservoir of dense rock inside Earth, illustrating how complex the magnetic shield is.

The ‘South Atlantic Anomaly’ refers to an area where Earth’s protective magnetic shield is weak. Image Credit: By Christopher C. Finlay, Clemens Kloss, Nils Olsen, Magnus D. Hammer, Lars Tøffner-Clausen, Alexander Grayver & Alexey Kuvshinov – “The CHAOS-7 geomagnetic field model and observed changes in the South Atlantic Anomaly”, Earth, Planets and Space, Volume 72, Article number 156 (2020), https://earth-planets-space.springeropen.com/articles/10.1186/s40623-020-01252-9, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=99760567

Scientists are uncertain about what effect the cosmic rays have on life when the magnetic shield is weak. It’s tempting to correlate extinctions with events like the Laschamps excursion when they line up temporally. But the poles have shifted, weakened, and reversed many times and life is still here and still thriving.

If humanity lasts long enough, we’ll go through one of these reversals. Then we’ll know.

The post 41,000 Years Ago Earth’s Shield Went Down appeared first on Universe Today.

No human being will ever encounter a black hole. But we can’t stop wondering what it would be like to fall into one of these massive, beguiling, physics-defying singularities.

NASA created a simulation to help us imagine what it would be like.

Jeremy Schnittman is an astrophysicist at NASA’s Goddard Space Flight Center and he created the visualizations. “People often ask about this, and simulating these difficult-to-imagine processes helps me connect the mathematics of relativity to actual consequences in the real universe,” he said. “So I simulated two different scenarios, one where a camera — a stand-in for a daring astronaut — just misses the event horizon and slingshots back out, and one where it crosses the boundary, sealing its fate.”

In one, the viewpoint plunges directly into the black hole like a free-falling astronaut, with explanatory text to guide us through what we’re seeing. The other is a 360-degree view of the black hole.

Schnittman created them with a NASA supercomputer called Discover in only five days, generating about 10 terabytes of data. The computer used only about 0.3% of its power. The same visualization would’ve taken more than a decade to create on an average laptop computer.

The black hole in the visualization is the same size as Sagittarius A star, the supermassive black hole (SMBH) at the heart of the Milky Way. It has 4.3 million solar masses and dominates the galaxy’s inner regions. Its event horizon reaches about 25 million km (16 million miles). That’s about 17% of the distance from Earth to the Sun. The event horizon is surrounded by an accretion disk, a swirling disk of superheated material drawn in by the black hole’s overpowering gravity.

Another type of black hole, the stellar-mass black hole, is much less massive. Schnittman says that if you’re going to fall into a black hole, you’d rather fall into the supermassive one.

“If you have the choice, you want to fall into a supermassive black hole,” Schnittman explained. “Stellar-mass black holes, which contain up to about 30 solar masses, possess much smaller event horizons and stronger tidal forces, which can rip apart approaching objects before they get to the horizon.”

Powerful gravity is the reason. The SMBH’s gravity is so strong that it pulls harder on the end of the object nearest it. That stretches the object and elongates it. Stephen Hawking was the first to call this ‘spaghettification,’ and the name has stuck. Presumably, you’d get a better look if you fall into an SMBH.

In the movies, the camera begins at a distance of 640 million km (400 million miles.) Since space-time is warped around a black hole, so are the images of the sky, the black hole’s disk, and the photon ring. It takes the camera three hours of real-time to fall into the event horizon, and it completes almost two 30-minute orbits as it falls. A distant observer would never see an object ever reach the black hole. From a distance, the object would freeze at the event horizon.

When a falling object reaches the event horizon, it and space-time itself reach the speed of light. After crossing the horizon, the object and the space-time around it surge toward the singularity, a point of infinite density and gravity. “Once the camera crosses the horizon, its destruction by spaghettification is just 12.8 seconds away,” Schnittman said.

In the second video, the camera never crosses the event horizon and instead escapes. But the powerful black hole still has an effect. Imagine if the camera were an astronaut, and they flew this six-hour roundtrip while a separate astronaut stayed far away from the SMBH. The astronaut would return and be 36 minutes younger than the astronaut who never approached the black hole.

“This situation can be even more extreme,” Schnittman noted. “If the black hole were rapidly rotating, like the one shown in the 2014 movie ‘Interstellar,’ she would return many years younger than her shipmates.”

The bottom line is, don’t fall into a black hole. In fact, resist your fascination and don’t even approach one.

Leave them for the physicists.

The post Fall Into a Black Hole With this New NASA Simulation appeared first on Universe Today.