Astronomy

The Centaurus constellation holds some of the best southern targets, including the Omega Centauri globular cluster and the Centaurus A galaxy.

The post Centaurus Constellation: Glimpse the Greatest Globular appeared first on Sky & Telescope.

Tai Chi, yoga, water exercises and other low-impact workouts may help prevent severe falls among older adults

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All issues encountered during the first astronaut mission of Boeing's Starliner capsule must be addressed before the vehicle is certified for long-duration crewed flights.

Microplastics are everywhere, Olympic ambitions for the Seine River are complicated by poop, and the Starliner spacecraft delays its return to Earth.

Two large asteroids will safely pass Earth this week, a rare occurrence perfectly timed to commemorate this year's Asteroid Day. Neither poses any risk to our planet, but one of them was only discovered a week ago, highlighting the need to continue improving our ability to detect potentially hazardous objects in our cosmic neighbourhood.

Save the date for ESA’s next Living Planet Symposium, set for 23–27 June 2025 at the Austria Center Vienna. Held every three years, this premier Earth observation conference continues to expand in both size and scope. With the climate crisis intensifying, this event emphasises transitioning from ‘observation to climate action and sustainability for Earth’. Don't miss it!

Four years ago, the supermassive black hole hidden in the heart of galaxy SDSS1335+0728 roared awake and announced its presence with a blast of radiation. It marks the first time astronomers witnessed a sudden activation of a supermassive black hole in real time.

“Imagine you’ve been observing a distant galaxy for years, and it always seemed calm and inactive,” said Paula Sánchez Sáez, an astronomer at ESO in Germany and lead author of the study of this object. “Suddenly, its [core] starts showing dramatic changes in brightness, unlike any typical events we’ve seen before.”

This is what happened to SDSS1335+0728, which is now officially classified as having an active galactic nucleus (AGN). It experienced what’s called a “nuclear transient.” Essentially, that means the galaxy now has a very bright compact region. However, it wasn’t always that bright and astronomers want to understand what caused it to wake up.

This artist’s impression shows two stages in the formation of a disc of gas and dust around the massive black hole at the center of the galaxy SDSS1335+0728. The core of this galaxy lit up in 2019 and keeps brightening today — the first time astronomers observed a massive black hole become active as it happened. Credit: ESO/M. Kornmesser Looking for Transients in all the Right Places

The unusual brightness variations were detected by the Zwicky Transient Facility in California, which gives constant, real-time alerts about such things as transient flaring and brightening in the hearts of galaxies like SDSS1335+0728. In addition, several other facilities observed the variations, too, and brightness changes were found in archival data from several other observatories.

The sudden brightenings could be due to many things, including the cannibalization of stars and clouds of gas that stray too near supermassive black holes. How often they brighten and how a quiescent galaxy nucleus changes to an active one are topics that astronomers are using such surveys and observations to understand. They’re looking not just at distant galaxies, but activity within the neighborhood of our own galaxy’s supermassive black hole, too.

A Galaxy and Its Supermassive Black Hole

Most galaxies have stupendously massive black holes at their hearts. They typically sequester away at least a hundred thousand times the mass of the Sun (sometimes more). It’s all trapped by gravity and nothing ever escapes, not even light. “These giant monsters usually are sleeping and not directly visible,” said study co-author Claudio Ricci, from Chile’s Diego Portales University. “In the case of SDSS1335+0728, we were able to observe the awakening of the massive black hole, [which] suddenly started to feast on gas available in its surroundings, becoming very bright.”

A black hole itself doesn’t emit any light at all. Instead, it sucks everything in, including light. However, the region around the black hole—called the accretion disk—is a pretty active place. It’s where material trapped by the intense gravitational pull of the black hole swirls around like water going down a drain. All that stuff—mostly gas, some dust—is threaded through with magnetic fields. Friction between accretions of the material heats it up. And, that act of heating gives off radiation. If there’s enough of it, we see light being given off. Intense active regions emit x-rays, which indicate the level of activity.

Gravity’s Slice-and-dice Activity

There’s also something called tidal disruption, which happens when something like a star or a cloud of gas gets trapped in the gravitational field. These things take time—on the order of years to occur. When they happen, the gravitational pull of the black hole eventually rips the star or cloud apart. That also gives off radiation. In fact, a very slow-motion tidal disruption event may be occurring at the heart of SDSS1335+0728. If so, it could be one of the longest and dimmest ones ever seen.

Regardless of what’s causing the brightening, the ultimate fate of some of the material is to end up inside the black hole. The rest of it gets superheated in the accretion disk and signals its fate through increased radiation.

Black Hole Growth and a Wake-up Call

The supermassive black holes in the hearts of galaxies grow from smaller ones to larger ones through mergers. We don’t see those growth patterns in real time, since they occur over millions of years. The merger scenario says that when galaxies come together, their central black holes (if they have them) do, too.

Simulation of merging supermassive black holes. Credit: NASA’s Goddard Space Flight Center/Scott Noble

Eventually you get these gargantuan monsters. They just sit there and nibble away at passing gas clouds to gain additional mass. That’s how they gain mass through acquisitions, which occur over shorter timescales. This is apparently what the one in SDSS1335+0728 is doing now. It’s just not often that astronomers get to see one wake up and start munching away in a short period of time.

So, a lot of questions remain about this one, mostly about its formation history. Since the mergers take a long time, it’s hard to know what’s happened to this one in the past. If this is a tidal disruption event, astronomers want to know how often such things happen.

This artist’s illustration depicts what astronomers call a “tidal disruption event,” or TDE, when an object such as a star wanders too close to a black hole and is destroyed by tidal forces generated from the black hole’s intense gravitational forces. (Credit: NASA/CXC/M.Weiss.)

At the moment, for SDSS1335+0728, there’s no immediate evidence of prior outbursts signaling prior awakenings of the supermassive black hole. Astronomers need to do a lot of follow-up observations to understand what’s really happening there, and perhaps find evidence for other eruptions and activity associated with the black hole, according to Sánchez Sáez. “Regardless of the nature of the variations, [this galaxy] provides valuable information on how black holes grow and evolve,” she said, noting that advanced instruments at ESO’s Very Large Telescope should give astronomers a better idea of the processes occurring at this black hole. In addition, further time-domain all-sky surveys with the upcoming Vera C. Rubin telescope should be able to track this galaxy’s nuclear brightenings.

For More Information

Astronomers See a Massive Black Hole Awaken in Real Time
SDSS1335+0728: The awakening of a ~10^6 M_sun Black Hole
arXiv preprint

The post Astronomers See a Black Hole Wake Up from its Ancient Slumber appeared first on Universe Today.

Astronomers have been scouring the outer solar system for signs of a hypothetical ninth planet for almost a decade, without success. However, we may finally be on the cusp of finding it, experts say.

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Squids on Earth aren't this big.

Watching meteoroids enter the Earth’s atmosphere and streak across the sky as the visual spectacle known as meteors, it is one of the most awe-inspiring spectacles on Earth, often exhibiting multiple colors as they blaze through the atmosphere, which often reveals their mineral compositions. But what if we could detect and observe meteors streaking through the atmospheres of other planets that possess atmospheres, like Venus, and use this to better determine meteoroid compositions and sizes?

This is what a recently accepted study to Icarus hopes to address as a pair of international researchers investigate how a future Venus orbiter could be used to study meteors streaking through the planet’s thick atmosphere. This study holds the potential to help scientists better understand meteoroids throughout the solar system.

Here, Universe Today discusses this study with Dr. Apostolos Christou, who is an astronomer at the Armagh Observatory and Planetarium, regarding the motivation behind the study, significant results, potential follow-up studies, potentially turning this concept into reality, and potentially observing meteors on other planets throughout the solar system. Therefore, what was the motivation behind the study?

“The underlying problem we want to solve is the measurement of the flux of solid particles in space,” Dr. Christou tells Universe Today. “The smallest particles (what we normally refer to as ‘dust’) can be efficiently counted with small-area impact detectors mounted on spacecraft, while objects larger than a meter or two (asteroids) we can find at the telescope. However, anything between a couple of hundred microns and a meter fall into a kind of gap; they are too rarefied to count with impact detectors and also too small to see with a telescope. The best way to look for those particles is to see them burning up as meteors in the atmosphere, essentially by treating entire planets as area detectors.”

For the study, the researchers used a survey simulation toolkit known as SWARMS (Simulator for Wide Area Recording of Meteors from Space) to ascertain the feasibility if a camera onboard a future Venus orbiter could observe meteors within Venus’ atmosphere. Parameters for SWARMS included using the same meteoroid populations observed on Earth for Venus, along with atmospheric modeling and the type of instrument, with the researchers putting a hypothetical meteor camera onboard the upcoming European Space Agency’s EnVision orbiter.  

In the end, the researchers found the number of meteors their orbiter camera could observe in the Venusian atmosphere would be 1.5 to 2.5 times greater than on Earth. The team notes this indicates the feasibility of observing meteors within the Venusian atmosphere, assuming the data would be successfully sent back to Earth. So, what were the most significant results from this study?

Dr. Christou tells Universe Today, “I’d say the two principal results are (a) that meteors at Venus occur well above the cloud layers, and (b) that they should be consistently brighter than their Earth counterparts. Point (a) removes one potential obstacle in detecting those particles in the orbital camera while point (b) tells us that any camera design flight-proven in Earth orbit should perform at least as well and probably better at Venus.”

Regarding follow-up studies, Dr. Christou tells Universe Today, “There were a number of assumptions made in the study that we want to explore in later work. One of the assumptions is that the camera is at a fixed altitude above the surface. We want to better understand the implications of observing from an elliptical orbit where the altitude and therefore the range to the target changes with time and location. In addition, Venus’s orbit is close to Earth’s, and it may just be possible to detect the brightest meteors (we call these fireballs) with telescopes from the ground as we have done with Jupiter. A future study will better quantify this possibility.”

This study comes as NASA plans to launch the VERITAS (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy) orbiter sometime between 2029 and 2031, whose goal is to obtain high-resolution maps of Venus’ surface using synthetic aperture radar and near-infrared spectroscopy to penetrate Venus’ thick atmosphere. The images obtained will provide updated data from NASA’s Magellan probe in the 1990s, as this is the most recent surface data available regarding Venus’ surface activity. Additionally, the European Space Agency is slated to launch EnVision in 2032 with the goal of mapping Venus’ surface using synthetic aperture radar, as well. Therefore, since this study involves putting a hypothetical meteor camera onboard the EnVision orbiter, what plans are in the works for putting such a camera on a future spacecraft?

Dr. Christou tells Universe Today, “There are no specific plans to my knowledge, however with the current level of international interest in exploring Venus, I believe this is the right time to advocate for it. Actually, there is an instrument called Mini-EUSO recording meteors from the ISS with a detection rate of ~16,000 meteors for every month of observing time. In comparison, a meteor survey of the kind we explore in the paper requires to detect ~200 meteors every month. This indicates that the concept is technically mature and could be implemented over the next 5-10 years say.”

Venus was the sole focus of this study due to its thick atmosphere, while also having the thickest atmosphere of the terrestrial planets additionally comprised of Mercury, Earth, and Mars. Given the results of this study, a future Venus orbiter designed to observe and detect meteors within Venus’ atmosphere could be feasible while providing valuable scientific knowledge pertaining to the properties and populations of meteoroids throughout the solar system.

However, Venus is not the only planet comprised of a thick atmosphere, as the gas giants of the outer solar system (Jupiter, Saturn, Uranus, and Neptune) boast even thicker atmospheres mostly comprised of hydrogen and helium with no visible surfaces underneath. Therefore, could this meteor survey method potentially be used to identify meteors on those planets?

Dr. Christou tells Universe Today, “In some sense, we already have! In 1994, the world observed the fragments of comet Shoemaker-Levy 9 enter the atmosphere of Jupiter. More recently, amateur astronomers have observed the meteors caused by smaller, decameter-class objects against the disk of the planet. To observe fainter meteors, one would have to bring the detector and the planet closer together but, given that the gas giants have 1-2 orders of magnitude (with an order of magnitude being a factor of 10) more surface area than Earth, the potential is definitely there. Actually, such fainter meteors were detected by Voyager 1 during the brief encounter in 1979 and again more recently by the Juno orbiter. These incidents bode well for future orbital surveys.”

Studying meteoroids and meteors enables scientists to better understand the composition and properties of other planetary bodies throughout the solar system which also teaches us about the formation and evolution of the solar system, as well. As the exploration of Venus expands in the coming years, studying meteors within its thick atmosphere could provide even more clues to how we came to be, overall.

Dr. Christou concludes by telling Universe Today, “Meteors should be ubiquitous to planets and moons with appreciable atmospheres. For instance, one should expect to see meteors on Titan and even on Triton, the largest moon of Neptune where the atmospheric pressure at the surface is 100,000x lower than Earth.”

Will scientists send a Venus orbiter to study meteors within the Venusian atmosphere in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

The post Venus is the Perfect Place to Count Meteors appeared first on Universe Today.

Does proton decay exist and how do we search for it? This is what a recently submitted study hopes to address as a team of international researchers investigate a concept of using samples from the Moon to search for evidence of proton decay, which remains a hypothetical type of particle decay that has yet to be observed and continues to elude particle physicists. This study holds the potential to help solve one of the longstanding mysteries in all of physics, as it could enable new studies into deep-level and the laws of nature, overall.

Here, Universe Today discusses this research with Dr. Patrick Stengel, who is a postdoctoral fellow in the Cosmology Group at INFN Ferrara Division, regarding the motivation behind the study, significant results, significance of searching for proton decay, implications for confirming the existence of proton decay, and turning their concept into reality. Therefore, what is the motivation behind the study?

Dr. Stengel tells Universe Today this research started around 2018 with lead author, Dr. Sebastian Baum, and other scientists regarding the use of paleo-detectors, which is a proposed method to examine particles that span vast periods of geological timeframes. This led to discussions with study co-author, Dr. Joshua Spitz—who became interested in paleo-detectors after several papers examined their potential to search for dark matter—and one of Dr. Spitz’s PhD students, regarding how paleo-detectors could be used to discover the existence of proton decay. However, the team published a study discussing how finding proton decay on Earth wasn’t possible due to atmospheric neutrinos.

“About one year after finishing atmospheric neutrino paper, Spitz suggested we consider mineral samples from the Moon,” Dr. Stengel tells Universe Today. “Due to the lack of an atmosphere, the cosmic ray-induced neutrino flux on the Moon is highly suppressed compared to the Earth. The corresponding suppression of the cosmic ray-induced neutrino interactions in paleo-detectors allows for a search for proton decay to at least be feasible in principle.”

For the study, the researchers proposed a hypothetical concept using paleo-detectors that would involve collecting mineral samples from more than 5 kilometers (3.1 miles) beneath the lunar surface and analyzing them for presence of proton decay, either on the Moon itself or back on Earth. The researchers note these lunar paleo-detector samples could yield proton lifetimes up to 1034 years. For context, the age of the universe is approximately 13.7 x 109 years. Therefore, what are the most significant results from this study?

Dr. Stengel tells Universe Today, “For a lunar mineral sample which is both sufficiently radiopure to mitigate radiogenic backgrounds and buried at sufficient depths for shielding from other cosmic ray backgrounds, we show that the sensitivity of paleo-detectors to proton decay could in principle be competitive with next-generation conventional proton decay experiments.”

As noted, proton decay continues to be a hypothetical type of particle decay and was first proposed in 1967 by the Soviet physicist and Nobel Prize laureate, Dr. Andrei Sakharov. As its name implies, proton decay is hypothesized to occur when protons decays into particle smaller than an atom, also called subatomic particles. As noted by this recent study and various previous studies, proton decay has yet to be discovered or observed. However, it is hypothesized to have the potential for better understanding our universe and the origin of life with quantum tunneling being proposed as a process of proton decay. Therefore, what is the significance of searching for proton decay, and what implications could its existence have for science, and specifically the field of particle physics, overall?

Dr. Stengel tells Universe Today, “Proton decay is a generic prediction of particle physics theories beyond the Standard Model (SM). In particular, proton decay could be one of the only low energy predictions of so-called Grand Unified Theories (GUTs), which attempt to combine all of the forces which mediate SM interactions into one force at very high energies. Physicists have been designing and building experiments to look for proton decay for over 50 years.”

Dr. Stengel continues, “The discovery of proton decay, whether in a mineral detector or a more conventional experiment, would have incredible implications for science in general and particle physics in particular. Such a discovery would be the first confirmation of particle physics beyond the SM. Depending on how well the proton decay signal could be characterized, we could learn something about the fundamental theory of nature.”

As noted, the hypothetical concept proposed by this study using pale-detectors to detect proton decay on the Moon would require collecting samples at least 5 kilometers (3.1 miles) beneath the lunar surface. For context, the deepest humans have ever collected samples from beneath the lunar surface was just under 300 centimeters (118 inches) with the drill core samples obtained from the Apollo 17 astronauts.

On Earth, the deepest human-made hole is the Kola Superdeep Borehole in northern Russia and measures approximately 12.3 kilometers (7.6 miles) in true vertical depth, along with requiring several holes to be drilled and several years to achieve. While the study notes the proposed concept using paleo-detectors on the Moon is “clearly futuristic”, what steps are required to take this concept from futuristic to realistic?

Dr. Stengel tells Universe Today, “As we are careful not to stray too far from our respective areas of expertise related to particle physics, we chose not to speculate much at all about the actual logistics of performing such an experiment on the Moon. However, we also thought that this concept was timely as various scientific agencies across different countries are considering a return to the Moon and planning for broad program of experiments.”

Dr. Stengel continues, “As you mention, the mineral samples would need to be extracted from at least about 5 km deep in the lunar crust. Thus, there would need to be a drilling rig delivered to and operated on the Moon which is capable of reaching such depths. While this logistical challenge seems daunting, we point out that e.g. NASA envisions sufficiently large payloads eventually being delivered to the Moon as part of the Artemis program.”

As noted, this study comes as NASA’s Artemis program plans to return astronauts to the lunar surface for the first time in more than 50 years with the goal of landing the first woman and person of color on the lunar surface, as well. Additionally, as scientific interest in paleo-detectors continues to grow, the concept proposed in this study could prove to be scientifically beneficial for not only discovering proton decay, but for us better understanding our place in the universe. Finally, it turns out that only a small sample will be necessary to make this proposed concept worth it.

Dr. Stengel tells Universe Today, “Due to the exposure of paleo-detectors to proton decay over billion-year timescales, only one kilogram of target material is necessary to be competitive with conventional experiments. In combination with the scientific motivation and the recent push towards returning humans to the Moon for scientific endeavors, we think paleo-detectors could represent the final frontier in the search for proton decay.”

How will paleo-detectors help scientists potentially discover proton decay in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

The post Do Protons Decay? The Answer Might be on the Moon appeared first on Universe Today.