Astronomy

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Using the NASA/ESA/CSA James Webb Space Telescope, scientists have found a record-breaking galaxy observed only 290 million years after the big bang.

Over the last two years, scientists have used the NASA/ESA/CSA James Webb Space Telescope to explore what astronomers refer to as Cosmic Dawn – the period in the first few hundred million years after the big bang where the first galaxies were born. These galaxies provide vital insight into the ways in which the gas, stars, and black holes were changing when the universe was very young. In October 2023 and January 2024, an international team of astronomers used Webb to observe galaxies as part of the JWST Advanced Deep Extragalactic Survey (JADES) programme. Using Webb’s NIRSpec (Near-Infrared Spectrograph), scientists obtained a spectrum of a record-breaking galaxy observed only two hundred and ninety million years after the big bang. This corresponds to a redshift of about 14, which is a measure of how much a galaxy’s light is stretched by the expansion of the Universe.

This infrared image from Webb’s NIRCam (Near-Infrared Camera) was captured as part of the JADES programme. The NIRCam data was used to determine which galaxies to study further with spectroscopic observations. One such galaxy, JADES-GS-z14-0 (shown in the pullout), was determined to be at a redshift of 14.32 (+0.08/-0.20), making it the current record-holder for the most distant known galaxy. This corresponds to a time less than 300 million years after the big bang.

In the background image, blue represents light at 0.9, 1.15, and 1.5 microns (filters F090W + F115W + F150W), green is 2.0 and 2.77 microns (F200W + F277W), and red is 3.56, 4.1, and 4.44 microns (F356W + F410M + F444W). The pullout image shows light at 0.9 and 1.15 microns (F090W + F115W) as blue, 1.5 and 2.0 microns (F150W + F200W) as green, and 2.77 microns (F277W) as red.

These results were captured as part of spectroscopic observations from the Guaranteed Time Observations (GTO) programme 1287, and the accompanying MIRI data as part of GTO programme 1180.

Note: This post highlights data from Webb science in progress, which has not yet been through the peer-review process.

[Image description: A field of thousands of small galaxies of various shapes and colors on the black background of space. A bright, foreground star with diffraction spikes is at lower left. Near the image center, a tiny white box outlines a region and two diagonal lines lead to a box in the upper right. Within the box is a banana-shaped blob that is blueish-red in one half and distinctly red in the other half. An arrow points to the redder portion and is labeled “JADES GS z 14 – 0”.]

Release on esawebb.org

Saturn will appear just above the third quarter moon in the sky in the early hours of Friday (May 31).

When the Arecibo Observatory dish in Puerto Rico collapsed in 2020, astronomers lost a powerful radio telescope and a unique radar instrument to map the surfaces of asteroids and other planetary bodies. Fortunately, a new, next-generation radar system called ngRADAR is under development, to eventually be installed at the 100-meter (328 ft.) Green Bank Telescope (GBT) in West Virginia. It will be able to track and map asteroids, with the ability to observe 85% of the celestial sphere. It will also be able to study comets, moons and planets in our Solar System.

“Right now, there is only one facility that can conduct high-power planetary radar, the 70-meter (230-foot) Goldstone antenna that is part of NASA’s Deep Space network,” said Patrick Taylor, the project director for ngRADAR and the radar division head for the National Radio Astronomy Observatory. “We had begun this process of developing a next generation radar system several years ago, but with the loss of Arecibo, this becomes even more important.”

The iconic Arecibo Radio Telescope, before its collapse in 2020: Credit: UCF

Planetary radar can reveal incredibly detailed information about the surfaces and makeup of asteroids, comets, planets, and moons. The ngRADAR system could provide unprecedented data on these objects. In fact, a recent test with a low-power prototype of ngRADAR at the GBT produced some of the highest resolution planetary radar images ever captured from Earth. But the hallmark of the new system will be seeking out near Earth asteroids and comets to evaluate any hazard they might present to our planet. 

“Radar is really powerful in determining the orbits of these asteroids and comets,” Taylor told Universe Today in an interview, “and the new system will deliver very precise data that will allow us to predict where these small bodies will be in the future. That will be one of the highest priority uses for the next generation radar system, where we can track and characterize near-Earth asteroids and comets to evaluate any hazard they might present to Earth in the future.”

A Radar Flashlight

Usually, radio telescopes collect weak light in the form of radio waves from distant stars, galaxies, and other energetic astronomical objects – including black holes or cold, dark objects that emit no visible light. While radio telescopes don’t take pictures in the same way visible-light telescopes do, the radio signals detected are amplified and converted into data that can be analyzed and used to create images. 

But radio telescopes can also be used to transmit and reflect radio light off planetary bodies in our Solar System. This is called planetary radar or Solar System radar.

This collage shows six planetary radar observations of 2011 AG5 a day after the asteroid made its close approach to Earth on Feb. 3, 2023. With dimensions comparable to the Empire State Building, 2011 AG5 is one of the most elongated asteroids to be observed by planetary radar to date. Credit: NASA/JPL-Caltech

What is planetary radar and how does it work?

“Essentially we have a flashlight that works in radio waves,” Taylor explained. “Our narrow flashlight beam does not look at the whole sky, but we point it in a very precise location – the surface of an asteroid or moon. We know very well what our flashlight’s properties are, so we know exactly what we send out. When we receive the echo back from wherever we pointed our flashlight, we analyze that signal and see how it changed compared to what we transmitted.”

That’s what makes planetary radar so powerful and different from any other type of astronomy.  

“When astronomers are studying light that is being made by a star, or galaxy, they’re trying to figure out its properties,” Taylor said. “But with radar, we already know what the properties of the signals are, and we leverage that to figure out the properties of whatever we bounced the signals off of. That allows us to characterize planetary bodies – like their shape, speed, and trajectory. That’s especially important for hazardous objects that might stray too close to Earth.”

In the past, planetary radar has been used to image asteroids, but also precisely measure the position and motion of the planets, allowing us to land spacecraft on Mars and to explore the outer Solar System. The technique has also made surprising discoveries, such as the finding the presence of water ice on Mercury.  

The 70m telescope at the Goldstone Deep Space Communications Complex in California’s Mojave Desert. (NASA/JPL)

Because radio waves are much longer than visible light waves, radio astronomy requires large antennas. The 70-meter Goldstone antenna located in California’s Mojave Desert, is primarily used to communicate with spacecraft as part of NASA’s Deep Space network. But it is also frequently used for planetary radar to study near Earth asteroids, and — as previously mentioned — is the only facility currently available to perform high-power planetary radar. (There are, however, are smaller facilities that can perform planetary radar, including smaller telescopes at the Goldstone site and a few in Australia, but they do not have the same scale of transmitter power as the Goldstone 70-meter dish.) Previously, the workhorse for planetary radar was the 1,000-foot-diameter (305 meters) Arecibo Observatory, which was about 20 times more sensitive and could detect asteroids about twice as far away than the Goldstone 70 meter.

However, because Arecibo’s dish was stationary and built inside a round sinkhole, it was fixed to the Earth and could only view whatever part of the sky happened to be straight overhead. That meant Arecibo’s dish could only see about one-third of the sky. Goldstone is fully steerable, can see about 80 percent of the sky, can track objects several times longer per day, and can image asteroids at finer spatial resolution.

ngRADAR

The Robert C. Byrd Green Bank Telescope is the world’s largest fully steerable radio telescope. The maneuverability of its large 100-meter dish allows it to quickly track objects across its field of view, and see 85% of the sky.

The GBT’s new radar system will introduce a high-resolution tool that will be a vast upgrade, collecting data at higher resolutions and at wavelengths not previously available. Scientists at GBT and the National Radio Astronomy Observatory (NRAO) are also developing advanced data reduction and analysis tools that have not been available before, providing astronomers with unprecedented planetary radar capabilities.

To test out the proof of concept, Taylor and his team worked with the company Raytheon — a long-time developer of radar systems for both the military and science applications — to build a small version of the transmitter, with a lot less power.

“Our friends at Raytheon built a transmitter that could output 700 watts, so about half the power of a microwave oven,” Taylor said. “Ultimately, we want to build a system with 500 kilowatts, so up by a factor of a thousand. But even with 700 watts, we were able to do some really impressive observations.”

Radar image of the Apollo 15 landing site. Credit: Raytheon/NRAO.

GBT’s planetary radar was aimed at the Moon, specifically at the Apollo 15 landing site in Hadley Rille, and at the giant Tycho Crater’s surface, and radar echoes were received with NRAO’s ten 25-meter VLBA antennas. At Tycho, the crater was captured with 5-meter resolution, showing unprecedented detail of the Moon’s surface from Earth. Taylor said the resolution with the ngRADAR prototype approached the optical resolution on Lunar Reconnaissance Orbiter, taking images with its high-resolution cameras from orbit around the Moon.

“The images of the crater floor were actually breathtaking,” Taylor said. “It’s pretty amazing what we’ve been able to capture so far, using less power than a common household appliance.”

A Synthetic Aperture Radar image of the Moon’s Tycho Crater, showing 5-meter resolution detail. Image credit Raytheon.

Additionally, the prototype radar also detected a potentially hazardous asteroid named (231937) 2001 FO32, which happened to be flying past Earth at about six times more distant than the Moon during their radar pings. The asteroid is considered potentially hazardous because of its size, approximately 1 kilometer in diameter, along with how close it can get to Earth, at just over 2 million kilometers away during the observations in 2021. The asteroid’s detection appeared as a spike in their data.

“Just from the spike in our data, we can now figure out how fast this object is moving, determine its orbit, and figure out its trajectory in the future,” Taylor explained. “We can determine its impact risk and assess how much of a hazard it is, and even constrain its spin state, its size, its composition, its scattering properties, and so on. So, even though the data spike doesn’t look like much, that one little detection can tell you a lot of information about the asteroid.”

Radar signals transmitted by the GBT will reflect off astronomical objects, and those reflected signals will be received by the Very Long Baseline Array (VLBA), a network of ten observing stations located across the United States.

“The idea is for GBT is to do the transmitting almost constantly and the VLBA — either all ten of those or any subset of those telescopes — doing the receiving,” Taylor said. “This new system will allow us to characterize the surfaces of many different objects in a different frequency or wavelength that hasn’t been used before.”

Next: Part 2 of this series will look at the details of ngRADAR, the history of planetary radar, and take you up close to the GBT.

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The journal pages of Israel's first astronaut have been added to the country's national library, more than 20 years after they were found among the debris from the tragedy that claimed his life.

A new study shows that hundreds of thousands more Black people in the U.S. would qualify for a lung disease diagnosis and disability payments if lung-function measurements weren’t adjusted for race

The cosmos is brimming with dark energy and other mysterious phenomena

Both expertise and the ability to release one’s focus can help people enter a state of effortless attention

A star in a distant galaxy appears to have been almost torn apart in a close shave with a supermassive black hole, not once but twice – and astronomers hope to see it happen again

A star in a distant galaxy appears to have been almost torn apart in a close shave with a supermassive black hole, not once but twice – and astronomers hope to see it happen again

The James Webb Space Telescope caught the Magellanic-like galaxy NGC 4449 is undergoing an intense bout of star formation.

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Solar storms that create auroras affect Earth’s magnetic field and may cause migratory species, such as many whales and birds, to lose their way

The "Star Trek: Discovery" finale seems to serve chiefly as a launch vehicle for the forthcoming Section 31 TV movie and Starfleet Academy series — and then there's all the other stuff.

Studying gas in the Universe is no easy task. We often look to ‘non-visible’ wavelengths of the electromagnetic spectrum such as X-rays. The Chandra X-Ray observatory has been observing a vent of hot gas blowing away from the centre of the Milky Way. Located about 26,000 light years away, the jet extends for hundreds of light years and is perpendicular to the disk of the Galaxy. It is now thought the gas has been forced away from the centre of the Milky Way because of a collision with cooler gas lying in its path and creating shockwaves. 

The Chandra X-ray observatory was launched by NASA in 1999. Since then, it has been orbiting above the atmosphere, probing space in high energy X-rays. It provides us with stunning, high resolution data that allows us to study black holes, supernova remnants and other high energy events in unprecedented detail. 

Artist’s illustration of Chandra

Using the power of the Chandra telescope to study the centre of our Galaxy, ridges that were perpendicular to the plane of the Milky Way were seen at a distance of 26,000 light years. The team of researchers believe the ridges are the walls of a tunnel that is shaped like a cylinder. The structure helps to funnel hot gas along, much as a chimney does over a fireplace, and away from the centre of the Galaxy. The vent is about 700 light years long and extends away from the core of the Milky Way. 

The structure was previously spotted using earlier data from Chandra but also from the XMM-Newton project too. The radio emission have been detected by the MeerKAT radio array ( based in South Africa this array is made up of 64 receivers ) too and shows the powerful effects of magnetic fields channeling gas along the chimney. Lead scientist Scott Mackey from the University of Chicago said “We suspected that magnetic fields are acting as the walls of the chimney and that hot gas is travelling up through them, like smoke.” He continued “Now we’ve discovered an exhaust vent near the top of the chimney.”

Exploring the Chandra data, the team think the vent formed from a collision as hot rising gas through the tunnel collided with cooler gas. The bright ridges in the walls are thought to be the result of shock waves generated by the collision. The left portion of the tunnel seems brighter because the gas flowing upwards has struck the chimney at a more direct angle and imparted more energy. 

As for the origins of the hot gas, it is thought this is coming from material falling into the black hole at the centre of the Galaxy. As material accretes around the black hole, a series of events can cause material to be ejected from the accretion disk, forcing the gas along the chimney.  X-ray flares are thought to take place every couple of hundred years near the black hole where blasts of X-ray radiation reflects off a build up of hot plasma. These flares are thought to drive the hot gas upwards and out through the vent. 

The diagonal line of bright objects in this image of the heart of our Milky Way Galaxy are all powerful sources of radio waves. The bright center is the home of the supermassive black hole, Sagittarius A*. The dense, bright circles are the nurseries of new, hot stars and the bubbles are the graveyards of exploded, massive stars. The thread-like shapes are not yet understood, but probably trace powerful magnetic field lines. This giant image was assembled from observations made by the Very Large Array (VLA).

One of the outstanding questions requiring extra research is the ultimate driving force behind the energy release. Is it a one off major event like the death of a star as it is ripped apart by the black hole or a series of smaller events that build up? Further studies are needed to fully understand the events at the centre of the Galaxy and to build a fuller picture of the nature of the vent at the centre of the Galaxy. 

Source : NASA’s Chandra Notices the Galactic Center is Venting

The post Hot Gas is Being Vented Away from the Center of the Milky Way appeared first on Universe Today.

As humanity returns to the Moon in the next few years, they’re going to need water to survive. While resupplies from Earth would work for a time, eventually the lunar base would have to become self-sustaining? So, how much water would be required to make this happen? This is what a recently submitted study hopes to address as a team of researchers from Baylor University explored water management scenarios for a self-sustaining moonbase, including the appropriate location of the base and how the water would be extracted and treated for safe consumption using appropriate personnel.

Here, Universe Today discusses this research with Dr. Jeffrey Lee, who is an assistant adjunct professor in the Center for Astrophysics, Space Physics & Engineering Research at Baylor University, and lead author of the study, regarding the motivation behind the study, significant results, the importance of having a self-sustaining moonbase, and what implications this study could have for the upcoming Artemis missions. Therefore, what is the motivation behind this study?

Dr. Lee tells Universe Today, “This paper is actually an eclectic diversion for me from my astrophysics research on primordial black holes, early universe cosmology, breakthrough propulsion physics, and my geophysics research on asteroid impacts. If human missions throughout the Solar System, particularly to Mars, are to be realized, then a permanent lunar facility seems to be a logical early step.”

For the study, the researchers investigated water management requirements for a 100-person self-sustaining lunar base measured at 500 m x 100 x 6 m (1640 ft x 328 ft x 20 ft), including the location of the lunar base near water ice deposits, the technology required to convert the water ice to water vapor (since liquid water can’t exist on the Moon), and the technology required for water treatment and recovery that would result in safe consumption for the 100-person base. The study used the current water usage estimates for American households, which is approximately 100 gallons per day (GPD) per person, which includes cleaning, cooking, drinking, flushing toilets, and washing clothes.

Additionally, the researchers examined the amount of water required for agricultural, technical, and overall needs for the lunar base. Regarding the location of the lunar base, the researchers deduced that the best location for the base would be either near, or exactly on, the Shackleton-de Gerlache Ridge, which is located at 89.9°S 0.0°E, or almost directly on the lunar south pole. The reason this location is ideal for water ice deposits is because Shackleton Crater resides within a permanently shadowed region (PSR), meaning it is shrouded in permanent darkness due to the Moon’s small axial tilt, and water ice has potentially built up over billions of years.

In the end, the team concluded the water requirements for the 100-person lunar base for human, agricultural, and technical needs are 12.3, 72, and 2 acre-feet per year. For context, one acre-foot is equivalent to approximately 326,000 gallons, so a 100-person lunar base would need more than 4,000,000 gallons per year for human needs, more than 23,000,000 gallons per year for agricultural needs, and 652,000 gallons per year for technical needs. So, based on these findings, what were the most significant results from this study, and what follow-up studies are currently in the works or being planned?

Dr. Lee tells Universe Today, “There is good evidence that sufficient water exists on the Moon to support a permanent lunar colony, and the acquisition, treatment, and distribution of the lunar water can be achieved with current technology. An appropriate administrative structure will be necessary to oversee all aspects of lunar water. The relative scarcity and management of water on the Moon can potentially provide insight for improving the management of water on Earth. The next study for my group will be to investigate the ways in which the management of lunar water could help to improve terrestrial water management. However, the timeline for this research is yet to be determined.”

The study discusses in-situ resource utilization (ISRU), which is using available, on-site resources for both sustainability and survivability. In this case, using water ice deposits on the Moon, and specifically near the south pole of the Moon, to meet the water needs of a 100-person, self-sustaining lunar base. The potential for NASA using ISRU has gained considerable traction in the last few years since sending water from the Earth to the Moon could prove to be extremely costly. But aside from the financial risks, if a resupply mission gets delayed or fails on the way to the Moon, the crew could face significant danger. Therefore, learning to “live off the land” for a lunar base could prove to be a viable, long-term option for mitigating the need of resupply missions from Earth. But what additional importance could a self-sustaining moonbase also provide?

Dr. Lee tells Universe Today, “Over the years, there has been a groundswell of excitement at the prospect of colonizing Mars. Indeed, at present, we are conceivably able to mount a short-term human voyage to the Red Planet in which the astronauts would collect samples, conduct experiments, plant flags, and when the next launch window occurs, return to Earth. However, the permanent colonization of Mars is much more ambitious and challenging. Mars is much farther away than the Moon, requiring 9 months to get there and a round trip time of 21 months (a 3-month stay on Mars is needed until the next launch window arrives).”

NASA’s goal is to send humans to Mars through the agency’s Moon to Mars Architecture, which is an elaborate, years-long endeavor to develop the necessary technologies on the Moon for use during a crewed mission to the Red Planet. This includes science, infrastructure, transportation, habitation, and operations, just to name a few. However, as noted, while we can (possibly) send humans to the Red Planet for short-term stays with our current technology, a long-term human presence on Mars would require significantly more time and resources.  

Dr. Lee tells Universe Today, “Beyond low Earth orbit, the Moon is a logical next destination. Lunar colonization is technologically achievable, and in comparison to Martian colonization, it is far easier. Being capable of establishing a moonbase seems like an obvious prerequisite for establishing a Mars base. Furthermore, the Moon would be an excellent jumping off point for further Solar System colonization including potentially the eventual establishment of small colonies in the interiors of Near-Earth Asteroids. Additionally, some have suggested that the Moon is an ideal location from which the interception of Earth-bound asteroids could be conducted.”

This study comes as NASA’s Artemis program plans to land the first woman and person of color on the lunar surface in the next few years. The current landing sites of the Artemis missions are near the south pole to access nearby water ice deposits within the aforementioned PSRs and could be ideal to develop ISRU technologies that can also be used on future Mars crewed missions, as well. Therefore, what implications could this study have for the upcoming Artemis missions?

“Short term lunar visits, such as the planned Artemis missions would not require lunar water,” Dr. Lee tells Universe Today. “In these instances, sufficient water could be brought from Earth. However, if at some point in the future, a lunar colony were to become a priority, future Artemis missions could serve to provide valuable in situ information about the presence and abundance of lunar water, particularly at the lunar south pole and in proximity to the Shackleton Crater (an ideal area for a moonbase).”

How will water management play a role in a self-sustaining lunar base 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 How Much Water Would a Self-Sustaining Moonbase Need? appeared first on Universe Today.

Over the last few months, Universe Today has explored a plethora of scientific fields, including impact craters, planetary surfaces, exoplanets, astrobiology, solar physics, comets, planetary atmospheres, planetary geophysics, cosmochemistry, meteorites, radio astronomy, extremophiles, and organic chemistry, and how these various disciplines help scientists and the public better understand our place in the cosmos.

Here, we will discuss the fascinating and mysterious field of black holes with Dr. Gaurav Khanna, who is a Professor in the Department of Physics at the University of Rhode Island, regarding the importance of studying black holes, the benefits and challenges, exciting aspects of studying black holes, and how upcoming students with to pursue studying black holes. So, what is the importance of studying black holes?

“Gravity is the oldest known, but the least understood force in nature,” Dr. Khanna tells Universe Today. “For students of gravity, black holes are amongst the most interesting objects to study because gravity is the dominant force there — in fact, it is infinitely strong! Then there are astrophysical reasons of interest in black holes. They play important roles in galaxies, perhaps even in the large-scale behavior of the universe and more. The other thing to note about black holes is that they are very ‘simple’ especially when compared to stars and other astrophysical objects. This is a consequence of the so-called ‘no hair’ theorem that states that black holes can be fully characterized by only 3 attributes — their mass, charge and spin. That simplicity makes them particularly appealing to study and research.”

Black holes are known for exhibiting gravity so strong that light can’t even escape, and while Albert Einstein’s theory of general relativity in 1915 is often credited with first proposing the concept of black holes, the concept of an object whose size and gravity would not allow light to escape was first proposed in a November 1784 letter by English philosopher and clergyman, John Mitchell. In this letter, Mitchell referred to these objects as “dark stars” since he postulated that stars whose diameters exceeded 500 times that of our Sun’s diameter would trigger the formation of these objects. Additionally, he suggested that gravitational waves influencing nearby celestial bodies would enable these objects to be detected.

Fast forward to Einstein’s theory of general relativity, which also predicted both the existence of black holes and gravitational waves, both of which continued to be scrutinized throughout the 20th century, which includes what’s called the “golden age of general relativity” during the 1960s and 1970s. This includes the first object accepted by the scientific community as a black hole, called Cygnus X-1, which was discovered in 1964. However, it took another 52 years for the existence of gravitational waves to be confirmed through a black hole merger, which was accomplished by the LIGO Scientific Collaboration. Therefore, given the extensive history combined with key discoveries only occurring within the last few years, what are some of the benefits and challenges of studying black holes?

Dr. Khanna tells Universe Today, “As I stated above, studying black holes, which are a consequence of Einstein’s relativity theory, offers insight on the nature of gravity, space and time at the most fundamental levels. As physicists, we are yet to develop a complete understanding of the quantum nature of gravity, and black holes are the key to unlocking that mystery. On the challenges, I’d say that the clearest one perhaps is that black holes can only be observed indirectly. Unlike stars, since they don’t emit radiation themselves, it is difficult for astronomers to collect data on them. At best, we can observe their influence on their environment (like gas, stars, etc.) and infer their properties and behavior. On the theoretical side, while it is indeed true that black holes are very “simple” compared to stars, there are still challenges. The mathematics and physics that describe them is fairly advanced and even computer simulations involving them are challenging requiring massive processing power and memory.”

While it took over 100 years between Einstein introducing his theory of general relativity in 1915 and the confirmation of gravitational waves in 2016, it only took another three years for astronomers to publish the first direct image of a black hole at the center of the Messier 87 galaxy. The results were published in The Astrophysical Journal Letters and based on observations taken in 2017 by the powerful Event Horizon Telescope (EHT). While Messier 87 is located approximately 53 million light-years from Earth, the closest hypothesized black hole, Gaia BH1, is located approximately 1,560 light-years from Earth. In 2022, astronomers published a direct image of Sagittarius A*, which is the supermassive black hole at the center of our Milky Way Galaxy.

Additionally, scientists hypothesize the number of black holes in our Milky Way Galaxy is in the hundreds of millions, despite only a few dozen known black holes having been confirmed, thus far. But what are the most exciting aspects about black holes that Dr. Khanna has studied during his career?

Dr. Khanna tells Universe Today, “I suppose I’d probably refer to my recent work on how very rapidly rotating black holes attempt to ‘grow hair’ but ultimately fail. The project is interesting because it appears to suggest a violation of the ‘no hair’ theorem that I mentioned earlier, but it ultimately doesn’t. So, it is provocative, but then relieving! More importantly, we are now using the main context of that research to develop a new observational ‘signature’ or test for rapidly rotating black holes, a.k.a. near-extremal black holes. Such black holes have several peculiar properties and aspects and are an area of active research.”

Black holes are studied by astronomers, physicists, and astrophysicists, who use a combination of theory and observations to construct what black holes might look like, and in rare cases, as discussed, obtain direct images of them. Regarding theory, researchers use mathematical calculations and computer models to simulate what black holes might look like, and then have used powerful ground-based telescopes like EHT to obtain the few direct images of black holes. It is important to note that these direct images don’t capture the black hole itself, but the gases that are encircling the black hole’s event horizon, or the unofficial boundary where light can’t escape the black hole. But what advice can Dr. Khanna offer upcoming students who wish to pursue studying black holes?

Dr. Khanna tells Universe Today, “I would offer them a lot of encouragement! There is a lot to do in this space and many mysteries to solve. New observations are going to open many new doors and brand-new avenues for research. This is amongst the best times to be a black hole astrophysicist!”

Dr. Khanna continues, “The one thing that I could say perhaps that isn’t as much emphasized elsewhere is about computing as a tool to study black holes. Mostly there is heavy emphasis on learning advanced mathematics as the background for serious research in black holes — and for good reason — that continues to be critical for every student of Einstein’s relativity theory which is the foundation for black hole physics.  In recent years, computer simulations have advanced rapidly, and one can now make major discoveries about deep questions using computational tools. In the long run, computer programming would be a very promising tool for advancing research in this field and many others as well.”

How will black holes help us better understand our place in the universe 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 Black Holes: Why study them? What makes them so fascinating? appeared first on Universe Today.

Dyson Spheres have been a tantalising digression in the hunt for alien intelligence. Just recently seven stars have been identified as potential candidates with most of their radiation given off in the infrared wavelengths. Potentially this is the signature of heat from a matrix of spacecraft around the star but alas, a new paper has another slightly less exciting explanation; dust obscured galaxies. 

There are a number of ways to hunt for aliens and one of them is to look for signs of large scale projects in space. Enter the Dyson Sphere. The idea was first proposed by Freeman Dyson in 1960 to describe that an advanced civilisations would position power collectors and even habitats around a star to harness its power. Eventually such infrastructure would likely surround the entire star and Dyson reasoned that a signature would be detectable such as an excess of infrared radiation. 

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)

The findings of Project Hephaistos revealed the seven M type stars from a sample of 5 million stars detected by Gaia. The astrometric satellite has been used to map stars in the Milky Way and has been of profound benefit to many pieces of research. Data from 2MASS (the Two Micron All Sky Survey) and WISE (the Wide Field Infrared Survey Explorer) were also used to identify the stars that seemed to display the expected Infrared excess. 

Artist’s impression of the Gaia spacecraft detecting artificial signals from a distant star system. In this synchronization scheme, the star system’s inhabitants send the signal shortly after witnessing a supernova, which is also seen by telescopes on Earth. (Credit: Danielle Futselaar / Breakthrough Listen)

In the recent paper by lead author Tongtian Ren and team, they explore the findings of the project and delve into the possible nature of the candidate spheres. The team cross-matched the information from data from the Very Large Array Sky Survey (VLASS) and several other radio surveys of the sky. They searched for radio sources within a radius of 10 arc seconds of the Gaia positions of the candidates. Note that the full Moon is 1,860 arc seconds across. 

Radio sources were found for three of the candidates, those named A, B and G. The accuracy of the sources was within 4.9, 0.4 and 5 arc seconds respectively and candidate G was found in multiple radio surveys. The conclusion from the team is that the seven stars are less likely to be Dyson Spheres but instead some sort of extra galactic phenomenon. The most likely explanation is a distant galaxy obscured by dust! The presence of the dust would contaminate the Infrared energy distribution in the spectra of the two objects. The other candidate, candidate B is also thought to be a distant galaxy but one that was within very close line of sight of an M type dwarf star. 

Very similar to candidates A and B, candidate G has a spectrum that reveals a radio loud active galactic nuclei with superluminal jets extending out. It is likely that galaxies are distant quasars which emit enormous amounts of radiation, but the obscuring hot dust clouds obscure most radiation, except infrared. 

What of the other four candidates? To date, no matching radio source has been found. That does not mean the hot, dust obscured galaxy model is not an adequate explanation but just that possible higher resolution radio surveys are required. Of course it may also be that they really are spheres of technology around distant stars. As much as I would love that to be true, there is no evidence for this yet. 

Source : Background Contamination of the Project Hephaistos Dyson Spheres Candidates

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