Tag Archives: Astronomers

Astronomers Find Supermassive Black Hole Wandering Around Distant Galaxy

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Can a supermassive black hole have wanderlust? That’s something astronomers have been wondering about for years, and a new study from the Harvard and Smithsonian Center for Astrophysics might have arrived at an answer: yep. By comparing the movement of black holes and their surrounding home galaxies, the researchers discovered one that appears to drift around. This could resolve some long-standing questions about the nature of these enormous dead stars. 

Supermassive black holes are usually found in the centers of galaxies, and they don’t have a reputation for moving around much. After all, they weigh as much as millions or billions of suns! It takes a lot of energy to get something that big moving, but the monster black hole in spiral galaxy J0437+2456, some 228 million light-years away, is almost definitely mobile. 

To spy on black holes, the team used a technique called very long baseline interferometry that relies on networks of radio telescopes. This technique allows scientists to measure the velocity of distant objects, but black holes don’t emit detectable radiation. That’s why the team focused its efforts on a class of active galactic nuclei known as megamaser — supermassive black holes with an accretion disk of material swirling around them. There are several molecules in megamasers that can be measured with high accuracy, including water. 

The M87 supermassive black hole imaged in 2019.

The analysis included 10 megamaser-type galaxies, and nine of them came up normal — the galaxy and the black hole are moving at the same velocity. However, J0437+2456 (top) showed a ton of variation. The neutral hydrogen floating around in the galaxy was moving away at 4,910 kilometers per second, but the water molecules in the black hole’s disk were only moving at 4,810 kilometers per second. What’s more, the inner part of the galaxy is moving at 4,860 kilometers per second. All those different velocities make for a very wobbly galaxy. 

There are several possible explanations for this wobble, including a past collision with another supermassive black hole. It’s also possible the varying velocity is due to another unseen supermassive black hole in a binary system. Scientists believe binary systems like this should exist, but there’s very little observational evidence. In either case, this galaxy could teach us a lot about black holes. It’s also feasible that the galaxy has been disrupted by a nearby massive object like another galaxy. That would be less interesting, but it would still show that central black holes can be nudged off course. The team plans to conduct more observations of J0437+2456 in hopes of figuring out which it is. 

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Astronomers Detect Another Possible Exoplanet Right Next Door

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In the last few decades, we’ve gone from zero known exoplanets to more than 4,000. Scientists have even found a few orbiting the closest stars to our own. A project called Near Earths in the Alpha Center Region (NEAR) has just spotted tantalizing signals that could point to a planet in the habitable zone of Alpha Centauri, which is a mere 4.37 light years away. That’s right next door in astronomical terms. 

Our solar system is pretty simple — one star, and a whole mess of planets orbiting it. Centauri is a bit different and consists of three stars. For starters, there’s Proxima Centauri, which is a red dwarf that sits a fraction of a light year closer to Earth. Proxima orbits Alpha Centauri A and B, which are larger, warmer stars like the sun. We know of at least two exoplanets orbiting Proxima Centauri, but a world around the sun-like members of the system would be even more interesting, and there might be one. 

The NEAR team used the European Southern Observatory’s Very Large Telescope (VLT) in Chile to check out our celestial neighbors. The project pushed for an upgrade to the VLT that included an instrument called a thermal chronograph. This allows astronomers to block out the light from a star to make faint thermal signals easier to detect. After more than 100 hours of cumulative observations, the researchers pinned down what appears to be a thermal signal in the habitable zone of Alpha Centauri A. No one is willing to say this is definitely a planet, but it could be. 

The possible exoplanet is labeled here as C1.

The exoplanet, if it exists, is in the habitable zone of the star. That means it could have liquid water, and therefore, the possibility of life. Early analysis suggests the exoplanet is a bit smaller than Neptune. That could mean it’s a small gas giant or possibly a very large rocky planet. If it’s a gas giant, life as we know it is off the table. However, there could be moons orbiting the world that have both liquid water and a solid surface on which life could evolve. 

There’s still more work to do before we can add another exoplanet to the list. The team notes the thermal signal could have other explanations, like a region of unusually hot cosmic dust or a warmer, distant object in the background. We’ll need more sophisticated instruments to know for sure. Luckily, the James Webb Space Telescope might finally launch later this year. Its infrared instruments should be able to determine if the thermal signature around Alpha Centauri A is a planet or just background noise.

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Astronomers Find Oldest Supermassive Black Hole in the Universe

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Astronomers have discovered about 750,000 quasars, which are among the brightest and most energetic objects in the universe. Despite its uninspiring designation, J0313-1806 is distinct from other quasars. This recently spotted object is the oldest known quasar in the universe, with a supermassive black hole more than 13 billion years old. In fact, it’s so old and huge that scientists don’t know exactly how it could have formed. 

The first quasars were discovered in the mid-20th century, but it wasn’t until several decades later that we began to understand what these objects were. A quasar is an active galactic nucleus in which the supermassive black hole that anchors the galaxy pulls in matter to form a gaseous accretion disk. All this matter colliding as it spirals into the black hole releases a torrent of electromagnetic energy that serves as the hallmark of these objects. J0313-1806, for example, shines 1,000 times brighter than our entire galaxy. 

J0313-1806 is far away — 13.03 billion light-years to be exact. That means we’re seeing this object as it was just 670 million years after the Big Bang, and it’s still huge. Astronomers estimate J0313-1806 to have about 1.6 billion solar masses as its observed age. That’s not out-of-line for a supermassive black hole elsewhere in the universe, but they’ve had longer to vacuum up matter and grow larger. J0313-1806 shouldn’t have had time in the early universe to grow so large. 

The team used ground-based instruments like the Atacama Large Millimeter/submillimeter Array (ALMA) and the Mauna Kea Observatories (MKO) to spot J0313-1806 last year. It unseated the previous record-holder for oldest quasar, which is about 20 million years younger. Current models of black hold formation assume a star collapses to form a singularity, but the “seed mass” for J0313-1806 would have had to be at least 10,000 solar masses to reach 1.6 billion so quickly. 

The M87 supermassive black hole imaged in 2019.

The study puts forward a hypothesis to explain the existence of this bizarre quasar, known as the direct collapse scenario. In this model, it wasn’t a star collapsing that formed the supermassive black hole. Instead, an enormous cloud of cold hydrogen gas collapsed inward to form a much larger black hole than any stellar source could produce. This could explain why astronomers see so many gigantic black holes in the early universe. 

Unfortunately, J0313-1806 is so distant that we can’t gather much more detail with current technology. The upcoming James Webb Space Telescope could, however, be sufficiently precise to image objects like J0313-1806. After many years of delays, NASA plans to launch the Webb telescope in late 2021.

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Astronomers Spot Potentially Artificial Radio Signal From Nearby Star

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(Credit: sharply_done/Getty Images)
In 2015, Billionaire Yuri Milner launched the Breakthrough Listen project, an effort to scan the million closest stars for radio signals that could indicate intelligent life. Astronomers working on the project have announced the discovery of just such a signal from Proxima Centauri, which is just 4.2 light years away. We don’t yet know what this signal is, but there’s a (very) small chance it could have alien origins. 

Breakthrough Listen uses radio telescopes like the Parkes telescope in Australia or the Green Bank Observatory in West Virginia. These instruments regularly record what look like signals from space but are actually due to local interference from Earth. In April and May of 2019, the team caught something different — a narrow beam transmission around 980MHz that lasted 30 hours. The signal, dubbed BLC1, also appeared to shift in such a way that it could have been coming from a planet orbiting the star.

The team is still preparing a paper that the scientific community can scrutinize, but there are a few reasons to be excited here. Proxima Centauri is the closest star to our solar system, and in 2016, researchers announced the discovery of an Earth-like exoplanet orbiting in the habitable zone. Later, astronomers spotted a second, larger planet farther out in the solar system. So, it’s theoretically possible there’s life on one of those planets, particularly the one in the habitable zone. 

The Green Bank Telescope used by Breakthrough Listen.

However, it’s still far too early to start celebrating the discovery of alien life. BLC1 is a candidate signal that needs to be analyzed, and if we’re being realistic, it’s doubtful that intelligent aliens live in the next solar system over. The Milky Way galaxy has an estimated 300 million exoplanets and is almost 14 billion years old. To find another intelligent species existing at the same time as us just a few light years away would be exceedingly improbable. If said aliens are also using radio frequency technology at the same time as we are, that’s an even bigger coincidence. 

This is not the first signal that could be interpreted as having artificial origins. The famous “Wow” signal detected in 1977 by SETI researchers is another example. That one didn’t pan out, but BLC1 could be the first serious contender in decades. If this isn’t it, well, there are a lot more stars out there. The only way we’re going to find them is to keep looking. 

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Astronomers Have Detected a Planet’s Radio Emissions 51 Light-Years Away

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Astronomers have detected thousands of exoplanets, but there’s only so much we can know about them from light-years away. A new study from Cornell University could help shed light on the conditions of exoplanets by analyzing radio emissions connected to their magnetic fields. The researchers claim this marks the first time an exoplanet has been detected in the radio bands

This project started with the study of Jupiter, which has a hugely powerful magnetic field. Several years ago, study lead author Jake Turner conducted an analysis of Jupiter’s magnetic field. In the new study, that data becomes the basis for hunting exoplanets. The team processed the Jupiter data to simulate the radio frequency signal from a distant gas giant. 

The results became a template for similar planets that might be 40 to 100 light-years away from the observer. Using the Low Frequency Array (LOFAR), the team scanned several nearby solar systems that are known to host exoplanets. If the signals from one of these stars matched the template, that would indicate they’d found an exoplanet’s emissions in the radio spectrum. 

It took more than 100 hours of observational time, but a star known as Tau Boötes 51 light-years distant exhibited exactly the kind of signal the researchers were hoping to find. Turner and his colleagues even used other radio telescopes to repeat the analysis, and the signal is still there. And that makes sense — Tau Boötes has one known exoplanet, a gas giant called Tau Boötes b that orbits very close to the star. 

The LOFAR radio telescope.

According to the researchers, the signal is understandably very weak. There were several other stars with radio pings that could have been planets, but the one in Tau Boötes was much more significant. The team is now calling on other researchers to confirm the findings — data on an exoplanet’s magnetic field could be invaluable, but it’s still possible the signal is coming from the star or some other local source rather than the planet. 

The researchers say that the magnetic field of a planet can offer hints of composition and habitability. For example, Earth’s magnetic field is a product of the planet’s iron core, and the field helps deflect dangerous radiation that can harm living things and strip away a planet’s atmosphere. Mars’ lack of a magnetic field is believed to be one of the reasons it’s so inhospitable. After confirming and refining Turner’s results, astronomers might be able to learn about distant worlds by scanning for radio frequency emissions.

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Astronomers Might Finally Know the Source of Fast Radio Bursts

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We know much more about how the universe works today than we did just a few decades ago, but there will always be new mysteries to solve. In recent years, scientists have puzzled over the riddle of fast radio bursts (FRBs). These short-lived electromagnetic beacons can outshine entire galaxies, and we haven’t been able to figure out what causes them. A trio of new studies report on an FRB within our own galaxy. Because this one was so much closer than past signals, scientists were able to track it to a particular type of neutron star known as a magnetar

Despite the immense amount of energy emitted during an FRB, scientists didn’t know they existed until 2007. That’s when a team discovered the first FRB hiding in data acquired back in 2001. Since then, astronomers have spotted numerous FRBs throughout the cosmos. However, this phenomenon seemed to be non-repeating until the discovery of FRB 121102. We now believe this radio source operates on a 157-day cycle, which makes it easier to study. 

With the data from FRB 121102, magnetars merged as a plausible candidate. Like pulsars, magnetars are a subset of neutron stars. They don’t spin as quickly as a pulsar, but they have an incredibly intense magnetic field. At about a trillion times as strong as Earth’s magnetic field, a magnetar can disrupt the electron orbitals in molecules, essentially halting chemistry in any normal matter that gets too close. 

magnetars head

That brings us to SGR 1935+2154, a magnetar about 30,000 light-years away. That’s not close by any means, but it’s still inside the Milky Way. Back in April, this dead star woke up and began firing off high-energy photons, which was normal. However, two instruments were on the hunt for FRBs at the same time, and that’s what they found exactly when SGR 1935+2154 lit up the sky. Both the Canadian Hydrogen Intensity Mapping Experiment (CHIME) and Survey for Transient Astronomical Radio Emission 2 (STARE2) detected an FRB from this object. 

We can’t call this one solved quite yet, though. As the researchers point out in the papers, the apparent FRB from SGR 1935+2154 was only about one percent as powerful as the FRBs we’ve seen from outside the galaxy. It’s possible only very young and energetic magnetars can produce bursts visible from a few galaxies away. Perhaps SGR 1935+2154 is displaying the same phenomenon at a lower level of power. If the team can prove that this object produced FRBs, we can refine our models and hopefully mark this one down as solved.

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Astronomers Spot Earth-Sized Rogue Planet Wandering the Galaxy

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Astronomers have identified more than 4,000 exoplanets orbiting other stars but just a few “rogue planets” wandering the galaxy without a star to call home. A new study claims to have spotted one of these worlds, and it may be a small, rocky world like Earth. If confirmed, the planet known as OGLE-2016-BLG-1928 would be a major milestone in our efforts to spot these unattached worlds. 

While scientists believe rogue planets are common throughout the universe, they’re very difficult to find. We currently lack the technology to directly image exoplanets in most instances, so we can only locate them by observing the stars they orbit. The dearly departed Kepler Space Telescope single-handedly detected more than 2,500 exoplanets, and that number continues to rise as scientists analyze its data. Kepler used the transit method, which involves watching stars for dips in brightness as a planet passes in front of them. Scientists have also used radial velocity measurements of stars to look for small wobbles caused by the mass of planets. 

Without a host star, spotting planets gets a lot harder. The Optical Gravitational Lensing Experiment (OGLE) project found the potential rogue planet using gravitational microlensing, which superficially similar to the transit method. This approach monitors the light from a distant star in hopes a massive object like a planet will pass in front of it. While the star and planet may be many light-years away, the planet bends or “lenses” the star’s light from our perspective on Earth. This can reveal the foreground object’s mass and size, but only if you happen to be looking in the right place at the right time. 

This light curve indicates a massive object passed in front of the star.

Andrzej Udalski of the OGLE project notes that you could watch a single star for a million years and only see a single lensing event. Luckily, Udalski and his team didn’t have to go one star at a time. They used the Las Campanas Observatory in Chile, which scans millions of stars in the direction of the galactic center on a daily basis. In analyzing this data, the OGLE team spotted a lensing event dubbed OGLE-2016-BLG-1928. At just 42 minutes long, it’s the shortest such detection ever recorded. That suggests the planet, if indeed that’s what it is, would be somewhere between the size of Earth and Mars. 

The team believes this object is a rogue planet because there are no known stars to which it could be connected. The data also showed no light sources within eight astronomical units of the lensing event. Other researchers will need to confirm this object is a planet before it goes in the history books, but if current theories are right, there are uncountable millions of similar objects out there just waiting to be discovered.

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Astronomers Directly Image Planet 63 Light-Years Away

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The last few decades of astronomical surveys have revealed several thousand exoplanets in the cosmos, but very few have ever been seen directly. We can only infer the presence of most exoplanets from their gravity or ability to block starlight. However, researchers using the Very Large Telescope (VLT) in Chile recently turned it toward a star 63 light-years away called Beta Pictoris to hunt for a gas giant (Beta Pictoris c), and they snapped an image of it

Our current level of technology makes it almost impossible to image exoplanets directly. Compared with stars, planets are so dim that we usually can’t resolve them in the halo of light. Beta Pictoris c joins a list of less than two-dozen extrasolar worlds (including Pictoris b) that scientists have spied directly, and some of those are still highly contentious. 

Scientists were able to get this new image thanks to all the interest in the Beta Pictoris system over the years. Beta Pictoris c and its sibling world Beta Pictoris b are less than two million years old. Pictoris b was discovered via direct imaging, which again, is quite rare. However, anomalies in its radial velocity prompted astronomers to look closer. Radial velocity analysis is a less common way of detecting exoplanets that relies on using telescopes to detect small wobbles in stars caused by the gravity of their planets. Just last year, a team discovered Beta Pictoris c while attempting to explain those anomalous radial velocity readings. 

The newly imaged Beta Pictoris c alongside Beta Pictoris b.

As a result of this planet-hunting endeavor in Beta Pictoris, scientists had an excellent data set describing the motion of these exoplanets. That’s exactly what the ExoGRAVITY team, led by astronomer Mathias Nowak of the University of Cambridge, needed to get started. Nowak’s effort uses the GRAVITY interferometer on the VLT to study exoplanets, and the wealth of data on Beta Pictoris helped the team know just where to look for Beta Pictoris c. All four VLT telescopes scanned the alien solar system, feeding data into a “virtual telescope” that combines them for a sharper image. And that’s how we ended up with an image of Beta Pictoris c, one of the first exoplanets studied via both direct imaging and radial velocity. 

There are still some mysteries to unravel in Beta Pictoris, though. The light from Beta Pictoris c is six times fainter than Pictoris b. However, Pictoris c is eight times the mass of Jupiter, so how big is Pictoris b? We thought it was just a little larger than Pictoris c, but it’s going to take more research to figure out exactly what’s going on here. That won’t be a problem — with two visible exoplanets, Beta Pictoris will be a target for plenty of astronomers. 

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Astronomers Spot Ancient Galaxies in a Supermassive Black Hole ‘Spider Web’

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The speed of light is a major inconvenience when you’re trying to land robots on another planet, but it’s a big help if you want to study the history of the universe. By peering into the far-away reaches of the cosmos, astronomers can see what the universe looked like millions or billions of years ago. A team using the European Southern Observatory’s (ESO) Very Large Telescope has spotted something unexpected: a cluster of six ancient galaxies caught in the gravity of a supermassive black hole. 

This study, led by astronomer Marco Mignoli from the National Institute for Astrophysics in Italy, sought to shed light on how objects like supermassive black holes could have developed in the early universe. To that end, the team used the Very Large Telescope (VLT) to scan a part of the universe more than 12 billion light years away. These objects, therefore, appear as they were just 900 million years after the Big Bang. 

In this early era of the universe, there would have been very few stars old enough to collapse into black holes. Astronomers have also struggled to explain how a black hole could accumulate so much mass in such a short time to become “supermassive.” The latest VLT discovery could help explain that. The central black hole discovered in this complex system had a mass of about a billion suns, and the galaxies surrounding it are embedded in a “spider’s web” of gas. The web crisscrosses a region of space more than 300 times the size of the Milky Way. 

According to the study, the team believes these streams of gas would have acted as conduits that allowed gas to move freely between the galaxies and the black hole. This could have supplied the singularity with all the matter it needed to bulk up in just a few hundred million years.

Assuming this study is accurate, we still need to figure out how this web of gaseous filaments formed. The team speculates dark matter might be the key. We know that this invisible material has gravitational effects on other matter, and many scientists believe it could have attracted large volumes of gas in the early universe. Could the galactic tendrils observed with the VLT have been bound together by dark matter? Maybe, according to Colin Norman of Johns Hopkins University. “Our finding lends support to the idea that the most distant and massive black holes form and grow within massive dark matter halos in large-scale structures, and that the absence of earlier detections of such structures was likely due to observational limitations,” he said. 

This study involved some of the dimmest objects visible with our current technology. It took many hours with the largest telescopes on Earth to gather data on the web of gas around this black hole. More powerful telescopes like the upcoming ESO Extremely Large Telescope and the James Webb Space Telescope might get us the rest of the way there.

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Astronomers May Have Detected a Planet in Another Galaxy

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Humanity spent years wondering if there were planets outside our solar system, and now we know the answer: very much yes. There are thousands of exoplanets in just our little corner of the galaxy, and there’s every reason to expect the same is true of other galaxies. In fact, a researcher from the Harvard-Smithsonian Center for Astrophysics has found strong evidence of a planet orbiting a pair of stars in the distant M51 galaxy. It’s not the first potential extragalactic planet detection, but it’s shaping up to be the most likely candidate. 

We lack the technology to image exoplanets directly (usually), even when they’re right next door in Proxima Centauri. Planets are so dim compared with the stars they orbit that we can only infer their presence by the way they affect the star’s gravity (radial velocity) or luminance (transits). Most exoplanets have been detected by the transit method, which involves watching for dips in brightness caused by planets passing in front of their host stars. That’s very similar to what astronomers did to spot the M51 planet candidate, which they’ve dubbed M51-ULS-1b. 

Past detections of extragalactic planets have relied on gravitational lensing, but M51-ULS-1b was detected via what appears to be an X-ray transit. However, that’s only possible because it’s orbiting a very strange pair of stars. It’s a perfect storm; M51-ULS-1 is a binary system, and one element of it is a neutron star or black hole that’s devouring a nearby star. That makes M51-ULS-1 a very bright, compact source of X-rays. In 2012, the Chandra X-ray Observatory was scanning M51, also known as the Whirlpool Galaxy, when the X-ray signal from the M51-ULS-1 system dipped. No one was watching for this, so it went unnoticed until just recently when Rosanne Di Stefano at the Harvard-Smithsonian Center took a closer look

Upon further analysis, the drop in X-ray brightness was symmetrical and lasted about three hours. It was very similar to the brightness changes seen when an exoplanet passes in front of a nearby star. One possible explanation for this is that a Saturn-sized planet in this solar system obscured the signal as it orbited to binary. Di Stefano and her team note that other options like a white dwarf transiting the system don’t match what we know about this part of the Whirlpool Galaxy. 

It’s going to be difficult to confirm M51-ULS-1b is an extragalactic planet. After all, the M51 galaxy is 23 million light-years away. Even instruments like the James Webb Space Telescope will struggle to resolve details that far away. However, teams around the world may start developing techniques to detect M51-ULS-1b and similar extragalactic planets. It may just be a matter of time until we have a confirmed planet in another galaxy.

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