Universe Today

April 2, 2008December 24, 2015 by Nancy Atkinson

Jobs Eliminated as Shuttle Program Transitions to Constellation

As the space shuttle program winds down and NASA transitions to the new Constellation program, more than 8,000 NASA contractor jobs in the manned space program could be eliminated after 2010, the U.S. space agency said at a press briefing on April 1, 2008. A NASA report sent to Congress predicts that between 5,700 and 6,400 jobs will be lost at the Kennedy Space Center, where the shuttle processing takes place, before 2012. After that time, a few hundred jobs will be added yearly as the new moon-landing program gets started, with the first Constellation launch tentatively scheduled for 2015. Some NASA managers believe that an update to Tuesday’s report, which is due to Congress in six months, won’t be quite so bleak, but NASA said it could be more than a year before it has more dependable job forecasts.

The most dramatic job cuts will be among private contractors. Bill Gerstenmaier, NASA associate administrator said that the estimates of job losses were preliminary and they do not take into account numerous factors of potential workload. “Don’t overreact to these numbers,” he said.

The report stated “Our (NASAâ€™s) greatest challenge over the next several years will be managing this extremely talented, experienced and geographically dispersed workforce as we transition from operating the space shuttle to utilizing the International Space Station.â€

Nationally, NASA said the number of full-time civil servants in its manned space program would fall to about 4,100 in 2011, a loss of about 600 jobs from this year. Including outside contractors, the number of jobs would fall to an estimated 12,500 to 13,800. About 21,000 are currently employed.

Rick Gilbrech, NASA associate administrator for exploration systems, said that many future contracts for the Constellation program to develop the new moon rockets and spacecraft to replace the shuttle fleet, could improve the local NASA jobs picture.

“There’s a lot of work that’s not folded into these numbers,” he said.

Gilbrech added that the next U.S. president and Congress might not support the Constellation program, which is President Bush’s vision for returning to the moon and going on to Mars.

“We do need stable support and long-term commitment,” he said.

KSC Director Bill Parsons said Tuesday he estimates the center’s 15,000 on payroll will drop to 10,000 people in the next few years before starting to climb slowly. He said, however, that there is hope that layoffs might be rare because up to one-third of KSC workers are eligible to retire before or around the time that the shuttle program ends in 2010. He does not expect workers to abandon their jobs for new careers before then.

“This is not a work force that panics,” he said, referring to the recovery from two shuttle accidents.

Retirement will provide a easier transition for some. However, younger workers may have to redirect their careers into the Constellation program. Those caught in the middle might have to learn new skills or relocate to avoid being laid off. There are also other ripple effects to other non-technical support jobs.

Original News Sources: Space.com, Florida Today

April 2, 2008December 24, 2015 by Tammy Plotner

Meteor Shower… On Mars!

What’s that? Another meteor shower we can’t possibly see? Of course you can. All you need to view this meteor shower is a backyard on Mars! A team of scientists led by Armagh Observatory have, for the first time, detected a storm of shooting stars on Red Planet.

What happens when the orbit of Mars intersects with debris from comet 79P/du Toit-Hartley? Scientists were hard at work making predictions. The detections were then cross-referenced with observations of activity in the Martian ionosphere by NASA’s Mars Global Surveyor (MGS) satellite. Says Dr. Apostolos Christou:

“Just as we can predict meteor outbursts at Earth, such as the Leonids, we can also predict when meteor showers are going to occur at Mars and Venus. We believe that shooting stars should appear at Venus and Mars with a similar brightness to those we see at Earth. However, as we are not in a position to watch them in the Martian sky directly, we have to sift through satellite data to look for evidence of particles burning up in the upper atmosphere.”

We’re all familiar with the cause of most meteor showers. They happen when a planet (and not always ours!) passes through the debris trail left by a comet as it moves along its orbital path. The material lets us glimpse into the age, size and composition of particles ejected from the comet’s nucleus, the speed at which it was thrown off, as well as general information about the structure and history of the comet itself. Oh, to be a comet watcher on Mars! About four times as many comets approach the orbit of Mars than the Earth’s and the greatest majority of these are Jupiter Family Comets.

Studying Martian meteor showers can definitely improve our understanding of meteor showers and the Jupiter Family Comets as well. JFC are short period comets with an orbital period of less than 20 years. Their orbits are controlled by Jupiter and many are believed to originate from the Edgeworth-Kuiper Belt, a vast population of small icy bodies that orbit just beyond Neptune. Famous JFCs include Comet 81P/Wild 2, which was encountered by the Stardust spacecraft in January 2004 and Comet Shoemaker-Levy 9, which broke up and collided with Jupiter in July 1994.

When meteor particles burn up in a planet’s atmosphere, metals contained within them are ionised to form a layer of plasma. On Earth, this layer has an altitude of approximately 95-100 kilometres and on Mars the layer is predicted to be around 80-95 kilometres above the Martian surface. Meteor showers leave a narrow layer of plasma superimposed on top of the main plasma layer, caused by meteors that are general debris from the Solar System. Dr. Christou and his colleagues developed a model to predict meteor showers caused by the intersection of Mars with dust trails from comet 79P/du Toit-Hartley. From the model, the team identified six predicted meteor showers since the MGS satellite entered into orbit around Mars in 1997. Although the metallic ions cannot be observed directly by MGS instruments, evidence for the plasma layer can be inferred by monitoring electron density in the Martian atmosphere using the spacecraft’s radio communication system.

Just like earthly meteor showers, we can predict all we want – but sometimes we draw a blank. In this instance only one of the six predictions came true. In the April 2003 data, the team found that an ionospheric disturbance appeared at the exact time of the predicted meteor outburst. The height of the disturbance corresponded with the predicted altitude for the formation of the metallic ion layer and its width and multi-peaked shape were similar to structures observed in the Earth’s ionosphere linked to the Perseid meteor shower.

For the 2005 data, no features were observed near or immediately after the predicted meteor shower. Dr Christou says, “We speculate that we don’t see anything in the 2005 data because the meteors burned up deeper in the atmosphere where their ionisation is less efficient. If we are going to get a clear picture of what is going on, we need more optical and ionospheric observations of meteor showers at both the Earth and Mars so we can establish a definitive link between cause and effect. Equally importantly, we need further observations of Martian meteor showers, either from orbit or from the planet’s surface, to confirm our predictions. Finally, we need to improve our prediction model by tracking more comets that might cause meteor showers on Mars.”

Dr Christou is now investigating the possibilities of making observations with Europe’s ExoMars mission, which is due to land on Mars in 2015.

April 2, 2008December 24, 2015 by Ian O'Neill

Lumpy Neutron Stars can Generate Gravitational Waves

A new simulation of neutron stars suggest they may not be as smooth as predicted. The rapidly spinning exotic bodies may have significant topological features like mountains. These “lumps” on the star’s surface may cause fluctuations in space-time as the variation of the huge gravitational field varies on each spin. This fluctuation may generate gravitational waves, propagating into the cosmos, and could be detected here on Earth…

Neutron stars are the remnants of massive stars after they have exploded as supernovae. The dense core remains behind, spinning fast and composed of only neutrons. They have immense gravitational fields and thought to have as much mass as our Sun, but measuring only 20 kilometres across. As they conserve the angular momentum of their massive sun predecessor, as they are so small, they are expected to spin hundreds of times per second.

But how can these strange objects be detected? Well, for one, they may be seen as highly radiating pulsars (or, possibly, “magnetars“), flashing a beam of radiation past the Earth asÂ they spinÂ like a lighthouse, beams of high energy photons emitted from the neutron star’s poles. But what about the effect they have on space-time? Can these massive bodies create gravitational waves? (Note: A gravitational wave is a totally different creature from an atmospheric “gravity wave“.)

To picture the scene: Imagine spinning a perfectly spherical ball in a swimming pool. If the ball is perfectly stationary (not bobbing up and down and not drifting), only spinning on its axis, no ripples in the pool will be seen. Therefore, any instrument measuring ripples in the pool will not detect the presence of the spinning ball. Now spin an object not spherical (like a rugby ball, or an American football) in the pool. As this object spins, the irregularities on the surface (i.e. the pointed ends) will produce a wave on each revolution of the irregular object. The ripple instrument will detect the presence of the ball in the pool.

This is the issue facing scientists trying to detect gravitational waves from neutron stars. If they are smooth objects (perhaps spherical, or slightly flattened due to the spin), they cannot produce ripples in space-time and therefore cannot be detected. If, on the other hand, they are irregularly-shaped spinning bodies, with inhomogeneities (lumps or “mountains”) on the surface, gravitational waves may be generated. The lump will sweep out a fluctuation in space-time on each rotation. This is fine, but are neutron stars lumpy?

Well, the outlook isn’t very good. The space-time “ripple” detectors set out to observe gravitational waves have so far not detected any sign of these rapidly spinning neutron stars. This could either mean that the technology we are using is not sensitive enough to detect gravitational waves or that neutron stars are naturally smooth and cannot produce gravitational waves in the first place.

Matthias Vigelius and Andrew Melatos, researchers from University of Melbourne in Australia, think they have new hope that some types of neutron star might be detected as they are naturally lumpy. Using a new computer modelling technique, the pair believes that even a small variation in the neutron star surface will produce detectable gravitational waves. But how do these lumps form? Often, stars evolve as part of a binary system (i.e. two stars orbiting a common centre of gravity), should one die as a supernova, leaving a neutron star behind, the intense gravitational field will strip its companion star of its gases. As the gas is funnelled into the neutron star, the intense magnetic field will give structural support to the incoming gas, creating an electron-proton mix of superheated plasma sitting on top of the neutron star surface. The lumps formed at the neutron star’s magnetic poles will be a long-living feature, sweeping around the star each time it rotates. Vigelius and Melatos think that detectors such as the Laser Interferometer Gravitational-Wave Observatory (LIGO) may be able to detect this characteristic signature of an irregularly shaped neutron star…. in time.

As yet, these “lumpy” neutron stars have not been detected, but through continued observation (exposure time), it is hoped that Earth-based gravitational wave observatories may eventually receive the signal.

Source: RAS, New Scientist

April 2, 2008December 24, 2015 by Tammy Plotner

Venus’ Variable Evolution

For every backyard astronomer, we know 4.5 billion years ago, both Venus and Earth were formed with nearly the same radius, mass, density and chemical composition. Venus is like Earth’s evil twin, but why is the climate on both worlds so widely varied? Scientists analysing the data from the orbiting European Venus Express spacecraft are finally putting the pieces of the geological and climatological puzzle together as they take a closer look at Venusian evolution.

Today, Professor Fred Taylor of Oxford University presented the scenario in a talk at the Royal Astronomical Society National Astronomy Meeting in Belfast. According to the studies, Venus appeared to have evolved very rapidly compared to the Earth during the early formation of the solar system. Thanks to data obtained from the Venus Express, it would appear our wicked sister planet once had significant volume of water covering the surface… Oceans which were lost in a very short geological timescale. As the water disappeared, the geological evolution of the surface of Venus slowed quickly – unable to develop plate tectonics like the Earth. Biological evolution could never happen. If, at one time, Venus mirrored Earth in climate and habitability terms, then it evolved too quickly at first, then too slowly.

‘They may have started out looking very much the same,’ said Professor Taylor, ‘but increasingly we have evidence that Venus lost most of its water and Earth lost most of its atmospheric carbon dioxide.’

Here on Earth, carbon dioxide is captive plant life, minerals and the crust itself. Not to harp on global warming, but the release CO2 back into the atmosphere is a source of climatic change. On Venus, the majority of the carbon dioxide resides it its atmosphere, leaving the surface temperature at a searing 450 degrees Celsius. This slows or stops geological as well as biological evolution.

‘The interesting thing is that the physics is the same in both cases’ said Prof Taylor. ‘The great achievement of Venus Express is that it is putting the climatic behaviour of both planets into a common framework of understanding.’

But, we haven’t heard the last from Venus Express just yet. Due to operate until May 2009, scientists involved in the project are already busy applying for an extension until 2011.

‘We have plans for joint operations with the Japanese spacecraft called Venus Climate Orbiter that will arrive in December 2010’, said Taylor. ‘Together, we can do things neither could do alone to crack some of the remaining puzzles about Venus.’

April 2, 2008December 24, 2015 by Tammy Plotner

The Sun’s Magnetic Fountains

For you solar observing fans, enjoy the beauty. Over the years both the public and astronomers alike have witnessed the Sun’s volatile and ever-changing atmosphere. Before our eyes huge geysers of hot gas spew into the solar corona at tens of thousands of km per hour. Every few minutes they erupt and reach dynamic proportions. Now a team of scientists have used the Hinode spacecraft to find the origin and progenitor of these fountains – immense magnetic structures that thread through the solar atmosphere.

Today at the Royal Astronomical Society National Astronomy Meeting in Belfast (NAM 2008), team leader Dr. Michelle Murray from the Mullard Space Science Laboratory (MSSL, University College London) presented the latest results from Hinode spacecraft combined with computer emulated solar conditions. Since its launch in October 2006, scientists have been using Hinode to examine the solar atmosphere in extraordinary detail. One of it’s premier instruments is the Extreme Ultraviolet Imaging Spectrometer. The EIS generates images of the Sun and gives information on the speed of the moving gases.

At the core of the solar magnetic field, immense jets of hot gas are forced to the surface through increases in pressure. Just like an earthly geyser, when the pressure releases the gases fall back towards the Sun’s surface. But what causes the pressure? Unlike the volcanic activity that drives the terrestrial phenomena, solar fountains are caused by rearrangements of the Sun’s magnetic field, a continual process that results in looping cycles of increasing and decreasing pressure.

“EIS has observed the Sun’s fountains in unprecedented detail and it has enabled us to narrow down the fountains’ origins for the first time”, comments team member and MSSL postgraduate student Deb Baker. “We have also been able to find what drives the fountains by using computer experiments to replicate solar conditions.”

The sun-observing Hinode satellite is now in a sun-synchronous orbit, which allows it to observe the sun for uninterrupted periods lasting months at a time. Using a combination of optical, EUV and X-ray instrumentation Hinode will study the interaction between the Sun’s magnetic field and its corona to increase our understanding of the causes of solar variability.

“The computer experiments demonstrate that when a new section of magnetic field pushes through the solar surface it generates a continual cycle of fountains”, explains Dr. Murray, “but new magnetic fields are constantly emerging across the whole of the solar surface and so our results can explain a whole multitude of fountains that have been observed with Hinode.”

April 2, 2008December 24, 2015 by Nancy Atkinson

New Search Technique May Lead to Discovery of Extra-solar Earth-Like Planets

The Holy Grail in the search for extra-solar planets would be to find an Earth-like world orbiting another star. A group of UK astronomers believe they have good chance of being the first to find such a planet with a revolutionary new camera called RISE. With RISE, scientists will search for extra-solar planets using a technique called â€œtransit timing,â€ which may provide a short-cut to discovering Earth-like planets with existing technology.

The two primary techniques to find extra-solar planets are usually only sensitive to massive, gas giant planets in close orbit around their parent star, so-called â€œHot Jupiters.â€ Firstly, planets can be found through their gravitational pull on the star they orbit – as the extra-solar planet moves the star wobbles back and forth, and by measuring this movement astronomers can deduce the presence of a planet. Secondly, the transit search technique looks for the changes in a starâ€™s brightness as a planet passes in front of it.

But neither of these techniques is currently good enough to find small extra-solar planets similar to the Earth. With the new transit timing technique, the RISE camera will look for Earth-mass planets in orbit around stars already known to host Hot Jupiters.

Transit timing works on the principle that an isolated hot Jupiter planet orbiting its host will have a constant orbital period (i.e. its ‘year’ remains the same) and therefore it will block out the light from its parent star in a regular and predictable way. During the planet’s transit events, RISE can very accurately measure the rise and fall in the amount of light reaching the Earth from the parent star – the camera can be used to pinpoint the time of the centre of the event to within 10 seconds. RISE is a fast-read camera. It has a fixed “V+R” filter and reimaging optics giving a 7 x 7 acrminute field of view to maximize the number of comparison stars available. An e2V frame transfer detector is used to obtain a cycle time of less than 1 second.

By observing and timing their transits, astronomers hope to detect small changes in the orbital periods of known hot Jupiters caused by the gravitational pull of other planets in the same system. In the right circumstances, even planets as small as the Earth could be found in this way.

â€œThe potential of transit timing is the result of some very simple physics, where multi-planet systems will gravitationally kick one another around in their orbits – an effect often witnessed in our own Solar System,â€ said PhD student Neale Gibson of Queen’s University Belfast. â€œIf Earth-mass planets are present in nearby orbits (which is predicted by current Hot-Jupiter formation theories) we will see their effect on the orbit of the larger transiting planets. RISE will allow us to observe and time the transits of extrasolar planets very accurately, which gives us the sensitivity required to detect the effect of even small Earth-mass planets.â€

RISE was designed by astronomers at Queen’s University in collaboration with Liverpool John Moores University and is now installed on the 2 meter Liverpool Telescope on the Canary Island of La Palma. For more information about the RISE Camera, see Neale Gibson’s homepage.

Original News Source: NAM Press Release

April 2, 2008December 24, 2015 by Nancy Atkinson

STEREO Spacecraft Captures Footage of a Solar Tsunami

A solar tsunami blasted its way through the sunâ€™s lower atmosphere on May, 19 2007, and the action was captured by the twin STEREO spacecraft. Solar tsunamis are launched by huge explosions near the Sun’s atmosphere, called coronal mass ejections (CMEs). Although solar tsunamis share much in common with tsunamis on Earth, the solar version can travel at over a million kilometers per hour. Last yearâ€™s tsunami blasted and rolled for about 35 minutes, reaching peak speeds around 20 minutes after the initial flare. The observations were made by a team from Trinity College, Dublin.

“The energy released in these explosions is phenomenal; about two billion times the annual world energy consumption in just a fraction of a second. In half an hour, we saw the tsunami cover almost the full disc of the Sun, nearly a million kilometers away from the epicenter,” said David Long, a member of the team that made the observations.

STEREO’s Extreme Ultraviolet Imager (EUVI) instruments monitor the Sun at four wavelengths which correspond to temperatures ranging between 60,000 and 2 million degrees Celsius. At the lowest of these temperatures, scientists can see structures in the chromosphere, a thin layer of the solar atmosphere that lies just above the Sun’s visible surface. At temperatures between 1 and 2 million degrees Celsius, scientist can monitor features at varying levels in the solar corona.

The SOHO spacecraft, which was launched in 1995, also monitors the Sun at these wavelengths but only took images four times per day, giving scientists rare snapshots of these tsunamis. STEREO’s EUVI instruments take an image every few minutes to create a series, making it possible for scientists to track how the wave spreads over time.

Click here for a Quicktime animation of the event.

This is the first time that a tsunami has been observed at all four wavelengths, which enabled the team to see how the wave moved through the different layers of the solar atmosphere.

“To our surprise, the tsunami seems to move with similar speed and acceleration through all the layers. As the chromosphere is much denser than the corona, we’d expect the pulse there to drag. It’s a real puzzle,” said Dr. Peter Gallagher, another member of the team.

To complicate matters, the interval between images is not the same for all four cameras. At the time of the tsunami, the cameras monitoring radiation at 1 million degrees Celsius were set to take an image every 2.5 minutes. They recorded much higher speeds and accelerations for the wave than the other cameras, which were on 10 or 20 minute cycles. By taking a sample of one image in four, the data from these cameras matched the lower values observed in the other layers.

“We’ve thought for some time that the tsunamis might be caused by magnetic shockwaves but, in previous snapshots, the waves appeared to be travelling too slowly. However, we’ve seen from this set of observations that if the time interval between images is too long, it’s easy to underestimate the speed that the waves are moving. With a few more rapid-sequence observations of solar tsunamis, we should finally be able to identify the cause of these waves,” said Gallagher.

The discovery will be presented by David Long at the RAS National Astronomy Meeting in Belfast on Wednesday April 2, 2008.

For more information and animations, see Trinity College’s pageabout the solar tsunami.

Original News Source: RAS press release

April 1, 2008December 24, 2015 by Ian O'Neill

So, What Does an Anti-Satellite Weapon Actually Look Like?

In February, the Universe Today followed the sad tale about a dead US satellite called US-193, lifelessly floating around in orbit, possibly threatening the world by dumping hazardous fuel onto a city somewhere. This was the perfect time for the US Navy to launch their Standard Missile-3 (SM-3) into space, smashing US-193 to tiny bits. It worked and it worked well.

Although we’ve seen loads of pictures of the rocket being launched, and the pinpoint accuracy it accomplished by detonating in low Earth orbit, but what technology goes into the actual warhead that takes out the satellite? Well, in an article just published, images of an older generation “Kinetic Energy” anti-satellite weapon are on display. And to be honest, it doesn’t look that scary…

There’s more than one way to kill a satellite. You can make it self destruct by firing its thrusters, sending it in a deadly descent through the atmosphere. But say if you don’t have communication with the craft? You could capture it in orbit using a robotic or manned spaceship. But this would be prohibitively expensive and dangerous. You could simply shoot it down… now this idea (although far from beingÂ “simple”) is the most popular and effective method to get rid of a satellite from orbit.

The anti-satellite (ASAT) idea has been around since the Cold War, as far back as the 1960’s, but very little information is available. In fact, according to Dwayne Day’s article in The Space Review on the 31st March, since the Cold War nobody has been bothered to write much about American ASAT technology development, policy, and doctrine. It is unclear if this is down to the military being (understandably) secretive, or whether people simply lost interest in the “Star Wars” program proposed by U.S. President Ronald Reagan in 1983.

But there are some clues as to the US anti-satellite capabilities back in the 1990’s, namely a cool-looking mock-up of one of Lockheed’s proposals for a kinetic energy anti-satellite warhead (or KE-ASAT, pictured left), the author discovered at the Aerospace Legacy Foundation’s offices located at the former North American Aviation Downey factory. The owner, a Dr. Jim Busby showed off a low fidelity mock-up of a Lockheed KE-ASAT, which he acquired in the early 1990s, when a previous owner discarded it.

It’s a strange-looking device, resembling a mini-spaceship capsule (although, from the images and description, it is unclear how big it is) that would have sat on top of a rocket booster to send it from the ground and into space to hit its satellite target. This type of anti-satellite does not explode on impact; it relies on huge velocities and a high mass to generate enough kinetic energy to destroy the target on impact.

Some variations on this theme may have included a Kevlar “fly swatter” that would expand on impact, making it easier to hit the satellite and destroy it.

It is obvious from the images that the mass of the warhead is packed in the red cone at the front of the weapon; the infrared heat-seeker targeting system would also be housed there. There is also a main thruster (that would fire to life once the rocket boosters had carried it into space), and attitude controls at the rear to guide the high velocity projectile to its target. A similar method was used by the February 20th US spy satellite intercept, so the proposed technology this KE-ASAT is built on is not far from the current method employed by the US Navy.

Alas, the KE-ASAT never made it to the production line as Lockheed’s bid for use in an anti-satellite program was beaten by the Rockwell company in July 1990, the US Army opted for a far different-looking design, not dissimilar to the ASAT used today. Personally I think the Lockheed concept looked better, but would have been very scary, causing a huge mess…

Source: The Space Review

April 1, 2008December 24, 2015 by Astronomy Cast

Podcast: Space Junk

We’re polluting every corner of our own planet, so it only makes sense that we’ll take our trashy habits out into space with us. This week we look at the myriad of ways we’re messing up space, from the trash orbiting the planet to the radiation we’re leaking out into space.

Click here to download the episode

Space Junk – Show notes and transcript

Or subscribe to: astronomycast.com/podcast.xml with your podcatching software.

April 1, 2008December 24, 2015 by Fraser Cain

Astronomers Find the Smallest Black Hole

Black holes seem to have no upper limit; some weigh in at hundreds of millions of times the mass of the Sun. But how small can they be? Astronomers have discovered what they think is the least massive black hole ever seen, with a mere 3.8 times the mass of the Sun, and a diameter of only 25 km (15 miles) across.

The announcement was made by Nikolai Shaposhnikov of NASAâ€™s Goddard Space Flight Center and his colleagues at the American Astronomical Society High-Energy Astrophysics Division currently being held in Los Angeles, California.

The “tiny” black hole, known as XTE J1650-500, was discovered back in 2001 in a binary system with a normal star. Astronomers had known about the binary system for several years, but they were finally able to make accurate measurements using NASA’s Rossi X-ray Timing Explorer (RXTE) to pin down the mass.

Although black holes themselves are invisible, they’re often surrounded by a disk of hot gas and dust – material chokes up, like water going down the drain. As the hot gas builds up, it releases torrents of X-rays at regular intervals.

Astronomers have long suspected that the frequency of these X-ray blasts depend on the mass of the stars. As the mass of the black hole increases, the size of the accretion disk expands outward too; there are less frequent X-ray emissions.

By cross referencing this method with other, established techniques for weighing black holes, the team is very confident that they’ve got the trick to measuring black hole mass.

When they applied their technique to XTE J1650-500, they turned up a mass of 3.8 Suns, give or take half a solar mass. This is dramatically smaller than the previous record holder at 6.3 Suns.

What’s the smallest possible black hole? Astronomers think it’s somewhere between 1.7 and 2.7 solar masses. Smaller than that and you get a neutron star. Finding black holes that approach this lower limit will help physicists better understand how matter behaves when its crushed down in this extreme environment.

Original Source: NASA News Release