Posted on by Matt Williams

Globular Clusters Might not be as Old as Astronomers Thought. Like, Billions of Years Younger

A binary star system in a globular cluster. Credit: University of Warwick

Globular clusters have been a source of fascination ever since astronomers first observed them in the 17th century. These spherical collections of stars are among the oldest known stars in the Universe, and can be found in the outer regions of most galaxies. Because of their age and the fact that almost all larger galaxies appear to have them, their role in galactic evolution has remained something of a mystery.

Previously, astronomers were of the opinion that globular clusters were some of the earliest stars to have formed in the Universe, roughly 13 billion years ago. However, new research has indicated that these clusters may actually be about 4 billion years younger, being roughly 9 billion years old. These findings may alter our understanding of how the Milky Way and other galaxies formed, and how the Universe itself came to be.

The study, titled “Reevaluating Old Stellar Populations“, recently appeared online and is being evaluated for publication in The Monthly Notices for the Royal Astronomical Society. The study was led by Dr. Elizabeth Stanway, an Associate Professor in the Astronomy group at the University of Warwick, UK, and was assisted by Dr. J.J. Eldridge, a Senior Lecturer at the University of Auckland, New Zealand.

Within larger galaxies, like the Milky Way, globular clusters are part of the galactic halo. Between 150 and 180 are estimated to be part of the Milky Way alone. Credit: ESO

For the sake of their study, Dr. Stanway and Dr. Eldridge developed a series of new research models designed to reconsider the evolution of stars. These models, known as Binary Population and Spectral Synthesis (BPASS) models, had previously proven effective in exploring the properties of young stellar populations within the Milky Way and throughout the Universe.

Using these same models, Dr. Stanway and Dr. Eldridge studied a sample of globular clusters in the Milky Way and nearby quiescent galaxies. They also took into account the details of binary star evolution within globular clusters and used them to explore the colors of light and spectra from old binary populations. In short, binary star system evolution consists of one star expanding into a giant while the gravitational force of the smaller star strips away the atmosphere of the giant.

What they found was that these binary systems were about 9 billion years old. Since these stars are thought to have formed at the same time as the globular clusters themselves, this demonstrated that globular clusters are not as old as other models have suggested. As Dr. Stanway said of the BPASS models she and Dr. Eldridge developed:

“Determining ages for stars has always depended on comparing observations to the models which encapsulate our understanding of how stars form and evolve. That understanding has changed over time, and we have been increasingly aware of the effects of stellar multiplicity – the interactions between stars and their binary and tertiary companions.

An artist’s impression of a millisecond pulsar and its companion. The presence of binaries in globular clusters is a good means of providing age estimates of those clusters. Credit: ESA & Francesco Ferraro (Bologna Astronomical Observatory)

If correct, this study could open up new pathways of research into how massive galaxies and their stars are formed. However, Dr. Stanway admits that much work still lies ahead, which includes looking at nearby star systems where individual stars can be resolved – rather than considering the integrated light of a cluster. Nevertheless, the study could have immense significant for our understanding of how and when galaxies in our Universe formed.

“If true, it changes our picture of the early stages of galaxy evolution and where the stars that have ended up in today’s massive galaxies, such as the Milky Way, may have formed,” she said. “We aim to follow up this research in the future, exploring both improvements in modelling and the observable predictions which arise from them.”

An integral part of cosmology is understanding when the Universe came to be the way it is, not just how. By determining how old globular clusters are, astronomers will have another crucial piece of the puzzle as to how and when the earliest galaxies formed. And these, combined with observations that look to the earliest epochs of the Universe, could just yield a complete model of cosmology.

Further Reading: University of Warwick, arXiv

Posted on by Matt Williams

Here’s the First Image From NOAA’s New Weather Satellite

GOES-17 took this stunning, full-disk snapshot of Earth’s Western Hemisphere from its checkout position at 12:00 p.m. EDT on May 20, 2018, using the Advanced Baseline Imager (ABI) instrument. GOES-17 observes Earth from an equatorial vantage point approximately 22,300 miles above the surface. Credit: NOAA/NASA

On March 1st, 2018, the GOES-17 weather satellite launched from Cape Canaveral Air Force Station in Florida. As a second generation GOES satellite operated by the National Oceanic and Atmospheric Administration, this and other satellites will extend the Geostationary Operational Environmental Satellite system’s (GOES) weather forecasting and meteorological research until 2036.

The purpose of this new generation of satellites is to improve the forecasts of weather, oceans, the environment and space weather by providing faster and more detailed data, real-time images, and advanced monitoring. Recently, the satellite’s Advanced Baseline Imager (ABI) made its debut by releasing its “first light“, which just happened to be some beautiful and breathtaking images of Earth from space.

The image featured above was taken on May 20th, 2018, where GOES-17 captured the sunset over Earth’s Western Hemisphere. This image was taken when the satellite was at a distance of 35,405 km (22,000 miles) from Earth and was presented in “GeoColor”, which captures features of the Earth’s surface and atmosphere in vivid detail and colors that are familiar to the human eye.

Compared to previous GOES satellites, GOES-17 can collect three times more data at four times the image resolution, and scan the planet five times faster than previous probes. These abilities were put to the test as the ABI created its beautiful images of Earth using two visible bands (blue and red) and one near-infrared “vegetation” band, and one of the ABI’s “longwave” infrared bands.

When combined as a “GeoColor” image, these bands provide valuable information for monitoring dust, haze, smoke, fog, clouds and winds in the atmosphere – which allows meteorologists to monitor and forecast where severe weather events will take place. It also allows scientists to monitor vegetation patterns to see how weather conditions can lead to increased drought or the expansions of greenery.

It also results in pictures depicting Earth in vivid and colorful detail, as you can plainly see! The satellite is currently in its post-launch checkout testing phase, where controllers on Earth are busy calibrating its instruments and systems and validating them for use. The imagery acquired by the ABI is one such example, which served as a preliminary check to ensure that the imaging instrument will function properly.

Other images included the picture of a series of dynamic marine stratocumulus clouds (shown above), which was captured by the satellite’s ABI off the western coast of Chile in the the southeastern Pacific Ocean. Once again, the improved resolution and sensitivity of the GOES-17 allows it to monitor clouds in our atmosphere with amazing detail and clarity.

GOES-17 also captured a deck of low level stratus clouds covering the southern California coast (above) and smoke plumes created by wildfires in central and northern Saskatchewan, Canada (below). These two images were also acquired by the ABI on May 20th, 2018, and demonstrate how effective GOES-17 will be when it comes to monitoring weather patterns, events that can trigger fires (i.e. lighting), and the resulting fires themselves.

Alongside GOES-17, NOAA’s operational geostationary constellation also consists of GOES-16 (operating as GOES-East), GOES-15 (operating as GOES-West), and GOES-14 – operating as the on-orbit spare. This satellite constellation is currently in good working order and is monitoring weather across the US and the planet each day.

While this data is still preliminary and non-operational, it does provide a good preview of what the GOES-17 can do. In the coming years, it and its third and fourth-generation cousins – GOES-T and GOES-U – will allow Earth observers to monitor weather, climate change and natural disasters with far greater detail, allowing for better early warning and response efforts.

To see more full-resolution images from the GOES-17 ABI, go to the NOAA page.

Further Reading: NOAA

Posted on by Matt Williams

Okay, Last Year’s Kilonova Did Probably Create a Black Hole

Artist's illustration of two merging neutron stars. The narrow beams represent the gamma-ray burst while the rippling spacetime grid indicates the isotropic gravitational waves that characterize the merger. Swirling clouds of material ejected from the merging stars are a possible source of the light that was seen at lower energies. Credit: National Science Foundation/LIGO/Sonoma State University/A. Simonnet

In August of 2017, another major breakthrough occurred when the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected waves that were believed to be caused by a neutron star merger. Shortly thereafter, scientists at LIGO, Advanced Virgo, and the Fermi Gamma-ray Space Telescope were able to determine where in the sky this event (known as a kilonova) occurred.

This source, known as GW170817/GRB, has been the target of many follow-up surveys since it was believed that the merge could have led to the formation of a black hole. According to a new study by a team that analyzed data from NASA’s Chandra X-ray Observatory since the event, scientists can now say with greater confidence that the merger created a new black hole in our galaxy.

The study, titled “GW170817 Most Likely Made a Black Hole“, recently appeared in The Astrophysical Journal Letters. The study was led by David Pooley, an assistant professor in physics and astronomy at Trinity University, San Antonio, and included members from the University of Texas at Austin, the University of California, Berkeley, and Nazarbayev University’s Energetic Cosmos Laboratory in Kazakhstan.

Illustration of the kilonova merger (top), and the resulting object (left and right) over time. Credit: NASA/CXC/Trinity University/D. Pooley et al. Illustration: NASA/CXC/M.Weiss

For the sake of their study, the team analyzed X-ray data from Chandra taken in the days, weeks, and months after the detection of gravitational waves by LIGO and gamma rays by NASA’s Fermi mission. While nearly every telescope in the world had observed the source, X-ray data was critical to understanding what happened after the two neutron stars collided.

While a Chandra observation two to three days after the event failed to detect an X-ray source, subsequent observations taken 9, 15, and 16 days after the event resulted in detections. The source disappeared for a time as GW170817 passed behind the Sun, but additional observations were made about 110 and 160 days after the event, both of which showed significant brightening.

While the LIGO data provided astronomers with a good estimate of the resulting object’s mass after the neutron stars merged (2.7 Solar Masses), this was not enough to determine what it had become. Essentially, this amount of mass meant that it was either the most massive neutron star ever found or the lowest-mass black hole ever found (the previous record holders being four or five Solar Masses). As Dave Pooley explained in a NASA/Chandra press release:

“While neutron stars and black holes are mysterious, we have studied many of them throughout the Universe using telescopes like Chandra. That means we have both data and theories on how we expect such objects to behave in X-rays.”

Illustration of the resulting black hole caused by GW170817. Credit: NASA/CXC/M.Weiss

If the neutron stars merged to form a heavier neutron star, then astronomers would expect it to spin rapidly and generate and very strong magnetic field. This would have also created an expanded bubble of high-energy particles that would result in bright X-ray emissions. However, the Chandra data revealed X-ray emissions that were several hundred times lower than expected from a massive, rapidly-spinning neutron star.

By comparing the Chandra observations with those by the NSF’s Karl G. Jansky Very Large Array (VLA), Pooley and his team were also able to deduce that the X-ray emission were due entirely to the shock wave caused by the merger smashing into surrounding gas. In short, there was no sign of X-rays resulting from a neutron star.

This strongly implies that the resulting object was in fact a black hole. If confirmed, these results would indicate that the formation process of a blackhole can sometimes be complicated. Essentially, GW170817 would have been the result of two stars undergoing a supernova explosion that left behind two neutron stars in a sufficiently tight orbit that they eventually came together. As Pawan Kumar explained:

“We may have answered one of the most basic questions about this dazzling event: what did it make? Astronomers have long suspected that neutron star mergers would form a black hole and produce bursts of radiation, but we lacked a strong case for it until now.”

Simulated view of a black hole. Credit: Bronzwaer/Davelaar/Moscibrodzka/Falcke, Radboud University

Looking ahead, the claims put forward by Pooley and his colleagues could be tested by future X-ray and radio observations. Next-generation instruments – like the Square Kilometer Array (SKA) currently under construction in South Africa and Australia, and the ESA’s Advanced Telescope for High-ENergy Astrophysics (Athena+) – would be especially helpful in this regard.

If the remnant turns out to be a massive neutron star with a strong magnetic field after all, then the source should get much brighter in the X-ray and radio wavelengths in the coming years as the high-energy bubble catches up with the decelerating shock wave. As the shock wave weakens, astronomers expect that it will continue to become fainter than it was when recently observed.

Regardless, future observations of GW170817 are bound to provide a wealth of information, according to J. Craig Wheeler, a co-author on the study also from the University of Texas. “GW170817 is the astronomical event that keeps on giving,” he said. “We are learning so much about the astrophysics of the densest known objects from this one event.”

If these follow-up observations find that a heavy neutron star is what resulted from the merger, this discovery would challenge theories about the structure of neutron stars and how massive they can get. On the other hand, if they find that it formed a tiny black hole, then it will challenge astronomers notions about the lower mass limits of black holes. For astrophysicists, it’s basically a win-win scenario.

As co-author Bruce Grossan of the University of California at Berkeley added:

“At the beginning of my career, astronomers could only observe neutron stars and black holes in our own galaxy, and now we are observing these exotic stars across the cosmos. What an exciting time to be alive, to see instruments like LIGO and Chandra showing us so many thrilling things nature has to offer.”

Indeed, looking farther out into the cosmos and deeper back in time has revealed much about the Universe that was previously unknown. And with improved instruments being developed for the sole purpose of studying astronomical phenomena in greater detail and at even greater distances, there seems to be no limit to what we might learn. And be sure to check out this video of the GW170817 merger, courtesy of the Chandra X-ray Observatory:

Further Reading: Chandra, The Astrophysical Journal Letters

Posted on by Matt Williams

Pluto has “Sand Dunes”, but Instead of Sand, it’s Grains of Frozen Methane

NASA's New Horizons spacecraft captured this image of Sputnik Planitia — a glacial expanse rich in nitrogen, carbon monoxide and methane ices — that forms the left lobe of a heart-shaped feature on Pluto’s surface. SwRI scientists studied the dwarf planet’s nitrogen and carbon monoxide composition to develop a new theory for its formation. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

In July of 2015, the New Horizons mission made history when it conducted the first flyby in history of Pluto. In the course of conducting its flyby, the probe gathered volumes of data about Pluto’s surface, composition, atmosphere and system of moons. It also provided breathtaking images of Pluto’s “heart”, its frozen plains, mountain chains, and it’s mysterious “bladed terrain”.

These strange features showed people for the first time how radically different the surface of Pluto is from Earth and the other planets of the inner Solar System. But strangely, they also showcased how this distant world is also quite similar to Earth. For instance, in a new study, a team of researchers working on the images from the New Horizons mission noticed “dunes” on the surface of Pluto that resemble sand dunes here on Earth.

The study, titled “Dunes on Pluto“, was recently published in the journal Science. The study was led by Matthew Telfer, a Lecturer in Physical Geography from the University of Plymouth, with significant contributions provided by Eric J. R. Parteli and Jani Radebaugh – geoscientists from the University of Cologne, and Brigham Young University, respectively.

The fine smudges on Sputnik Planum have been identified as transverse dunes because of the way they run perpendicular to the dark “wind streaks”. Credit: NASA/JPL/New Horizons

They were joined by members from the Carl Sagan Center at the SETI Institute, NASA’s Ames Research Center, the Lowell Observatory, the Southwest Research Institute (SwRI), the National Optical Astronomy Observatory, the Massachusetts Institute of Technology (MIT), the Johns Hopkins University Applied Physics Laboratory (JHUAPL), and multiple universities.

On Earth, dunes are formed by wind-blown sand that create repeated ridges in the desert or along beaches. Similar patterns have been observed along river beds and alluvial plains, where water deposits sediment over time. In all cases, dune-like formations are the result of solid particles being transported by a moving medium (i.e. air or water). Beyond Earth, such patterns have been observed on Mars, Titan, and even on Comet 67P/Churyumov-Gerasimenko.

However, when consulting images from New Horizons probe, Telfer and his colleagues noted similar formations in the Sputnik Planitia region on Pluto. This region, which constitutes the western lobe of the heart-shaped Tombaugh Regio, is essentially a massive ice-covered basin. Already, researchers have noted that the surface appears to consist of irregular polygons bordered by troughs, which appear to be indications of convection cells.

As Dr. Telfer told Universe Today via email:

“We first saw some features looked kind of dune-like within the first few days, but as time passed, and new images came in, most of these seemed less and less convincing. But one area became more and more convincing with every pass. This is what we’re reporting on.”

Another interesting feature is the dark streams that are a few kilometers long and are all aligned in the same direction. But equally interesting were the features that Telfer and his team noticed, which looked like dunes that ran perpendicular to the wind streaks. This indicated that they were transverse dunes, the kinds that pile up due to prolonged wind activity in the desert.

New Horizon images showing the patterns on Pluto’s surface that were hypothesized to be dunes. Credit: NASA/JPL/University of Arizona

To determine if this was a plausible hypothesis, the researchers constructed models that took into account what kind of particles would make up these dunes. They concluded that either methane or nitrogen ice would be able to form sand-sized grains that could be transported by typical winds. They then modeled the physics of Pluto’s winds, which would be strongest coming down the slopes of the mountains that border Sputnik Planum.

However, they also determined that Pluto’s winds would not be strong enough to push the particles around on their own. This is where sublimation played a key role, where surface ice goes from a solid phase directly to a gas when warmed by sunlight. This sublimation would provide the upward force necessary to lift the particles, at which point they would be caught by Pluto’s winds and blown around.

As Dr. Telfer explained, this conclusion was made possible thanks to the immense amount of support his team got, much of which came from the New Horizons Geology, Geophysics and Imaging Science Theme Team:

“Once we’d done the spatial analysis that made us really sure that these features made sense as dunes, we had the great opportunity to hook up with Eric Parteli at Cologne; he showed us through his modelling that the dunes should form, as long as the grains become airborne in the first place. The NASA New Horizons team really helped here, as they pointed out that mixed nitrogen/methane ices would preferentially fling methane ice grains upwards as the ices sublimated.”

Comparison of dune features on Pluto with those on Earth and Mars. Credit: NASA/JPL/University of Arizona

In addition to showing that Pluto, one of the most distant objects in the Solar System, has a few things in common with Earth, this study has also shown just how active Pluto’s surface is. “It shows us that not only is Pluto’s surface affecting its atmosphere, the converse is also true,” said Dr. Telfer. “We have a really dynamic world’s surface, so far out in the solar system.

On top of that, understanding how dunes can form under Pluto’s conditions will help scientists to interpret similar features found elsewhere in the Solar System. For example, NASA is planning on sending a mission to Titan in the coming decade to study its many interesting surface features, which include its dune formations. And many more missions are being sent to explore the Red Planet before a crewed mission takes place in the 2030s.

Knowing how such formations were created are key to understanding the dynamics of the planet, which will help answer some of the deeper questions about what is taking place on the surface.

Further Reading: ArsTechnica, Science

Posted on by Matt Williams

Engineers Propose a Rocket that Consumes Itself as it Flies to Space

A team of engineers from the University of Glasgow and the Ukraine have created an engine that could cut costs by "eating itself". Credit: Ken Kremer/kenkremer.com

When it comes to the new era of space exploration, one of the primary focuses has been on cutting costs. By reducing the costs associated with individual launches, space agencies and private aerospace companies will not only be able to commercialize Low Earth-Orbit (LEO), but also mount far more in the way of exploration missions and maybe even colonize space.

Several methods have been proposed so far for reducing launch costs, which include reusable rockets and single-stage-to-orbit rockets. However, a team of engineers from the University of Glasgow and the Ukraine recently proposed an entirely different idea that could make launching small payloads affordable – a self-eating rocket! This “autophage” rocket could easily send small satellites into space more easily and more affordably.

The study which describes how they built and tested the “autophage” engine recently appeared in the Journal of Spacecraft and Rockets under the title “Autophage Engines: Toward a Throttleable Solid Motor“. The team was led by Vitaly Yemets and Patrick Harkness – a Professor from the Oles Honchar Dnipro National University in the Ukraine and a Senior Lecturer from the University of Glasgow, respectively.

The autophage engine, being tested at the Dnipro testing lab in the Ukraine. Credit: University of Glasgow

Together, the team addressed one the most pressing issues when it comes to rockets today. This has to do with the fact that storage tanks, which contain the rocket’s propellants as they climb, weight many times the spacecraft’s payload. This reduces the efficiency of the launch vehicle and also adds to the problem of space debris, since these fuel tanks are disposable and fall away when spent.

As Dr Patrick Harkness, who led Glasgow’s contribution to the work, explained in a recent University of Glasgow press release:

“Over the last decade, Glasgow has become a centre of excellence for the UK space industry, particularly in small satellites known as ‘CubeSats’, which provide researchers with affordable access to space-based experiments. There’s also potential for the UK’s planned spaceport to be based in Scotland. However, launch vehicles tend to be large because you need a large amount of propellant to reach space. If you try to scale down, the volume of propellant falls more quickly than the mass of the structure, so there is a limit to how small you can go. You will be left with a vehicle that is smaller but, proportionately, too heavy to reach an orbital speed.”

In contrast, an autophage engine consumes its own structure during ascent, so more cargo capacity could be freed-up and less debris would enter orbit. The propellant consists of a solid fuel rod (made of a solid plastic like polyethylene) on the outside and an oxidizer on the inside. By driving the rod into a hot engine, the fuel and oxidizer are vaporized to create gas that then flows into the combustion chamber to produce thrust.

The use of autophage engines on rockets could allow for the deployment of small satellites cheaply and efficiently, without adding to the problem of space debris. Credit: AMNH.

“A rocket powered by an autophage engine would be different,” said Dr. Harkness. “The propellant rod itself would make up the body of the rocket, and as the vehicle climbed the engine would work its way up, consuming the body from base to tip. That would mean that the rocket structure would actually be consumed as fuel, so we wouldn’t face the same problems of excessive structural mass. We could size the launch vehicles to match our small satellites, and offer more rapid and more targeted access to space.”

The research team also showed that the engine could be throttled by simply varying the speed at which the rod is driven into the engine, which is something rare in a solid motor. During the lab tests, the team has been able to sustain rocket operations for 60 seconds at a time. As Dr. Harkness said, the team hopes to build on this and eventually conduct a launch test:

“While we’re still at an early stage of development, we have an effective engine testbed in the laboratory in Dnipro, and we are working with our colleagues there to improve it still further. The next step is to secure further funding to investigate how the engine could be incorporated into a launch vehicle.”

Another challenge of the modern space age is how to deliver additional payloads and satellites into orbit without creating more in the way of orbital clutter. By introducing an engine that can make for cheap launches that also has no disposable parts, the autophage could be a game-changing technology, one which is right up there with fully-recoverable rockets.

The research team also consisted of Mykola Dron and Anatoly Pashkov – a Professor and Senior Researcher from Oles Honchar Dnipro National University – and Kevin Worrall and Michael Middleton – a Research Associate and M.S. student from the University of Glasgow.

Further Reading: University of Glasgow, Journal of Spacecraft and Rockets

 

Posted on by Matt Williams

Clearly a Fan. Jeff Bezos Himself Announced that Amazon was Picking up The Expanse

Jeff Bezos recently announced that Amazon Prime will be renewing science fiction series The Expanse. Credit: savetheexpanse.org

At Comic-Con 2015, fans of space opera and science fiction were treated to their first glimpse of The Expanse, the miniseries adaptation of Daniel Abraham and Ty Franck’s novels. Needless to say, the reaction was magnificent, and is perhaps best up by IO9’s Lauren Davis, who penned a review of the trailer titled, “The Expanse Is the Show We’ve Been Wanting Since Battlestar Galactica.

It was therefore a bit of a blow when recently, the Syfy network announced that the third season (which is currently airing) would be the show’s last. Reaction to the news was swift, prompting fans to mount multiple campaigns to have the show picked up by Netflix, Amazon Prime, or another video streaming service. And on Friday, May 25th, Jeff Bezos (founder of Amazon and Blue Origin) obliged them.

The announcement was made at the National Space Society’s International Space Development Conference in Los Angeles Friday night. Bezos was attending the conference to receive the prestigious Gerard K. O’Neill Memorial Award for Space Settlement Advocacy, thanks to his advancement of commercial space exploration through his company, Blue Origin.

The award was conferred by O’Neill’s widow, Tasha O’Neill. In the midst of laying out his company’s vision for the future of space exploration, which included colonies in space, he announced that the science fiction show was being picked up by Amazon Prime, Amazon’s subscription service that offers access to music, videos and other media. As Bezos said, to general applause:

“I was talking to the cast half an hour ago, before the break for dinner started. I was telling them that we are working hard at Amazon to save The Expanse but it wasn’t a done deal yet. During dinner, ten minutes ago, I just got word that The Expanse is saved. The show is extraordinary and these guys are unbelievably talented.”

The news quickly went viral and fan sites dedicated to getting the show renewed quickly responded. In fact, #SaveTheExpanse.com went so far as to declare victory:

“We did it!  Thanks to the incredible, historic efforts of the cast, crew and fans of the critically acclaimed sci-fi epic, “The Expanse,” the television show has been resurrected by Amazon Studios and Alcon Entertainment for a fourth season. Just two weeks after being cancelled by Syfy, the massive grassroots effort that followed the news achieved its goal in saving the series, which is now set to appear on Amazon Prime.”

Jeff Bezos recently announced that Amazon Prime will be renewing science fiction series The Expanse. Credit: savetheexpanse.org

Alcon Entertainment co-founders and co-CEOs Andrew Kosove and Broderick Johnson were also very happy with the fact that their show had been picked up by Amazon Prime. As they were quoted as saying by Variety Magazine:

“We couldn’t be more excited that ‘The Expanse’ is going to continue on Amazon Prime. We are deeply grateful that Jeff Bezos, Jen Salke, and their team at Amazon have shown such faith in our show. We also want to thank Laura Lancaster, head of Alcon Television for her tireless efforts. We are fully aware that this wouldn’t have been possible if it wasn’t for the staggering outpouring of support from the most creative, hardest working sci-fi fans around the world. From reddit campaigns to airplanes, we say thank you. It worked!”

Bezos also took the opportunity to honor Gerard K. O’Neill, a physicist and well-known proponent of space colonization. Among the many ideas he proposed for creating settlements in space, the most-well known is arguably the concept of the O’Neill Cylinder (aka. O’Neill Colony). This would consist of two counter-rotating cylinders in space that would rotate to provide artificial gravity.

Bezos also acknowledged a debt to O’Neill seminal work, The High Frontier: Human Colonies in Space. “Professor O’Neill was very formative for me,” he said. “I read ‘The High Frontier’ in high school. I read it multiple times. And I was already primed. And as soon as I read it, it made sense to me. It seemed very clear that planetary surfaces were not the right place for an expanding civilization inside the solar system.”

Artist’s depiction of a pair of O’Neill cylinders. Credit: Rick Guidice/NASA Ames Research Center

On the subject of O’Neill Cylinders, Bezos indicated that they are a good means for creating accessible space habitats. “For one, they’re not that big,” he explained. “There’s another argument I always make too, [which] is, they’re hard to get to. [If] we build our own colonies, we can do them in near-Earth vicinity, because people will want to come back to Earth. Very few people – for a long time, anyway – are going to want to abandon Earth altogether.”

It seems rather fitting that an entrepreneur who is dedicated to making science fiction a reality has chosen to renew a science fiction show. Clearly, Bezos is a fan, or perhaps he knows that fans of shows like The Expanse are also fans of his commercial space efforts. In either case, fans of the series are happy to know that there will be more seasons to come!

Further Reading: Variety, Space.com, savetheexpanse.org

Posted on by Matt Williams

What are the Chances that the Next Generation LSST Could Find New Planets in the Solar System?

Artist's concept of the hypothetical "Planet Nine." Could it have moons? Credit: NASA/JPL-Caltech/Robert Hurt

In the past few decades, thanks to improvements in ground-based and space-based observatories, astronomers have discovered thousands of planets orbiting neighboring and distant stars (aka. extrasolar planets). Strangely enough, it is these same improvements, and during the same time period, that enabled the discovery of more astronomical bodies within the Solar System.

These include the “minor planets” of Eris, Sedna, Haumea, Makemake, and others, but also the hypothesized planetary-mass objects collectively known as Planet 9 (or Planet X). In a new study led by Northern Arizona University and the Lowell Observatory, a team of researchers hypothesize that the Large Synoptic Survey Telescope (LSST) – a next-generation telescope that will go online in 2022 – has a good chance of finding this mysterious planet.

Their study, titled “On the detectability of Planet X with LSST“, recently appeared online. The study was led by David E. Trilling, an astrophysicist from the Northern Arizona University and the Lowell Observatory, and included Eric C. Bellm from the University of Washington and Renu Malhotra of the Lunar and Planetary Laboratory at The University of Arizona.

Artist’s impression of the Large Synoptic Survey Telescope (LSST). Credit: lsst.org

Located on the Cerro Pachón ridge in north-central Chile, the 8.4-meter LSST will conduct a 10-year survey of the sky that will deliver 200 petabytes worth of images and data that will address some of the most pressing questions about the structure and evolution of the Universe and the objects in it. In addition to surveying the early Universe in order to understand the nature of dark matter and dark energy, it will also conduct surveys of the remote areas of the Solar System.

Planet 9/X is one such object. In recent years, the existence of two planetary-mass bodies have been hypothesized to explain the orbital distribution of distant Kuiper Belt Objects. While neither planet is thought to be exceptionally faint, the sky locations of these planets are poorly constrained – making them difficult to pinpoint. As such, a wide area survey is needed to detect these possible planets.

In 2022, the LSST will carry out an unbiased, large and deep survey of the southern sky, which makes it an important tool when it comes to the search of these hypothesized planets. As they state in their study:

“The possibility of undiscovered planets in the solar system has long fascinated astronomers and the public alike. Recent studies of the orbital properties of very distant Kuiper belt objects (KBOs) have identified several anomalies that may be due to the gravitational influence of one or more undiscovered planetary mass objects orbiting the Sun at distances comparable to the distant KBOs.

Animated diagram showing the spacing of the Solar Systems planet’s, the unusually closely spaced orbits of six of the most distant KBOs, and the possible “Planet 9” (aka. “Planet X”). Credit: Caltech/nagualdesign

These studies include Trujillo & Sheppard’s 2014 study where they noticed similarities in the orbits of distant Trans-Neptunian Objects (TNOs) and postulated that a massive object was likely influencing them. This was followed by a 2016 study by Sheppard & Trujillo where they suggested that the high perihelion objects Sedna and 2012 VP113 were being influence by an unknown massive planet.

This was followed in 2016 by Konstantin Batygin and Michael E. Brown of Caltech suggesting that an undiscovered planet was the culprit. Finally, Malhotra et al. (2016) noted that the most distant KBOs have near-integer period ratios, which was suggestive of a dynamical resonance with a massive object in the outer Solar System. Between these studies, various mass and distance estimates were formed that became the basis of the search for this planet.

Overall, these estimates indicated that Planet 9/X was a super-Earth with anywhere between 5 to 20 Earth masses, and orbited the Sun at a distance of between 150 – 600 AU. Concurrently, these studies have also attempted to narrow down where this Super-Earth’s orbit will take it throughout the outer Solar System, as evidenced by the perturbations it has on KBOs.

Unfortunately, the predicted locations and brightness of the object are not yet sufficiently constrained for astronomers to simply look in the right place at the right time and pick it out. In this respect, a large area sky survey must be carried out using moderately large telescopes with a very wide field of view. As Dr. Trilling told Universe Today via email:

“The predicted Planet X candidates are not particularly faint, but the possible locations on the sky are not very well constrained at all. Therefore, what you really need to find Planet X is a medium-depth telescope that covers a huge amount of sky. This is exactly LSST. LSST’s sensitivity will be sufficient to find Planet X in almost all its (their) predicted configurations, and LSST will cover around half of the known sky to this depth. Furthermore, the cadence is well-matched to finding moving objects, and the data processing systems are very advanced. If you were going to design a tool to find Planet X, LSST is what you would design.”
The orbits of several KBOs provide indications about the possible existence of Planet 9. Credit: Caltech/R. Hurt (IPAC)

However, the team also acknowledges that within certain parameters, Planet 9/X may not be detectable by the LSST. For example, it is possible that that there is a very narrow slice of predicted Planet 9/X parameters where it might be slightly too faint to be easily detected in LSST data. In addition, there is also a small possibility that irregularities in the Planet 9/X cadence might lead to it being missed.

There is the even the unlikely ways in which Planet 9/X could go undetected in LSST data, which would come down to a simple case of bad luck. However, as Dr. Trilling indicated, the team is prepared for these possibilities and is hopeful they will find Planet 9/X, assuming there’s anything to find:
“The more likely conclusion if planet X is not detected in LSST data is that planet X doesn’t exist – or at least not the kind of planet X that has been predicted. In this case, we’ve got to work harder to understand how the Universe created this pattern of orbits in the outer Solar System that I described above. This is a really fun part of science: make a prediction and test it, and find that the result is rarely what is predicted. So now we’ve got to work harder to understand the universe. Hopefully this new understanding makes new predictions that we then can test, and we repeat the cycle.”
The existence of Planet 9/X has been one of the more burning questions for astronomers in recent years. If its existence can be confirmed, astronomers may finally have a complete picture of the Solar System and its dynamics. If it’s existence can be ruled out, this will raise a whole new series of questions about what is going on in the Outer Solar System!

Further Reading: arXiv

Posted on by Matt Williams

This is What Happens When a Black Hole Gobbles up a Star

Close-up of star near a supermassive black hole (artist’s impression). Credit: ESA/Hubble, ESO, M. Kornmesser

At the center of our galaxy resides a Supermassive Black Hole (SMBH) known as Sagittarius A. Based on ongoing observations, astronomers have determined that this SMBH measures 44 million km (27.34 million mi) in diameter and has an estimated mass of 4.31 million Solar Masses. On occasion, a star will wander too close to Sag A and be torn apart in a violent process known as a tidal disruption event (TDE).

These events cause the release of bright flares of radiation, which let astronomers know that a star has been consumed. Unfortunately, for decades, astronomers have been unable to distinguish these events from other galactic phenomena. But thanks to a new study from by an international team of astrophysicists, astronomers now have a unified model that explains recent observations of these extreme events.

The study – which recently appeared in the Astrophysical Journal Letters under the title “A Unified Model for Tidal Disruption Events” – was led by Dr. Jane Lixin Dai, a physicist with the Niels Bohr Institute’s Dark Cosmology Center. She was joined by members from University of Maryland’s Joint Space-Science Institute and the University of California Santa Cruz (UCSC).

Illustration of the supermassive black hole at the center of the Milky Way. Credit: NRAO/AUI/NSF
Illustration of the supermassive black hole at the center of the Milky Way. Credit: NRAO/AUI/NSF

As Enrico Ramirez-Ruiz – the professor and chair of astronomy and astrophysics at UC Santa Cruz, the Niels Bohr Professor at the University of Copenhagen, and a co-author on the paper – explained in a UCSC press release:

“Only in the last decade or so have we been able to distinguish TDEs from other galactic phenomena, and the new model will provide us with the basic framework for understanding these rare events.”

In most galaxies, SMBHs do not actively consume any material and therefore do not emit any light, which distinguishes them from galaxies that have Active Galactic Nuclei (AGNs). Tidal disruption events are therefore rare, occurring only once about every 10,000 years in a typical galaxy. However, when a star does get torn apart, it results in the release of an intense amount of radiation. As Dr. Dai explained:

“It is interesting to see how materials get their way into the black hole under such extreme conditions. As the black hole is eating the stellar gas, a vast amount of radiation is emitted. The radiation is what we can observe, and using it we can understand the physics and calculate the black hole properties. This makes it extremely interesting to go hunting for tidal disruption events.”

Illustration of emissions from a tidal disruption event shows in cross section what happens when the material from a disrupted star is devoured by a black hole. Credit: Jane Lixin Dai

In the past few years, a few dozen candidates for tidal disruption events (TDEs) have been detected using wide-field optical and UV transient surveys as well as X-ray telescopes. While the physics are expected to be the same for all TDEs, astronomers have noted that a few distinct classes of TDEs appear to exist. While some emit mostly x-rays, others emit mostly visible and ultraviolet light.

As a result, theorists have struggled to understand the diverse properties observed and create a coherent model that can explain them all. For the sake of their model, Dr. Dai and her colleagues combined elements from general relativity, magnetic fields, radiation, and gas hydrodynamics. The team also relied on state-of-the-art computational tools and some recently-acquired large computer clusters funded by the Villum Foundation for Jens Hjorth (head of DARK Cosmology Center), the U.S. National Science Foundation and NASA.

Using the model that resulted, the team concluded that it is the viewing angle of the observer that accounts for the differences in observation.  Essentially, different galaxies are oriented randomly with respect to observers on Earth, who see different aspects of TDEs depending on their orientation. As Ramirez-Ruiz explained:

“It is like there is a veil that covers part of a beast. From some angles we see an exposed beast, but from other angles we see a covered beast. The beast is the same, but our perceptions are different.”

Artist’s impression of the Large Synoptic Survey Telescope. Credit: lsst.org

In the coming years, a number of planned survey projects are expected to provide much more data on TDEs, which will help expand the field of research into this phenomena. These include the Young Supernova Experiment (YSE) transient survey, which will be led by the DARK Cosmology Center at the Niels Bohr Institute and UC Santa Cruz, and the Large Synoptic Survey Telescopes (LSST) being built in Chile.

According to Dr. Dai, this new model shows what astronomers can expect to see when viewing TDEs from different angles and will allow them to fit different events into a coherent framework. “We will observe hundreds to thousands of tidal disruption events in a few years,” she said. “This will give us a lot of ‘laboratories’ to test our model and use it to understand more about black holes.”

This improved understanding of how black holes occasionally consume stars will also provide additional tests for general relativity, gravitational wave research, and help astronomers to learn more about the evolution of galaxies.

Further Reading: UCSC, Astrophysical Journal Letters

Posted on by Matt Williams

Virgin Galactic Performs the Second Test of VSS Unity, Reaching Mach 1.9

Virgin Galactic’s VSS Unity conducted her second powered test flight on Tuesday, May 29th. With six flights under their belts, the VG crews are planning for more in 2024. Credit: Virgin Galactic
Virgin Galactic’s VSS Unity conducted her second powered test flight on Tuesday, May 29th. With six flights under their belts, the VG crews are planning for more in 2024. Credit: Virgin Galactic

When it comes to the dream of commercial space exploration and space tourism, a few names really stand out. In addition to Elon Musk and Jeff Bezos, you have Richard Branson – the founder and CEO of the Virgin Group. For years, Branson has sought to make space tourism a reality through Virgin Galactic, which would take passengers into suborbit using his SpaceShipTwo class of rocket planes.

Unfortunately, Virgin Galactic suffered a number of setbacks in recent years, at the same time that competitors like SpaceX and Blue Origin emerged as competitors. However, the VSS Unity (part of the Virgin Galactic fleet) recently conducted its second powered test flight from the Mojave Air and Space Port on Tuesday, May 29th. While this test is years behind schedule, it marks a significant step towards Branson’s realization of flying customers to space.

This was the second time that the VSS Unity flew since 2014, when the VSS Enterprise suffered a terrible crash while attempting to land, killing one pilot and injuring the other. The first propulsive test took place two months ago after several additional tests were performed on the craft. And with that last success, Virgin Galactic moved ahead with its second powered test earlier this week.

The focus of the latest test flight was to learn more about how the spaceship handles at supersonic speeds. It was also intended to test the control system’s performance when the vehicle was closer to its ultimate commercial configuration. As the company stated, “This involved shifting the vehicle’s center of gravity rearward via the addition of passenger seats and related equipment.”

This statement is a possible indication that the test program is reaching the final stretch before Virgin Galactic allows passengers on the vehicle. However, the company will need to conduct a full-duration flight (which will include a full-duration burn of its rocket motor) before that can happen. This latest test involved only a partial rocket burn, but nevertheless demonstrated the spacecraft’s capabilities at supersonic speed.

The company live-tweeted the entire event, which began at 8:34 AM with the VSS Unity and its carrier mothership (VMS Eve) taxing out to the runway for final checks. For this flight, the pilots were Dave Mackay and Mark “Forger” Stucky while CJ Sturckow and Nicola Pecile piloted of the carrier aircraft. At 8:42 AM (PDT), both craft lifted off, with the company tweeting, “We have take-off. VMS Eve & VSS Unity have taken to the skies and have begun their climb.”

By 9:43 AM, the company announced that the VSS Unity had detached from the VMS Eve and was “flying free”. What followed was a series of live-tweets that indicated the ignition of the VSS Unity’s rocket motor, the shutting down of the motor, and the raising of the tail fins to the “feathered” re-entry position. By 9:55 AM, the company announced a smooth landing for the VSS Unity, signaling the end of the test.

Branson, who was at the Mojave Air and Space Port for the test, released the following statement shortly thereafter:

“It was great to see our beautiful spaceship back in the air and to share the moment with the talented team who are taking us, step by step, to space. Seeing Unity soar upwards at supersonic speeds is inspiring and absolutely breathtaking. We are getting ever closer to realizing our goals. Congratulations to the whole team!”

Branson was also at the center to take in a tour of the facilities of The Spaceship Company (TSC), a sister company of Virgin Galactic that is responsible for developing Virgin Galactic’s future fleet. While there, Branson viewed the next two spaceships that TSC is currently manufacturing, as well as the production facilities for TSC’s spaceship rocket motors.

With the latest test flight complete, the company’s teams will be reviewing the data from this flight and making preparations for the next flight. No indication has been given as to when that will be, or if this test flight will include a full-duration burn of the motor. However, Branson was very happy with the test results, stating:

“Today we saw VSS Unity in her natural environment, flying fast under rocket power and with a nose pointing firmly towards the black sky of space. The pathway that Unity is forging is one that many thousands of us will take over time, and will help share a perspective that is crucial to solving some of humanity’s toughest challenges on planet Earth.”

Artists’ impression of Moon Base Alpha, SpaceX’s envisioned lunar outpost supplied with the BFR. Credit: SpaceX

Meanwhile, Bezos continues to pursue his plans for sending passengers into orbit using his fleet of New Shepard rockets. And of course, Musk continues to pursue the idea of sending tourists to the Moon and Mars using his Big Falcon Rocket (BFR). And with many other private aerospace ventures looking to provide trips into orbit or to the surface of the Moon, there is sure to be no shortage of options for going into space in the near future!

And be sure to check out this video of the VSS Unity’s second test flight, courtesy of Virgin Galactic:

Further Reading: NASA Space Flight

Posted on by Matt Williams

Here’s What Really Happened to That Camera That Melted During a Rocket Launch

NASA Photographer Bill Ingalls's camera after it was caught in brushfire caused by the launch of the NASA/German GRACE-FO from Vandenberg Air Force Base on May 22, 2018. Credits: NASA/Bill Ingalls

NASA photographers have always understood that taking pictures of space launches is a risky business. No one is more familiar with this than Bill Ingalls, a NASA photographer who has taking pictures for the agency for the past 30 years. Both within the agency and without, his creativity and efforts are well known, as his ability to always know exactly where to set up his cameras to get the perfect shots.

Which naturally begs the question, what happened to the camera featured in the image above? This photograph, which shows one of Ingalls remote cameras thoroughly-melted, has been making the rounds on social media of late. As the accompanying gif (seen below) shows, the camera was not far from the launch pad and was then quickly consumed by the resulting fire.

As Ingalls explained in a recent NASA press release, the destruction of the camera was the result of an unexpected brush fire that was triggered when flames from the launching rocket set some of the nearby grass on fire.

“I had six remotes, two outside the launch pad safety perimeter and four inside,” he said. “Unfortunately, the launch started a grass fire that toasted one of the cameras outside the perimeter.”

The event he was photographing was the launch of the NASA/German Gravity Recovery and Climate Experiment Follow-on (GRACE-FO) satellite, which took place at Vandenberg Air Force Base on May 22nd, 2018. As part of a partnership between NASA and the German Research Center for Geosciences (GFZ), this satellite is the successor to the original GRACE mission, which began orbiting Earth on March 17th, 2002.

Unfortunately, the launch triggered a brush fire which engulfed the camera and cause its body to melt. Firefighters reported to the scene to put out the fire, who then met Ingalls where he returned to the site. Luckily for Ingalls, and the viewing public, he was able to force open the body and retrieve the memory card, which had not been damaged. As a result, the footage of the fire as it approached the camera was caught.

NASA Photographer Bill Ingalls’s remote camera setup before the NASA/German GRACE-FO launch from Vandenberg Air Force Base on May 22, 2018. Credits: NASA/Bill Ingalls

Oddly enough, this camera was the one posted furthest from the launch pad, about 400 meters (a quarter of a mile) away. The four other cameras that were set up inside the perimeter were undamaged, as was the other remote camera. But before anyone starts thinking that this remote was the unfortunate one, the “toasty” camera, as Ingalls calls it, is likely to put on display at NASA Headquarters in Washington, DC.

In the meantime, Ingalls will be traveling to Kazakhstan to photograph the June 3rd landing of the International Space Station’s Expedition 55 crew. He anticipates that that assignment, unlike this last one, will have no surprises!

Further Reading: NASA