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September 6, 2016 by Evan Gough

The Solar System Gets A Second Mercury

Freddie Mercury on stage in 1977. Image: By FreddieMercurySinging21978.jpg: Carl Lender derivative work: Lošmi - FreddieMercurySinging21978.jpg, CC BY-SA 3.0

Freddie Mercury, the frontman from the rock band Queen, is getting his name etched in the night sky. No, they’re not naming another planet after him. That would be confusing. Instead, an asteroid will bear the name of the iconic singer.

If you don’t know much about the band Queen, there’s a connection between them and astronomy. Brian May, the band’s guitarist, holds a PhD. in astrophysics. He studied reflected light from interplanetary dust and the velocity of dust in the plane of the Solar System. But when Queen became mega-popular in the 70’s, he abandoned astrophysics, for the most part.

Brian May is still involved with space, and has an interest in asteroids. He helped the ESA launch Asteroid Day in June 2016, to raise awareness of the threat that asteroids pose to Earth. So there’s the connection.

As for the asteroid that will bear Freddie Mercury’s name, it was previously named Asteroid 17473, but will now be known as Asteroid FreddieMercury 17473. It’s a rock about 3.5 km in diameter in the asteroid belt between Mars and Jupiter.

Today would have been Freddie’s 70th birthday, if he were still alive. So this naming is a fitting commemorative gesture. According to the International Astronomical Union, who handles the naming of objects in space, the naming of the asteroid is in honour of “Freddie’s outstanding influence in the world.”

Brian May explains things in this video:

We’re mostly science-minded people, so you may be skeptical of Freddie’s influence in the world. He was no scientist, that’s for sure. But if you lived through Queen’s heyday, as I did, you can sort of see it.

Freddie Mercury was a very polished entertainer, with a great voice and fantastic stage presence. He mastered the theatrical side of performing as a rock frontman, and his voice spanned four octaves. The music he made with his band-members in Queen was very original. Mercury was a creative force, that’s for sure.

Check out “Killer Queen” from 1974.

Plus, William Shatner (aka Captain James Tiberius Kirk) clearly had a warm spot in his heart for Freddie and the rest of Queen. How else to explain his version of Queen’s timeless tune “Bohemian Rhapsody?”

If that isn’t a ringing endorsement of Freddie Mercury and Queen, I don’t know what is.

The asteroid that will bear Freddie Mercury’s name was discovered by Belgian astronomer Henri Debehogne in 1991. It travels an elliptical path around the Sun, and never comes closer than 350 million km to Earth. It isn’t very reflective, so only powerful telescopes can see it. But there it’ll be, for anyone with a powerful enough telescope to look with, as long as human civilization lasts.

Freddie Mercury isn’t the first entertainer to have something in space bear his name. In fact, he’s not even the first member of Queen to have that honor. An asteroid first seen in 1998 now bears the name Asteroid 52665 Brianmay, in honor of the guitarist from Queen.

Other musicians and singers who’ve had space rocks named after them include the Beatles, Enya, Frank Zappa, David Bowie, Aretha Franklin, Yes, and Bruce Springsteen. Authors Kurt Vonnegut, Vladimir Nabokov, and Douglas Adams and the characters Don Quixote, James Bond, Sherlock Holmes and Dr Watson also have the honor.

As for the rock itself, Oxford astrophysics professor Chris Lintott told the Guardian, “I think it’s wonderful to name an asteroid after Freddie Mercury. Pleasingly, it’s on a slightly eccentric orbit about the sun, just as the man himself was.”

Freddie died in 1991 from complications from AIDS, but his music still lives on. Maybe Asteroid FreddieMercury 17473 will help us remember him.

Sources:

September 2, 2016October 5, 2016 by Evan Gough

Juno Captures Jupiter’s Enthralling Poles From 2,500 Miles

JunoCam captured this image of Jupiter's north pole region from a distance of 78,000 km (48,000 miles) above the planet.

Juno is sending data from Jupiter back to us, courtesy of the Deep Space Network, and the first images are meeting our hyped-up expectations. On August 27, the Juno spacecraft came within about 4,200 km. (2,500 miles) of Jupiter’s cloud tops. All of Juno’s instruments were active, and along with some high-quality images in visual and infrared, Juno also captured the sound that Jupiter produces.

Juno has captured the first images of Jupiter’s north pole. Beyond their interest as pure, unprecedented eye candy, the images of the pole reveal things never before seen. They show storm activity and weather patterns that are seen nowhere else in our solar system. Even on the other gas giants.

“…like nothing we have seen or imagined before.”

“First glimpse of Jupiter’s north pole, and it looks like nothing we have seen or imagined before,” said Scott Bolton, principal investigator of Juno from the Southwest Research Institute in San Antonio. “It’s bluer in color up there than other parts of the planet, and there are a lot of storms. There is no sign of the latitudinal bands or zone and belts that we are used to — this image is hardly recognizable as Jupiter. We’re seeing signs that the clouds have shadows, possibly indicating that the clouds are at a higher altitude than other features.”

The iconic storm bands of Jupiter are absent in this JunoCam image of Jupiter's northern polar region. Instead, the region is dominated by swirling storm patterns reminiscent of hurricanes here on Earth. Image: NASA/JPL-Caltech/SwRI/MSSS — The iconic storm bands of Jupiter are absent in this JunoCam image of Jupiter’s northern polar region. Instead, the region is dominated by swirling storm patterns reminiscent of hurricanes here on Earth. Image: NASA/JPL-Caltech/SwRI/MSSS

The visible light images of Jupiter’s north pole are very different from our usual perception of Jupiter. People have been looking at Jupiter for a long time, and the gas giant’s storm bands, and the Great Red Spot, are iconic. But the north polar region looks completely different, with whirling, rotating storms similar to hurricanes here on Earth.

The Junocam instrument is responsible for the visible light pictures of Jupiter that we all enjoy. But the Jovian Infrared Auroral Mapper (JIRAM) is showing us a side of Jupiter that the naked eye will never see.

The Juno Infrared Auroral Mapper (JIRAM) captured this infrared image of Jupiter's south pole. This part of Jupiter cannot be seen from Earth. Image: NASA/JPL-Caltech/SwRI/MSSS — The Juno Infrared Auroral Mapper (JIRAM) captured this infrared image of Jupiter’s south pole. This part of Jupiter cannot be seen from Earth. Image: NASA/JPL-Caltech/SwRI/MSSS

“JIRAM is getting under Jupiter’s skin, giving us our first infrared close-ups of the planet,” said Alberto Adriani, JIRAM co-investigator from Istituto di Astrofisica e Planetologia Spaziali, Rome. “These first infrared views of Jupiter’s north and south poles are revealing warm and hot spots that have never been seen before. And while we knew that the first-ever infrared views of Jupiter’s south pole could reveal the planet’s southern aurora, we were amazed to see it for the first time.”

“No other instruments, both from Earth or space, have been able to see the southern aurora.”

Even when we’re prepared to be amazed by what Juno and other spacecraft show us, we are still amazed. It’s impossible to see Jupiter’s south pole from Earth, so these are everybody’s first glimpses of it.

“No other instruments, both from Earth or space, have been able to see the southern aurora,” said Adriani. “Now, with JIRAM, we see that it appears to be very bright and well-structured. The high level of detail in the images will tell us more about the aurora’s morphology and dynamics.”

Beyond the juicy images of Jupiter are some sound recordings. It’s been known since about the 1950’s that Jupiter is a noisy planet. Now Juno’s Radio/Plasma Wave Experiment (WAVE) has captured a recording of that sound.

“Jupiter is talking to us in a way only gas-giant worlds can,” said Bill Kurth, co-investigator for the Waves instrument from the University of Iowa, Iowa City. “Waves detected the signature emissions of the energetic particles that generate the massive auroras which encircle Jupiter’s north pole. These emissions are the strongest in the solar system. Now we are going to try to figure out where the electrons come from that are generating them.”

Oddly enough, that’s pretty much exactly what I expected Jupiter to sound like. Like something from an early sci-fi film.

There’s much more to come from Juno. These images and recordings of Jupiter are just the result of Juno’s first orbit. There are over 30 more orbits to come, as Juno examines the gas giant as it orbits beneath it.

September 2, 2016October 5, 2016 by Matt Williams

Newly Found Ancient Fossils Show Possibilities For Finding Martian Life

Fossilized remains found in Greenland have been dated to 3.7 billion years ago, 220 million years older than when life is believed to have emerged. Credit: A.P. Nutman et al./Nature

Fossilized remains are a fascinating thing. For paleontologists, these natural relics offer a glimpse into the past and a chance to understand what kind of lifeforms lurked there. But for astronomers, fossils are a way of ascertaining precisely when it was that life first began here on our planet – and perhaps even the Solar System.

And thanks to a team of Australian scientists, the oldest fossils to date have been uncovered. These fossilized remains have been dated to 3.7 billion years of age, and were of a community of microbes that lived on the ancient seafloor. In addition to making scientists reevaluate their theories of when life emerged on Earth, they could also tell us if there was ancient life on Mars.

The fossil find was made in what is known as the Isua Supracrustal Belt (ISB), an area in southwest Greenland that recently became accessible due to the ice melting in the area. According to the team, these fossils – basically tiny humps in rock measuring between one and four centimeters (0.4 and 1.6 inches) tall – are stromatolites, which are layers of sediment packed together by ancient, water-based bacterial colonies.

*The Australian team searching for fossilized remains in the Isua supracrustal belt (ISB) in southwest Greenland. Credit: uow.edu.au*

According to the team’s research paper, which appeared recently in Nature Communications, the fossilized microbes grew in a shallow marine environment, which is indicated by the seawater-like rare-earth elements and samples of sedimentary rock that were found with them.

They are also similar to colonies of microbes that can be found today, in shallow salt-water environments ranging from Bermuda to Australia. But of course, what makes this find especially interesting is just how old it is. Basically, the stone in the ISB is dated back to the early Archean Era, which took place between 4 and 3.6 billion years ago.

Based on their isotopic signatures, the team dated the fossils to 3.7 billion years of age, which makes them 220 million years older than remains that had been previously uncovered in the Pilbara Craton in north-western Australia. At the time of their discovery, those remains were widely believed to be the earliest fossil evidence of life on Earth.

As such, scientists are now reconsidering their estimates on when microbial life first emerged on planet Earth. Prior to this discovery, it was believed that Earth was a hellish environment 3.7 billion years ago. This was roughly 300 million years after the planet had finished cooling, and scientists believed it would take at least half a billion years for life to form after this point.

4.5 billion years ago, during the Hadean Eon, Earth was bombarded regularly by meteorites. Credit: NASA — *4.5 billion years ago, during the Hadean Eon, Earth had a much different environment than it does today. Credit: NASA*

But with this new evidence, it now appears that life could have emerged faster than that. As Allen P. Nutman – a professor from the University of Wallongong, Australia, and the study’s lead author – said in a university press release:

“The significance of stromatolites is that not only do they provide obvious evidence of ancient life that is visible with the naked eye, but that they are complex ecosystems. This indicates that as long as 3.7 billion years ago microbial life was already diverse. This diversity shows that life emerged within the first few hundred millions years of Earth’s existence, which is in keeping with biologists’ calculations showing the great antiquity of life’s genetic code.”

When life emerged is a major factor when it comes to Earth’s chemical cycles. Essentially, Earth’s atmosphere during the Hadean was believed to be composed of heavy concentrations of CO² atmosphere, hydrogen and water vapor, which would be toxic to most life forms today. During the following Archean era, this primordial atmosphere slowly began to be converted into a breathable mix of oxygen and nitrogen, and the protective ozone layer was formed.

The emergence of microbial life played a tremendous role in this transformation, allowing for the sequestration of CO² and the creation of oxygen gas through photosynthesis. Therefore, when it comes to Earth’s evolution, the question of when life arose and began to affect the chemical cycles of the planet has always been paramount.

The Curiosity rover took this photo of the Martian landscape on July 12, 2016. Imagine if we could listen to it at the same time. NASA now plans to include a microphone on the upcoming Mars 2020 Mission. Credit: NASA/JPL-Caltech — *Could fossilized remains of microbes be found underneath Mars’ cold, dry landscape? Credit: NASA/JPL-Caltech*

“This discovery turns the study of planetary habitability on its head,” said associate Professor Bennett, one of the study’s co-authors. “Rather than speculating about potential early environments, for the first time we have rocks that we know record the conditions and environments that sustained early life. Our research will provide new insights into chemical cycles and rock-water-microbe interactions on a young planet.”

The find has also inspired some to speculation that similar life structures could be found on Mars. Thanks to the ongoing efforts of Martian rovers, landers and orbiters, scientists now know with a fair degree of certainty that roughly 3.7 billion years ago, Mars had a warmer, wetter environment.

As a result, it is possible that life on Mars had enough time to form before its atmosphere was stripped away and the waters in which the microbe would have emerged dried up. As Professor Martin Van Kranendonk, the Director of the Australian Centre for Astrobiology at UNSW and a co-author on the paper, explained:

“The structures and geochemistry from newly exposed outcrops in Greenland display all of the features used in younger rocks to argue for a biological origin. This discovery represents a new benchmark for the oldest preserved evidence of life on Earth. It points to a rapid emergence of life on Earth and supports the search for life in similarly ancient rocks on Mars.”

Another thing to keep in mind is that compared to Earth, Mars experiences far less movement in its crust. As such, any microbial life that existed on Mars roughly 3.7 billion years ago would likely be easier to find.

This is certainly good news for NASA, since one of the main objectives of their Mars 2020 rover is to find evidence of past microbial life. I for one am looking forward to seeing what it leaves for us to pickup in its cache of sample tubes!

Further Reading: Nature Communications

September 1, 2016October 5, 2016 by Evan Gough

Grab Your Smartphone And Become A Citizen Scientist For NASA

NASA's new app, the Globe Observer, will allow users to collect observations of clouds, and engage in a little citizen science. Image: NASA GLOBE Observer

It’s long been humanity’s dream to do something useful with our smartphones. Sure, we can take selfies, and post pictures of our meals, but true smartphone greatness has eluded us. Until now, that is.

Thanks to NASA, we can now do some citizen science with our ubiquitous devices.

For over 20 years, and in schools in over 110 countries, NASA’s Global Learning and Observations to Benefit the Environment (GLOBE) program has helped students understand their local environment in a global context. Now NASA has released the GLOBE Observer app, which allows users to capture images of clouds in their local environment, and share them with scientists studying the Earth’s climate.

“With the launch of GLOBE Observer, the GLOBE program is expanding beyond the classroom to invite everyone to become a citizen Earth scientist,” said Holli Riebeek Kohl, NASA lead of GLOBE Observer. The app will initially be used to capture cloud observations and images because they’re such an important part of the global climate system. But eventually, GLOBE Observer will also be used to observe land cover, and to identify types of mosquito larvae.

GLOBE has two purposes. One is to collect solid scientific data, the other is to increase users’ awareness of their own environments. “Once you collect environmental observations with the app, they are sent to the GLOBE data and information system for use by scientists and students studying the Earth,” said Kohl. “You can also use these observations for your own investigations and interact with a vibrant community of individuals from around the world who care about Earth system science and our global environment.”

Clouds are a dynamic part of the Earth’s climate system. Depending on their type, their altitude, and even the size of their water droplets, they either trap heat in the atmosphere, or reflect sunlight back into space. We have satellites to observe and study clouds, but they have their limitations. An army of citizen scientists observing their local cloud population will add a lot to the efforts of the satellites.

“Clouds are one of the most important factors in understanding how climate is changing now and how it’s going to change in the future,” Kohl said. “NASA studies clouds from satellites that provide either a top view or a vertical slice of the clouds. The ground-up view from citizen scientists is valuable in validating and understanding the satellite observations. It also provides a more complete picture of clouds around the world.”

The observations collected by GLOBE users could end up as part of NASA's Earth Observatory, which tracks the cloud fraction around the world. Image: NASA/NASA Earth Observation. — The observations collected by GLOBE users could end up as part of NASA’s Earth Observatory, which tracks the cloud fraction around the world. Image: NASA/NASA Earth Observation.

The GLOBE team has issued a challenge to any interested citizen scientists who want to use the app. Over the next two weeks, the team is hoping that users will make ground observations of clouds at the same time as a cloud-observing satellite passes overhead. “We really encourage all citizen scientists to look up in the sky and take observations while the satellites are passing over through Sept. 14,” said Kohl.

The app makes this easy to do. It informs users when a satellite will be passing overhead, so we can do a quick observation at that time. We can also use Facebook or Twitter to view daily maps of the satellite’s path.

“Ground measurements are critical to validate measurements taken from space through remote sensing,” said Erika Podest, an Earth scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, who is working with GLOBE data. “There are some places in the world where we have no ground data, so citizen scientists can greatly contribute to advancing our knowledge this important part of the Earth system.”

The app itself seems pretty straightforward. I checked for upcoming satellite flyovers and was notified of 6 flyovers that day. It’s pretty quick and easy to step outside and take an observation at one of those times.

I did a quick observation from the street in front of my house and it took about 2 minutes. To identify cloud types, you just match what you see with in-app photos of the different types of clouds. Then you estimate the percentage of cloud cover, or specify if the sky is obscured by blowing snow, or fog, or something else. You can also add pictures, and the app guides you in aiming the camera properly.

The GLOBE Observer app is easy to use, and kind of fun. It’s simple enough to fit a quick cloud observation in between selfies and meal pictures.

Download it and try it out.

You can download the IOS version from the App Store, and the Android version from Google Play.

August 31, 2016May 5, 2019 by Matt Williams

On The Origin Of Phobos’ Groovy Mystery

Mars’ natural satellites – Phobos and Deimos – have been a mystery since they were first discovered. While it is widely believed that they are former asteroids that were captured by Mars’ gravity, this remains unproven. And while some of Phobos’ surface features are known to be the result of Mars’ gravity, the origin of its linear grooves and crater chains (catenae) have remained unknown.

But thanks to a new study by Erik Asphaug of Arizona State University and Michael Nayak from the University of California, we may be closer to understanding how Phobos’ got its “groovy” surface. In short, they believe that re-accretion is the answer, where all the material that was ejected when meteors impacted the moon eventually returned to strike the surface again.

Naturally, Phobos’ mysteries extend beyond its origin and surface features. For instance, despite being much more massive than its counterpart Deimos, it orbits Mars at a much closer distance (9,300 km compared to over 23,000 km). It’s density measurements have also indicated that the moon is not composed of solid rock, and it is known to be significantly porous.

(a) Spacecraft image of Phobos (photo credit: ESA/Mars Express) showing the observed catena of interest (red arrows); (b) reimpact map for a primary impact at Grildrig, azimuth ?? [0: ) rendered in three dimensions. Relative sizes and orientations between a and b are similar and may be correlated from Drunlo, Clustril, Grildrig, Gulliver and Roche craters, respectively. From the correlation, the highlighted catena likely originates from sesquinary ejecta from Grildrig. — *Image of Phobos showing the observed catena of interest (left) and reimpact map for a primary impact at Grildrig (right). Credit: ESA/Mars Express*

Because of this proximity, it is subject to a lot of tidal forces exerted by Mars. This causes its interior, a large portion of which is believed to consist of ice, to flex and stretch. This action, it has been theorized, is what is responsible for the stress fields that have been observed on the moon’s surface.

However, this action cannot account for another common feature on Phobos, which are the striation patterns (aka. grooves) that run perpendicular to the stress fields. These patterns are essentially chains of craters that typically measure 20 km (12 mi) in length, 100 – 200 meters (330 – 660 ft) in width, and usually 30 m (98 ft) in depth.

In the past, it was assumed that these craters were the result of the same impact that created Stickney, the largest impact crater on Phobos. However, analysis from the Mars Express mission revealed that the grooves are not related to Stickney. Instead, they are centered on Phobos’ leading edge and fade away the closer one gets to its trailing edge.

For the sake of their study, which was recently published in Nature Communications, Asphaug and Nayak used computer modeling to simulate how other meteoric impacts could have created these crater patterns, which they theorized were formed when the resulting ejecta circled back and impacted the surface in other locations.

*Image showing the Stickney crater (left) and how ejecta from an impact can form patterns (right) and crater chains (catenae). Credit: ESA/DLR/FU Berlin-Neukum*

As Dr. Asphaug told Universe Today via email, their work was the result of a meeting of minds that spawned an interesting theory:

“Dr. Nayak had been studying with Prof. Francis Nimmo (of UCSC), the idea that ejecta could swap between the Martian moons. So Mikey and I met up to talk about that, and the possibility that Phobos could sweep up its own ejecta. Originally I had been thinking that seismic events (triggered by impacts) might cause Phobos to shed material tidally, since it’s inside the Roche limit, and that this material would thin out into rings that would be reaccreted by Phobos. That still might happen, but for the prominent catenae the answer turned out to be much simpler (after a lot of painstaking computations) – that crater ejecta is faster than Phobos’ escape velocity, but much slower than Mars orbital velocity, and much of it gets swept up after several co-orbits about Mars, forming these patterns.”

Basically, they theorized that if a meteorite stuck Phobos in just the right place, the resulting debris could have been thrown off into space and swept up later as Phobos swung back around mars. Thought Phobos does not have sufficient gravity to re-accrete ejecta on its own, Mars’ gravitational pull ensures that anything thrown off by the moon will be pulled into orbit around it.

Once this debris is pulled into orbit around Mars, it will circle the planet a few times until it eventually falls into Phobos’ orbital path. When that happens, Phobos will collide with it, triggering another impact that throws off more ejecta, thus causing the whole process to repeat itself.

The streaked and stained surface of Phobos. (Image: NASA) — *The streaked and stained surface of Phobos, with the Stickney crater shown in the center. Credit: NASA/JPL/Mars Express*

In the end, Asphaug and Nayak concluded that if an impact hit Phobos at a certain point, the subsequent collisions with the resulting debris would form a chain of craters in discernible patterns – possibly within days. Testing this theory required some computer modeling on an actual crater.

Using Grildrig (a 2.6 km crater near Phobos’ north pole) as a reference point, their model showed that the resulting string of craters was consistent with the chains that have been observed on Phobos’ surface. And while this remains a theory, this initial confirmation does provide a basis for further testing.

“The initial main test of the theory is that the patterns match up, ejecta from Grildrig for example,” said Asphaug. “But it’s still a theory. It has some testable implications that we’re now working on.”

In addition to offering a plausible explanation of Phobos’ surface features, their study is also significant in that it is the first time that sesquinary craters (i.e. craters caused by ejecta that went into orbit around the central planet) were traced back to their primary impacts.

The many faces of Mars inner moon, Phobos (Credit: NASA) — *Mosaic of space images showing the many “faces” of Mars inner moon, Phobos. Credit: NASA*

In the future, this kind of process could prove to be a novel way to assess the surface characteristics of planets and other bodies – such as the heavily cratered moons of Jupiter and Saturn. These findings will also help us to learn more about Phobos history, which in turn will help shed light on the history of Mars.

“[It] expands our ability to make cross-cutting relationships on Phobos that will reveal the sequence of geologic history,” Asphaug added. “Since Phobos’ geologic history is slaved to the tidal dissipation of Mars, in learning the timescale of Phobos geology we learn about the interior structure of Mars”

And all of this information is likely to come in handy when it comes time for NASA to mount crewed missions to the Red Planet. One of the key steps in the proposed “Journey to Mars” is a mission to Phobos, where the crew, a Mars habitat, and the mission’s vehicles will all be deployed in advance of a mission to the Martian surface.

Learning more about the interior structure of Mars is a goal shared by many of NASA’s future missions to the planet, which includes NASA’s InSight Lander (schedules for launch in 2018). Shedding light on Mars geology is expected to go a long way towards explaining how the planet lost its magnetosphere, and hence its atmosphere and surface water, billions of years ago.

Further Reading: Nature Communications

August 31, 2016September 26, 2016 by Matt Williams

Sentinel-1A Satellite Takes A Direct Hit From Millimetre Size Particle

Sentinel-1 satellite, the first satellite to be launched as part of the ESA/EC's Copernicus program. Credit: ESA/ATG medialab

One of the worst things that can happen during an orbital mission is an impact. Near-Earth orbit is literally filled with debris and particulate matter that moves at very high speeds. At worst, a collision with even the smallest object can have catastrophic consequences. At best, it can delay a mission as technicians on the ground try to determine the damage and correct for it.

This was the case when, on August 23rd, the European Space Agency’s Sentinel-1A satellite was hit by a particle while it orbited the Earth. And after several days of reviewing the data from on-board cameras, ground controllers have determined what the culprit was, identified the affected area, and concluded that it has not interrupted the satellite’s operations.

The Sentinel-1A mission was the first satellite to be launched as part of the ESA’s Copernicus program – which is the worlds largest single earth observation program to date. Since it was deployed in 2014, Sentinel-1A has been monitoring Earth using its C-band Synthetic Aperture Radar, which allows for crystal clear images regardless of weather or light conditions.

The picture shows Sentinel-1A’s solar array before and after the impact of a millimetre-size particle on the second panel. The damaged area has a diameter of about 40 cm, which is consistent on this structure with the impact of a fragment of less than 5 millimetres in size. Credit: ESA — *Picturing obtained by one of the Sentinel-1A’s onboard cameras, showing the solar array before and after the impact of a millimeter-size particle on the second panel. Credit: ESA*

In addition to tracking oil spills and mapping sea ice, the satellite has also been monitoring the movement of land surfaces. Recently, it provided invaluable insight into the earthquake in Italy that claimed at least 290 lives and caused widespread damage. These images were used by emergency aid organizations to assist in evacuations, and scientists have begun to analyze them for indications of how the quake occurred.

The first indication that something was wrong came on Tuesday, August 23rd, at 17:07 GMT (10:07 PDT, 13:07 EDT), when controllers noted a small power reduction. At the time, the satellite was at an altitude of 700 km, and slight changes in it’s orientation and orbit were also noticed.

After conducting a preliminary investigation, the operations team at the ESA’s control center hypothesized that the satellite’s solar wing had suffered from an impact with a tiny object. After reviewing footage from the on-board cameras, they spotted a 40 cm hole in one of the solar panels, which was consistent with the impact of a fragment measuring less than 5 mm in size.

However, the power loss was not sufficient to interrupt operations, and the ESA was quick to allay fears that this would result in any interruptions of the Sentinel-1A‘s mission. They also indicated that the object’s small size prevented them from advanced warning.

Artist's impression of Sentinel-1A, showing its solar panels fully deployed. Credit and copyright: ESA–P. Carril, 2014 — *Artist’s impression of Sentinel-1A, showing its solar panels fully deployed. Credit and copyright: ESA–P. Carril, 2014*

As Holger Krag – Head of the Space Debris Office at ESA’s establishment in Darmstadt, Germany – said in an agency press release:

“Such hits, caused by particles of millimeter size, are not unexpected. These very small objects are not trackable from the ground, because only objects greater than about 5 cm can usually be tracked and, thus, avoided by maneuvering the satellites. In this case, assuming the change in attitude and the orbit of the satellite at impact, the typical speed of such a fragment, plus additional parameters, our first estimates indicate that the size of the particle was of a few millimeters.

While it is not clear if the object came from a spent rocket or dead satellite, or was merely a tiny clump of rock, Krag indicated that they are determined to find out. “Analysis continues to obtain indications on whether the origin of the object was natural or man-made,” he said. “The pictures of the affected area show a diameter of roughly 40 cm created on the solar array structure, confirming an impact from the back side, as suggested by the satellite’s attitude rate readings.”

In the meantime, the ESA expects that Sentinel-1A will be back online shortly and doing the job for which it was intended. Beyond monitoring land movements, land use, and oil spills, Sentinel-1A also provides up-to-date information in order to help relief workers around the world respond to natural disasters and humanitarian crises.

The Sentinel-1 satellites, part of the European Union’s Copernicus Program, are operated by ESA on behalf of the European Commission.

Further Reading: Sentinel-1

August 30, 2016September 26, 2016 by Evan Gough

6 Million Years Ago The Milky Way’s Supermassive Black Hole Raged

Artist's concept of Sagittarius A, the supermassive black hole at the center of our galaxy. Credit: NASA/JPL

6 million years ago, when our first human ancestors were doing their thing here on Earth, the black hole at the center of the Milky Way was a ferocious place. Our middle-aged, hibernating black hole only munches lazily on small amounts of hydrogen gas these days. But when the first hominins walked the Earth, Sagittarius A was gobbling up matter and expelling gas at speeds reaching 1,000 km/sec. (2 million mph.)

The evidence for this hyperactive phase in Sagittarius’ life, when it was an Active Galactic Nucleus (AGN), came while astronomers were searching for something else: the Milky Way’s missing mass.

There’s a funny problem in our understanding of our galactic environment. Well, it’s not that funny. It’s actually kind of serious, if you’re serious about understanding the universe. The problem is that we can calculate how much matter we should be able to see in our galaxy, but when we go looking for it, it’s not there. This isn’t just a problems in the Milky Way, it’s a problem in other galaxies, too. The entire universe, in fact.

Our measurements show that the Milky Way has a mass about 1-2 trillion times greater than the Sun. Dark matter, that mysterious and invisible hobgoblin that haunts cosmologists’ nightmares, makes up about five sixths of that mass. Regular, normal matter makes up the last sixth of the galaxy’s mass, about 150-300 billion solar masses. But we can only find about 65 billion solar masses of that normal matter, made up of the familiar protons, neutrons, and electrons. The rest is missing in action.

Astrophysicists at the Harvard-Smithsonian Center for Astrophysics have been looking for that mass, and have written up their results in a new paper.

“We played a cosmic game of hide-and-seek. And we asked ourselves, where could the missing mass be hiding?” says lead author Fabrizio Nicastro, a research associate at the Harvard-Smithsonian Center for Astrophysics (CfA) and astrophysicist at the Italian National Institute of Astrophysics (INAF).

“We analyzed archival X-ray observations from the XMM-Newton spacecraft and found that the missing mass is in the form of a million-degree gaseous fog permeating our galaxy. That fog absorbs X-rays from more distant background sources,” Nicastro continued.

Artist's impression of the ESA's XMM Newton Spacecraft. Image credit: ESA — Artist’s impression of the ESA’s XMM Newton Spacecraft. Image credit: ESA

Nicastro and the other scientists behind the paper analyzed how the x-rays were absorbed and were able to calculate the amount and distribution of normal matter in that fog. The team relied heavily on computer models, and on the XMM-Newton data. But their results did not match up with a uniform distribution of the gaseous fog. Instead, there is an empty “bubble”, where this is no gas. And that bubble extends from the center of the galaxy two-thirds of the way to Earth.

What can explain the bubble? Why would the gaseous fog not be spread more uniformly through the galaxy?

Clearing gas from an area that large would require an enormous amount of energy, and the authors point out that an active black hole would do it. They surmise that Sagittarius A was very active at that time, both feeding on gas falling into itself, and pumping out streams of hot gas at up to 1000 km/sec.

Which brings us to present day, 6 million years later, when the shock-wave caused by that activity has travelled 20,000 light years, creating the bubble around the center of the galaxy.

Another piece of evidence corroborates all this. Near the galactic center is a population of 6 million year old stars, formed from the same material that at one time flowed toward the black hole.

“The different lines of evidence all tie together very well,” says Smithsonian co-author Martin Elvis (CfA). “This active phase lasted for 4 to 8 million years, which is reasonable for a quasar.”

The numbers all match up, too. The gas accounted for in the team’s models and observations add up to 130 billion solar masses. That number wraps everything up pretty nicely, since the missing matter in the galaxy is thought to be between 85 billion and 235 billion solar masses.

This is intriguing stuff, though it’s certainly not the final word on the Milky Way’s missing mass. Two future missions, the European Space Agency’s Athena X-ray Observatory, planned for launch in 2028, and NASA’s proposed X-Ray Surveyor could provide more answers.

Who knows? Maybe not only will we learn more about the missing matter in the Milky Way and other galaxies, we may learn more about the activity at the center of the galaxy, and what ebbs and flows it has gone through, and how that has shaped galactic evolution.

August 30, 2016September 26, 2016 by Matt Williams

Planet 9 Search Turning Up Wealth Of New Objects

Artist's impression of the the possible Planet 9 at the edge of the Solar System. Credit: Robin Dienel/Carnegie Science

In 2014, Scott Sheppard of the Carnegie Institution for Science and Chadwick Trujillo of Northern Arizona University proposed an interesting idea. Noting the similarities in the orbits of distant Trans-Neptunian Objects (TNOs), they postulated that a massive object was likely influencing them. This was followed in 2016 by Konstantin Batygin and Michael E. Brown of Caltech suggesting that an undiscovered planet was the culprit.

Since that time, the hunt has been on for the infamous “Planet 9” in our Solar System. And while no direct evidence has been produced, astronomers believe they are getting closer to discerning its location. In a paper that was recently accepted by The Astronomical Journal, Sheppard and Trujillo present their latest discoveries, which they claim are further constraining the location of Planet 9.

For the sake of their study, Sheppard and Trujillo relied on information obtained by the Dark Energy Camera on the Victor Blanco 4-meter telescope in Chile and the Japanese Hyper Suprime-Camera on the 8-meter Subaru Telescope in Hawaii. With the help of David Tholen from the University of Hawaii, they have been conducting the largest deep-sky survey for objects beyond Neptune and the Kuiper Belt.

An illustration of the orbits of the new and previously known extremely distant Solar System objects. The clustering of most of their orbits indicates that they are likely be influenced by something massive and very distant, the proposed Planet X. Credit: Robin Dienel/Carnegie Science — An illustration of the orbits of the new and previously known extremely distant Solar System objects – showing the clustering in orbits that indicates that possible presence of Planet X. Credit: Robin Dienel/Carnegie Science

This survey is intended to find more objects that show the same clustering in their orbits, thus offering greater evidence that a massive planet exists in the outer Solar System. As Sheppard explained in a recent Carnegie press release:

“Objects found far beyond Neptune hold the key to unlocking our Solar System’s origins and evolution. Though we believe there are thousands of these small objects, we haven’t found very many of them yet, because they are so far away. The smaller objects can lead us to the much bigger planet we think exists out there. The more we discover, the better we will be able to understand what is going on in the outer Solar System.”

Their most recent discovery was a small collection of more extreme objects who’s peculiar orbits differ from the extreme and inner Oort cloud objects, in terms of both their eccentricities and semi-major axes. As with discoveries made using other instruments, these appear to indicate the presence of something massive effecting their orbits.

All of these objects have been submitted to the International Astronomical Union’s (IAU) Minor Planet Center for designation. They include 2014 SR349, an extreme TNO that has similar orbital characteristics as the previously-discovered extreme bodies that led Sheppard and Trujillo to infer the existence of a massive object in the region.

Another is 2014 FE72, an object who’s orbit is so extreme that it reaches about 3000 AUs from the Sun in a massively-elongated ellipse – something which can only be explained by the influence of a strong gravitational force beyond our Solar System. And in addition to being the first object observed at such a large distance, it is also the first distant Oort Cloud object found to orbit entirely beyond Neptune.

Artist's impression of Planet Nine as an ice giant eclipsing the central Milky Way, with a star-like Sun in the distance. Neptune's orbit is shown as a small ellipse around the Sun. The sky view and appearance are based on the conjectures of its co-proposer, Mike Brown. — *Artist’s impression of Planet Nine as an ice giant eclipsing the central Milky Way, with a star-like Sun in the distance. Credit: ESO/Tomruen/nagualdesign*

And then there’s 2013 FT28, which is similar but also different from the other extreme objects. For instance, 2013 FT28 shows similar clustering in terms of its semi-major axis, eccentricity, inclination, and argument of perihelion angle, but is different when it comes to its longitude of perihelion. This would seem to indicates that this particular clustering trend is less strong among the extreme TNOs.

Beyond the work of Sheppard and Trujillo, nearly 10 percent of the sky has now been explored by astronomers. Relying on the most advanced telescopes, they have revealed that there are several never-before-seen objects that orbit the Sun at extreme distances.

And as more distant objects with unexplained orbital parameters emerge, their interactions seem to fit with the idea of a massive distant planet that could pay a key role in the mechanics of the outer Solar System. However, as Sheppard has indicated, there really isn’t enough evidence yet to draw any conclusions.

“Right now we are dealing with very low-number statistics, so we don’t really understand what is happening in the outer Solar System,” he said. “Greater numbers of extreme trans-Neptunian objects must be found to fully determine the structure of our outer Solar System.”

Alas, we don’t yet know if Planet 9 is out there, and it will probably be many more years before confirmation can be made. But by looking to the visible objects that present a possible sign of its path, we are slowly getting closer to it. With all the news in exoplanet hunting of late, it is interesting to see that we can still go hunting in our own backyard!

Further Reading: The Astrophysical Journal Letters

August 30, 2016February 8, 2023 by Matt Williams

Dark Matter: Hot Or Not?

Illustris simulation, showing the distribution of dark matter in 350 million by 300,000 light years. Galaxies are shown as high-density white dots (left) and as normal, baryonic matter (right). Credit: Markus Haider/Illustris

For almost a century, astronomers and cosmologists have postulated that space is filled with an invisible mass known as “dark matter”. Accounting for 27% of the mass and energy in the observable universe, the existence of this matter was intended to explain all the “missing” baryonic matter in cosmological models. Unfortunately, the concept of dark matter has solved one cosmological problem, only to create another.

If this matter does exist, what is it made of? So far, theories have ranged from saying that it is made up of cold, warm or hot matter, with the most widely-accepted theory being the Lambda Cold Dark Matter (Lambda-CDM) model. However, a new study produced by a team of European astronomer suggests that the Warm Dark Matter (WDM) model may be able to explain the latest observations made of the early Universe.

Continue reading “Dark Matter: Hot Or Not?”

August 29, 2016September 26, 2016 by Matt Williams

Who Else Is Looking For Cool Worlds Around Proxima Centauri?

Artist's impression of a system of exoplanets orbiting a low mass, red dwarf star. Credit: NASA/JPL

Finding exoplanets is hard work. In addition to requiring seriously sophisticated instruments, it also takes teams of committed scientists; people willing to pour over volumes of data to find the evidence of distant worlds. Professor Kipping, an astronomer based at the Harvard-Smithsonian Center for Astrophysics, is one such person.

Within the astronomical community, Kipping is best known for his work with exomoons. But his research also extends to the study and characterization of exoplanets, which he pursues with his colleagues at the Cool Worlds Laboratory at Columbia University. And what has interested him most in recent years is finding exoplanets around our Sun’s closest neighbor – Proxima Centauri.

Kipping describes himself as a “modeler”, combining novel theoretical modeling with modern statistical data analysis techniques applied to observations. He is also the Principal Investigator (PI) of The Hunt for Exomoons with Kepler (HEK) project and a fellow at the Harvard College Observatory. For the past few years, he and his team have been taking the hunt for exoplanets to the local stellar neighborhood.

The inspiration for this search goes back to 2012, when Kipping was at a conference and heard the news about a series of exoplanets being discovery around Kepler 42 (aka. KOI-961). Using data from the Kepler mission, a team from the California Institute of Technology discovered three exoplanets orbiting this red dwarf star, which is located about 126 light years from Earth.

At the time, Kipping recalled how the author of the study – Professor Philip Steven Muirhead, now an associate professor at the Institute for Astrophysical Research at Boston University – commented that this star system looked a lot like our nearest red dwarf stars – Barnard’s Star and Proxima Centauri.

In addition, Kepler 42’s planets were easy to spot, given that their proximity to the star meant that they completed an orbital period in about a day. Since they pass regularly in front of their star, the odds of catching sight of them using the Transit Method were good.

As Prof. Kipping told Universe Today via email, this was the “ah-ha moment” that would inspire him to look at Proxima Centauri to see if it too had a system of planets:

“We were inspired by the discovery of planets transiting KOI-961 by Phil Muirhead and his team using the Kepler data. The star is very similar to Proxima, a late M-dwarf harboring three sub-Earth sized planets very close to the star. It made me realize that if that system was around Proxima, the transit probability would be 10% and the star’s small size would lead to quite detectable signals.”

*The MOST satellite, a Canadian built space telescope. Credit: Canadian Space Agency*

In essence, Kipping realized that if such a planetary system also existed around Proxima Centauri, a star with similar characteristics, then they would very easy to detect. After that, he and his team began attempting to book time with a space telescope. And by 2014-15, they had been given permission to use the Canadian Space Agency’s Microvariability and Oscillation of Stars (MOST) satellite.

Roughly the same size as a suitcase, the MOST satellite weighs only 54 kg and is equipped with an ultra-high definition telescope that measures just 15 cm in diameter. It is the first Canadian scientific satellite to be placed in orbit in 33 years, and was the first space telescope to be entirely designed and built in Canada.

Despite its size, MOST is ten times more sensitive than the Hubble Space Telescope. In addition, Kipping and his team knew that a mission to look for transiting exoplanets around Proxima Centauri would be too high-risk for something like Hubble. In fact, the CSA initially rejected their applications for this same reason.

“MOST initially denied us because they wanted to look at Alpha Centauri following the announcement by Dumusque et al. of a planet there,” said Kipping. “So understandably Proxima, for which no planets were known at the time, was not as high priority as Alpha Cen. We never even tried for Hubble time, it would be a huge ask to stare HST at a single star for months on end with just a a 10% chance for success.”

Artist's impression of the Earth-like exoplanet discovered orbiting Alpha Centauri B iby the European Southern Observatory on October 17, 2012. Credit: ESO — *Artist’s impression of the Earth-like exoplanet discovered orbiting Alpha Centauri B iby the European Southern Observatory on October 17, 2012. Credit: ESO*

By 2014 and 2015, they secured permission to use MOST and observed Proxima Centauri twice – in May of both years. From this, they acquired a month and half’s-worth of space-based photometry, which they are currently processing to look for transits. As Kipping explained, this was rather challenging, since Proxima Centauri is a very active star – subject to star flares.

“The star flares very frequently and prominently in our data,” he said. “Correcting for this effect has been one the major obstacles in our analysis. On the plus side, the rotational activity is fairly subdued. The other issue we have is that MOST orbits the Earth once every 100 minutes, so we get data gaps every time MOST goes behind the Earth.”

Their efforts to find exoplanets around Proxima Centauri are especially significant in light of the European Southern Observatory’s recent announcement about the discovery of a terrestrial exoplanet within Proxima Centauri’s habitable zone (Proxima b). But compared to the ESO’s Pale Red Dot project, Kipping and his team were relying on different methods.

As Kipping explained, this came down to the difference between the Transit Method and the Radial Velocity Method:

“Essentially, we seek planets which have the right alignment to transit (or eclipse) across the face of the star, whereas radial velocities look for the wobbling motion of a star in response to the gravitational influence of an orbiting planet. Transits are always less likely to succeed for a given star, because we require the alignment to be just right. However, the payoff is that we can learn way more about the planet, including things like it’s size, density, atmosphere and presence of moons and rings.”

*Artist’s impression of the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. Credit: ESO/M. Kornmesser*

In the coming months and years, Kipping and his team may be called upon to follow up on the success of the ESO’s discovery. Having detected Proxima b using the Radial Velocity method, it now lies to astronomers to confirm the existence of this planet using another detection method.

In addition, much can be learned about a planet through the Transit Method, which would be helpful considering all the things we still don’t know about Proxima b. This includes information about its atmosphere, which the Transit Method is often able to reveal through spectroscopic measurements.

Suffice it to say, Kipping and his colleagues are quite excited by the announcement of Proxima b. As he put it:

“This is perhaps the most important exoplanet discovery in the last decade. It would be bitterly disappointing if Proxima b does not transit though, a planet which is paradoxically so close yet so far in terms of our ability to learn more about it. For us, transits would not just be the icing on the cake, serving merely as a confirmation signal – rather, transits open the door to learning the intimate secrets of Proxima, changing Proxima b from a single, anonymous data point to a rich world where each month we would hear about new discoveries of her nature and character.”

This coming September, Kipping will be joining the faculty at Columbia University, where he will continue in his hunt for exoplanets. One can only hope that those he and his colleagues find are also within reach!

Further Reading: Cool Worlds