Tag Archives: science

The Earth and Moon, as seen from Mars

The Earth and Moon as seen from Mars

Cool image time! The image above, a composite of four separate Mars Reconnaissance Orbiter pictures, was taken on November 20, 2016.

Each was separately processed prior to combining them so that the moon is bright enough to see. The moon is much darker than Earth and would barely be visible at the same brightness scale as Earth. The combined view retains the correct sizes and positions of the two bodies relative to each other.

The reddish region on Earth is Australia, with Antarctica the bright white area below that.

Hubble takes a look at both Voyagers’ interstellar path

Using the Hubble Space Telescope astronomers have taken a peek at the interstellar material that the two Voyager spacecraft will travel through as they move out and leave the solar system in the coming decades.

Voyager 1 is 13 billion miles from Earth, making it the farthest human-made object ever built. In about 40,000 years, after the spacecraft will no longer be operational and will not be able to gather new data, it will pass within 1.6 light-years of the star Gliese 445, in the constellation Camelopardalis. Its twin, Voyager 2, is 10.5 billion miles from Earth, and will pass 1.7 light-years from the star Ross 248 in about 40,000 years.

For the next 10 years, the Voyagers will be making measurements of interstellar material, magnetic fields, and cosmic rays along their trajectories. Hubble complements the Voyagers’ observations by gazing at two sight lines along each spacecraft’s path to map interstellar structure along their star-bound routes. Each sight line stretches several light-years to nearby stars. Sampling the light from those stars, Hubble’s Space Telescope Imaging Spectrograph measured how interstellar material absorbed some of the starlight, leaving telltale spectral fingerprints.

Hubble found that Voyager 2 will move out of the interstellar cloud that surrounds the solar system in a couple thousand years. The astronomers, based on Hubble data, predict that the spacecraft will spend 90,000 years in a second cloud before passing into a third interstellar cloud.

This is very clever science. It allows data from Hubble to complement the data from the two Voyager spacecraft to better understand the interstellar regions that surround our solar system.

Could Venus’ atmospheric dark streaks be life? Mission proposes to find out

A clever mission concept, proposed as a joint Russian/U.S. unmanned probe to Venus, would use a solar-powered unmanned aerial vehicle (UAV) to fly through the atmosphere for at least a year in order to try to find out the nature of the planet’s atmospheric mysterious dark streaks.

Descending hypersonically into the atmosphere after detaching from the orbiter, the UAV would be filled with hydrogen or helium gas, keeping it buoyant at a nominal floating altitude of 50 kilometers, allowing it to glide through the clouds while moving through the night-time hemisphere. Upon daylight, the solar-powered propellors would kick in and raise the craft’s altitude to around 60 kilometers.

Over the course of three to four days, the craft could move around the planet along the upper atmosphere’s ‘super-rotation,’ the strange phenomenon where the atmosphere seems to be uncoupled from the solid planet and rotates much faster. The UAV would therefore be able to explore the clouds at different altitudes, moving from air mass to air mass, from regions with UV absorbers to regions devoid of them, sampling and measuring the composition of the atmosphere.

The dark streaks, first photographed when Mariner 10 flew past on February 5, 1974 and took more than four thousand pictures, are made of a still unknown material in the upper clouds that absorbs ultraviolet light. The scientists of this mission concept propose that these dark streaks could even be Venusian life.

Finding life at high altitude in the atmosphere of a planet would make sense. After all, microbes have been found at similar heights in Earth’s atmosphere. The challenge for life on Venus is the planet’s extreme temperature. The surface, at 462º C (864º F), is hot enough to melt lead, and the surface pressure of 92 bar is the equivalent of being almost a kilometer under water.

However, in a region beginning around 50 kilometers in altitude and extending a dozen kilometers outward is a sweet spot where the temperature ranges between 30ºC and 70ºC (86ºF to 158ºF) and the pressure is similar to Earth’s surface. Life could potentially survive in this zone where the dark-streaking UV absorber is found.

Intriguingly, the sulfuric acid droplets within the clouds aren’t necessarily a show-stopper to life. Earlier Venera missions detected elongated particles in the lower cloud layer that are about a micron long, about the width of a small bacterium. These particles could be coated in ring-shaped polymers of eight sulphur atoms, called S8 molecules, which are known to exist in Venus’ clouds and which are impervious to the corrosive effects of sulfuric acid. Furthermore, S8 absorbs ultraviolet light, re-radiating it in visible wavelengths. If the particles are microbes, they could have coated themselves in S8, making them resistant to the corrosive effects of sulfuric acid. It has even been postulated that the S8 exists as a result of microbial activity.

Astronomers predict binary stellar merger in 2022

Astronomers are predicting that a two binary stars that orbit so close together that they share an atmosphere will merge and explode as a bright red nova in approximately five years.

According to the actual paper [pdf], they also predict that this will be a naked eye event, visible in the northern hemisphere.

Note that a red nova is not a supernova. These are different types of explosions, with the supernova many times more powerful and rare. Nonetheless, the event itself will spectacular, should the prediction be correct.

Launch of joint NOAA/NASA weather satellite delayed again

Bad timing for NASA’s climate program: The launch of the first Joint Polar Satellite System (JPSS-1), a project of both NOAA and NASA, has been delayed from March 2017 to at least July because of problems with one instrument as well as delays in completing the satellite’s ground systems.

“The main factors delaying the JPSS-1 launch are technical issues discovered during environmental testing of the satellite and the Advanced Technology Microwave Sounder (ATMS) instrument,” Leslie said in a statement. ATMS issues were also one of the reasons for the previous delay. In addition, he cited “challenges in the completion of the common ground system” that will be used for JPSS and other NOAA polar-orbiting weather satellites.

The latest decays prompted NOAA to seek financial relief for the program. A provision in the continuing resolution (CR) passed Dec. 9, which funds the federal government through late April at 2016 levels, gives NOAA the authority to spend at higher levels for the JPSS program.

The goal with the JPSS program was to combine NOAA weather satellites with NASA’s climate research satellites. The program however has had technical and budgetary problems, as this is not the first launch delay or cost overrun.. Moreover, the origins of the JPSS program came from a failed effort in the 1990s and 2000s [pdf] to combine NOAA, Defense Department, and NASA weather satellites under what was then called the NPOESS program. When that program was restructured in 2010 to become JPSS the Defense Department pulled out.

Considering the strong rumors now suggesting that the Trump administration plans to slash NASA’s climate budget while shifting the remains of the program to NOAA, this delay of JPSS-1 is an especially good example of bad timing. It provides the new administration strong ammunition for such proposed changes.

Astronomers identify for the first time the source of a fast radio burst

For the first time astronomers have pinned down the location of a fast radio burst (FRBs), short bursts lasting only seconds that were only discovered about a decade ago.

A dim dwarf galaxy 2.5 billion light years from Earth is sending out the mysterious millisecond-long blasts of radio waves, researchers report Wednesday in Nature and Astrophysical Journal Letters. The bursts traverse vast expanses of time and intergalactic space before reaching our planet. “This really is the first ironclad association of a fast radio burst with another astronomical source, so it’s a pretty huge result,” said Duncan Lorimer, an astronomer at West Virginia University who reported the first detection of a fast radio burst (FRB) in 2007.

The uncertainty of science: Only 18 FRBs have been identified since they were first discovered. Until now, it was unclear whether they occurred in our galaxy or beyond, though it was suspected they were coming from other galaxies. This discovery proves that. What remains unknown is what causes the burst, which signals an energy pulse equivalent to that of 500 million suns.

“I am not exaggerating when I say there are more models for what FRBs could be than there are FRBs,” said Cornell astronomer Shami Chatterjee, the lead author of the new Nature paper. Many scientists think the bursts are emitted by distant neutron stars, the super-dense embers of exploded suns. But some believe they must originate in our own galaxy. Still more suggest that FRBs could be caused by cataclysms like a supernova or a collision of two stars. This last theory was compelling because most FRB detections were one-off events — astronomers never spotted more than one flare from a single source.

Today’s announcement was made possible by the fact that the burst itself is repeating. In fact, it is the only FRB so far known to do so, which also means that what they learn about it might not be applicable to the other bursts.

NASA approves two new asteroid missions

NASA has approved two new unmanned missions aimed at studying the asteroids.

Lucy will take a close look at six Trojan asteroids orbiting near Jupiter, after first visiting a main belt asteroid.

Lucy, a robotic spacecraft, is scheduled to launch in October 2021. It’s slated to arrive at its first destination, a main belt asteroid, in 2025. From 2027 to 2033, Lucy will explore six Jupiter Trojan asteroids. These asteroids are trapped by Jupiter’s gravity in two swarms that share the planet’s orbit, one leading and one trailing Jupiter in its 12-year circuit around the sun. The Trojans are thought to be relics of a much earlier era in the history of the solar system, and may have formed far beyond Jupiter’s current orbit.

Psyche will visit 16 Psyche, an unusual metal-rich asteroid made up mostly of iron and nickel.

While Psyche will use an ion engine, allowing it great freedom and even the potential to go elsewhere, like Dawn, when its primary mission is complete, I have not been able to determine whether Lucy will use conventional chemical altitude thrusters or an ion-type engine.

First sunspot for the next solar cycle spotted

Solar scientists have spotted the first sunspot on the Sun with a reversed polarity, meaning that it really belongs to the next sunspot cycle.

This is not unusual. The sunspots from different cycles routinely overlap by several years, with the sunspots from the old cycle moving close to the equator with time and the new cycle sunspots appearing at high latitudes. What this does suggest is that there will be sunspots after the upcoming solar minimum, rather than the beginning of a new Grand Minimum with no sunspots for decades.

Curiosity looks at Mount Sharp

Looking at Mount Sharp

Cool image time! During the ten day holiday period, during which the Curiosity science and engineering teams generally got a break, they programmed the rover to take a variety of observations over the entire period. Some of those observations included repeated snapshots of the view ahead, using the rover’s navigation camera. The image above, reduced slightly from the full resolution image to show here, is one example of that view.

You can see the dark sandy dune region in the foreground, and the increasing steepness of the slope in the background. What I find most interesting are what look like canyon washes flowing downhill on the right, in what appear to be diagonally parallel cuts. That they do not flow directly downhill suggest to me that they were not created by water flow but by wind erosion, though it is possible that the geology of different bedding plains could have forced the flows in a diagonal direction down the slope. If wind erosion is the cause, however, it suggests a process that took a very long time to occur, as the atmosphere of Mars is so thin.

The route the rover will take is through a much larger canyon slightly off camera to the right. While the slope up the mountain on the left of the image appears to be an easier route, the geology there is not as interesting. Note also that we are not looking at the peak of Mount Sharp, which is much farther south and far higher.

Debris inside Curiosity drill might be cause of problem

Engineers now suspect that a piece of debris inside Curiosity’s drill might be the cause of the recent intermittent problems with the drill’s feed motor, the equipment that extends the drill for drilling.

Experts believe they found a pattern in the way the drill feed motor behaves over time, Eriskson said, and the pattern observed so far matches what engineers would expect to see if a piece of foreign object debris, or FOD, was embedded somewhere inside the drill.

Erickson said the ground team is not sure of the source of the potential debris. It could be a piece of Martian soil or a pebble that somehow got into the mechanism and is gumming up the drill feed motor, or it might be something carried from Earth. “It some sense, it probably doesn’t matter,” Erickson said, detailing how engineers are focused, for now, on recovering use of the drill, one of the rover’s primary tools.

NASA estimates one month to address Webb vibration issues

NASA now expects it will take a month to assess and fix the issues uncovered during vibration testing of the James Webb Space Telescope.

Thomas Zurbuchen, the new head of NASA’s Science Mission Directorate (SMD), told SpacePolicyOnline.com that dealing with the problem likely will consume one of the remaining six months of schedule reserve.

No one at NASA has as yet explained exactly what the “anomalous readings” were during vibration testing. Nor did Zurbuchen indicate what the fix would be.

The recent changes in Earth’s magnetic field

New data from Europe’s Swarm constellation of satellites detail the recent bigger-than-expected changes that have been occurring in the Earth’s magnetic field.

Data from Swarm, combined with observations from the CHAMP and Ørsted satellites, show clearly that the field has weakened by about 3.5% at high latitudes over North America, while it has strengthened about 2% over Asia. The region where the field is at its weakest – the South Atlantic Anomaly – has moved steadily westward and weakened further by about 2%. These changes have occured over the relatively brief period between 1999 and mid-2016.

It was already known that the field has weakened globally by about 10% since the 19th century. These changes appear to be part of that generally weakening. Some scientists have proposed that this is the beginning of an overall flip of the magnetic field’s polarity, something that happens on average about every 300,000 years and last occurred 780,000 years ago. At the moment, however, we have no idea if this theory is correct.

A rover review of 2016

Link here. While my rover updates are focused entirely on where the rovers are, where they will be heading in the immediate future, and the present condition of the rovers themselves, this update provides a very good summary of the entire year’s events for both rovers, focused especially on the science learned by Curiosity. Definitely worth a read.

ESA signs contract for construction of its part of ExoMars 2020

On Friday the European Space Agency signed a contract with Thales Alenia Space for the construction of the European portion of the ExoMars 2020 lander/rover mission.

The contract signed in Rome, Italy, secures the completion of the European elements and the rigorous tests to prove they are ready for launch. These include the rover itself, which will be accommodated within the Russian descent module, along with the carrier module for cruise and delivery to Mars. ESA is also contributing important elements of the descent module, such as the parachute, radar, inertial measurement unit, UHF radio elements, and the onboard computer and software. The science instruments for the rover and surface platform are funded by national agencies of ESA member states, Roscosmos and NASA following calls to the scientific community.

I had missed this last week. The Thales Alenia press release has more information.

I wish them luck, especially the Russians, whose luck with missions to Mars has been truly terrible. I suspect that the Russians will use some variation of their bouncing balloon technology for the lander, which worked on their 1960s lunar rover missions and was successfully copied by NASA for its 1997 Pathfinder/Sojourner rover mission.

Mars rover update: December 22, 2016

Curiosity

Curiosity's location, Sol 1555

For the overall context of Curiosity’s travels, see Pinpointing Curiosity’s location in Gale Crater.

After weeks of drill diagnostics and enforced lack of travel while those diagnostics were on-going, Curiosity finally moved last weekend (Sol 1553). The traverse map to the right, cropped and reduced in resolution to show here, indicates where they went, which wasn’t far and doesn’t really tell us yet which route they plan to take to pick their way through the surrounding dune fields. Thus, the options I indicated in my November 14, 2016 rover update all remain possible. If you go to that update you can see a much better Mars Reconnaissance Orbiter (MRO) overhead image showing the upcoming terrain.

In the meantime, the Curiosity science team is preparing to take a well deserved Christmas-New Year’s break (see update for sols 1566-1568). So that Curiosity doesn’t sit idle during that time, they have uploaded to it an 8-sol plan to cover December 22 to December 30 followed by a 3-sol plan from December 31 to January 2. The rover will not move during this period, but will take lots of different observations in situ.

As they note rightly at the link above, “It’s been quite the year for our rover: we have drilled six holes, performed two scoops, driven 3 km, and climbed 85 vertical meters!” What is more significant is that the best is yet to come!

Opportunity

For the overall context of Opportunity’s travels at Endeavour Crater, see Opportunity’s future travels on Mars.
» Read more

Lace on Mars

Lace on Mars

Cool image time! The image on the right, cropped and reduced in resolution to show here, was taken by Mars Reconnaissance Orbiter June 21, 2016. It shows a region in the high northern latitudes, 80 degrees.

Some seasonal ice on Mars is transparent so that the sunlight penetrates to the bottom of the ice. Heat from this sunlight can turn the ice directly into a gas in a process called sublimation and this gas can scour channels in the loose dirt under the ice. Channels formed by sublimation of a layer of seasonal dry ice are so dense in this area that they look like lace. Gas flow erodes channels as it escapes to the surface of the overlying seasonal ice layer seeking the path of least resistance.

The resolution of the full image is 9.7 feet per pixel. This means that if Curiosity was driving across this surface we would see it. I guarantee however that Curiosity would not find driving here very easy. The ice surface is likely very delicate, and would likely cause any vehicle to bog down. The surface is also likely very alien-looking, which makes me very much want to see what it looks like, up close. This look will unfortunately have to wait, as we as yet do not have the right technology to do it. We would need I think a drone, capable of flying in Mars’s thin atmosphere.

Close-up of Pandora

Pandora

Cool image time! The image on the right, cropped and reduced to show here, is that of Saturn’s small moon Pandora. The full resolution image was taken on December 18, 2016 during Cassini’s closest fly-by of the Moon ever. It was taken from a distance of 25,200 miles, and has a resolution of 787 feet per pixel.

Note the pooling of dust-like material in the crater. Note also the brighter exposed surfaces on the inner crater rim above that pooled material. It appears to my eye almost as if the dust that had coated the higher elevations of this inner rim has for some unknown reason suddenly settled into the crater’s floor.

Pandora orbits just outside Saturn’s F ring, which means it is well exposed to the material in the ring. I would also expect that much of its surface is well coated with particles from the rings.

Fatal clinical drug trial failed because company did not review all data

The company that conducted a fatal French clinical drug trial that killed one and left four permanently damaged has revealed that it did not review all the available data before administering increased dosages to patients.

Not only is it astonishing that they failed to use all the available data, it is even more amazing that the company itself admits to this.

As I noted when this story first broke in February, this is a big deal, and should get major coverage by news organizations.

…it is disturbing that a research company could be so cavalier about the lives of the human beings it is using as test subjects.

This story also illustrates indirectly the significant decline in the state of today’s modern mainstream press as well as the greater interests of the general public. This is a major science story. For a clinical drug study to kill one of its test subjects is a big deal. Yet I am certain that this will get no coverage in any cable news outlet. (If anyone see a video story about this, please let me know.) The written news outlets on the web will likely do a story, but it will not give it wide exposure.

As far as I can tell, this story got no coverage in the press then, and I expect none now. A dark age is surely coming.

Computer modeling suggests light fluctuations at Tabby’s Star are natural

A computer analysis of the light fluctuations of Tabby’s Star suggest to astronomers that the changes are not caused by objects blocking the star (such as an alien Dyson Sphere under construction) but are instead natural variations caused as the star evolves.

This conclusion is decidedly uncertain. They do not know the nature of this stellar evolution. And they are applying avalanche models to the star to come to this conclusion.

The squealing of pigs

Back in October 2010, just days before the mid-term elections, I wrote the following:

For the sake of argument, let’s assume that, come Tuesday, the Republicans take both houses, in a stunning landslide not seen in more than a century. Let’s also assume that the changes in Congress are going to point decidedly away from the recent liberal policies of large government (by both parties). Instead, every indication suggests that the new Congress will lean heavily towards a return to the principles of small government, low taxes, and less regulation.

These assumptions are not unreasonable. Not only do the polls indicate that one or both of the houses of Congress will switch from Democratic to Republican control, the numerous and unexpected primary upsets of established incumbents from both parties — as well the many protests over the past year by large numbers of ordinary citizens — make it clear that the public is not interested in half measures. Come January, the tone and direction of Congress is going to undergo a shocking change.

Anyway, based on these assumptions, we should then expect next year’s Congress to propose unprecedented cuts to the federal budget, including the elimination of many hallowed programs. The recent calls to defund NPR and the Corporation for Public Broadcastings are only one example.

When Congress attempts this, however, the vested interests that have depended on this funding for decades are not going to take the cuts lightly. Or to put it more bluntly, they are going to squeal like pigs, throwing temper tantrums so loud and insane that they will make the complaints of a typical three-year-old seem truly statesman-like. And they will do so in the hope that they will garner sympathy and support from the general voting public, thereby making the cuts difficult to carry out.

The real question then is not whether the new Congress will propose the cuts required to bring the federal government under control, but whether they, as well as the public, will have the courage to follow through, to defy the howls from these spoiled brats, and do what must be done.

The legislative situation with NASA over the summer and fall might give us a hint about whether the next Congress will have the courage to make the cuts that are necessary. In this case Obama actually proposed doing something close to what conservatives have dreamed of for decades: take NASA (and the government) out of the business of building rockets and spacecraft and pass it over to the private sector.

Moreover, despite the strong dislike the right has for Obama and his leftist policies, many conservative pundits both inside and outside of the space activist community publicly supported the President in this effort.

Nonetheless, these policies were not accepted by Congress. Instead, the legislative body passed an authorization bill that requires NASA to build a new heavy-lift rocket and the manned capsule to go with it. Congress did this partly for national security reasons, but mostly because they wanted to protect the jobs in Houston, Florida, and elsewhere that NASA provides, and thus bring home the bacon to their constituents. And they did this because those constituents had squealed at them about the threatened loss of funding.

In other words, elected officials from both parties had teamed up to authorize this pork-laden program in order to keep the pigs quiet. In other words, NASA’s legislative history this past year does not give us an encouraging view of the future. It appears that Congress will give us the same-old same-old, when asked.

More than six years have passed, and my analysis of the situation in 2010 appears almost perfect. While the Republicans did not win both houses of Congress in 2010, they did in 2014. Despite these victories from voters who clearly wanted them to cut back on the power of government, they did exactly what I expected, based on their actions in connection with NASA and SLS: maintain the pork and chicken out whenever challenged by Obama, the Democrats, the press (I repeat myself), and too many spoiled members of the general public.

After the 2016 elections, things have moved even more to the right. The Republicans not only control both houses of Congress, they have a Republican president (though a very unpredictable one) and the leftwing mainstream press has been discredited and no longer monopolizes the distribution of information. What will happen in the coming years?
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“Anomalous readings” detected during testing of Webb telescope

During standard vibration testing to simulate launch, engineers have detected what they call “anomalous readings” in the James Webb Space Telescope.

During the vibration testing on December 3, at Goddard Space Flight Center in Greenbelt, Maryland, accelerometers attached to the telescope detected anomalous readings during a particular test. Further tests to identify the source of the anomaly are underway. The engineering team investigating the vibe anomaly has made numerous detailed visual inspections of the Webb telescope and has found no visible signs of damage.

It is a good sign that they have found no damage. It is also a good thing that they detected these issues now, on the ground, where they can fix them. Webb, almost a decade behind schedule and $8 billion over budget, will be placed at a point a million miles from Earth, where no repair crew will be able to reach it.

Betelgeuse might have eaten a star

Because the red giant star Betelgeuse rotates far faster than it should, astronomers are now theorizing that when it expanded into its present red giant phase about 100,000 years ago it swallowed a companion star which contributed its own angular momentum to the system to speed up the rotation.

This theory is bolstered by evidence of a shell of matter surrounding Betelgeuse that is possibly a remnant of that destroyed star.

Flying over Occator Crater on Ceres

Cool movie time! Using data from Dawn the German Aerospace Center (DLR) has produced a short animation that gives a 3D flyover of Occator Crater on Ceres.

The animated flyover includes topographic and enhanced-color views of the crater, highlighting the central dome feature. The central area has been named Cerealia Facula. Occator’s secondary group of bright spots is called Vinalia Faculae.

The movie is definitely worth watching, especially the sections that show in close-up the bright areas near the crater’s center.

Lots of ice on Ceres

New data from Dawn now suggests that Ceres contains a large amount of ice on or near its surface.

“On Ceres, ice is not just localized to a few craters. It’s everywhere, and nearer to the surface with higher latitudes,” said Thomas Prettyman, principal investigator of Dawn’s gamma ray and neutron detector (GRaND), based at the Planetary Science Institute, Tucson, Arizona. Researchers used the GRaND instrument to determine the concentrations of hydrogen, iron and potassium in the uppermost yard (or meter) of Ceres. GRaND measures the number and energy of gamma rays and neutrons coming from Ceres. Neutrons are produced as galactic cosmic rays interact with Ceres’ surface. Some neutrons get absorbed into the surface, while others escape. Since hydrogen slows down neutrons, it is associated with a fewer neutrons escaping. On Ceres, hydrogen is likely to be in the form of frozen water (which is made of two hydrogen atoms and one oxygen atom).

Rather than a solid ice layer, there is likely to be a porous mixture of rocky materials in which ice fills the pores, researchers found. The GRaND data show that the mixture is about 10 percent ice by weight.

Juno completes third Jupiter flyby

On December 11 Juno successfully completed its third close flyby of Jupiter.

They have released one quite spectacular image taken during the close approach. Expect more to follow soon.

Though they continue to say that they are still considering firing the spacecraft’s main engine to lower and shorten the orbit, I am getting the impression that they are increasingly leaning to leaving things as they are. While this longer orbit will produce larger gaps in their data of the gas giant’s atmosphere (53 days between close approaches versus 14 days), it will also allow them to tract changes over a much longer time period. Considering the risk of a catastrophic failure should they fire the questionable engine, this choice seems quite reasonable.

OSIRIS-REx to search for Earth’s Trojan asteroids

As it heads outward for a rendezvous with the asteroid Bennu, OSIRIS-REx will turn on its instruments for 12 days in February 2017 to hunt for the Trojan asteroids that likely orbit the Sun in the Earth’s orbit 60 degrees ahead and behind it.

Six planets in our solar system are known to harbor Trojan asteroids — Jupiter, Neptune, Mars, Venus, Uranus and Earth. Although more than 6,000 Trojan asteroids are known to be orbiting along with Jupiter, scientists have discovered only one Earth Trojan to date: 2010 TK7, found by NASA’s NEOWISE project in 2010. Scientists predict that there should be more Trojans orbiting Earth, but these asteroids are difficult to detect because they appear close to the sun from Earth’s point of view. In mid-February 2017, however, the OSIRIS-REx spacecraft will be ideally positioned to undertake a survey of the stable point in front of Earth.

Over 12 days, the OSIRIS-REx Earth-Trojan asteroid search will employ the spacecraft’s MapCam imager to methodically scan the space where Earth Trojans are expected to exist. MapCam is part of the OSIRIS-REx Camera Suite, or OCAMS, which was designed and built by researchers at the UA’s Lunar and Planetary Laboratory.

Did a giant black hole eat a star?

New data now suggests that what astronomers had thought was the brightest supernova ever detect might have instead been the ripping apart of a star as it passed too close to a supermassive black hole.

In this scenario, the extreme gravitational forces of a supermassive black hole, located in the centre of the host galaxy, ripped apart a Sun-like star that wandered too close — a so-called tidal disruption event, something so far only observed about 10 times. In the process, the star was “spaghettified” and shocks in the colliding debris as well as heat generated in accretion led to a burst of light. This gave the event the appearance of a very bright supernova explosion, even though the star would not have become a supernova on its own as it did not have enough mass. The team based their new conclusions on observations from a selection of telescopes, both on the ground and in space. Among them was the NASA/ESA Hubble Space Telescope, the Very Large Telescope at ESO’s Paranal Observatory and the New Technology Telescope at ESO’s La Silla Observatory

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