I know, you all yearn for it, to have your brains seeded with the knowledge of things to come and knowledge that is gifted to us that may reveal the very secrets of our Universe.
TESS readies for takeoff
NASA’s Transiting Exoplanet Survey Satellite (TESS) is set to launch on a SpaceX Falcon 9 rocket from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida no earlier than April 16, 2018. Once in orbit, TESS will spend about two years surveying 200,000 of the brightest stars near the sun to search for planets outside our solar system. Credit: NASA
(phys.org) - - Satellite developed by MIT aims to discover thousands of nearby exoplanets, including at least 50 Earth-sized ones.
There are potentially thousands of planets that lie just outside our solar system—galactic neighbors that could be rocky worlds or more tenuous collections of gas and dust. Where are these closest exoplanets located? And which of them might we be able to probe for clues to their composition and even habitability? The Transiting Exoplanet Survey Satellite (TESS) will be the first to seek out these nearby worlds.
The NASA-funded spacecraft, not much larger than a refrigerator, carries four cameras that were conceived, designed, and built at MIT, with one wide-eyed vision: to survey the nearest, brightest stars in the sky for signs of passing planets.
Now, more than a decade since MIT scientists first proposed the mission, TESS is about to get off the ground. The spacecraft is scheduled to launch on a SpaceX Falcon 9 rocket from Cape Canaveral Air Force Station in Florida, no earlier than April 16, at 6:32 p.m. EDT.
TESS will spend two years scanning nearly the entire sky—a field of view that can encompass more than 20 million stars. Scientists expect that thousands of these stars will host transiting planets, which they hope to detect through images taken with TESS's cameras.
Amid this extrasolar bounty, the TESS science team at MIT aims to measure the masses of at least 50 small planets whose radii are less than four times that of Earth. Many of TESS's planets should be close enough to our own that, once they are identified by TESS, scientists can zoom in on them using other telescopes, to detect atmospheres, characterize atmospheric conditions, and even look for signs of habitability.
"TESS is kind of like a scout," says Natalia Guerrero, deputy manager of TESS Objects of Interest, an MIT-led effort that will catalog objects captured in TESS data that may be potential exoplanets.
"We're on this scenic tour of the whole sky, and in some ways we have no idea what we will see," Guerrero says. "It's like we're making a treasure map: Here are all these cool things. Now, go after them."
A seed, planted in space
TESS's origins arose from an even smaller satellite that was designed and built by MIT and launched into space by NASA on Oct. 9, 2000. The High Energy Transient Explorer 2, or HETE-2, orbited Earth for seven years, on a mission to detect and localize gamma-ray bursts—high-energy explosions that emit massive, fleeting bursts of gamma and X-rays.
To detect such extreme, short-lived phenomena, scientists at MIT, led by principal investigator George Ricker, integrated into the satellite a suite of optical and X-ray cameras outfitted with CCDs, or charge-coupled devices, designed to record intensities and positions of light in an electronic format.
"With the advent of CCDs in the 1970s, you had this fantastic device ... which made a lot of things easier for astronomers," says HETE-2 team member Joel Villasenor, who is now also instrument scientist for TESS. "You just sum up all the pixels on a CCD, which gives you the intensity, or magnitude, of light. So CCDs really broke things open for astronomy."
In 2004, Ricker and the HETE-2 team wondered whether the satellite's optical cameras could pick out other objects in the sky that had begun to attract the astronomy community: exoplanets. Around this time, only a handful of planets outside our solar system had been discovered. These were found with a technique known as the transit method, which involves looking for periodic dips in the light from certain stars, which may signal a planet passing in front of the star.
"We were thinking, was the photometry of HETE-2's cameras sufficient so that we could point to a part of the sky and detect one of these dips? Needless to say, it didn't exactly work," Villasenor recalls. "But that was sort of the seed that started us thinking, maybe we should try to fly CCDs with a camera to try and detect these things."
A path, cleared
In 2006, Ricker and his team at MIT proposed a small, low cost satellite (HETE-S) to NASA as a Discovery class mission, and later on as a privately funded mission for $20 million. But as the cost of, and interest in, an all-sky exoplanet survey grew, they decided instead to seek NASA funding, at a higher level of $120 million. In 2008, they submitted a proposal for a NASA Small Explorer (SMEX) Class Mission with the new name—TESS.
At this time, the satellite design included six CCD cameras, and the team proposed that the spacecraft fly in a low-Earth orbit, similar to that of HETE-2. Such an orbit, they reasoned, should keep observing efficiency relatively high, as they already had erected data-receiving ground stations for HETE-2 that could also be put to use for TESS.
But they soon realized that a low-Earth orbit would have a negative impact on TESS's much more sensitive cameras. The spacecraft's reaction to the Earth's magnetic field, for example, could lead to significant "spacecraft jitter," producing noise that hides an exoplanet's telltale dip in starlight.
NASA bypassed this first proposal, and the team went back to the drawing board, this time emerging with a new plan that hinged on a completely novel orbit. With the help of engineers from NASA's Goddard Space Flight Center and the Aerospace Corporation, the team identified a never-before-used "lunar-resonant" orbit that would keep the spacecraft extremely stable, while giving it a full-sky view.
Once TESS reaches this orbit, it will slingshot between the Earth and the moon on a highly elliptical path that could keep TESS orbiting for decades, shepherded by the moon's gravitational pull.
"The moon and the satellite are in a sort of dance," Villasenor says. "The moon pulls the satellite on one side, and by the time TESS completes one orbit, the moon is on the other side tugging in the opposite direction. The overall effect is the moon's pull is evened out, and it's a very stable configuration over many years. Nobody's done this before, and I suspect other programs will try to use this orbit later on."
In its current planned trajectory, TESS will swing out toward the moon for less than two weeks, gathering data, then swing back toward the Earth where, on its closest approach, it will transmit the data back to ground stations from 67,000 miles above the surface before swinging back out. Ultimately, this orbit will save TESS a huge amount of fuel, as it won't need to burn its thrusters on a regular basis to keep on its path.
With this revamped orbit, the TESS team submitted a second proposal in 2010, this time as an Explorer class mission, which NASA approved in 2013. It was around this time that the Kepler Space Telescope ended its original survey for exoplanets. The observatory, which was launched in 2009, stared at one specific patch of the sky for four years, to monitor the light from distant stars for signs of transiting planets.
By 2013, two of Kepler's four reaction wheels had worn out, preventing the spacecraft from continuing its original survey. At this point, the telescope's measurements had enabled the discovery of nearly 1,000 confirmed exoplanets. Kepler, designed to study far-off stars, paved the way for TESS, a mission with a much wider view, to scan the nearest stars to Earth.
"Kepler went up, and was this huge success, and researchers said, 'We can do this kind of science, and there are planets everywhere," says TESS member Jennifer Burt, an MIT-Kavli postdoc. "And I think that was really the scientific check box that we needed for NASA to say, 'Okay, TESS makes a lot of sense now.' It'll enable not just detecting planets, but finding planets that we can thoroughly characterize after the fact."
Stripes in the sky
With the selection by NASA, the TESS team set up facilities on campus and in MIT's Lincoln Laboratory to build and test the spacecraft's cameras. The engineers designed "deep depletion" CCDs specifically for TESS, meaning that the cameras can detect light over a wide range of wavelengths up to the near infrared. This is important, as many of the nearby stars TESS will monitor are red-dwarfs—small, cool stars that emit less brightly than the sun and in the infrared part of the electromagnetic spectrum.
If scientists can detect periodic dips in the light from such stars, this may signal the presence of planets with significantly tighter orbits than that of Earth. Nevertheless, there is a chance that some of these planets may be within the "habitable zone," as they would circle much cooler stars, compared with the sun. Since these stars are relatively close by, scientists can do follow-up observations with ground-based telescopes to help identify whether conditions might indeed be suitable for life.
TESS's cameras are mounted on the top of the satellite and surrounded by a protective cone to shield them from other forms of electromagnetic radiation. Each camera has a 24 by 24 degree view of the sky, large enough to encompass the Orion constellation. The satellite will start its observations in the Southern Hemisphere and will divide the sky into 13 stripes, monitoring each segment for 27 days before pivoting to the next. TESS should be able to observe nearly the entire sky in the Southern Hemisphere in its first year, before moving on to the Northern Hemisphere in its second year.
While TESS points at one stripe of the sky, its cameras will take pictures of the stars in that portion. Ricker and his colleagues have made a list of 200,000 nearby, bright stars that they would particularly want to observe. The satellite's cameras will create "postage stamp" images that include pixels around each of these stars. These images will be taken every two minutes, in order to maximize the chance of catching the moment that a planet crosses in front of its star. The cameras will also take full-frame images of all the stars in a particular stripe of the sky, every 30 minutes.
"With the two-minute pictures, you can get a movie-like image of what the starlight is doing as the planet is crossing in front of its host star," Guerrero says. "For the 30-minute images, people are excited about maybe seeing supernovae, asteroids, or counterparts to gravitational waves. We have no idea what we're going to see at that timescale."
Are we alone?
After TESS launches, the team expects that the satellite will reestablish contact within the first week, during which it will turn on all its instruments and cameras. Then, there will be a 60-day commissioning phase, as engineers at NASA and MIT calibrate the instruments and monitor the satellite's trajectory and performance. After that, TESS will begin to collect and downlink images of the sky. Scientists at MIT and NASA will take the raw data and convert it into light curves that indicate the changing brightness of a star over time.
From there, the TESS Science Team, including Sara Seager, the Class of 1941 Professor of Earth, Atmospheric and Planetary Sciences, and deputy director of science for TESS, will look through thousands of light curves, for at least two similar dips in starlight, indicating that a planet may have passed twice in front of its star. Seager and her colleagues will then employ a battery of methods to determine the mass of a potential planet.
"Mass is a defining planetary characteristic," Seager says. "If you just know that a planet is twice the size of Earth, it could be a lot of things: a rocky world with a thin atmosphere, or what we call a "mini-Neptune"—a rocky world with a giant gas envelope, where it would be a huge greenhouse blanket, and there would be no life on the surface. So mass and size together give us an average planet density, which tells us a huge amount about what the planet is."
During TESS's two-year mission, Seager and her colleagues aim to measure the masses of 50 planets with radii less than four times that of Earth—dimensions that could signal further observations for signs of habitability. Meanwhile, the whole scientific community and public will get a chance to search through TESS data for their own exoplanets. Once the data are calibrated, the team will make them publicly available. Anyone will be able to download the data and draw their own interpretations, including high school students, armchair astronomers, and other research institutions.
With so many eyes on TESS'S data, Seager says there's a chance that, some day, a nearby planet discovered by TESS might be found to have signs of life.
"There's no science that will tell us life is out there right now, except that small rocky planets appear to be incredibly common," Seager says. "They appear to be everywhere we look. So it's got to be there somewhere."
TESS is a NASA Astrophysics Explorer mission led and operated by MIT in Cambridge, Massachusetts, and managed by NASA's Goddard Space Flight Center in Greenbelt, Maryland. George Ricker of MIT's Kavli Institute for Astrophysics and Space Research serves as principal investigator for the mission. Additional partners include Orbital ATK, NASA's Ames Research Center, the Harvard-Smithsonian Center for Astrophysics, and the Space Telescope Science Institute. More than a dozen universities, research institutes, and observatories worldwide are participants in the mission.
Source: https://phys.org/news/2018-04-tess-readies-takeoff.html#jCp
STEVE RETURNS
(spaceweather.com) - - Last night in Alberta, Canada, photographer Alan Dyer looked up and saw a mauve ribbon of light bisecting the night sky. Auroras? Not exactly. "It was STEVE," says Dyer, who took these pictures of the glowing arc:
STEVE (Strong Thermal Emission Velocity Enhancement) often appears alongside auroras, but it is not the same thing. Researchers are only beginning to understand the phenomenon--aided by a chance encounter between STEVE and a European satellite. In situ measurements suggest that STEVE is the afterglow of a hot ribbon of gas that flows through Earth's magnetosphere during some geomagnetic storms.
Dyer caught STEVE just as it was fading. Other photographers saw a more spectacular display.
"My dog barked at STEVE for the entire hour it was visible," reports Matthew Wheeler of Robson Valley, British Columbia. "We spotted the ribbon just after midnight, and even without dark-adapted eyes it was easy to see the textures moving at astonishing speed."
Video, looking straight up at STEVE, shows the beautiful interaction between the purple ribbon and nearby green "picket fence" auroras. "The purple ribbon was moving much faster than the green pickets," says Wheeler. "And while their forms varied from smooth to ragged and back again, their path across the sky was almost constant for the whole hour--as it has since I first noticed STEVE over this valley in the 1980s."
Much about STEVE remains a mystery. Researchers still don't understand why STEVE is purple, nor can they predict which geomagnetic storms will lure the arc out of hiding. Recent research suggests that STEVE loves equinoxes. The arc is seen most often during spring and fall. This means now is the season for STEVE. More sightings are possible in the nights ahead as the solar wind continues to blow.
Source & Videos of STEVE in Action!: http://spaceweather.com/
New 4K NASA video will take you on a breathtaking tour of Earth's moon
(newatlas.com) - - NASA has released a stunningly detailed 4K virtual tour of a selection of the Moon's most fascinating and historically important features. Earth's satellite remains the only alien world ever to be visited by a crewed mission, and is likely to be revisited in the coming decades, as space agencies across the globe look to extend the boundaries of human exploration.
The new video was constructed from nine years' worth of data harvested by NASA's Lunar Reconnaissance Orbiter (LRO), which has been studying Earth's moon since its arrival there in June 2009. The LRO has revealed the Moon to be a surprisingly complex, dynamic world, and helped scientists gain a clearer picture of how our solar system evolved into the stunningly diverse cosmic environment we see today.
The tour takes the viewer from fascinating geological features, such as the 2,500-km (1,600-mile)-wide South Pole-Aitken Basin, to the historic landing site of the Apollo 17 mission in the Taurus-Littrow Valley.
Earth's moon is of tremendous scientific and cultural importance to the human race. Its face has been seen by almost every person to inhabit our blue planet, but until very recently, at least in terms of human history, it has been beyond our grasp.
Over the course of the Apollo era, which ran through the 1960s and early 70s, 12 astronauts set foot on the Moon. Sadly, following the Apollo 17 mission in 1972, Earth's satellite was abandoned to the remit of robotic exploration. Thankfully, ambitious plans are in the works to return man to lunar space, and eventually, back to the surface.
Observations made by probes like the LRO will be pivotal in selecting the locations of future Moon exploration missions. Shackleton crater, for example, could be an ideal site for a lunar colony due to the relative ease of access to water ice, which was discovered lurking in the perennial shade at the bottom of the ominous crater by the LRO. Frozen water could be used for any number of purposes, the most ambitious of which involves using the resource as a component in rocket fuel production.
Returning to the Moon is an integral step in NASA's overarching goal to send a crewed mission to Mars. Earth's closest celestial partner is set to be used as a proving ground for the technologies needed to keep astronauts alive during a long-haul return trip to the Red Planet. Other nations, including China and Russia, are also seeking to plant their flags, both metaphorically, and physically, on the Moon and Mars.
One of the key technologies that could make an eventual lunar base a reality is additive manufacturing, otherwise known as 3D printing. Space agencies are exploring the possibility of deploying robot workers to print protective habitats using lunar soil, otherwise known as regolith, as one of the main ingredients. If feasible, constructing protective domes in situ would be enormously preferable in terms of cost and logistics when compared to the option of lifting a ready-made base up through Earth's atmosphere, transporting it to the Moon, and setting it down on the lunar surface.
Before any ambitious crewed missions can come to fruition, a new generation of robotic explorers will trundle across the lunar surface, collecting samples, and further exploring our planet's enigmatic partner, in order to make ready for the arrival of their fleshy overlords.
Watch this jaw dropping video of our Moon in stunning 4K video!:
Source With More Pix & Video
Beyond the Milky Way: The sublime beauty of our galactic neighbors
This image by NASA's Hubble Space Telescope shows a face-on view of the spiral galaxy M51, dubbed the Whirlpool Galaxy(Credit: Credit: NASA, ESA, S. Beckwith (STScI) and the Hubble Heritage Team (STScI/AURA))
(newatlas.com) - - With the upcoming 2020 launch of the James Webb Space Telescope promising to capture pictures of universe with a degree of detail never before seen, we take a look back at some of the most breathtaking intergalactic images humanity has snapped, from early 18th century mysteries to more recent mind-blowing shots from the revolutionary Hubble Space Telescope.
In 1888 an amateur astronomer in England named Isaac Roberts captured a groundbreaking image. This long-exposure photograph taken at Roberts' home observatory was one of the first images even taken of the galaxy Andromeda. At the time Roberts identified it as the Andromeda Nebula, as it wasn't until the next century that we truly understood we were seeing a completely different galaxy, outside of our own Milky Way.
Over the 20th century our knowledge of the universe expanded, as did our technological ability to capture images its outer reaches. The Hubble Space Telescope allowed us to pull back the curtains on the deep limits of the universe and the new millennium promises an even higher definition imaging with the James Webb Space Telescope.
Despite ongoing delays, the JWT promises to take us even closer to the edge of time and space, delivering a new perspective on some of the oldest galaxies in the universe, potentially just a few hundred million years after the big bang.
See more spectacular photos Here!
Newly discovered salty subglacial lakes could help search for life in solar system
A cold and windy spring night on the vast landscape of Devon Ice Cap -- twosubglacial lakes are lurking 750 m below the surface. Credit: Anja Rutishauser
(phys.org) - - An analysis of radar data led scientists to an unexpected discovery of two lakes located beneath 550 to 750 metres of ice underneath the Devon Ice Cap, one of the largest ice caps in the Canadian Arctic. They are thought to be the first isolated hypersaline subglacial lakes in the world.
"We weren't looking for subglacial lakes. The ice is frozen to the ground underneath that part of the Devon Ice Cap, so we didn't expect to find liquid water," said Anja Rutishauser, PhD student at the University of Alberta, who made the discovery while studying airborne radar data acquired by NASA and The University of Texas Institute for Geophysics (UTIG) to describe the bedrock conditions underneath the Devon Ice Cap. Ice penetrating radar sounding measurements are based on electromagnetic waves that are sent through the ice and reflected back at contrasts in the subsurface materials, essentially allowing scientists to see through the ice.
"We saw these radar signatures telling us there's water, but we thought it was impossible that there could be liquid water underneath this ice, where it is below -10C."
While there are more than 400 known subglacial lakes in the world, concentrated primarily in Antarctica with a few in Greenland, these are the first found in the Canadian Arctic. And unlike all the others—which are believed to contain freshwater—these two appear to consist of hypersaline water. Rutishauser explained that the source of the salinity comes from salt-bearing geologic outcrops underneath the ice.
In transit view during an aerogeophysical survey flight over Canadian Arcticice caps. Credit: Gregory Ng
Rutishauser collaborated with her PhD supervisor, UAlberta glaciologist Martin Sharp and University of Texas geophysicist Don Blankenship as well as other scientists from University of Texas at Austin, Montana State University, Stanford University, and the Scott Polar Research Institute to test her hypothesis. The bodies of water—roughly eight and five kilometres squared, respectively—exist at temperatures below freezing and are not connected to any marine water sources or surface meltwater inputs, but rather are hypersaline, containing water four to five times saltier than seawater, which allows the water to remain liquid at these cold temperatures.
These newly discovered lakes are a potential habitat for microbial life and may assist scientists in the search for life beyond earth. Though all subglacial lakes are good analogues for life beyond Earth, the hypersaline nature of the Devon lakes makes them particularly tantalizing analogues for ice-covered moons in our solar system.
"We think they can serve as a good analogue for Europa, one of Jupiter's icy moons, which has similar conditions of salty liquid water underneath—and maybe within—an ice shell," said Rutishauser.
Pilots' view from the cockpit of a Kenn Borek Air Ltd. DC-3 aircraft duringan aerogeophysical survey flight over Canadian Arctic ice caps. Credit: Gregory Ng
"If there is microbial life in these lakes, it has likely been under the ice for at least 120,000 years, so it likely evolved in isolation. If we can collect a sample of the water, we may determine whether microbial life exists, how it evolved, and how it continues to live in this cold environment with no connection to the atmosphere."
Rutishauser believes that similar salty rock outcrops occur underneath other Canadian Arctic ice caps. "Although the Devon hypersaline subglacial lakes are very unique discoveries, we may find networks of brine-rich subglacial water systems elsewhere in the Canadian Arctic."
Rutishauser and her colleagues are now partnering with The W. Garfield Weston Foundation to undertake a more detailed airborne geophysical survey over the Devon Ice Cap this spring to derive more information about the lakes and their geological and hydrological contexts. For three generations, The W. Garfield Weston Foundation has pursued its mission to enhance and enrich the lives of Canadians. With a focus on medical research, the environment, and education, the Foundation aims to catalyze inquiry and innovation to bring about long-term change. As the Foundation marks its 60th anniversary, it continues to collaborate with a broad range of Canadian charities to further world-class research, explore new ideas, and create tangible benefits for the communities in which it works.
Following completion of her PhD with Sharp at the University of Alberta this summer, Rutishauser will start a postdoctoral fellowship in the fall at the University of Texas at Austin.
"Discovery of a hypersaline subglacial lake complex beneath Devon Ice Cap, Canadian Arctic" was published in the April 11 edition of Science Advances.
Source
And Now, some baby goats!
TESS readies for takeoff
(phys.org) - - Satellite developed by MIT aims to discover thousands of nearby exoplanets, including at least 50 Earth-sized ones.
There are potentially thousands of planets that lie just outside our solar system—galactic neighbors that could be rocky worlds or more tenuous collections of gas and dust. Where are these closest exoplanets located? And which of them might we be able to probe for clues to their composition and even habitability? The Transiting Exoplanet Survey Satellite (TESS) will be the first to seek out these nearby worlds.
The NASA-funded spacecraft, not much larger than a refrigerator, carries four cameras that were conceived, designed, and built at MIT, with one wide-eyed vision: to survey the nearest, brightest stars in the sky for signs of passing planets.
Now, more than a decade since MIT scientists first proposed the mission, TESS is about to get off the ground. The spacecraft is scheduled to launch on a SpaceX Falcon 9 rocket from Cape Canaveral Air Force Station in Florida, no earlier than April 16, at 6:32 p.m. EDT.
TESS will spend two years scanning nearly the entire sky—a field of view that can encompass more than 20 million stars. Scientists expect that thousands of these stars will host transiting planets, which they hope to detect through images taken with TESS's cameras.
Amid this extrasolar bounty, the TESS science team at MIT aims to measure the masses of at least 50 small planets whose radii are less than four times that of Earth. Many of TESS's planets should be close enough to our own that, once they are identified by TESS, scientists can zoom in on them using other telescopes, to detect atmospheres, characterize atmospheric conditions, and even look for signs of habitability.
"TESS is kind of like a scout," says Natalia Guerrero, deputy manager of TESS Objects of Interest, an MIT-led effort that will catalog objects captured in TESS data that may be potential exoplanets.
"We're on this scenic tour of the whole sky, and in some ways we have no idea what we will see," Guerrero says. "It's like we're making a treasure map: Here are all these cool things. Now, go after them."
A seed, planted in space
TESS's origins arose from an even smaller satellite that was designed and built by MIT and launched into space by NASA on Oct. 9, 2000. The High Energy Transient Explorer 2, or HETE-2, orbited Earth for seven years, on a mission to detect and localize gamma-ray bursts—high-energy explosions that emit massive, fleeting bursts of gamma and X-rays.
To detect such extreme, short-lived phenomena, scientists at MIT, led by principal investigator George Ricker, integrated into the satellite a suite of optical and X-ray cameras outfitted with CCDs, or charge-coupled devices, designed to record intensities and positions of light in an electronic format.
"With the advent of CCDs in the 1970s, you had this fantastic device ... which made a lot of things easier for astronomers," says HETE-2 team member Joel Villasenor, who is now also instrument scientist for TESS. "You just sum up all the pixels on a CCD, which gives you the intensity, or magnitude, of light. So CCDs really broke things open for astronomy."
In 2004, Ricker and the HETE-2 team wondered whether the satellite's optical cameras could pick out other objects in the sky that had begun to attract the astronomy community: exoplanets. Around this time, only a handful of planets outside our solar system had been discovered. These were found with a technique known as the transit method, which involves looking for periodic dips in the light from certain stars, which may signal a planet passing in front of the star.
"We were thinking, was the photometry of HETE-2's cameras sufficient so that we could point to a part of the sky and detect one of these dips? Needless to say, it didn't exactly work," Villasenor recalls. "But that was sort of the seed that started us thinking, maybe we should try to fly CCDs with a camera to try and detect these things."
A path, cleared
In 2006, Ricker and his team at MIT proposed a small, low cost satellite (HETE-S) to NASA as a Discovery class mission, and later on as a privately funded mission for $20 million. But as the cost of, and interest in, an all-sky exoplanet survey grew, they decided instead to seek NASA funding, at a higher level of $120 million. In 2008, they submitted a proposal for a NASA Small Explorer (SMEX) Class Mission with the new name—TESS.
At this time, the satellite design included six CCD cameras, and the team proposed that the spacecraft fly in a low-Earth orbit, similar to that of HETE-2. Such an orbit, they reasoned, should keep observing efficiency relatively high, as they already had erected data-receiving ground stations for HETE-2 that could also be put to use for TESS.
But they soon realized that a low-Earth orbit would have a negative impact on TESS's much more sensitive cameras. The spacecraft's reaction to the Earth's magnetic field, for example, could lead to significant "spacecraft jitter," producing noise that hides an exoplanet's telltale dip in starlight.
NASA bypassed this first proposal, and the team went back to the drawing board, this time emerging with a new plan that hinged on a completely novel orbit. With the help of engineers from NASA's Goddard Space Flight Center and the Aerospace Corporation, the team identified a never-before-used "lunar-resonant" orbit that would keep the spacecraft extremely stable, while giving it a full-sky view.
Once TESS reaches this orbit, it will slingshot between the Earth and the moon on a highly elliptical path that could keep TESS orbiting for decades, shepherded by the moon's gravitational pull.
"The moon and the satellite are in a sort of dance," Villasenor says. "The moon pulls the satellite on one side, and by the time TESS completes one orbit, the moon is on the other side tugging in the opposite direction. The overall effect is the moon's pull is evened out, and it's a very stable configuration over many years. Nobody's done this before, and I suspect other programs will try to use this orbit later on."
In its current planned trajectory, TESS will swing out toward the moon for less than two weeks, gathering data, then swing back toward the Earth where, on its closest approach, it will transmit the data back to ground stations from 67,000 miles above the surface before swinging back out. Ultimately, this orbit will save TESS a huge amount of fuel, as it won't need to burn its thrusters on a regular basis to keep on its path.
With this revamped orbit, the TESS team submitted a second proposal in 2010, this time as an Explorer class mission, which NASA approved in 2013. It was around this time that the Kepler Space Telescope ended its original survey for exoplanets. The observatory, which was launched in 2009, stared at one specific patch of the sky for four years, to monitor the light from distant stars for signs of transiting planets.
By 2013, two of Kepler's four reaction wheels had worn out, preventing the spacecraft from continuing its original survey. At this point, the telescope's measurements had enabled the discovery of nearly 1,000 confirmed exoplanets. Kepler, designed to study far-off stars, paved the way for TESS, a mission with a much wider view, to scan the nearest stars to Earth.
"Kepler went up, and was this huge success, and researchers said, 'We can do this kind of science, and there are planets everywhere," says TESS member Jennifer Burt, an MIT-Kavli postdoc. "And I think that was really the scientific check box that we needed for NASA to say, 'Okay, TESS makes a lot of sense now.' It'll enable not just detecting planets, but finding planets that we can thoroughly characterize after the fact."
Stripes in the sky
With the selection by NASA, the TESS team set up facilities on campus and in MIT's Lincoln Laboratory to build and test the spacecraft's cameras. The engineers designed "deep depletion" CCDs specifically for TESS, meaning that the cameras can detect light over a wide range of wavelengths up to the near infrared. This is important, as many of the nearby stars TESS will monitor are red-dwarfs—small, cool stars that emit less brightly than the sun and in the infrared part of the electromagnetic spectrum.
If scientists can detect periodic dips in the light from such stars, this may signal the presence of planets with significantly tighter orbits than that of Earth. Nevertheless, there is a chance that some of these planets may be within the "habitable zone," as they would circle much cooler stars, compared with the sun. Since these stars are relatively close by, scientists can do follow-up observations with ground-based telescopes to help identify whether conditions might indeed be suitable for life.
TESS's cameras are mounted on the top of the satellite and surrounded by a protective cone to shield them from other forms of electromagnetic radiation. Each camera has a 24 by 24 degree view of the sky, large enough to encompass the Orion constellation. The satellite will start its observations in the Southern Hemisphere and will divide the sky into 13 stripes, monitoring each segment for 27 days before pivoting to the next. TESS should be able to observe nearly the entire sky in the Southern Hemisphere in its first year, before moving on to the Northern Hemisphere in its second year.
While TESS points at one stripe of the sky, its cameras will take pictures of the stars in that portion. Ricker and his colleagues have made a list of 200,000 nearby, bright stars that they would particularly want to observe. The satellite's cameras will create "postage stamp" images that include pixels around each of these stars. These images will be taken every two minutes, in order to maximize the chance of catching the moment that a planet crosses in front of its star. The cameras will also take full-frame images of all the stars in a particular stripe of the sky, every 30 minutes.
"With the two-minute pictures, you can get a movie-like image of what the starlight is doing as the planet is crossing in front of its host star," Guerrero says. "For the 30-minute images, people are excited about maybe seeing supernovae, asteroids, or counterparts to gravitational waves. We have no idea what we're going to see at that timescale."
Are we alone?
After TESS launches, the team expects that the satellite will reestablish contact within the first week, during which it will turn on all its instruments and cameras. Then, there will be a 60-day commissioning phase, as engineers at NASA and MIT calibrate the instruments and monitor the satellite's trajectory and performance. After that, TESS will begin to collect and downlink images of the sky. Scientists at MIT and NASA will take the raw data and convert it into light curves that indicate the changing brightness of a star over time.
From there, the TESS Science Team, including Sara Seager, the Class of 1941 Professor of Earth, Atmospheric and Planetary Sciences, and deputy director of science for TESS, will look through thousands of light curves, for at least two similar dips in starlight, indicating that a planet may have passed twice in front of its star. Seager and her colleagues will then employ a battery of methods to determine the mass of a potential planet.
"Mass is a defining planetary characteristic," Seager says. "If you just know that a planet is twice the size of Earth, it could be a lot of things: a rocky world with a thin atmosphere, or what we call a "mini-Neptune"—a rocky world with a giant gas envelope, where it would be a huge greenhouse blanket, and there would be no life on the surface. So mass and size together give us an average planet density, which tells us a huge amount about what the planet is."
During TESS's two-year mission, Seager and her colleagues aim to measure the masses of 50 planets with radii less than four times that of Earth—dimensions that could signal further observations for signs of habitability. Meanwhile, the whole scientific community and public will get a chance to search through TESS data for their own exoplanets. Once the data are calibrated, the team will make them publicly available. Anyone will be able to download the data and draw their own interpretations, including high school students, armchair astronomers, and other research institutions.
With so many eyes on TESS'S data, Seager says there's a chance that, some day, a nearby planet discovered by TESS might be found to have signs of life.
"There's no science that will tell us life is out there right now, except that small rocky planets appear to be incredibly common," Seager says. "They appear to be everywhere we look. So it's got to be there somewhere."
TESS is a NASA Astrophysics Explorer mission led and operated by MIT in Cambridge, Massachusetts, and managed by NASA's Goddard Space Flight Center in Greenbelt, Maryland. George Ricker of MIT's Kavli Institute for Astrophysics and Space Research serves as principal investigator for the mission. Additional partners include Orbital ATK, NASA's Ames Research Center, the Harvard-Smithsonian Center for Astrophysics, and the Space Telescope Science Institute. More than a dozen universities, research institutes, and observatories worldwide are participants in the mission.
Source: https://phys.org/news/2018-04-tess-readies-takeoff.html#jCp
STEVE RETURNS
(spaceweather.com) - - Last night in Alberta, Canada, photographer Alan Dyer looked up and saw a mauve ribbon of light bisecting the night sky. Auroras? Not exactly. "It was STEVE," says Dyer, who took these pictures of the glowing arc:
STEVE (Strong Thermal Emission Velocity Enhancement) often appears alongside auroras, but it is not the same thing. Researchers are only beginning to understand the phenomenon--aided by a chance encounter between STEVE and a European satellite. In situ measurements suggest that STEVE is the afterglow of a hot ribbon of gas that flows through Earth's magnetosphere during some geomagnetic storms.
Dyer caught STEVE just as it was fading. Other photographers saw a more spectacular display.
"My dog barked at STEVE for the entire hour it was visible," reports Matthew Wheeler of Robson Valley, British Columbia. "We spotted the ribbon just after midnight, and even without dark-adapted eyes it was easy to see the textures moving at astonishing speed."
Video, looking straight up at STEVE, shows the beautiful interaction between the purple ribbon and nearby green "picket fence" auroras. "The purple ribbon was moving much faster than the green pickets," says Wheeler. "And while their forms varied from smooth to ragged and back again, their path across the sky was almost constant for the whole hour--as it has since I first noticed STEVE over this valley in the 1980s."
Much about STEVE remains a mystery. Researchers still don't understand why STEVE is purple, nor can they predict which geomagnetic storms will lure the arc out of hiding. Recent research suggests that STEVE loves equinoxes. The arc is seen most often during spring and fall. This means now is the season for STEVE. More sightings are possible in the nights ahead as the solar wind continues to blow.
Source & Videos of STEVE in Action!: http://spaceweather.com/
New 4K NASA video will take you on a breathtaking tour of Earth's moon
(newatlas.com) - - NASA has released a stunningly detailed 4K virtual tour of a selection of the Moon's most fascinating and historically important features. Earth's satellite remains the only alien world ever to be visited by a crewed mission, and is likely to be revisited in the coming decades, as space agencies across the globe look to extend the boundaries of human exploration.
The new video was constructed from nine years' worth of data harvested by NASA's Lunar Reconnaissance Orbiter (LRO), which has been studying Earth's moon since its arrival there in June 2009. The LRO has revealed the Moon to be a surprisingly complex, dynamic world, and helped scientists gain a clearer picture of how our solar system evolved into the stunningly diverse cosmic environment we see today.
The tour takes the viewer from fascinating geological features, such as the 2,500-km (1,600-mile)-wide South Pole-Aitken Basin, to the historic landing site of the Apollo 17 mission in the Taurus-Littrow Valley.
Earth's moon is of tremendous scientific and cultural importance to the human race. Its face has been seen by almost every person to inhabit our blue planet, but until very recently, at least in terms of human history, it has been beyond our grasp.
Over the course of the Apollo era, which ran through the 1960s and early 70s, 12 astronauts set foot on the Moon. Sadly, following the Apollo 17 mission in 1972, Earth's satellite was abandoned to the remit of robotic exploration. Thankfully, ambitious plans are in the works to return man to lunar space, and eventually, back to the surface.
Observations made by probes like the LRO will be pivotal in selecting the locations of future Moon exploration missions. Shackleton crater, for example, could be an ideal site for a lunar colony due to the relative ease of access to water ice, which was discovered lurking in the perennial shade at the bottom of the ominous crater by the LRO. Frozen water could be used for any number of purposes, the most ambitious of which involves using the resource as a component in rocket fuel production.
Returning to the Moon is an integral step in NASA's overarching goal to send a crewed mission to Mars. Earth's closest celestial partner is set to be used as a proving ground for the technologies needed to keep astronauts alive during a long-haul return trip to the Red Planet. Other nations, including China and Russia, are also seeking to plant their flags, both metaphorically, and physically, on the Moon and Mars.
One of the key technologies that could make an eventual lunar base a reality is additive manufacturing, otherwise known as 3D printing. Space agencies are exploring the possibility of deploying robot workers to print protective habitats using lunar soil, otherwise known as regolith, as one of the main ingredients. If feasible, constructing protective domes in situ would be enormously preferable in terms of cost and logistics when compared to the option of lifting a ready-made base up through Earth's atmosphere, transporting it to the Moon, and setting it down on the lunar surface.
Before any ambitious crewed missions can come to fruition, a new generation of robotic explorers will trundle across the lunar surface, collecting samples, and further exploring our planet's enigmatic partner, in order to make ready for the arrival of their fleshy overlords.
Watch this jaw dropping video of our Moon in stunning 4K video!:
Source With More Pix & Video
Beyond the Milky Way: The sublime beauty of our galactic neighbors
(newatlas.com) - - With the upcoming 2020 launch of the James Webb Space Telescope promising to capture pictures of universe with a degree of detail never before seen, we take a look back at some of the most breathtaking intergalactic images humanity has snapped, from early 18th century mysteries to more recent mind-blowing shots from the revolutionary Hubble Space Telescope.
In 1888 an amateur astronomer in England named Isaac Roberts captured a groundbreaking image. This long-exposure photograph taken at Roberts' home observatory was one of the first images even taken of the galaxy Andromeda. At the time Roberts identified it as the Andromeda Nebula, as it wasn't until the next century that we truly understood we were seeing a completely different galaxy, outside of our own Milky Way.
Over the 20th century our knowledge of the universe expanded, as did our technological ability to capture images its outer reaches. The Hubble Space Telescope allowed us to pull back the curtains on the deep limits of the universe and the new millennium promises an even higher definition imaging with the James Webb Space Telescope.
Despite ongoing delays, the JWT promises to take us even closer to the edge of time and space, delivering a new perspective on some of the oldest galaxies in the universe, potentially just a few hundred million years after the big bang.
See more spectacular photos Here!
(phys.org) - - An analysis of radar data led scientists to an unexpected discovery of two lakes located beneath 550 to 750 metres of ice underneath the Devon Ice Cap, one of the largest ice caps in the Canadian Arctic. They are thought to be the first isolated hypersaline subglacial lakes in the world.
"We weren't looking for subglacial lakes. The ice is frozen to the ground underneath that part of the Devon Ice Cap, so we didn't expect to find liquid water," said Anja Rutishauser, PhD student at the University of Alberta, who made the discovery while studying airborne radar data acquired by NASA and The University of Texas Institute for Geophysics (UTIG) to describe the bedrock conditions underneath the Devon Ice Cap. Ice penetrating radar sounding measurements are based on electromagnetic waves that are sent through the ice and reflected back at contrasts in the subsurface materials, essentially allowing scientists to see through the ice.
"We saw these radar signatures telling us there's water, but we thought it was impossible that there could be liquid water underneath this ice, where it is below -10C."
While there are more than 400 known subglacial lakes in the world, concentrated primarily in Antarctica with a few in Greenland, these are the first found in the Canadian Arctic. And unlike all the others—which are believed to contain freshwater—these two appear to consist of hypersaline water. Rutishauser explained that the source of the salinity comes from salt-bearing geologic outcrops underneath the ice.
Rutishauser collaborated with her PhD supervisor, UAlberta glaciologist Martin Sharp and University of Texas geophysicist Don Blankenship as well as other scientists from University of Texas at Austin, Montana State University, Stanford University, and the Scott Polar Research Institute to test her hypothesis. The bodies of water—roughly eight and five kilometres squared, respectively—exist at temperatures below freezing and are not connected to any marine water sources or surface meltwater inputs, but rather are hypersaline, containing water four to five times saltier than seawater, which allows the water to remain liquid at these cold temperatures.
These newly discovered lakes are a potential habitat for microbial life and may assist scientists in the search for life beyond earth. Though all subglacial lakes are good analogues for life beyond Earth, the hypersaline nature of the Devon lakes makes them particularly tantalizing analogues for ice-covered moons in our solar system.
"We think they can serve as a good analogue for Europa, one of Jupiter's icy moons, which has similar conditions of salty liquid water underneath—and maybe within—an ice shell," said Rutishauser.
"If there is microbial life in these lakes, it has likely been under the ice for at least 120,000 years, so it likely evolved in isolation. If we can collect a sample of the water, we may determine whether microbial life exists, how it evolved, and how it continues to live in this cold environment with no connection to the atmosphere."
Rutishauser believes that similar salty rock outcrops occur underneath other Canadian Arctic ice caps. "Although the Devon hypersaline subglacial lakes are very unique discoveries, we may find networks of brine-rich subglacial water systems elsewhere in the Canadian Arctic."
Rutishauser and her colleagues are now partnering with The W. Garfield Weston Foundation to undertake a more detailed airborne geophysical survey over the Devon Ice Cap this spring to derive more information about the lakes and their geological and hydrological contexts. For three generations, The W. Garfield Weston Foundation has pursued its mission to enhance and enrich the lives of Canadians. With a focus on medical research, the environment, and education, the Foundation aims to catalyze inquiry and innovation to bring about long-term change. As the Foundation marks its 60th anniversary, it continues to collaborate with a broad range of Canadian charities to further world-class research, explore new ideas, and create tangible benefits for the communities in which it works.
Following completion of her PhD with Sharp at the University of Alberta this summer, Rutishauser will start a postdoctoral fellowship in the fall at the University of Texas at Austin.
"Discovery of a hypersaline subglacial lake complex beneath Devon Ice Cap, Canadian Arctic" was published in the April 11 edition of Science Advances.
Source
And Now, some baby goats!
No comments:
Post a Comment