The New Shepard rocket launching from its facility in West Texas. Image: Blue Origin
One of the greatest challenges of modern spaceflight is finding a way to make launching rockets into space commercially viable. Reduced costs will not only mean more launches, but the ability to conduct more ambitious programs in Low Earth Orbit (LEO) and beyond. To this end, many private aerospace companies are investing in reusability, where the first-stages of a rocket and even entire vehicles are retrieved after launch and reused.
In recent years, Elon Musk has become famous for his development of reusable first-stage boosters and fairings. But Blue Origin’s Jeff Bezos has also been no slouch when it comes to making the company’s fleet of rockets reusable. On Sunday, April 29th, the company is passing another milestone with the 8th test flight of the New Shephard rocket, an event which is being live-streamed.
As a fully reusable vertical takeoff, vertical landing (VTVL) space vehicle, the New Shephard is crucial to Blue Origins’ vision of commercial spaceflight and space tourism. Consisting of a pressurized capsule aboard a booster, the combined vehicle launches vertically and accelerates for two and a half minutes before the engine cuts off. The capsule then separates and floats into suborbit while the booster returns to Earth under its own power and with the help of parachutes.
Launch preparations are underway for New Shepard’s 8th test flight, as we continue our progress toward human spaceflight. Currently targeting Sunday 4/29 with launch window opening up at 830am CDT. Livestream info to come. @BlueOrigin#GradatimFerociterpic.twitter.com/zAYpAGWB8C
Named in honor of famed astronaut Alan Shepard, the rocket’s crew capsule has room for six people. These will consist of customers looking to take a flight to suborbital altitudes and experience the sensation of weightlessness. As they state on their website:
“The New Shepard capsule’s interior is an ample 530 cubic feet – offering over 10 times the room Alan Shepard had on his Mercury flight. It seats six astronauts and is large enough for you to float freely and turn weightless somersaults.”
The announcement for the 8th test launch came on Friday, April. 27th, when Bezos tweeted that “launch preparations are underway for New Shepard’s 8th test flight, as we continue our progress toward human spaceflight. Currently targeting Sunday 4/29 with launch window opening up at 830am CDT.” The launch would take place at the company’s suborbital launch and engine test site near the town of Van Horn in West Texas.
As with the previous New Shepard test launch, which took place on Dec. 12th, 2017, the crew for this mission would be the mannequin known as “Mannequin Skywalker” (check out the video of this flight below). As with the previous uncrewed flight, Mannequin Skywalker will be testing the capsule’s safety restrains in advance of a crewed test flight.
At 0526 (0826 PST), Bezos tweeted that the flight window – which was originally set for 0845 CDT (0630 PDT) – had been delayed due to thunderstorm over West Texas. At 0950 CDT (0750 PDT), Bezos issued a follow-up tweet that the liftoff target was now 1113 CDT (0913 PST). Live streaming will begin 15 minutes before the launch, which you can watch by going to Blue Origin’s website.
If successful, this launch test will place Blue Origin one step closer to conducting space tourism. As Bob Smith, the CEO of Blue Origin, recently indicated in an interview with CNBC, he hopes the company will begin these launches by the end of this year. In addition, he said that the company continues to pursue the development of engine technology, which it hopes United Launch Alliance will use on its Vulcan rockets as well.
Be sure to check out the live-steam of the launch, and feel free to enjoy this video of the New Shepard conducting a space tourism flight while you’re waiting:
NASA's James Webb Telescope, shown in this artist's conception, will provide more information about previously detected exoplanets. Beyond 2020, many more next-generation space telescopes are expected to build on what it discovers. Credit: NASA
With the recent launch of the Transiting Exoplanet Survey Satellite (TESS) – which took place on Wednesday, April 18th, 2018 – a lot of attention has been focused on the next-generation space telescopes that will be taking to space in the coming years. These include not only the James Webb Space Telescope, which is currently scheduled for launch in 2020, but some other advanced spacecraft that will be deployed by the 2030s.
Such was the subject of the recent 2020 Decadal Survey for Astrophysics, which included four flagship mission concepts that are currently being studied. When these missions take to space, they will pick up where missions like Hubble, Kepler, Spitzer and Chandra left off, but will have greater sensitivity and capability. As such, they are expected to reveal a great deal more about our Universe and the secrets it holds.
As expected, the mission concepts submitted to the 2020 Decadal Survey cover a wide range of scientific goals – from observing distant black holes and the early Universe to investigating exoplanets around nearby stars and studying the bodies of the Solar System. These ideas were thoroughly vetted by the scientific community, and four have been selected as being worthy of pursuit.
Artist’s concept of the Large Ultraviolet/Optical/Infrared Surveyor (LUVOIR) space telescope. Credits: NASA/GSFC
“This is game time for astrophysics. We want to build all these concepts, but we don’t have the budget to do all four at the same time. The point of these decadal studies is to give members of the astrophysics community the best possible information as they decide which science to do first.”
The four selected concepts include the Large Ultraviolet/Optical/Infrared Surveyor (LUVOIR), a giant space observatory developed in the tradition of the Hubble Space Telescope. As one of two concepts being investigated by NASA’s Goddard Space Flight Center, this mission concept calls for a space telescope with a massive segmented primary mirror that measures about 15 meters (49 feet) in diameter.
In comparison, the JWST‘s (currently the most advanced space telescope) primary mirror measures 6.5 m (21 ft 4 in) in diameter. Much like the JWST, LUVOIR’s mirror would be made up of adjustable segments that would unfold once it deployed to space. Actuators and motors would actively adjust and align these segments in order to achieve the perfect focus and capture light from faint and distant objects.
With these advanced tools, LUVOIR would be able to directly image Earth-sized planets and assess their atmospheres. As Study Scientist Aki Roberge explained:
“This mission is ambitious, but finding out if there is life outside the solar system is the prize. All the technology tall poles are driven by this goal… Physical stability, plus active control on the primary mirror and an internal coronagraph (a device for blocking starlight) will result in picometer accuracy. It’s all about control.”
There’ also the Origins Space Telescope (OST), another concept being pursued by the Goddard Space Flight Center. Much like the Spitzer Space Telescope and the Herschel Space Observatory, this far-infrared observatory would offer 10,000 times more sensitivity than any preceding far-infrared telescope. Its goals include observing the farthest reaches of the universe, tracing the path of water through star and planet formation, and searching for signs of life in the atmospheres of exoplanets.
Its primary mirror, which would measure about 9 m (30 ft) in diameter, would be the first actively cooled telescope, keeping its mirror at a temperature of about 4 K (-269 °C; -452 °F) and its detectors at a temperature of 0.05 K. To achieve this, the OST team will rely on flying layers of sunshields, four cryocoolers, and a multi-stage continuous adiabatic demagnetization refrigerator (CADR).
Artist’s concept of the the Origins Space Telescope (OST). Credits: NASA/GSFC
According to Dave Leisawitz, a Goddard scientist and OST study scientist, the OST is especially reliant on large arrays of superconducting detectors that measure in the millions of pixels. “When people ask about technology gaps in developing the Origins Space Telescope, I tell them the top three challenges are detectors, detectors, detectors,” he said. “It’s all about the detectors.”
Specifically, the OST would rely on two emerging types of detectors: Transition Edge Sensors (TESs) or Kinetic Inductance Detectors (KIDs). While still relatively new, TES detectors are quickly maturing and are currently being used in the HAWC+ instrument aboard NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA).
Then there’s the Habitable Exoplanet Imager (HabEx) which is being developed by NASA’s Jet Propulsion Laboratory. Like LUVOIR, this telescope would also directly image planetary systems to analyze the composition of planets’ atmospheres with a large segmented mirror. In addition, it would study the earliest epochs in the history of the Universe and the life cycle of the most massive stars, thus shedding light on how the elements that are necessary for life are formed.
Also like LUVOIR, HabEx would be able to conduct studies in the ultraviolet, optical and near-infrared wavelengths, and be able to block out a parent star’s brightness so that it could see light being reflected off of any planets orbiting it. As Neil Zimmerman, a NASA expert in the field of coronagraphy, explained:
“To directly image a planet orbiting a nearby star, we must overcome a tremendous barrier in dynamic range: the overwhelming brightness of the star against the dim reflection of starlight off the planet, with only a tiny angle separating the two. There is no off-the-shelf solution to this problem because it is so unlike any other challenge in observational astronomy.”
Artist’s rendition of the Habitable Exoplanet Imager (HabEx) space telescope. Credits: NASA/JPL
To address this challenge, the HabEx team is considering two approaches, which include external petal-shaped star shades that block light and internal coronagraphs that prevent starlight from reaching the detectors. Another possibility being investigated is to apply carbon nanotubes onto the coronagraphic masks to modify the patterns of any diffracted light that still gets through.
Last, but not least, is the X-ray Surveyor known as Lynx being developed by the Marshall Space Flight Center. Of the four space telescopes, Lynx is the only concept which will examine the Universe in X-rays. Using an X-ray microcalorimeter imaging spectrometer, this space telescope will detect X-rays coming from Supermassive Black Holes (SMBHs) at the center of the earliest galaxies in the Universe.
This technique consists of X-ray photos hitting a detector’s absorders and converting their energy to heat, which is measured by a thermometer. In this way, Lynx will help astronomers unlock how the earliest SMBHs formed. As Rob Petre, a Lynx study member at Goddard, described the mission:
“Supermassive black holes have been observed to exist much earlier in the universe than our current theories predict. We don’t understand how such massive objects formed so soon after the time when the first stars could have formed. We need an X-ray telescope to see the very first supermassive black holes, in order to provide the input for theories about how they might have formed.”
Artist’s impression of the X-ray Surveyor (Lynx) space telescope. Credits: NASA/MSFC
Regardless of which mission NASA ultimately selects, the agency and individual centers have begun investing in advanced tools to pursue such concepts in the future. The four teams submitted their interim reports back in March. By next year, they are expected to finish final reports for the National Research Council (NRC), which will be used to inform its recommendations to NASA in the coming years.
As Thai Pham, the technology development manager for NASA’s Astrophysics Program Office, indicated:
“I’m not saying it will be easy. It won’t be. These are ambitious missions, with significant technical challenges, many of which overlap and apply to all. The good news is that the groundwork is being laid now.”
With TESS now deployed and the JWST scheduled to launch by 2020, the lessons learned in the next few years will certainly be incorporated into these missions. At present, it is not clear which of the following concepts will be going to space by the 2030s. However, between their advanced instruments and the lessons learned from past missions, we can expect that they will make some profound discoveries about the Universe.
Using information from Gaia's second data release, a team of scientists have made refined estimates of the Milky Way's mass. Credit: ESA/Gaia/DPAC
On December 19th, 2013, the European Space Agency’s (ESA) Gaia spacecraft took to space with one of the most ambitious missions ever. Over the course of its planned 5-year mission (which was recently extended), this space observatory would map over a billion stars, planets, comets, asteroids and quasars in order to create the largest and most precise 3D catalog of the Milky Way ever created.
The first release of Gaia data, which took place in September 2016, contained the distances and motions of over two million stars. But the second data release, which took place on April 25th, 2018, is even more impressive. Included in the release are the positions, distance indicators and motions of more than one billion stars, asteroids within our Solar System, and even stars beyond the Milky Way.
Whereas the first data release was based on just over a year’s worth of observations, the new data release covers a period of about 22 months – which ran from July 25th, 2014, to May 23rd, 2016. Preliminary analysis of this data has revealed fine details about 1.7 billion stars in the Milky Way and how they move, which is essential to understanding how our galaxy evolved over time.
ESA’s Gaia is currently on a five-year mission to map the stars of the Milky Way. Image credit: ESA/ATG medialab; background: ESO/S. Brunier.
As Günther Hasinger, the ESA Director of Science, explained in a recent ESA press release:
“The observations collected by Gaia are redefining the foundations of astronomy. Gaia is an ambitious mission that relies on a huge human collaboration to make sense of a large volume of highly complex data. It demonstrates the need for long-term projects to guarantee progress in space science and technology and to implement even more daring scientific missions of the coming decades.“
The precision of Gaia‘s instruments has allowed for measurements that are so accurate that it was possible to separate the parallax of stars – the apparent shift caused by the Earth’s orbit around the Sun – from their movements through the galaxy. Of the 1.7 billion stars cataloged, the parallax and velocity (aka. proper motion) of more than 1.3 billion were measured and listed.
For about 10% of these, the parallax measurements were so accurate that astronomers can directly estimate distances to the individual stars. As Anthony Brown of Leiden University, who is also the chair of the Gaia Data Processing and Analysis Consortium Executive Board, explained:
“The second Gaia data release represents a huge leap forward with respect to ESA‘s Hipparcos satellite, Gaia‘s predecessor and the first space mission for astrometry, which surveyed some 118 000 stars almost thirty years ago… The sheer number of stars alone, with their positions and motions, would make Gaia‘s new catalogue already quite astonishing. But there is more: this unique scientific catalogue includes many other data types, with information about the properties of the stars and other celestial objects, making this release truly exceptional.“
In addition to the proper motions of stars, the catalog provides information on a wide range of topics that will be of interest to astronomers and astrophysicists. These include brightness and color measurements of nearly all of the 1.7 billion stars cataloged, as well as information on how the brightness and color change for half a million variable stars over time.
It also contains the velocities along the line of sight of seven million stars, the surface temperatures of about 100 million, and the effect interstellar dust has on 87 million. The Gaia data also contains information on objects in our Solar System, which includes the positions of 14,000 known asteroids (which will allow for the precise determination of their orbits).
Beyond the Milky Way, Gaia obtained more accurate measurements of the positions of half a million distant quasars – bright galaxies that emit massive amounts of energy due to the presence of a supermassive black hole at their centers. In the past, quasars have been used as a reference frame for the celestial coordinates of all objects in the Gaia catalogue based on radio waves.
However, this information will now be available at optical wavelengths for the first time. This, and other developments made possible by Gaia, could revolutionize how we study our galaxy and the Universe. As Antonella Vallenari, from the Istituto Nazionale di Astrofisica (INAF), the Astronomical Observatory of Padua, Italy, and the deputy chair of the Data Processing Consortium Executive Board, indicated:
“The new Gaia data are so powerful that exciting results are just jumping at us. For example, we have built the most detailed Hertzsprung-Russell diagram of stars ever made on the full sky and we can already spot some interesting trends. It feels like we are inaugurating a new era of Galactic archaeology.“
The Hertzsprung-Russell diagram, which is named after the two astronomers who devised it in the early 20th century, is fundamental to the study of stellar populations and their evolution. Based on four million stars that were selected from the catalog (all of which are withing five thousand light-years from the Sun), scientist were able to reveal many fine details about stars beyond our Solar System for the first time.
Along with measurements of their velocities, the Gaia Hertzsprung-Russell diagram enables astronomers to distinguish between populations of stars that are of different ages, are located in different regions of the Milky Way (i.e. the disk and the halo), and that formed in different ways. These include fast moving stars that were previously thought to belong to the halo, but are actually part of two stellar populations.
“Gaia will greatly advance our understanding of the Universe on all cosmic scales,” said Timo Prusti, a Gaia project scientist at ESA. “Even in the neighborhood of the Sun, which is the region we thought we understood best, Gaia is revealing new and exciting features.”
For instance, for a subset of stars within a few thousand light-years of the Sun, Gaia measured their velocity in all three dimensions. From this, it has been determined that they follow a similar pattern to stars that are orbiting the galaxy at similar speeds. The cause of these patterns will be the subject of future research, as it is unclear whether its caused by our galaxy itself or are the result of interactions with smaller galaxies that merged with us in the past.
Last, but not least, Gaia data will be used to learn more about the orbits of 75 globular clusters and 12 dwarf galaxies that revolve around the Milky Way. This information will shed further light on the evolution of our galaxy, the gravitational forces affecting it, and the role played by dark matter. As Fred Jansen, the Gaia mission manager at ESA, put it:
“Gaia is astronomy at its finest. Scientists will be busy with this data for many years, and we are ready to be surprised by the avalanche of discoveries that will unlock the secrets of our Galaxy.“
The third release of Gaia data is scheduled to take place in late 2020, with the final catalog being published in the 2020s. Meanwhile, an extension has already been approved for the Gaia mission, which will now remain in operation until the end of 2020 (to be confirmed at the end of this year). A series of scientific papers describing what has been learned from this latest release will also appear in a special issue of Astronomy & Astrophysics.
From the evolution of stars to the evolution of our galaxy, the second Gaia data release is already proving to be a boon for astronomers and astrophysicists. Even after the mission concludes, we can expect scientists will still be analyzing the data and learning a great deal more about the structure and evolution of our Universe.
Pow: The July 1994 impact of Comet Shoemaker-Levy 9 on Jupiter, captured by the Hubble Space Telescope. Credit: R. Evans/J. Trauger/H. Hammel/HST Comet Science Team/NASA.
Pow: The July 1994 impact of Comet Shoemaker-Levy 9 on Jupiter, captured by the Hubble Space Telescope. Credit: R. Evans/J. Trauger/H. Hammel/HST Comet Science Team/NASA.
Are you keeping a eye on Jupiter? The King of the Planets, Jove presents a swirling upper atmosphere full of action, a worthy object of telescopic study as it heads towards another fine opposition on May 9th, 2018.
Now, an interesting international study out of the School of Engineering in Bilbao, Spain, the Astronomical Society of France, the Meath Astronomical Group in Dublin Ireland, the Astronomical Society of Australia, and the Esteve Duran Observatory in Spain gives us a fascinating and encouraging possibly, and another reason to keep a sharp eye on old Jove: Jupiter may just get smacked with asteroids on a more regular basis than previously thought.
The study is especially interesting, as it primarily focused in on flashes chronicled by amateur imagers and observers in recent years. In particular, researchers focused on impact events witnessed on March 17th 2016 and May 26th, 2017, along with the comparison of exogenous (of cosmic origin) dust measured in the upper atmosphere. This allowed researchers to come up with an interesting estimate: Jupiter most likely gets hit by an asteroid 5-20 meters in diameter (for comparison, the Chelyabinsk bolide was an estimated 20 meters across) 10 to 65 times every year, though researchers extrapolate that a dedicated search might only nab an impact flash or scar once every 0.4 to 2.4 years or so.
Compare this impact rate with the Earth, which gets hit by a Chelyabinsk-sized 20-meter impactor about once every half century or so. Incidentally, we know this impact rate on Earth better than ever before, largely due to U.S. Department of Defense classified assets in space continually watching for nuclear tests and missile launches, which also pick up an occasional meteor “photobomb.”
Small asteroid impacts over the span of the Earth over a 20 year period. NASA/Planetary Science.
One reason we may never have witnessed a meteor impact on Jupiter is, astronomers (both professional and amateur) never thought to look for them. The big wake-up call was the impact of Comet Shoemaker-Levy 9 in July 1994, an event witnessed by the newly refurbished Hubble Space Telescope as the resulting impact scars were easily visible in backyard telescopes for weeks afterward. Back in the day, speculation was rampant in the days leading up to the impact: would the collision be visible at all? Or would gigantic Jupiter simply gobble up the tiny comet fragments with nary a belch?
Australian amateur astronomer Anthony Wesley also caught an interesting impact (scar?) in 2009, and every few years or so, we get word of an elusive flash reported on the Jovian cloudtops, sometimes corroborated by a secondary independent observation or a resulting impact scar, and sometimes not.
An impact scar (top center on the disk) on Jupiter, captured on July 19th, 2009. Image credit: Anthony Wesley.
Of course, there are factors which will lower said ideal versus the actual observed impact rate. There’s always a month or so a year, for example, when Jupiter is near solar conjunction on the far side of the Sun, and out of range for observation. Also, we only see half of the Jovian disk from our Earthly perspective at any given time, and we’re about to lose our only set of eyes in orbit around Jupiter – NASA’s Juno spacecraft – later this summer, unless there’s a last minute mission extension.
On the plus side, however, Jupiter is a fast rotator, spinning on its axis once every 9.9 hours. This also means that near opposition, you can also track Jupiter through one full rotation in a single evening.
Finding Jupiter: looking eastward tonight at around 11PM local. Credit Stellarium.
Then there’s the planet’s location in the sky: Currently, Jupiter’s crossing the southern constellation of Libra, and opposition for Jove moves about one astronomical constellation eastward along the ecliptic a year. Jupiter will bottom out along the ecliptic in late 2019, and won’t pop back up north of the celestial equator until May 2022. And while it’s not impossible for northern observers to keep tabs on Jupiter when it’s down south, we certainly get more gaps in coverage around this time.
Hale-Bopp’s close inbound passage near Jupiter in 1996. Credit: NASA/JPL-Horizons.
Should we hail Jove as a protective ‘cosmic goal-tender,’ or fear it as the bringer of death and destruction? There are theories that Jupiter may be both: for example, Jupiter altered the inbound path of Comet Hale-Bopp in 1997, shortening its orbital period from 4,200 to 2,533 years. The 2000 book Rare Earth even included the hypothesis of Jupiter as a cosmic debris sweeper as one of the factors for why life evolved on Earth… if this is true, it’s an imperfect one, as Earth does indeed still get hit as well.
All reasons to keep an eye on Jupiter in the 2018 opposition season.
But just how many planets is TESS expected to find? That was the subject of a new study by a team researchers who attempted to estimate just how many planets TESS is likely to discover, as well as the physical properties of these planets and the stars that they orbit. Altogether, they estimate TESS will find thousands of planets orbiting a variety of stars during its two-year primary mission.
The study, titled “A Revised Exoplanet Yield from the Transiting Exoplanet Survey Satellite (TESS)“, recently appeared online. The study was led by Thomas Barclay, an associate research scientist at the NASA Goddard Space Flight Center and the University of Maryland, and included Joshua Pepper (an astrophysicist at Lehigh University) and Elisa Quintana (a research scientist with the SETI Institute and NASA Ames Research Center).
As Thomas Barclay told Universe Today via email:
“TESS builds off the legacy of Kepler. Kepler was primarily a statistical mission and taught us that planets are everywhere. However, it wasn’t optimized for finding excellent individual planets for further study. Now that we know planets are common, we can launch something like TESS to search for the planets that we will undertake intensive studies of using ground and space-based telescopes. Planets that TESS will find will on average be 10x closer and 100x brighter.”
For the sake of their study, the team created a three-step model that took into account the stars TESS will observe, the number of planets each one is likely to have, and the likelihood of TESS spotting them. These included the kinds of planets that would be orbiting around dwarf stars ranging from A-type to K-type (like our Sun), and lower-mass M-type (red dwarf) stars.
“To estimate how many planets TESS will find we took stars that will be observed by TESS and simulated a population of planets orbiting them,” said Barclay. “The exoplanet population stats all come from studies that used Kepler data. Then, using models of TESS performance, we estimated how many of those planets would be detected by TESS. This is where we get our yield numbers from.”
The first step was straightforward, thanks to the availability of the Candidate Target List (CTL) – a prioritized list of target stars that the TESS Target Selection Working Group determined were the most suitable stars for detecting small planets. They then ranked the 3.8 million stars that are included in the latest version based on their brightness and radius and determined which of these TESS is likely to observe.
Liftoff of the SpaceX Falcon 9 rocket carrying NASA’s TESS spacecraft. Image credit: NASA TV
The second step consisted of assigning planets to each star based on a Poisson distribution, a statistical technique where a given number is assigned to each star (in this case, 0 or more). Each planet was then assigned six physical properties drawn at random, including an orbital period, a radius, an eccentricity, a periastron angle, an inclination to our line of sight, and a mid-time of first transit.
Last, they attempted to estimate how many of these planets would generate a detectable transit signal. As noted, TESS will rely on the Transit Method, where periodic dips in a star’s brightness are used to determine the presence of one or more orbiting planets, as well as place constraints on their sizes and orbital periods. For this, they considered the flux contamination of nearby stars, the number of transits, and the transit duration.
Ultimately, they determined with 90% confidence that TESS is likely to detect 4430–4660 new exoplanets during its two years mission:
“The results is that we predict that TESS will find more than 4000 planets, with hundreds smaller than twice the size of Earth. The primary goal of TESS is to find planets that are bright enough for ground-based telescope to measure their mass. We estimate that TESS could lead to triple the number of planets smaller than 4 Earth-radii with mass measurements.”
As of April 1st, 2018, a total 3,758 exoplanets have been confirmed in 2,808 systems, with 627 systems having more than one planet. In other words, Barclay and his team estimate that the TESS mission will effectively double the number of confirmed exoplanets and triple the number of Earth-sized and Super-Earth’s during its primary mission.
This will begin after a series of orbital maneuvers and engineering tests, which are expected to last for about two months. With the exoplanet catalog thus expanded, we can expect that there will be many more “Earth-like” candidates available for study. And while we still will not be able to determine if any of them have life, we may perhaps find some that show signs of a viable atmosphere and water on the surfaces.
The hunt for life beyond Earth will continue for many years to come! And in the meantime, be sure to enjoy this video about the TESS mission, courtesy of NASA:
A single frame from the animation created by twitter user landru79. The images were taken by the Rosetta spacecraft of 67P on June 1st, 2016. Credit: Europeans Space Agency -ESAC
The European Space Agency’s Rosetta mission was an ambitious one. As the first-ever space probe to rendezvous with and then orbit a comet, Rosetta and its lander (Philae) revealed a great deal about the comet 67p/Churyumov-Gerasimenko. In addition to the learning things about the comet’s shape, composition and tail, the mission also captured some incredible images of the comet’s surface before it ended.
For instance, Rosetta took a series of images on June 1st, 2016, that showed what looks like a blizzard on the comet’s surface. Using these raw images (which were posted on March 22nd, 2018), twitter user landru79 created an eye-popping video that shows just what it would be like to stand on the comet’s surface. As you can see, its like standing in a blizzard on Earth, though scientists have indicated that it’s a little more complicated than that.
The video, which consists of 25 minutes worth of images taken by Rosetta’s Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS), was posted by landru79 on April 23rd, 2018. It shows the surface of 67p/Churyumov-Gerasimenko on the loop, which lends it the appearance of panning across the surface in the middle of a snowstorm.
#ROSETTA ? OSIRIS #67P/CHURYUMOV-GERASIMENKO new albums ?–ROSETTA EXTENSION 2 MTP030– Miércoles 1 Junio 2016 all filters stacked pic.twitter.com/Bf173Z5g79
However, according to the ESA, the effect is likely caused by three separate phenomena. For instance, the snow-like particles seen in the video are theorized to be a combination of dust from the comet itself as well as high-energy particles striking the camera. Because of OSIRIS’ charge-coupled device (CCD) – a radiation-sensing camera – even invisible particles appear like bright streaks when passing in front of it.
As for the white specks in the background, those are stars belonging to the Canis Major constellation (according to ESA senior advisor Mark McCaughrean). Since originally posting the video, landru79 has posted another GIF on Twitter (see below) that freezes the starfield in place. This makes it clearer that the comet is moving, but the stars are remaining still (at least, relative to the camera’s point of view).
And of course, the entire video has been sped up considerably for dramatic effect. According to a follow-up tweet posted by landru79, the first image was shot on June 1st, 2016 at 3.981 seconds past 17:00 (UTC) while the last one was shot at 170.17 seconds past 17:25.
Si apilamos todo el set alineando con las estrellas de fondo se distingue mejor que son estrellas y q es polvo (olvidaos de rayos cósmicos ) #ROSETTA ? OSIRIS #67P/CHURYUMOV-GERASIMENKO new albums ?–ROSETTA EXTENSION 2 MTP030– Miércoles 1 Junio 2016 all filters stacked? pic.twitter.com/UyZ628JxKP
Still, one cannot deny that it is both captivating and draws attention to what Rosetta the mission accomplished. The mission launched in 2004 and reached 67P/Churyumov-Gerasimenko in 2014. After two years of gathering data, it was deliberately crashed on its surface in 2016. And yet, years later, what it revealed is still captivating people all over the world.
Evolution diagram of a galaxy. First the galaxy is dominated by the disk component (left) but active star formation occurs in the huge dust and gas cloud at the center of the galaxy (center). Then the galaxy is dominated by the stellar bulge and becomes an elliptical or lenticular galaxy. Credit: NAOJ
A lot of attention has been dedicated to the machine learning technique known as “deep learning”, where computers are capable of discerning patterns in data without being specifically programmed to do so. In recent years, this technique has been applied to a number of applications, which include voice and facial recognition for social media platforms like Facebook.
However, astronomers are also benefiting from deep learning, which is helping them to analyze images of galaxies and understand how they form and evolve. In a new study, a team of international researchers used a deep learning algorithm to analyze images of galaxies from the Hubble Space Telescope. This method proved effective at classifying these galaxies based on what stage they were in their evolution.
A ‘deep learning’ algorithm trained on images from cosmological simulations is surprisingly successful at classifying real galaxies in Hubble images. Credit: HST/CANDELS
In the past, Marc Huertas-Company has already applied deep learning methods to Hubble data for the sake of galaxy classification. In collaboration with David Koo and Joel Primack, both of whom are professor emeritus’ at UC Santa Cruz (and with support from Google), Huertas-Company and the team spent the past two summers developing a neural network that could identify galaxies at different stages in their evolution.
“This project was just one of several ideas we had,” said Koo in a recent USCS press release. “We wanted to pick a process that theorists can define clearly based on the simulations, and that has something to do with how a galaxy looks, then have the deep learning algorithm look for it in the observations. We’re just beginning to explore this new way of doing research. It’s a new way of melding theory and observations.”
For the sake of their study, the researchers used computer simulations to generate mock images of galaxies as they would look in observations by the Hubble Space Telescope. The mock images were used to train the deep learning neural network to recognize three key phases of galaxy evolution that had been previously identified in the simulations. The researchers then used the network to analyze a large set of actual Hubble images.
As with previous images anaylzed by Huertas-Company, these images part of Hubble’s Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) project – the largest project in the history of the Hubble Space Telescope. What they found was that the neural network’s classifications of simulated and real galaxies was remarkably consistent. As Joel Primack explained:
“We were not expecting it to be all that successful. I’m amazed at how powerful this is. We know the simulations have limitations, so we don’t want to make too strong a claim. But we don’t think this is just a lucky fluke.”
A spiral galaxy ablaze in the blue light of young stars from ongoing star formation (left) and an elliptical galaxy bathed in the red light of old stars (right). Credit: SDSS
The research team was especially interested in galaxies that have a small, dense, star-forming region known as a “blue nugget”. These regions occur early in the evolution of gas-rich galaxies, when big flows of gas into the center of a galaxy cause the formation of young stars that emit blue light. To simulate these and other types of galaxies, the team relied on state-of-the-art VELA simulations developed by Primack and an international team of collaborators.
In both the simulated and observational data, the computer program found that the “blue nugget” phase occurs only in galaxies with masses within a certain range. This was followed by star formation ending in the central region, leading to the compact “red nugget” phase, where the stars in the central region exit their main sequence phase and become red giants.
The consistency of the mass range was exciting because it indicated that the neural network was identifying a pattern that results from a key physical process in real galaxies – and without having to be specifically told to do so. As Koo indicated, this study as a big step forward for astronomy and AI, but a lot of research still needs to be done:
“The VELA simulations have had a lot of success in terms of helping us understand the CANDELS observations. Nobody has perfect simulations, though. As we continue this work, we will keep developing better simulations.”
Artist’s representation of an active galactic nucleus (AGN) at the center of a galaxy. Credit: NASA/CXC/M.Weiss
For instance, the team’s simulations did not include the role played by Active Galactic Nuclei (AGN). In larger galaxies, gas and dust is accreted onto a central Supermassive Black Hole (SMBH) at the core, which causes gas and radiation to be ejected in huge jets. Some recent studies have indicated how this may have an arresting effect on star formation in galaxies.
However, observations of distant, younger galaxies have shown evidence of the phenomenon observed in the team’s simulations, where gas-rich cores lead to the blue nugget phase. According to Koo, using deep learning to study galactic evolution has the potential to reveal previously undetected aspects of observational data. Instead of observing galaxies as snapshots in time, astronomers will be able to simulate how they evolve over billions of years.
“Deep learning looks for patterns, and the machine can see patterns that are so complex that we humans don’t see them,” he said. “We want to do a lot more testing of this approach, but in this proof-of-concept study, the machine seemed to successfully find in the data the different stages of galaxy evolution identified in the simulations.”
In the future, astronomers will have more observation data to analyze thanks to the deployment of next-generation telescopes like the Large Synoptic Survey Telescope (LSST), the James Webb Space Telescope (JWST), and the Wide-Field Infrared Survey Telescope (WFIRST). These telescopes will provide even more massive datasets, which can then be analyzed by machine learning methods to determine what patterns exist.
Astronomy and artificial intelligence, working together to better our understanding of the Universe. I wonder if we should put it on the task of finding a Theory of Everything (ToE) too!
Artist’s impression of how an an Earth-like exoplanet might look. Credit: ESO.
In the past few decades, there has been an explosion in the number of extra-solar planets that have been discovered. As of April 1st, 2018, a total of 3,758 exoplanets have been confirmed in 2,808 systems, with 627 systems having more than one planet. In addition to expanding our knowledge of the Universe, the purpose of this search has been to find evidence of life beyond our Solar System.
In the course of looking for habitable planets, astronomers have used Earth as a guiding example. But would we recognize a truly “Earth-like” planet if we saw one? This question was addressed in a recent paper by two professors, one of whom is an exoplanet-hunter and the other, an Earth science and astrobiology expert. Together, they consider what advances (past and future) will be key to the search for Earth 2.0.
The paper, titled “Earth as an Exoplanet“, recently appeared online. The study was conducted by Tyler D. Robinson, a former NASA Postdoctoral Fellow and an assistant professor from Northern Arizona University, and Christopher T. Reinhard – an assistant professor from the Georgia Institute of Technology’s School of of Earth and Atmospheric Studies.
Thanks to advances in technology and detection methods, astronomers have detected multiple Earth-like planets in our galaxy. Credit: NASA/JPL
For the sake of their study, Robinson and Reinhard focus on how the hunt for habitable and inhabited planets beyond our Solar System commonly focuses on Earth analogs. This is to be expected, since Earth is the only planet that we know of that can support life. As Professor Robinson told Universe Today via email:
“Earth is – currently! – our only example of a habitable and an inhabited world. Thus, when someone asks, “What will a habitable exoplanet look like?” or “What will a life-bearing exoplanet look like?”, our best option is to point to Earth and say, “Maybe it will look a lot like this.” While many studies have hypothesized other habitable planets (e.g., water-covered super-Earths), our leading example of a fully-functioning habitable planet will always be Earth.”
The authors therefore consider how observations made by spacecraft of the Solar System have led to the development of approaches for detecting signatures of habitability and life on other worlds. These include the Pioneer 10 and 11 missions and Voyager 1 and 2 spacecraft, which conducted flybys of many Solar System bodies during the 1970s.
These missions, which conducted studies on the planets and moons of the Solar System using photometry and spectroscopy allowed scientists to learn a great deal about these bodies’ atmospheric chemistry and composition, as well as meteorlogical patterns and chemistry. Subsequent missions have added to this by revealing key details about the surface details and geological evolution of the Solar planets and moons.
The “pale blue dot” of Earth captured by Voyager 1 spacecraft on Feb 14th, 1990. Credit: NASA/JPL
In addition, the Galileo probe conducted flybys of Earth in December of 1990 and 1992, which provided planetary scientists with the first opportunity to analyze our planet using the same tools and techniques that had previously been applied throughout the Solar System. It was also the Voyager 1 probe that took a distant image of Earth, which Carl Sagan referred to as the “Pale Blue Dot” photo.
However, they also note that Earth’s atmosphere and surface environment has evolved considerably over the past 4.5 billion years ago. In fact, according to various atmospheric and geological models, Earth has resembled many environments in the past that would be considered quite “alien” by today’s standards. These include Earth’s many ice ages and the earliest epochs, when Earth’s primordial atmosphere was the product of volcanic outgassing.
As Professor Robinson explained, this presents some complications when it comes to finding other examples of “Pale Blue Dots”:
“The key complication is being careful to not fall into the trap of thinking that Earth has always appeared the way it does today. So, our planet actually presents a huge array of options for what a habitable and/or inhabited planet might look like.”
In other words, our hunt for Earth analogs could reveal a plethora of worlds which are “Earth-like”, in the sense that they resemble a previous (or future) geological period of Earth. These include “Snowball Earth’s”, which would be covered by glacial sheets (but could still be life-bearing), or even what Earth looked like during the Hadean or Archean Eons, when oxygenic photosynthesis had not yet taken place.
Ice ages are characterized by a drop in average global temperatures, resulting in the expansion of ice sheets globally. Credit: NASA
This would also have implications when it comes to what kinds of life would be able to exist there. For instance, if the planet is still young and its atmosphere was still in its primordial state, life could be strictly in microbial form. However, if the planet was billions of years old and in an interglacial period, more complex life forms may have evolved and be roaming the Earth.
Robinson and Reinhard go on to consider what future developments will aid in the spotting of “Pale Blue Dots”. These include next-generation telescopes like the James Webb Space Telescope (JWST) – scheduled for deployment in 2020 – and the Wide-Field Infrared Survey Telescope (WFIRST), which is currently under development. Other technologies include concepts like Starshade, which is intended to eliminate the glare of stars so that exoplanets can be directly imaged.
“Spotting true Pale Blue Dots – water-covered terrestrial worlds in the habitable zone of Sun-like stars – will require advancements in our ability to “directly image” exoplanets,” said Robinson. “Here, you use either optics inside the telescope or a futuristic-sounding “starshade” flying beyond the telescope to cancel out the light of a bright star thereby enabling you to see a faint planet orbiting that star. A number of different research groups, including some at NASA centers, are working to perfect these technologies.”
Once astronomers are able to image rocky exoplanets directly, they will at last be able to study their atmospheres in detail and place more accurate constraints on their potential habitability. Beyond that, there may come a day when we will be able to image the surfaces of these planets, either through extremely sensitive telescopes or spacecraft missions (such as Project Starshot).
Whether or not we find another “Pale Blue Dot” remains to be seen. But in the coming years, we may finally get a good idea of just how common (or rare) our world truly is.
The new DARKNESS camera developed by an international team of researchers will allow astronomers to directly study nearby exoplanets. Credit: Stanford/SRL
The hunt for planets beyond our Solar System has led to the discovery of thousands of candidates in the past few decades. Most of these have been gas giants that range in size from being Super-Jupiters to Neptune-sized planets. However, several have also been determined to be “Earth-like” in nature, meaning that they are rocky and orbit within their stars’ respective habitable zones.
Unfortunately, determining what conditions might be like on their surfaces is difficult, since astronomers are unable to study these planets directly. Luckily, an international team led by UC Santa Barbara physicist Benjamin Mazin has developed a new instrument known as DARKNESS. This superconducting camera, which is the world’s largest and most sophisticated, will allow astronomers to detect planets around nearby stars.
The team’s study which details their instrument, titled “DARKNESS: A Microwave Kinetic Inductance Detector Integral Field Spectrograph for High-contrast Astronomy“, recently appeared in the Publications of the Astronomy Society of the Pacific. The team was led by Benjamin Mazin, the Worster Chair in Experimental Physics at UCSB, and also includes members from NASA’s Jet Propulsion Laboratory, the California Institute of Technology, the Fermi National Accelerator Laboratory, and multiple universities.
The DARKNESS instrument is the worlds most advanced camera and will enable the detection of planets around the nearest stars. Credit: UCSB
Essentially, it is extremely difficult for scientists to study exoplanets directly because of the interference caused by their stars. As Mazin explained in a recent UCSB press release, “Taking a picture of an exoplanet is extremely challenging because the star is much brighter than the planet, and the planet is very close to the star.” As such, astronomers are often unable to analyze the light being reflected off of a planet’s atmosphere to determine its composition.
These studies would help place additional constraints on whether or not a planet is potentially habitable. At present, scientists are forced to determine if a planet could support life based on its size, mass, and distance from its star. In addition, studies have been conducted that have determined whether or not water exists on a planet’s surface based on how its atmosphere loses hydrogen to space.
The DARK-speckle Near-infrared Energy-resolved Superconducting Spectrophotometer (aka. DARKNESS), the first 10,000-pixel integral field spectrograph, seeks to correct this. In conjunction with a large telescope and adaptive optics, it uses Microwave Kinetic Inductance Detectors to quickly measure the light coming from a distant star, then sends a signal back to a rubber mirror that can form into a new shape 2,000 times a second.
MKIDs allow astronomers to determine the energy and arrival time of individual photons, which is important when it comes to distinguishing a planet from scattered or refracted light. This process also eliminates read noise and dark current – the primary sources of error in other instruments – and cleans up the atmospheric distortion by suppressing the starlight.
UCSB physicist Ben Mazin, who led the development of the DARKNESS camera. Credit: Sonia Fernandez
Mazin and his colleagues have been exploring MKIDs technology for years through the Mazin Lab, which is part of the UCSB’s Department of Physics. As Mazin explained:
“This technology will lower the contrast floor so that we can detect fainter planets. We hope to approach the photon noise limit, which will give us contrast ratios close to 10-8, allowing us to see planets 100 million times fainter than the star. At those contrast levels, we can see some planets in reflected light, which opens up a whole new domain of planets to explore. The really exciting thing is that this is a technology pathfinder for the next generation of telescopes.”
DARKNESS is now operational on the 200-inch Hale Telescope at the Palomar Observatory near San Diego, California, where it is part of the PALM-3000 extreme adaptive optics system and the Stellar Double Coronagraph. During the past year and a half, the team has conducted four runs with the DARKNESS camera to test its contrast ratio and make sure it is working properly.
In May, the team will return to gather more data on nearby planets and demonstrate their progress. If all goes well, DARKNESS will become the first of many cameras designed to image planets around nearby M-type (red dwarf) stars, where many rocky planets have been discovered in recent years. The most notable example is Proxima b, which orbits the nearest star system to our own (Proxima Centauri, roughly 4.25 light years away).
The Palomar Observatory, where the DARKNESS camera is currently installed. Credit: IPTF/Palomar Observatory
“Our hope is that one day we will be able to build an instrument for the Thirty Meter Telescope planned for Mauna Kea on the island of Hawaii or La Palma,” Mazin said. “With that, we’ll be able to take pictures of planets in the habitable zones of nearby low mass stars and look for life in their atmospheres. That’s the long-term goal and this is an important step toward that.”
In addition to the study of nearby rocky planets, this technology will also allow astronomers to study pulsars in greater detail and determine the redshift of billions of galaxies, allowing for more accurate measurements of how fast the Universe is expanding. This, in turn, will allow for more detailed studies of how our Universe has evolved over time and the role played by Dark Energy.
These and other technologies, such as NASA’s proposed Starshade spacecraft and Stanford’s mDot occulter, will revolutionize exoplanet studies in the coming years. Paired with next-generation telescopes – such as the James Webb Space Telescope and the Transiting Exoplanet Survey Satellite (TESS), which recently launched – astronomers will not only be able to discover more in the way exoplanets, but will be able to characterize them like never before.
The magnetic field and electric currents in and around Earth generate complex forces that have immeasurable impact on every day life. Credit: ESA/ATG medialab
Earth’s magnetic field is one of the most mysterious features of our planet. It is also essential to life as we know it, ensuring that our atmosphere is not stripped away by solar wind and shielding life on Earth from harmful radiation. For some time, scientists have theorized that it is the result of a dynamo action in our core, where the liquid outer core revolves around the solid inner core and in the opposite direction of the Earth’s rotation.
In addition, Earth’s magnetic field is affected by other factors, such as magnetized rocks in the crust and the flow of the ocean. For this reason, the European Space Agency’s (ESA) Swarm satellites, which have been continually monitoring Earth’s magnetic field since its deployment, recently began monitoring Earth’s oceans – the first results of which were presented at this year’s European Geosciences Union meeting in Vienna, Austria.
The Swarm mission, which consists of three Earth-observation satellites, was launched in 2013 for the sake of providing high-precision and high-resolution measurements of Earth’s magnetic field. The purpose of this mission is not only to determine how Earth’s magnetic field is generated and changing, but also to allow us to learn more about Earth’s composition and interior processes.
Artist’s impression of the ESA’s Swarm satellites, which are designed to measure the magnetic signals from Earth’s core, mantle, crust, oceans, ionosphere and magnetosphere. Credit: ESA/AOES Medialab
Beyond this, another aim of the mission is to increase our knowledge of atmospheric processes and ocean circulation patterns that affect climate and weather. The ocean is also an important subject of study to the Swarm mission because of the small ways in which it contributes to Earth’s magnetic field. Basically, as the ocean’s salty water flows through Earth’s magnetic field, it generates an electric current that induces a magnetic signal.
Because this field is so small, it is extremely difficult to measure. However, the Swarm mission has managed to do just that in remarkable detail. These results, which were presented at the EGU 2018 meeting, were turned into an animation (shown below), which shows how the tidal magnetic signal changes over a 24 hour period.
As you can see, the animation shows temperature changes in the Earth’s oceans over the course of the day, shifting from north to south and ranging from deeper depths to shallower, coastal regions. These changes have a minute effect on Earth’s magnetic field, ranging from 2.5 to -2.5 microtesla. As Nils Olsen, from the Technical University of Denmark, explained in a ESA press release:
“We have used Swarm to measure the magnetic signals of tides from the ocean surface to the seabed, which gives us a truly global picture of how the ocean flows at all depths – and this is new. Since oceans absorb heat from the air, tracking how this heat is being distributed and stored, particularly at depth, is important for understanding our changing climate. In addition, because this tidal magnetic signal also induces a weak magnetic response deep under the seabed, these results will be used to learn more about the electrical properties of Earth’s lithosphere and upper mantle.”
By learning more about Earth’s magnetic field, scientists will able to learn more about Earth’s internal processes, which are essential to life as we know it. This, in turn, will allow us to learn more about the kinds of geological processes that have shaped other planets, as well as determining what other planets could be capable of supporting life.
Be sure to check out this comic that explains how the Swarm mission works, courtesy of the ESA.
