TL;DR
- NASA’s Mars 2020 Perseverance rover mission is on its way to the Red Planet to search for signs of ancient life and collect samples to send back to Earth.
- A new study identified 37 recently active volcanic structures on Venus. The study provides some of the best evidence yet that Venus is still a geologically active planet.
- Although no life has been detected on the Martian surface, a new study from astrophysicist and research scientist finds that conditions below the surface could potentially support it.
- The immune systems of mammals — including humans — might struggle to detect and respond to germs from other planets, new research suggests.
- Using known distances of 50 galaxies from Earth to refine calculations in Hubble’s constant, astronomers estimates the age of the universe at 12.6 billion years.
- For just the second time ever, astrophysicists have spotted a spectacular flash of ultraviolet (UV) light accompanying a white dwarf explosion. An extremely rare type of supernova, the event is poised to offer insights into several long-standing mysteries, including what causes white dwarfs to explode, how dark energy accelerates the cosmos and how the universe creates heavy metals, such as iron.
- The European Southern Observatory’s Very Large Telescope has taken the first ever image of a young, Sun-like star accompanied by two giant exoplanets. Images of systems with multiple exoplanets are extremely rare, and — until now — astronomers had never directly observed more than one planet orbiting a star similar to the Sun. The observations can help astronomers understand how planets formed and evolved around our own Sun.
- Researchers have presented a new, detailed look inside the ‘central engine’ of a large solar flare accompanied by a powerful eruption by the Owens Valley Solar Array. The new findings offer the first measurements characterizing the magnetic fields and particles at the heart of the explosion.
- Saturn is truly the lord of the rings in this latest snapshot from NASA’s Hubble Space Telescope, when the opulent giant world was 839 million miles from Earth. A new Saturn image was taken during summer in the planet’s northern hemisphere.
- The rediscovery of a lost planet could pave the way for the detection of a world within the habitable ‘Goldilocks zone’ in a distant solar system.
- By applying a machine-learning algorithm, scientists have developed a method to classify all gamma-ray bursts (GRBs), rapid highly energetic explosions in distant galaxies, without needing to find an afterglow — by which GRBs are presently categorized. This breakthrough, initiated by first-year B.Sc. students, may prove key in finally discovering the origins of these mysterious bursts.
- Space Force unveils logo, ‘Semper Supra’ motto.
- Upcoming industry events. And more!
Space industry in numbers
Last summer, the Space Foundation published the second-quarter findings of its 2019 issue of The Space Report, revealing that:
- The global space economy grew 8.1% in 2018 to USA 414.75 billion, exceeding USD 400 billion for the first time.
- Global launches in 2018 increased by 46% over the number of launches a decade ago.
- Global launches in 2018 exceeded 100 for the first time since 1990.
Analysts at Morgan Stanley and Goldman Sachs have predicted that economic activity in space will become a multi-trillion-dollar market in the coming decades. Morgan Stanley’s Space Team estimates that the roughly USD 350 billion global space industry could surge to over USD 1 trillion by 2040.
Space industry news
Mars 2020 Perseverance Rover Mission to Red Planet successfully launched
NASA’s Mars 2020 Perseverance rover mission is on its way to the Red Planet to search for signs of ancient life and collect samples to send back to Earth.
Humanity’s most sophisticated rover launched with the Ingenuity Mars Helicopter at 7:50 a.m. EDT (4:50 a.m. PDT) Friday on a United Launch Alliance (ULA) Atlas V rocket from Space Launch Complex 41 at Cape Canaveral Air Force Station in Florida.
“With the launch of Perseverance, we begin another historic mission of exploration,” said NASA Administrator Jim Bridenstine. “This amazing explorer’s journey has already required the very best from all of us to get it to launch through these challenging times. Now we can look forward to its incredible science and to bringing samples of Mars home even as we advance human missions to the Red Planet. As a mission, as an agency, and as a country, we will persevere.”
The ULA Atlas V’s Centaur upper stage initially placed the Mars 2020 spacecraft into a parking orbit around Earth. The engine fired for a second time and the spacecraft separated from the Centaur as expected. Navigation data indicate the spacecraft is perfectly on course to Mars.
Mars 2020 sent its first signal to ground controllers via NASA’s Deep Space Network at 9:15 a.m. EDT (6:15 a.m. PDT). However, telemetry (more detailed spacecraft data) had not yet been acquired at that point. Around 11:30 a.m. EDT (8:30 a.m. PDT), a signal with telemetry was received from Mars 2020 by NASA ground stations. Data indicate the spacecraft had entered a state known as safe mode, likely because a part of the spacecraft was a little colder than expected while Mars 2020 was in Earth’s shadow. All temperatures are now nominal and the spacecraft is out of Earth’s shadow.
When a spacecraft enters safe mode, all but essential systems are turned off until it receives new commands from mission control. An interplanetary launch is fast-paced and dynamic, so a spacecraft is designed to put itself in safe mode if its onboard computer perceives conditions are not within its preset parameters. Right now, the Mars 2020 mission is completing a full health assessment on the spacecraft and is working to return the spacecraft to a nominal configuration for its journey to Mars.
The Perseverance rover’s astrobiology mission is to seek out signs of past microscopic life on Mars, explore the diverse geology of its landing site,Jezero Crater, and demonstrate key technologies that will help us prepare for future robotic and human exploration.
“Jezero Crater is the perfect place to search for signs of ancient life,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate at the agency’s headquarters in Washington. “Perseverance is going to make discoveries that cause us to rethink our questions about what Mars was like and how we understand it today. As our instruments investigate rocks along an ancient lake bottom and select samples to return to Earth, we may very well be reaching back in time to get the information scientists need to say that life has existed elsewhere in the universe.”
The Martian rock and dust Perseverance’s Sample Caching System collects could answer fundamental questions about the potential for life to exist beyond Earth. Two future missions currently under consideration by NASA, in collaboration with ESA (European Space Agency), will work together to get the samples to an orbiter for return to Earth. When they arrive on Earth, the Mars samples will undergo in-depth analysis by scientists around the world using equipment far too large to send to the Red Planet.
An Eye to a Martian Tomorrow
While most of Perseverance’s seven instruments are geared toward learning more about the planet’s geology and astrobiology, the MOXIE (Mars Oxygen In-Situ Resource Utilization Experiment) instrument’s job is focused on missions yet to come. Designed to demonstrate that converting Martian carbon dioxide into oxygen is possible, it could lead to future versions of MOXIE technology that become staples on Mars missions, providing oxygen for rocket fuel and breathable air.
Also future-leaning is the Ingenuity Mars Helicopter, which will remain attached to the belly of Perseverance for the flight to Mars and the first 60 or so days on the surface. A technology demonstrator, Ingenuity’s goal is a pure flight test — it carries no science instruments.
Over 30 sols (31 Earth days), the helicopter will attempt up to five powered, controlled flights. The data acquired during these flight tests will help the next generation of Mars helicopters provide an aerial dimension to Mars explorations — potentially scouting for rovers and human crews, transporting small payloads, or investigating difficult-to-reach destinations.
The rover’s technologies for entry, descent, and landing also will provide information to advance future human missions to Mars.
“Perseverance is the most capable rover in history because it is standing on the shoulders of our pioneers Sojourner, Spirit, Opportunity, and Curiosity,” said Michael Watkins, director of NASA’s Jet Propulsion Laboratory in Southern California. “In the same way, the descendants of Ingenuity and MOXIE will become valuable tools for future explorers to the Red Planet and beyond.”
About seven cold, dark, unforgiving months of interplanetary space travel lay ahead for the mission — a fact never far from the mind of Mars 2020 project team.
“There is still a lot of road between us and Mars,” said John McNamee, Mars 2020 project manager at JPL. “About 290 million miles of them. But if there was ever a team that could make it happen, it is this one. We are going to Jezero Crater. We will see you there Feb. 18, 2021.”
The Mars 2020 Perseverance mission is part of America’s larger Moon to Mars exploration approach that includes missions to the Moon as a way to prepare for human exploration of the Red Planet. Charged with sending the first woman and next man to the Moon by 2024, NASA will establish a sustained human presence on and around the Moon by 2028 through NASA’s Artemis program.
JPL, which is managed for NASA by Caltech in Pasadena, California, built and will manage operations of the Mars Perseverance rover. NASA’s Launch Services Program, based at the agency’s Kennedy Space Center in Florida, is responsible for launch management, and ULA provided the Atlas V rocket.
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Space exploration
Corona structures driven by plume–lithosphere interactions and evidence for ongoing plume activity on Venus
by Anna J. P. Gülcher, Taras V. Gerya, Laurent G. J. Montési, Jessica Munch in Nature Geoscience
A new study identified 37 recently active volcanic structures on Venus. The study provides some of the best evidence yet that Venus is still a geologically active planet.
“This is the first time we are able to point to specific structures and say ‘Look, this is not an ancient volcano but one that is active today, dormant perhaps, but not dead,’” said Laurent Montési, a professor of geology at UMD and co-author of the research paper. “This study significantly changes the view of Venus from a mostly inactive planet to one whose interior is still churning and can feed many active volcanoes.”
Scientists have known for some time that Venus has a younger surface than planets like Mars and Mercury, which have cold interiors. Evidence of a warm interior and geologic activity dots the surface of the planet in the form of ring-like structures known as coronae, which form when plumes of hot material deep inside the planet rise through the mantle layer and crust. This is similar to the way mantle plumes formed the volcanic Hawaiian Islands.
But it was thought that the coronae on Venus were probably signs of ancient activity, and that Venus had cooled enough to slow geological activity in the planet’s interior and harden the crust so much that any warm material from deep inside would not be able to puncture through. In addition, the exact processes by which mantle plumes formed coronae on Venus and the reasons for variation among coronae have been matters for debate.
In the new study, the researchers used numerical models of thermo-mechanic activity beneath the surface of Venus to create high-resolution, 3D simulations of coronae formation. Their simulations provide a more detailed view of the process than ever before.
The results helped Montési and his colleagues identify features that are present only in recently active coronae. The team was then able to match those features to those observed on the surface of Venus, revealing that some of the variation in coronae across the planet represents different stages of geological development. The study provides the first evidence that coronae on Venus are still evolving, indicating that the interior of the planet is still churning.
“The improved degree of realism in these models over previous studies makes it possible to identify several stages in corona evolution and define diagnostic geological features present only at currently active coronae,” Montési said. “We are able to tell that at least 37 coronae have been very recently active.”
The active coronae on Venus are clustered in a handful of locations, which suggests areas where the planet is most active, providing clues to the workings of the planet’s interior. These results may help identify target areas where geologic instruments should be placed on future missions to Venus, such as Europe’s EnVision that is scheduled to launch in 2032.
Investigating the biological potential of galactic cosmic ray-induced radiation-driven chemical disequilibrium in the Martian subsurface environment
by Dimitra Atri in Scientific Reports, 2020
Although no life has been detected on the Martian surface, a new study from astrophysicist and research scientist finds that conditions below the surface could potentially support it.
Atri’s findings are reported in the study Investigating the biological potential of galactic cosmic ray-induced radiation-driven chemical disequilibrium in the Martian subsurface environment in the journal Scientific Reports, Springer Nature.
There is growing evidence suggesting the presence of an aqueous environment on ancient Mars, raising the question of the possibility of a life-supporting environment. The erosion of the Martian atmosphere resulted in drastic changes in its climate, surface water disappeared, shrinking habitable spaces on the planet, with only a limited amount of water remaining near the surface in form of brines and water-ice deposits. Life, if it ever existed, would have had to adapt to harsh modern conditions, which include low temperatures and surface pressure, and high radiation dose.
The subsurface of Mars has traces of water in the form of water-ice and brines, and undergoes radiation-driven redox chemistry. Using a combination of numerical models, space mission data, and studies of deep-cave ecosystems on Earth for his research, Atri proposes mechanisms through which life, if it ever existed on Mars, could survive and be detected with the upcoming ExoMars mission (2022) by the European Space Agency and Roscosmos. He hypothesizes that galactic cosmic radiation, which can penetrate several meters below the surface, will induce chemical reactions that can be used for metabolic energy by extant life, and host organisms using mechanisms seen in similar chemical and radiation environments on Earth.
“It is exciting to contemplate that life could survive in such a harsh environment, as few as two meters below the surface of Mars,” said Atri. “When the Rosalind Franklin rover on board the ExoMars mission (ESA and Roscosmos), equipped with a subsurface drill, is launched in 2022, it will be well-suited to detect extant microbial life and hopefully provide some important insights.”
A Weakened Immune Response to Synthetic Exo-Peptides Predicts a Potential Biosecurity Risk in the Retrieval of Exo-Microorganisms
by Katja Schaefer, Ivy M. Dambuza, Sergio Dall’Angelo, Raif Yuecel, Marcel Jaspars, Laurent Trembleau, Matteo Zanda, Gordon D. Brown, Mihai G. Netea, Neil A. R. Gow in Microorganisms
The immune systems of mammals — including humans — might struggle to detect and respond to germs from other planets, new research suggests.
The discovery of liquid water at several locations in the solar system raises the possibility that microbial life may have evolved outside Earth and as such could be accidently introduced into the Earth’s ecosystem. Unusual sugars or amino acids, like non-proteinogenic isovaline and α-aminoisobutyric acid that are vanishingly rare or absent from life forms on Earth, have been found in high abundance on non-terrestrial carbonaceous meteorites. It is therefore conceivable that exo-microorganisms might contain proteins that include these rare amino acids. Researchers therefore asked whether the mammalian immune system would be able to recognize and induce appropriate immune responses to putative proteinaceous antigens that include these rare amino acids. To address this, we synthesised peptide antigens based on a backbone of ovalbumin and introduced isovaline and α-aminoisobutyric acid residues and demonstrated that these peptides can promote naïve OT-I cell activation and proliferation, but did so less efficiently than the canonical peptides. This is relevant to the biosecurity of missions that may retrieve samples from exoplanets and moons that have conditions that may be permissive for life, suggesting that accidental contamination and exposure to exo-microorganisms with such distinct proteomes might pose an immunological challenge.
The Spectacular Ultraviolet Flash from the Peculiar Type Ia Supernova 2019yvq
by A. Miller, M. R. Magee, A. Polin, K. Maguire, E. Zimmerman, Y. Yao, J. Sollerman, S. Schulze, D. A. Perley, M. Kromer, S. Dhawan, M. Bulla, I. Andreoni, E. C. Bellm, K. De, R. Dekany, A. Delacroix, C. Fremling, A. Gal-Yam, et al. in The Astrophysical Journal, 2020
For just the second time ever, astrophysicists have spotted a spectacular flash of ultraviolet (UV) light accompanying a white dwarf explosion. An extremely rare type of supernova, the event is poised to offer insights into several long-standing mysteries, including what causes white dwarfs to explode, how dark energy accelerates the cosmos and how the universe creates heavy metals, such as iron.
An extremely rare type of supernova, the event is poised to offer insights into several long-standing mysteries, including what causes white dwarfs to explode, how dark energy accelerates the cosmos and how the universe creates heavy metals, such as iron.
“The UV flash is telling us something very specific about how this white dwarf exploded,” said Northwestern University astrophysicist Adam Miller, who led the research. “As time passes, the exploded material moves farther away from the source. As that material thins, we can see deeper and deeper. After a year, the material will be so thin that we will see all the way into the center of the explosion.”
At that point, Miller said, his team will know more about how this white dwarf — and all white dwarfs, which are dense remnants of dead stars — explode.
Miller is a fellow in Northwestern’s Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and director of the Legacy Survey of Space and Time Corporation Data Science Fellowship Program.
Common event with a rare twist
Using the Zwicky Transient Facility in California, researchers first spotted the peculiar supernova in December 2019 — just a day after it exploded. The event, dubbed SN2019yvq, occurred in a relatively nearby galaxy located 140 million light-years from Earth, very close to tail of the dragon-shaped Draco constellation.
Within hours, astrophysicists used NASA’s Neil Gehrels Swift Observatory to study the phenomenon in ultraviolet and X-ray wavelengths. They immediately classified SN2019yvq as a type Ia (pronounced “one-A”) supernova, a fairly frequent event that occurs when a white dwarf explodes.
“These are some of the most common explosions in the universe,” Miller said. “But what’s special is this UV flash. Astronomers have searched for this for years and never found it. To our knowledge, this is actually only the second time a UV flash has been seen with a type Ia supernova.”
Heated mystery
The rare flash, which lasted for a couple days, indicates that something inside or nearby the white dwarf was incredibly hot. Because white dwarfs become cooler and cooler as they age, the influx of heat puzzled astronomers.
“The simplest way to create UV light is to have something that’s very, very hot,” Miller said. “We need something that is much hotter than our sun — a factor of three or four times hotter. Most supernovae are not that hot, so you don’t get the very intense UV radiation. Something unusual happened with this supernova to create a very hot phenomenon.”
Miller and his team believe this is an important clue to understanding why white dwarfs explode, which has been a long-standing mystery in the field. Currently, there are multiple competing hypotheses. Miller is particularly interested in exploring four different hypotheses, which match his team’s data analysis from SN2019yvq.
Potential scenarios that could cause a white dwarf to explode with a UV flash are:
1. A white dwarf consumes its companion star and becomes so large and unstable that it explodes. The white dwarf’s and companion star’s materials collide, causing a flash of UV emission;
2. Extremely hot radioactive material in the white dwarf’s core mixes with its outer layers, causing the outer shell to reach higher temperatures than usual;
3. An outer layer of helium ignites carbon within the white dwarf, causing an extremely hot double explosion and a UV flash;
4. Two white dwarfs merge, triggering an explosion with colliding ejecta that emit UV radiation.
Earth-shattering insights
Once the researchers know what caused the explosion, they will apply those findings to learn more about planet formation and dark energy.
Because most of the iron in the universe is created by type Ia supernovae, better understanding this phenomenon could tell us more about our own planet. Iron from exploded stars, for example, formed the core of all rocky planets, including Earth.
“If you want to understand how the Earth formed, you need to understand where iron came from and how much iron was needed,” Miller said. “Understanding the ways in which a white dwarf explodes gives us a more precise understanding of how iron is created and distributed throughout the universe.”
Illuminating dark energy
White dwarfs already play an enormous role in physicists’ current understanding of dark energy as well. Physicists predict that white dwarfs all have the same brightness when they explode. So type Ia supernovae are considered “standard candles,” allowing astronomers to calculate exactly how far the explosions lie from Earth. Using supernovae to measure distances led to the discovery of dark energy, a finding recognized with the 2011 Nobel Prize in Physics.
“We don’t have a direct way to measure the distance to other galaxies,” Miller explained. “Most galaxies are actually moving away from us. If there is a type Ia supernova in a distant galaxy, we can use it to measure a combination of distance and velocity that allows us to determine the acceleration of the universe. Dark energy remains a mystery. But these supernovae are the best way to probe dark energy and understand what it is.”
And by better understanding white dwarfs, Miller believes we potentially could better understand dark energy and how fast it causes the universe to accelerate.
Using the Baryonic Tully–Fisher Relation to Measure H o
by James Schombert, Stacy McGaugh, Federico Lelli in The Astronomical Journal
Using known distances of 50 galaxies from Earth to refine calculations in Hubble’s constant, astronomers estimates the age of the universe at 12.6 billion years.
Approaches to date the Big Bang, which gave birth to the universe, rely on mathematics and computational modeling, using distance estimates of the oldest stars, the behavior of galaxies and the rate of the universe’s expansion. The idea is to compute how long it would take all objects to return to the beginning.
A key calculation for dating is the Hubble’s constant, named after Edwin Hubble who first calculated the universe’s expansion rate in 1929. Another recent technique uses observations of leftover radiation from the Big Bang. It maps bumps and wiggles in spacetime — the cosmic microwave background, or CMB — and reflects conditions in the early universe as set by Hubble’s constant.
However, the methods reach different conclusions, said James Schombert, a professor of physics at the UO. In a paper published July 17 in the Astronomical Journal, he and colleagues unveil a new approach that recalibrates a distance-measuring tool known as the baryonic Tully-Fisher relation independently of Hubble’s constant.
“The distance scale problem, as it is known, is incredibly difficult because the distances to galaxies are vast and the signposts for their distances are faint and hard to calibrate,” Schombert said.
Schombert’s team recalculated the Tully-Fisher approach, using accurately defined distances in a linear computation of the 50 galaxies as guides for measuring the distances of 95 other galaxies. The universe, he noted, is ruled by a series of mathematical patterns expressed in equations. The new approach more accurately accounts for the mass and rotational curves of galaxies to turn those equations into numbers like age and expansion rate.
His team’s approach determines the Hubble’s constant — the universe’s expansion rate — at 75.1 kilometers per second per megaparsec, give or take 2.3. A megaparsec, a common unit of space-related measurements, is equal to one million parsecs. A parsec is about 3.3 light years.
All Hubble’s constant values lower than 70, his team wrote, can be ruled out with 95 percent degree of confidence.
Traditionally used measuring techniques over the past 50 years, Schombert said, have set the value at 75, but CMB computes a rate of 67. The CMB technique, while using different assumptions and computer simulations, should still arrive at the same estimate, he said.
“The tension in the field occurs from the fact that it does not,” Schombert said. “This difference is well outside the observational errors and produced a great deal of friction in the cosmological community.”
Calculations drawn from observations of NASA’s Wilkinson Microwave Anisotropy Probe in 2013 put the age of the universe at 13.77 billion years, which, for the moment, represents the standard model of Big Bang cosmology. The differing Hubble’s constant values from the various techniques generally estimate the universe’s age at between 12 billion and 14.5 billion years.
The new study, based in part on observations made with the Spitzer Space Telescope, adds a new element to how calculations to reach Hubble’s constant can be set, by introducing a purely empirical method, using direct observations, to determine the distance to galaxies, Schombert said.
“Our resulting value is on the high side of the different schools of cosmology, signaling that our understanding of the physics of the universe is incomplete with the hope of new physics in the future,” he said.
Two Directly Imaged, Wide-orbit Giant Planets around the Young, Solar Analog TYC 8998–760–1
by Alexander J. Bohn, Matthew A. Kenworthy, Christian Ginski, Steven Rieder, Eric E. Mamajek, Tiffany Meshkat, Mark J. Pecaut, Maddalena Reggiani, Jozua de Boer, Christoph U. Keller, Frans Snik, John Southworth in The Astrophysical Journal
The European Southern Observatory’s Very Large Telescope has taken the first ever image of a young, Sun-like star accompanied by two giant exoplanets. Images of systems with multiple exoplanets are extremely rare, and — until now — astronomers had never directly observed more than one planet orbiting a star similar to the Sun. The observations can help astronomers understand how planets formed and evolved around our own Sun.
Just a few weeks ago, ESO revealed a planetary system being born in a new, stunning VLT image. Now, the same telescope, using the same instrument, has taken the first direct image of a planetary system around a star like our Sun, located about 300 light-years away and known as TYC 8998–760–1.
“This discovery is a snapshot of an environment that is very similar to our Solar System, but at a much earlier stage of its evolution,” says Alexander Bohn, a PhD student at Leiden University in the Netherlands, who led the new research published today in the Astrophysical Journal Letters.
“Even though astronomers have indirectly detected thousands of planets in our galaxy, only a tiny fraction of these exoplanets have been directly imaged,” says co-author Matthew Kenworthy, Associate Professor at Leiden University, adding that “direct observations are important in the search for environments that can support life.” The direct imaging of two or more exoplanets around the same star is even more rare; only two such systems have been directly observed so far, both around stars markedly different from our Sun. The new ESO’s VLT image is the first direct image of more than one exoplanet around a Sun-like star. ESO’s VLT was also the first telescope to directly image an exoplanet, back in 2004, when it captured a speck of light around a brown dwarf, a type of ‘failed’ star.
“Our team has now been able to take the first image of two gas giant companions that are orbiting a young, solar analogue,” says Maddalena Reggiani, a postdoctoral researcher from KU Leuven, Belgium, who also participated in the study. The two planets can be seen in the new image as two bright points of light distant from their parent star, which is located in the upper left of the frame (click on the image to view the full frame). By taking different images at different times, the team were able to distinguish these planets from the background stars.
The two gas giants orbit their host star at distances of 160 and about 320 times the Earth-Sun distance. This places these planets much further away from their star than Jupiter or Saturn, also two gas giants, are from the Sun; they lie at only 5 and 10 times the Earth-Sun distance, respectively. The team also found the two exoplanets are much heavier than the ones in our Solar System, the inner planet having 14 times Jupiter’s mass and the outer one six times.
Bohn’s team imaged this system during their search for young, giant planets around stars like our Sun but far younger. The star TYC 8998–760–1 is just 17 million years old and located in the Southern constellation of Musca (The Fly). Bohn describes it as a “very young version of our own Sun.”
These images were possible thanks to the high performance of the SPHERE instrument on ESO’s VLT in the Chilean Atacama desert. SPHERE blocks the bright light from the star using a device called coronagraph, allowing the much fainter planets to be seen. While older planets, such as those in our Solar System, are too cool to be found with this technique, young planets are hotter, and so glow brighter in infrared light. By taking several images over the past year, as well as using older data going back to 2017, the research team have confirmed that the two planets are part of the star’s system.
Further observations of this system, including with the future ESO Extremely Large Telescope (ELT), will enable astronomers to test whether these planets formed at their current location distant from the star or migrated from elsewhere. ESO’s ELT will also help probe the interaction between two young planets in the same system. Bohn concludes: “The possibility that future instruments, such as those available on the ELT, will be able to detect even lower-mass planets around this star marks an important milestone in understanding multi-planet systems, with potential implications for the history of our own Solar System.”
Measurement of magnetic field and relativistic electrons along a solar flare current sheet
by Bin Chen, Chengcai Shen, Dale E. Gary, Katharine K. Reeves, Gregory D. Fleishman, Sijie Yu, Fan Guo, Säm Krucker, Jun Lin, Gelu M. Nita, Xiangliang Kong in Nature Astronomy
Researchers have presented a new, detailed look inside the ‘central engine’ of a large solar flare accompanied by a powerful eruption by the Owens Valley Solar Array. The new findings offer the first measurements characterizing the magnetic fields and particles at the heart of the explosion.
In the standard model of solar flares, a large-scale reconnection current sheet is postulated to be the central engine for powering the flare energy release and accelerating particles. However, where and how the energy release and particle acceleration occur remain unclear owing to the lack of measurements of the magnetic properties of the current sheet. Here scientists report the measurement of the spatially resolved magnetic field and flare-accelerated relativistic electrons along a current-sheet feature in a solar flare. The measured magnetic field profile shows a local maximum where the reconnecting field lines of opposite polarities closely approach each other, known as the reconnection X point. The measurements also reveal a local minimum near the bottom of the current sheet above the flare loop-top, referred to as a ‘magnetic bottle’. This spatial structure agrees with theoretical predictions and numerical modelling results. A strong reconnection electric field of about 4,000 V m−1 is inferred near the X point. This location, however, shows a local depletion of microwave-emitting relativistic electrons. These electrons instead concentrate at or near the magnetic bottle structure, where more than 99% of them reside at each instant. The observations suggest that the loop-top magnetic bottle is probably the primary site for accelerating and confining the relativistic electrons.
Hubble sees summertime on Saturn
Saturn is truly the lord of the rings in this latest snapshot from NASA’s Hubble Space Telescope, taken on July 4, 2020, when the opulent giant world was 839 million miles from Earth. A new Saturn image was taken during summer in the planet’s northern hemisphere.
Hubble found a number of small atmospheric storms. These are transient features that appear to come and go with each yearly Hubble observation. The banding in the northern hemisphere remains pronounced as seen in Hubble’s 2019 observations, with several bands slightly changing color from year to year. The ringed planet’s atmosphere is mostly hydrogen and helium with traces of ammonia, methane, water vapor, and hydrocarbons that give it a yellowish-brown color.
Hubble photographed a slight reddish haze over the northern hemisphere in this color composite. This may be due to heating from increased sunlight, which could either change the atmospheric circulation or perhaps remove ices from aerosols in the atmosphere. Another theory is that the increased sunlight in the summer months is changing the amounts of photochemical haze produced. “It’s amazing that even over a few years, we’re seeing seasonal changes on Saturn,” said lead investigator Amy Simon of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Conversely, the just-now-visible south pole has a blue hue, reflecting changes in Saturn’s winter hemisphere.
Hubble’s sharp view resolves the finely etched concentric ring structure. The rings are mostly made of pieces of ice, with sizes ranging from tiny grains to giant boulders. Just how and when the rings formed remains one of our solar system’s biggest mysteries. Conventional wisdom is that they are as old as the planet, over 4 billion years. But because the rings are so bright — like freshly fallen snow — a competing theory is that they may have formed during the age of the dinosaurs. Many astronomers agree that there is no satisfactory theory that explains how rings could have formed within just the past few hundred million years. “However, NASA’s Cassini spacecraft measurements of tiny grains raining into Saturn’s atmosphere suggest the rings can only last for 300 million more years, which is one of the arguments for a young age of the ring system,” said team member Michael Wong of the University of California, Berkeley.
Two of Saturn’s icy moons are clearly visible in this exposure: Mimas at right, and Enceladus at bottom.
This image is taken as part of the Outer Planets Atmospheres Legacy (OPAL) project. OPAL is helping scientists understand the atmospheric dynamics and evolution of our solar system’s gas giant planets. In Saturn’s case, astronomers continue tracking shifting weather patterns and storms.
NGTS-11 b (TOI-1847 b): A Transiting Warm Saturn Recovered from a TESS Single-transit Event
by Samuel Gill, Peter J. Wheatley, Benjamin F. Cooke, Andrés Jordán, Louise D. Nielsen, Daniel Bayliss, David R. Anderson, Jose I. Vines, Monika Lendl, Jack S. Acton, David J. Armstrong, François Bouchy, Rafael Brahm, Edward M. Bryant, Matthew R. Burleigh, Sarah L. Casewell, et al. in The Astrophysical Journal
The rediscovery of a lost planet could pave the way for the detection of a world within the habitable ‘Goldilocks zone’ in a distant solar system.
The planet, the size and mass of Saturn with an orbit of thirty-five days, is among hundreds of ‘lost’ worlds that University of Warwick astronomers are pioneering a new method to track down and characterise in the hope of finding cooler planets like those in our solar system, and even potentially habitable planets.
Reported in Astrophysical Journal Letters, the planet named NGTS-11b orbits a star 620 light years away and is located five times closer to its sun than Earth is to our own.
The planet was originally found in a search for planets in 2018 by the Warwick-led team using data from NASA’s TESS telescope. This uses the transit method to spot planets, scanning for the telltale dip in light from the star that indicates that an object has passed between the telescope and the star. However, TESS only scans most sections of the sky for 27 days. This means many of the longer period planets only transit once in the TESS data. And without a second observation the planet is effectively lost. The University of Warwick led team followed up one of these ‘lost’ planets using the telescopes at the Next-Generation Transit Survey (NGTS) in Chile and observed the star for seventy-nine nights, eventually catching the planet transiting for a second time nearly a year after the first detected transit.
Dr Samuel Gill from the Department of Physics at the University of Warwick said:
“By chasing that second transit down we’ve found a longer period planet. It’s the first of hopefully many such finds pushing to longer periods.
“These discoveries are rare but important, since they allow us to find longer period planets than other astronomers are finding. Longer period planets are cooler, more like the planets in our own Solar System.
“NGTS-11b has a temperature of only 160°C — cooler than Mercury and Venus. Although this is still too hot to support life as we know it, it is closer to the Goldilocks zone than many previously discovered planets which typically have temperatures above 1000°C.”
The Goldilocks zone refers to a range of orbits that would allow a planet or moon to support liquid water: too close to its star and it will be too hot, but too far away and it will be too cold.
Co-author Dr Daniel Bayliss from the University of Warwick said: “This planet is out at a thirty-five days orbit, which is a much longer period than we usually find them. It is exciting to see the Goldilocks zone within our sights.”
Co-author Professor Pete Wheatley from the University of Warwick said: “The original transit appeared just once in the TESS data, and it was our team’s painstaking detective work that allowed us to find it again a year later with NGTS.
“NGTS has twelve state-of-the-art telescopes, which means that we can monitor multiple stars for months on end, searching for lost planets. The dip in light from the transit is only 1% deep and occurs only once every 35 days, putting it out of reach of other telescopes.”
An Unambiguous Separation of Gamma-Ray Bursts into Two Classes from Prompt Emission Alone
by Christian K. Jespersen, Johann B. Severin, Charles L. Steinhardt, Jonas Vinther, Johan P. U. Fynbo, Jonatan Selsing, Darach Watson in The Astrophysical Journal
By applying a machine-learning algorithm, scientists have developed a method to classify all gamma-ray bursts (GRBs), rapid highly energetic explosions in distant galaxies, without needing to find an afterglow — by which GRBs are presently categorized. This breakthrough, initiated by first-year B.Sc. students, may prove key in finally discovering the origins of these mysterious bursts.
Ever since gamma-ray bursts (GRBs) were accidentally picked up by Cold War satellites in the 70s, the origin of these rapid bursts have been a significant puzzle. Although many astronomers agree that GRBs can be divided into shorter (typically less than 1 second) and longer (up to a few minutes) bursts, the two groups are overlapping. It has been thought that longer bursts might be associated with the collapse of massive stars, while shorter bursts might instead be caused by the merger of neutron stars. However, without the ability to separate the two groups and pinpoint their properties, it has been impossible to test these ideas.
So far, it has only been possible to determine the type of a GRB about 1% of the time, when a telescope was able to point at the burst location quickly enough to pick up residual light, called an afterglow. This has been such a crucial step that astronomers have developed worldwide networks capable of interrupting other work and repointing large telescopes within minutes of the discovery of a new burst. One GRB was even detected by the LIGO Observatory using gravitational waves, for which the team was awarded the 2017 Nobel Prize.
Breakthrough achieved using machine-learning algorithm
Now, scientists at the Niels Bohr Institute have developed a method to classify all GRBs without needing to find an afterglow. The group, led by first-year B.Sc. Physics students Johann Bock Severin, Christian Kragh Jespersen and Jonas Vinther, applied a machine-learning algorithm to classify GRBs. They identified a clean separation between long and short GRB’s. Their work, carried out under the supervision of Charles Steinhardt, will bring astronomers a step closer to understanding GRB’s.
This breakthrough may prove the key to finally discovering the origins of these mysterious bursts. As Charles Steinhardt, Associate Professor at the Cosmic Dawn Center of the Niels Bohr Institute explains, “Now that we have two complete sets available, we can start exploring the differences between them. So far, there had not been a tool to do that.”
From algorithm to visual map
Instead of using a limited set of summary statistics, as was typically done until then, the students decided to encode all available information on GRB’s using the machine learning algorithm t-SNE. The t-distributed Stochastic neighborhood embedding algorithm takes complex high-dimensional data and produces a simplified and visually accessible map. It does so without interfering with the structure of the dataset. “The unique thing about this approach,” explains Christian Kragh Jespersen, “is that t-SNE doesn’t force there to be two groups. You let the data speak for itself and tell you how it should be classified.”
Shining light on the data
The preparation of the feature space — the input you give the algorithm — was the most challenging part of the project, says Johann Bock Severin. Essentially, the students had to prepare the dataset in such a way that its most important features would stand out. “I like to compare it to hanging your data points from the ceiling in a dark room,” explains Christian Kragh Jespersen. “Our main problem was to figure out from what direction we should shine light on the data to make the separations visible.”
“Step 0 in understanding GRB’s”
The students explored the t-SNE machine-learning algorithm as part of their 1st Year project, a 1st year course in the Bachelor of Physics. “By the time we got to the end of the course, it was clear we had quite a significant result,” their supervisor Charles Steinhardt says. The students’ mapping of the t-SNE cleanly divides all GRB’s from the Swift observatory into two groups. Importantly, it classifies GRB’s that previously were difficult to classify. “This essentially is step 0 in understanding GRB’s,” explains Steinhardt. “For the first time, we can confirm that shorter and longer GRB’s are indeed completely separate things.”
Without any prior theoretical background in astronomy, the students have discovered a key piece of the puzzle surrounding GRB’s. From here, astronomers can start to develop models to identify the characteristics of these two separate classes.
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