Hide and Seek – How NASA’s Lucy Mission Team Discovered Eurybates’ Satellite (Astronomy)

On Jan. 9, 2020, NASA’s Lucy mission officially announced that it would be visiting not seven, but eight asteroids. As it turns out, Eurybates, one of the asteroids along Lucy’s path, has a small satellite.

Video: On Jan. 9, 2020, the Lucy Mission officially announced that it would be visiting not seven, but eight asteroids. As it turns out, Eurybates, one of the asteroids along Lucy’s path, has a small satellite. Shortly after the Lucy team discovered the satellite, both it and Eurybates moved behind the Sun, preventing the team from observing it further. However, the asteroids emerged from behind the Sun in July 2020, and since then, the Lucy team has been able to observe the satellite with Hubble on multiple occasions, allowing the team to precisely define the satellite’s orbit and allowing the little satellite to finally get an official name – Queta.Credits: NASA’s Goddard Space Flight Center

Though searching for satellites is one of the mission’s central goals, finding these tiny worlds before Lucy is launched gives the team the opportunity to investigate their orbits and plan for more detailed follow-up observations with the spacecraft. Without searching for these asteroid companions before launch, Lucy could also run the risk of encountering an unexpected binary pair. Seeing two asteroids when the spacecraft is expecting only one could confuse its autonomous tracking system.

Fortunately, the Lucy science team is already familiar with the perfect tool to use. “One of the ways that you can try to look for satellites is to use Hubble. And that’s something that I’ve done a lot with the Kuiper Belt,” says Keith Noll, the mission’s project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and one of the discoverers of Eurybates’ satellite. “We know more than 100 binaries in the Kuiper Belt, and the vast majority of those were found with Hubble.”

And understandably so. The orbiting telescope, 13.3 meters (43.5 feet) long, which has a primary mirror with a diameter of 2.4 meters (7 feet, 10.5 inches), is unencumbered by the normal blurring effects of Earth’s atmosphere, since it resides comfortably above the atmosphere. Though some of the larger earthbound telescopes are sometimes able to observe the heavens with similar clarity, Hubble can detect a small, dim satellite orbiting very close to a larger, brighter asteroid that a telescope on Earth might miss.

To know where to look for satellites, the science team had to calculate the Hill spheres of the asteroids they wanted to examine. The Hill sphere is an imaginary sphere around a body, inside of which the body has the dominant gravitational influence. In other words, all stable satellites of a body orbit within its Hill sphere. Earth’s Hill sphere, for instance, has a radius of nearly 1.5 million km (930,000 miles), and the Moon orbits safely inside at approximately 380,000 km (236,000 miles).

Noll’s team submitted a proposal to use Hubble to search for satellites and made their first round of observations in the fall of 2018. They then scoured the images for evidence of satellites. This process is difficult, since raw images from Hubble can be messy. “It’s got a lot of bumps and blobs, it’s not a clean thing,” remarks Noll. For instance, raw images of bright objects often show diffraction spikes, the bright X-shapes that resemble cartoon four-pointed stars. Hubble’s cameras are also susceptible to cosmic rays (particles traveling at close to the speed of light) which can appear as bright dots on the images. “So when you look at [the images], you say, ‘Well, is that blob a satellite, or is it just part of… the way that the light gets scattered from the entire optical assembly throughout the telescope?’” Except for a brief false alarm when it appeared that another Lucy target, Orus, might be a binary, the team saw no new evidence of satellites.

That is, until November 2019. The night before a large science team meeting, Noll was preparing a presentation on searching for satellites. In looking for photos to demonstrate the difficulties of distinguishing between satellites and other bright blobs, he came across one of his team’s Hubble photos from Sept. 12, 2018. After experimenting with the brightness and contrast, he saw one peculiar bright spot near Eurybates. “I said, ‘Gosh, that one really looks like what I would expect a satellite to look like.’” Realizing it was getting late, he circled the object and finished making the presentation. In his talk the next day, he pointed out the object’s striking resemblance to a satellite. In the audience was Mike Brown, one of the mission’s science co-investigators. Brown interrupted to ask Noll if he had looked at the data from the other observation on Sept. 14, but Noll admitted that he had not had a chance yet. According to Noll, before he finished presenting, Brown examined the data from Sept. 14 and exclaimed, “I see it there too!” 

people huddled around a conference table; one person points at a laptop
The Lucy science team examines images of the satellite. Co-discoverer Keith Noll and Mike Brown sit opposite each other in front of the screen as other science team members look on.Credits: SwRI/J. Spencer

Everyone crowded around Brown’s laptop. Had they actually discovered a satellite of Eurybates? The team noticed that as they compared the two photos, the object appeared to have moved a little, like a satellite might. A check revealed that the object’s observed positions fit many possible orbits. From a planetary dynamics perspective, it also made sense that Eurybates might have a satellite. Eurybates is one of a massive set of fragments created by the same asteroid collision, so the idea that one of these fragments might be orbiting Eurybates is not far-fetched. These were all steps in the right direction, but not conclusive evidence. The team had only two observations so far, and according to Noll, “You never really believe anything until you’ve seen it the third time, so we had to get more data.” They submitted an urgent proposal to use Hubble again, which was approved quickly enough that the team was able to get their observations about a month later. They requested 12 chances to observe the satellite, but they were granted three. If they could see the satellite again on at least one of the three, they would be given the other nine.

Their first chance was on Dec. 11. The satellite was a no-show. The team wasn’t worried – yet – because they knew there was a good chance that it might be simply too close to Eurybates, and lost in the glare. They tried a second time on Dec. 21, but much to their consternation, the shy little rock was nowhere to be found. The team began to doubt that their so-called satellite even existed. “Maybe we’re just kidding ourselves. Maybe it’s not real,” Noll remembers thinking.

Finally, on Jan. 3, they found it. The tiny, dim satellite was clearly visible on the new images. As they’d suspected, in the previous two observations it was too close to Eurybates (which is over 6,000 times brighter than its companion) to be seen. The difference in brightness suggests that the satellite is probably less than 1 km (0.6 miles) in diameter, puny compared to Eurybates (64 km, or 40 miles).

Shortly after the Lucy team discovered the satellite, both it and Eurybates moved behind the Sun, preventing the team from observing it further. However, the asteroids emerged from behind the Sun in July 2020, and since then, the Lucy team has been able to observe the satellite with Hubble on multiple occasions, allowing the team to precisely define the satellite’s orbit and allowing the little satellite to finally get an official name – Queta.

translucent-blue illustration of Eurybates with tiny natural satellite "Queta" labeled
Illustration of the Lucy Trojan asteroid target Eurybates and its satellite, Queta.Credits: NASA’s Goddard Space Flight Center

Queta is the first Trojan asteroid named under a newly revised naming convention for Trojan asteroids. Though the Trojans were previously only named for heroes from Homer’s Iliad, smaller Trojans are now named after Olympic and Paralympic athletes, in recognition of these modern day heroes. Queta is named in honor of Mexican track and field athlete Norma Enriqueta “Queta” Basilio Sotelo. At the 1968 Summer Olympics, she became the first woman in history to light the Olympic cauldron. The name “Queta” was selected for Eurybates’ satellite because Basilio’s role is similar to that of Eurybates, a Greek herald. In ancient Greece, heralds were messengers in the service of kings or governments, an occupation that sometimes involved running long distances. According to the ancient Greek historian Herodotus, a herald named Pheidippides ran 260 km (160 mi) from Athens to Sparta to request the Spartans’ aid in the Battle of Marathon. (It is from this legend that we get the word “marathon.”) Heralds were also tasked with announcing the start of the ancient Olympic Games, similar to how the torch ceremony announces the start of the modern Olympic Games. Though the torch ceremony was not a part of the ancient Olympics, it is inspired by an ancient Greek tradition called the lampadedromia, a relay race in which the runners pass a torch while trying to keep its sacred fire burning. Several other members of the Eurybates family, a group of asteroids that are actually fragments formed by the same collision, have been named after heroes of the 1968 Olympic and Paralympic Games. As a fellow trailblazer of the 1968 Games, Queta fits right in.

Featured image: Hubble images of Eurybates and its satellite on Jan. 3, 2020, when the satellite was visible (circled in green), and on Dec. 11, 2019, when the satellite was too close to Eurybates to be seen.Credits: NASA/Hubble/K. Noll/SwRI


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NASA’s Ingenuity Mars Helicopter Succeeds in Historic First Flight (Astronomy)

Monday, NASA’s Ingenuity Mars Helicopter became the first aircraft in history to make a powered, controlled flight on another planet. The Ingenuity team at the agency’s Jet Propulsion Laboratory in Southern California confirmed the flight succeeded after receiving data from the helicopter via NASA’s Perseverance Mars rover at 6:46 a.m. EDT (3:46 a.m. PDT).

“Ingenuity is the latest in a long and storied tradition of NASA projects achieving a space exploration goal once thought impossible,” said acting NASA Administrator Steve Jurczyk. “The X-15 was a pathfinder for the space shuttle. Mars Pathfinder and its Sojourner rover did the same for three generations of Mars rovers. We don’t know exactly where Ingenuity will lead us, but today’s results indicate the sky – at least on Mars – may not be the limit.”

The solar-powered helicopter first became airborne at 3:34 a.m. EDT (12:34 a.m. PDT) – 12:33 Local Mean Solar Time (Mars time) – a time the Ingenuity team determined would have optimal energy and flight conditions. Altimeter data indicate Ingenuity climbed to its prescribed maximum altitude of 10 feet (3 meters) and maintained a stable hover for 30 seconds. It then descended, touching back down on the surface of Mars after logging a total of 39.1 seconds of flight. Additional details on the test are expected in upcoming downlinks.

Video: In this video captured by NASA’s Perseverance rover, the agency’s Ingenuity Mars Helicopter took the first powered, controlled flight on another planet on April 19, 2021.Credits: NASA/JPL-Caltech/ASU/MSSS

Ingenuity’s initial flight demonstration was autonomous – piloted by onboard guidance, navigation, and control systems running algorithms developed by the team at JPL. Because data must be sent to and returned from the Red Planet over hundreds of millions of miles using orbiting satellites and NASA’s Deep Space Network, Ingenuity cannot be flown with a joystick, and its flight was not observable from Earth in real time.

NASA Associate Administrator for Science Thomas Zurbuchen announced the name for the Martian airfield on which the flight took place.

“Now, 117 years after the Wright brothers succeeded in making the first flight on our planet, NASA’s Ingenuity helicopter has succeeded in performing this amazing feat on another world,” Zurbuchen said. “While these two iconic moments in aviation history may be separated by time and 173 million miles of space, they now will forever be linked. As an homage to the two innovative bicycle makers from Dayton, this first of many airfields on other worlds will now be known as Wright Brothers Field, in recognition of the ingenuity and innovation that continue to propel exploration.”

Ingenuity’s chief pilot, Håvard Grip, announced that the International Civil Aviation Organization (ICAO) – the United Nations’ civil aviation agency – presented NASA and the Federal Aviation Administration with official ICAO designator IGY, call-sign INGENUITY.

These details will be included officially in the next edition of ICAO’s publication Designators for Aircraft Operating Agencies, Aeronautical Authorities and Services. The location of the flight has also been given the ceremonial location designation JZRO for Jezero Crater.

As one of NASA’s technology demonstration projects, the 19.3-inch-tall (49-centimeter-tall) Ingenuity Mars Helicopter contains no science instruments inside its tissue-box-size fuselage. Instead, the 4-pound (1.8-kg) rotorcraft is intended to demonstrate whether future exploration of the Red Planet could include an aerial perspective.

This first flight was full of unknowns. The Red Planet has a significantly lower gravity – one-third that of Earth’s – and an extremely thin atmosphere with only 1% the pressure at the surface compared to our planet. This means there are relatively few air molecules with which Ingenuity’s two 4-foot-wide (1.2-meter-wide) rotor blades can interact to achieve flight. The helicopter contains unique components, as well as off-the-shelf-commercial parts – many from the smartphone industry – that were tested in deep space for the first time with this mission.

“The Mars Helicopter project has gone from ‘blue sky’ feasibility study to workable engineering concept to achieving the first flight on another world in a little over six years,” said Michael Watkins, director of JPL. “That this project has achieved such a historic first is testimony to the innovation and doggedness of our team here at JPL, as well as at NASA’s Langley and Ames Research Centers, and our industry partners. It’s a shining example of the kind of technology push that thrives at JPL and fits well with NASA’s exploration goals.”

Parked about 211 feet (64.3 meters) away at Van Zyl Overlook during Ingenuity’s historic first flight, the Perseverance rover not only acted as a communications relay between the helicopter and Earth, but also chronicled the flight operations with its cameras. The pictures from the rover’s Mastcam-Z and Navcam imagers will provide additional data on the helicopter’s flight.   

“We have been thinking for so long about having our Wright brothers moment on Mars, and here it is,” said MiMi Aung, project manager of the Ingenuity Mars Helicopter at JPL. “We will take a moment to celebrate our success and then take a cue from Orville and Wilbur regarding what to do next. History shows they got back to work – to learn as much as they could about their new aircraft – and so will we.”

Perseverance touched down with Ingenuity attached to its belly on Feb. 18. Deployed to the surface of Jezero Crater on April 3, Ingenuity is currently on the 16th sol, or Martian day, of its 30-sol (31-Earth day) flight test window. Over the next three sols, the helicopter team will receive and analyze all data and imagery from the test and formulate a plan for the second experimental test flight, scheduled for no earlier than April 22. If the helicopter survives the second flight test, the Ingenuity team will consider how best to expand the flight profile.

More About Ingenuity

JPL, which built Ingenuity, also manages the technology demonstration project for NASA. It is supported by NASA’s Science, Aeronautics, and Space Technology mission directorates. The agency’s Ames Research Center in California’s Silicon Valley and Langley Research Center in Hampton, Virginia, provided significant flight performance analysis and technical assistance during Ingenuity’s development.

Dave Lavery is the program executive for the Ingenuity Mars Helicopter, MiMi Aung is the project manager, and Bob Balaram is chief engineer.

More About Perseverance

A key objective for Perseverance’s mission on Mars is astrobiology, including the search for signs of ancient microbial life. The rover will characterize the planet’s geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rock and regolith (broken rock and dust).

Subsequent NASA missions, in cooperation with ESA (European Space Agency), would send spacecraft to Mars to collect these sealed samples from the surface and return them to Earth for in-depth analysis.

JPL built and manages operations of the Perseverance rover. JPL is managed for NASA by Caltech in Pasadena, California.

Featured image: NASA’s Ingenuity Mars Helicopter captured this shot as it hovered over the Martian surface on April 19, 2021, during the first instance of powered, controlled flight on another planet. It used its navigation camera, which autonomously tracks the ground during flight.Credits: NASA/JPL-Caltech


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How Scientists Are ‘Looking’ Inside Asteroids? (Planetary Science)

Asteroids can pose a threat to life on Earth but are also a valuable source of resources to make fuel or water to aid deep space exploration. Devoid of geological and atmospheric processes, these space rocks provide a window onto the evolution of the solar system. But to really understand their secrets, scientists must know what’s inside them.

Only four spacecraft have ever landed on an asteroid – most recently in October 2020 – but none has peered inside one. Yet understanding the internal structures of these cosmic rocks is crucial for answering key questions about, for example, the origins of our own planet.

‘Asteroids are the only objects in our solar system that are more or less unchanged since the very beginning of the solar system’s formation,’ said Dr Fabio Ferrari, who studies asteroid dynamics at the University of Bern, Switzerland. ‘If we know what’s inside asteroids, we can understand a lot about how planets formed, how everything that we have in our solar system has formed and might evolve in the future.’

Then are also more practical reasons for knowing what’s inside an asteroid, such as mining for materials to facilitate human exploration of other celestial bodies, but also defending against an Earth-bound rock.

NASA’s upcoming Double Asteroid Redirection Test (DART) mission, expected to launch later this year, will crash into the 160m in diameter asteroid moon Dimorphos in 2022, with the aim of changing its orbit. The experiment will demonstrate for the first time whether humans can deflect a potentially dangerous asteroid.

But scientists have only rough ideas about how Dimorphos will respond to the impact as they know very little about both this asteroid moon, and its parent asteroid, Didymos.

To better address such questions, scientists are investigating how to remotely tell what’s inside an asteroid and discern its type.

Types

There are many types of asteroids. Some are solid blocks of rock, rugged and sturdy, others are conglomerates of pebbles, boulders and sand, products of many orbital collisions, held together only by the power of gravity. There are also rare metallic asteroids, heavy and dense.

‘To deflect the denser monolithic asteroids, you would need a bigger spacecraft, you would need to travel faster,’ said Dr Hannah Susorney, a research fellow in planetary science at the University of Bristol, the UK. ‘The asteroids that are just bags of material – we call them rubble piles – can, on the other hand, blow apart into thousands of pieces. Those pieces could by themselves become dangerous.’

Dr Susorney is exploring what surface features of an asteroid can reveal about the structure of its interior as part of a project called EROS.  

This information could be useful for future space mining companies who would want to know as much as possible about a promising asteroid before investing into a costly prospecting mission as well as knowing more about potential threats.

‘There are thousands of near-Earth asteroids, those whose trajectories could one day intersect with that of the Earth,’ she said. ‘We have only visited a handful of them. We know close to nothing about the vast majority.’

During the fourth ever landing on an asteroid, Bennu was mapped thanks to a mosaic of images collected by NASA’s OSIRIS-REx spacecraft. Peering inside an asteroid is the next crucial step. Image credit – NASA/Goddard/University of Arizona

Topography

Dr Susorney is trying to create detailed topography models of two of the most well-studied asteroids – Itokawa (the target of the 2005 Japanese Hayabusa 1 mission) and Eros (mapped in detail by the NEAR Shoemaker space probe in the late 1990s).

‘The surface topography can actually tell us a lot,’ Dr Susorney said. ‘If you have a rubble pile asteroid, such as Itokawa, which is essentially just a bag of fluff, you cannot expect very steep slopes there. Sand cannot be held up into an infinite slope unless it’s supported. A solid cliff can. The rocky monolithic asteroids, such as Eros, do tend to have much more pronounced topographical features, much deeper and steeper craters.’

Susorney wants to take the high-resolution models derived from spacecraft data and find parameters in them that could then be used in the much lower resolution asteroid shape models created from ground-based radar observations.

‘The difference in the resolution is quite substantial,’ she admits. ‘Tens to hundreds of metres in the high-res spacecraft models and kilometres from ground-based radar measurements. But we have found that, for example, the slope distribution gives us a hint. How much of the asteroid is flat and how much is steep?’

Coloured topographical maps from Dr Susorney show Eros (left), a rocky monolithic asteroid, as having steeper craters than Itokawa (right), a rubble pile asteroid. Image credit – Hannah Susorney

Dr Ferrari is working with the team preparing the DART mission. As part of a project called GRAINS, he developed a tool that enables modelling of the interior of Dimorphos, the impact target, as well as other rubble pile asteroids.

‘We expect that Dimorphos is a rubble pile because we think that it formed from matter ejected by the main asteroid, Didymos, when it was spinning very fast,’ Dr Ferrari said. ‘This ejected matter then re-accreted and formed the moon. But we have no observations of its interior.’

An aerospace engineer by education, Dr Ferrari borrowed a solution for the asteroid problem from the engineering world, from a discipline called granular dynamics.

‘On Earth, this technique can be used to study problems such as sand piling or various industrial processes involving small particles,’ Dr Ferrari said. ‘It’s a numerical tool that allows us to model the interaction between the different particles (components) – in our case, the various boulders and pebbles inside the asteroid.’

‘Asteroids are the only objects in our solar system that are more or less unchanged since the very beginning of the solar system’s formation.’

— Dr Fabio Ferrari, University of Bern, Switzerland

Rubble pile

The researchers are modelling various shapes and sizes, various compositions of the boulders and pebbles, the gravitational interactions and the friction between them. They can run thousands of such simulations and then compare them with surface data about known asteroids to understand rubble pile asteroids’ behaviour and make-up.

‘We can look at the external shape, study various features on the surface, and compare that with our simulations,’ Dr Ferrari said. ‘For example, some asteroids have a prominent equatorial bulge,’ he says, referring to the thickening around the equator that can appear as a result of the asteroid spinning.

In the simulations, the bulge might appear more prominent for some internal structures than others.

For the first time, Dr Ferrari added, the tool can work with non-spherical elements, which considerably improves accuracy.

‘Spheres behave very differently from angular objects,’ he said.

The model suggests that in the case of Dimorphos, the DART impact will create a crater and throw up a lot of material from the asteroid’s surface. But there are still many questions, particularly the size of the crater, according to Dr Ferrari.

‘The crater might be as small as ten metres but also as wide as a hundred metres, taking up half the size of the asteroid. We don’t really know,’ said Dr Ferrari. ‘Rubble piles are tricky. Because they are so loose, they might as well just absorb the impact.’

No matter what happens on Dimorphos, the experiment will provide a treasure trove of data for refining future simulations and models. We can see whether the asteroid behaves as we expected and learn how to make more accurate predictions for future missions that lives on Earth may very well depend on.

The solar system’s asteroid belt contains C-type asteroids, which likely consist of clay and silicate rocks, M-type, which are composed mainly of metallic iron, and S-type, which are formed of silicate materials and nickel-iron. Image credit – Horizon

The research in this article was funded by the EU.

Featured image: The shape of asteroids such as 243 Ida can reveal information about what they’re made of, which can, in turn, tell us more about the formation of the solar system. Image credit – NASA/JPL/USGS


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Can a New Type of Glacier on Mars Aid Future Astronauts? (Planetary Science)

On April 21, 1908, near Earth’s North Pole, the Arctic explorer Frederick Albert Cook scrawled in his diary a memorable phrase: “We were the only pulsating creatures in a dead world of ice.” These words may soon take on new significance for humankind in another dead world of hidden ice, submerged beneath the red sand of its frigid deserts. This dead world is Mars, and the desert is the planet’s mid-latitude region known as Arcadia Planitia.

Sharon Hibbard is a Ph.D. candidate in geology and planetary science at the University of Western Ontario and the lead author of a new scientific paper on glaciers and glacier-like activity in Arcadia Planitia, recently published in Icarus. Hibbard and associates have identified evidence of a glacier in this region that defies expectations and, due to its unique characteristics, could serve as a water source for future human landings and exploration.

Evidence of Martian glaciers, referred to more cautiously by the scientific community as “viscous flow features”, were first investigated in the 1970s using satellite imagery from NASA’s Viking program, the second and third spacecraft to reach the surface of Mars. Scientists were intrigued by widespread ripples and flows in the Martian surface, many with moraine-like features that bore striking resemblance to the glacial landscapes of Earth.

The new study investigates viscous flow features in the lower mid-latitudes of Arcadia Planitia, exhaustively mapping dozens of surface features likely produced by Mars’ subterranean glaciers made of water ice. In the process of mapping, the team found something rather unexpected: evidence of ice flow in a large, flat plain. This type of ice flow is not commonly seen on Mars, where most of the prominent ice-related features take the form of ripples and furrows in valleys and on hillsides where gravity can prompt ice to flow downhill. Hibbard’s team found these “sinuous features” in a flat-lying region of Arcadia Planitia, mysteriously isolated from any bluffs or slopes. How could this ice in the plains of Arcadia Planitia possibly be flowing?

Evidence of Martian glaciers in Ismeniae Fossae, taken by the High Resolution Stereo Camera on European Space Agency’s Mars Express. Source: ESA/DLR/FU Berlin

Examining the presence of water on Mars

Informed guesses about the existence of water and ice on Mars preceded the era of spaceflight by hundreds of years. Telescopic observation of Mars’ greater landforms and polar ice caps led astronomer William Herschel to speculate in 1784 that the red planet was populated by intelligent life.

Advances in telescope technology had largely dispelled this theory by the 20th century, but the existence of water and water ice on Mars remained uncertain until the first orbiters and landers arrived in the 1970s. Not only did NASA’s Viking program discover trace amounts of atmospheric water vapor, but its orbital imagery also revealed the existence of numerous glacier-like features. Exposed water ice sublimates away in the low pressures and freezing temperatures present on the surface of Mars, so if water ice glaciers were responsible for the observed Earth-like flows, researchers conjectured that the ice must be protected by a thick layer of debris. Further observations confirmed this hypothesis, and in ensuing decades the scientific community proceeded to map, catalog and categorize many thousands of glacier candidates with varying degrees of confidence. Over time, our capabilities grew from speculation in telescope eyepieces to precise, on-site observations across the electromagnetic spectrum.

The presence of water ice below the surface of Mars was confirmed in 2008 by the Phoenix lander, reinforcing the findings of Mars Odyssey, whose sensors indicated massive amounts of subsurface water ice at the more temperate mid-latitudes in 2002. For example, the subterranean water ice of the flat Arcadian plains was directly measured by Mars Reconnaissance Orbiter’s radar and found to begin 6 centimeters below the surface layer of dust and debris, and extend downward to an average depth of 38 meters.

Water frost on the surface of Mars, captured by the Viking Lander 2 on May 18, 1979. Source: NASA/JPL

Understanding the unexpected ice flow

Seeing to the bottom of an ice sheet to discern what makes it flow is no easy task, and only grows more complex when the ice sheet is 170 million miles away. Fortunately, the mysterious flow features Hibbard’s team found in the flat Arcadian plains are not unique in this solar system—in fact, we need not travel far at all to study an analog. Hibbard and associates identified remarkable similarities to Antarctica’s ice streams, regions in its flat ice sheets where a certain volume of ice moves more rapidly than its surroundings.

While contemporary science still lacks a detailed understanding of what causes these ice streams on Earth, researchers have inferred that subsurface topography and melting at the bottom of the ice sheet may both play a role. Hibbard notes that the Arcadian flows exhibit several of the key features of Earth’s ice streams. The Arcadian ice has since stopped flowing, accumulating a thicker layer of surface debris, becoming a stagnant ice stream.

“Finding possible flow features in this flat-lying region was very exciting” said Hibbard in an interview with GlacierHub. “Previous studies have suggested there is a buried ice sheet at our study site, and our evidence of channelized ice within this ice sheet indicates that there are more complex glacial dynamics at hand on Mars.”

Comparison of sinuous features in Antarctica (left) and Arcadia Planitia (right) that may indicate the presence of an ice stream. Source: (a) Synthetic Aperture Radar (Alley et al., 2004). (b) THEMIS Daytime IR (Edwards et al., 2011Hill and Christensen, 2017)

Implications for human exploration

These unique characteristics of the Arcadian plains ice sheet raise another question, one that William Herschel certainly would have loved to hear: could the water ice be extracted and used by human astronauts?

While most Martian glaciers and their subsurface ice lie near bluffs and on slopes, this ice sits near the surface and forms a temperate, flat ice sheet covered with few boulders or other geographical hazards. It would make for an ideal landing site. Hibbard proposes that this region is “favorable for future in situ resource utilization and human missions,” due to the sheer volume and reasonable purity of the near-surface ice.

Nilton Renno, an astrobiologist at the University of Michigan emphasizes the difficulty of water ice extraction on Mars, writing to GlacierHub that “[many] glaciers are in regions more challenging for human exploration because of the lower temperatures during the winter and topography,” even though “in high latitudes, the water ice is easily accessible.” The Phoenix Lander easily uncovered subsurface water ice at high northern Martian latitudes, an area humans are unlikely to visit due to its extreme cold and lack of sunlight.

Germán Martínez, a staff scientist at the Lunar and Planetary Institute in Houston, affirms the feasibility of the mid-latitude Arcadia Planitia as a landing site, writing to GlacerHub that “in general, it’s more feasible to go to low and mid latitudes, where temperatures are milder and solar energy is available throughout the year … in these mid and low latitudes, though, water ice is typically deeper in the subsurface than in polar latitudes.”

The shallow ice found by Hibbard and associates stands apart from this trend, only slightly buried and much more easily accessible than other water ice deposits typically found at mid-Martian latitudes. In time, the frozen water in Arcadia Planitia may see the surface once more, finding use at the hands of future astronauts, transforming the dead surface of an icy world into one with a little more life.

Featured image: An artist’s rendering from NASA HiRISE data of a mid-latitude glacier on Mars, insulated by a surface layer of dust and rock. Located at Mesa Wall in Protonilus Mensae on Mars. Source: Kevin Gill / Flickr


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This story is republished here from Earth Institute, Columbia University http://blogs.ei.columbia.edu.

NASA’s New Horizons Reaches a Rare Space Milestone (Astronomy)

Now 50 times as far from the Sun as Earth, History-Making Pluto Explorer Photographs Voyager 1’s Location from the Kuiper Belt

In the weeks following its launch in early 2006, when NASA’s New Horizons was still close to home, it took just minutes to transmit a command to the spacecraft, and hear back that the onboard computer received and was ready to carry out the instructions.

Scale of the Solar System

Here’s one way to imagine just how far 50 AU is: Think of the solar system laid out on a neighborhood street; the Sun is one house to the left of “home” (or Earth), Mars would be the next house to the right, and Jupiter would be just four houses to the right. New Horizons would be 50 houses down the street, 17 houses beyond Pluto! 

As New Horizons crossed the solar system, and its distance from Earth jumped from millions to billions of miles, that time between contacts grew from a few minutes to several hours. And on April 17 at 12:42 UTC (or April 17 at 8:42 a.m. EDT), New Horizons will reach a rare deep-space milepost — 50 astronomical units from the Sun, or 50 times farther from the Sun than Earth is. 

New Horizons is just the fifth spacecraft to reach this great distance, following the legendary Voyagers 1 and 2 and their predecessors, Pioneers 10 and 11. It’s almost 5 billion miles (7.5 billion kilometers) away; a remote region where one of those radioed commands, even traveling at the speed of light, needs seven hours to reach the far flung spacecraft. Then add seven more hours before its control team on Earth finds out if the message was received.   

“It’s hard to imagine something so far away,” said Alice Bowman, the New Horizons mission operations manager at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland. “One thing that makes this distance tangible is how long it takes for us on Earth to confirm that the spacecraft received our instructions. This went from almost instantaneous to now being on the order of 14 hours. It makes the extreme distance real.” 

To mark the occasion, New Horizons recently photographed the star field where one of its long-distance cousins, Voyager 1, appears from New Horizons’ unique perch in the Kuiper Belt. Never before has a spacecraft in the Kuiper Belt photographed the location of an even more distant spacecraft, now in interstellar space. Although Voyager 1 is far too faint to be seen directly in the image, its location is known precisely due to NASA’s radio tracking.

Hello, Voyager! From the distant Kuiper Belt at the solar system’s frontier, on Christmas Day, Dec. 25, 2020, NASA’s New Horizons spacecraft pointed its Long Range Reconnaissance Imager in the direction of the Voyager 1 spacecraft, whose location is marked with the yellow circle. Voyager 1, the farthest human-made object and first spacecraft to actually leave the solar system, is more than 152 astronomical units (AU) from the Sun—about 14.1 billion miles or 22.9 billion kilometers—and was 11.2 billion miles (18 billion kilometers) from New Horizons when this image was taken. Voyager 1 itself is about 1 trillion times too faint to be visible in this image. Most of the objects in the image are stars, but several of them, with a fuzzy appearance, are distant galaxies. New Horizons reaches the 50 AU mark on April 18, 2021, and will join Voyagers 1 and 2 in interstellar space in the 2040s. Credits: NASA/Johns Hopkins APL/Southwest Research Institute

“That’s a hauntingly beautiful image to me,” said Alan Stern, New Horizons principal investigator from the Southwest Research Institute in Boulder, Colorado. 

“Looking back at the flight of New Horizons from Earth to 50 AU almost seems in some way like a dream,” he continued. “Flying a spacecraft across our entire solar system to explore Pluto and the Kuiper Belt had never been done before New Horizons. Most of us on the team have been a part of this mission since it was just an idea, and during that time our kids have grown up, and our parents, and we ourselves, have grown older. But most importantly, we made many scientific discoveries, inspired countless STEM careers, and even made a little history.”

New Horizons was practically designed to make history. Dispatched at 36,400 miles per hour (58,500 kilometers per hour) on Jan. 19, 2006, New Horizons was and is still the fastest human-made object ever launched from Earth. Its gravity-assist flyby of Jupiter in February 2007 not only shaved about three years from its voyage to Pluto, but allowed it to make the best views ever of Jupiter’s faint ring, and capture the first movie of a volcano erupting anywhere in the solar system except Earth. 

New Horizons successfully pulled off the first exploration of the Pluto system in July 2015, followed by the farthest flyby in history – and first close-up look at a Kuiper Belt object (KBO) — with its flight past Arrokoth on New Year’s day 2019. From its unique perch in the Kuiper Belt, New Horizons is making observations that can’t be made from anywhere else; even the stars look different from the spacecraft’s point of view

Currently exploring the Kuiper Belt beyond Pluto, New Horizons is just one of five spacecraft to reach 50 astronomical units – 50 times the distance between the Sun and Earth – on its way out of the solar system and, eventually, into interstellar space. Credits: NASA/Johns Hopkins APL/Southwest Research Institute

New Horizons team members use giant telescopes like the Japanese Subaru observatory to scan the skies for another potential (and long-shot) KBO flyby target, New Horizons itself remains healthy, collecting data on the solar wind and space environment in the Kuiper Belt, other Kuiper Belt objects, and distant planets like Uranus and Neptune. This summer, the mission team will transmit a software upgrade to boost New Horizons’ scientific capabilities. For future exploration, the spacecraft’s nuclear battery should provide enough power to keep New Horizons operating until the late-2030s.


Provided by NASA

Giant Planet at Large Distance From Sun-like Star Puzzles Astronomers (Planetary Science)

A team of astronomers led by Dutch scientists has directly imaged a giant planet orbiting at a large distance around a sun-like star. Why this planet is so massive and how it got to be there is a mystery. The researchers will publish their findings in the journal Astronomy & Astrophysics.

The planet in question is YSES 2b, located 360 light years from Earth in the direction of the southern constellation of Musca (Latin for The Fly). The gaseous planet is six times heavier than Jupiter, the largest planet in our solar system. The newly discovered planet orbits 110 times more distant from its star than the Earth does from the sun (or 20 times the distance between the sun and Jupiter). The accompanying star is only 14 million years old and resembles our sun in its childhood.

The large distance from the planet to the star presents a puzzle to astronomers because it does not seem to fit either of the two most well-known models for the formation of large gaseous planets. If the planet had grown in its current location far from the star by means of core accretion, it would be too heavy because there is not enough material to make a huge planet at this large distance from the star. If the planet was created by so-called gravitational instability in the planetary disk, it appears to be not heavy enough. A third possibility is that the planet formed close to the star by core accretion and then migrated outwards. Such a migration, however, would require the gravitational influence of a second planet, which the researchers have not yet found.

The astronomers will continue to investigate the surroundings of this unusual planet and its star in the near future and hope to learn more about the system, and they will continue to search for other gaseous planets around young, sun-like stars. Current telescopes are not yet large enough to carry out direct imaging of earth-like planets around sun-like stars.

Lead researcher Alexander Bohn (Leiden University): “By investigating more Jupiter-like exoplanets in the near future, we will learn more about the formation processes of gas giants around sun-like stars.”

The planet YSES 2b was discovered with the Young suns Exoplanet Survey (YSES). This survey already provided the first direct image of a multi-planet system around a sun-like star in 2020. The researchers made their observations in 2018 and 2020 using the Very Large Telescope of the European Southern Observatory (ESO) in Chile. They used the telescope’s SPHERE instrument for this. This instrument was co-developed by the Netherlands and can capture direct and indirect light from exoplanets.

Featured image: A direct image of the exoplanet YSES 2b (bottom right) and its star (centre). The star is blocked by a so-called coronagraph. Credit: ESO/SPHERE/VLT/Bohn et al.


Reference: Alexander J. Bohn, Christian Ginski et al., “Discovery of a directly imaged planet to the young solar analog YSES 2”, A&A 648, A73 (2021). Link to paper


Provided by Netherlands Research School for Astronomy

What Would Happen if Earth Stopped Spinning? (Planetary Science)

The thought experiment reveals just how important our planet’s rotation really is.

In the 1951 film The Day the Earth Stood Still, an extraterrestrial named Klaatu and his robot companion Gort stop nearly all of the electronics on Earth simultaneously, using their advanced alien technology. Cars, factories, television sets and more all cease to work, and the planet settles into an eerie pause.

But what if the movie meant its title more literally? Imagine an alien with a still more powerful tool, one that could actually stop Earth in its tracks and halt our planet’s rotation.

The Day the Earth Stopped Spinning would be a far more destructive movie than the Hollywood original. We may not realize it, but our planet’s rotation underlies some of the most basic processes on Earth. Indeed, we probably wouldn’t be here if Earth was a stationary planet.

Stopping Earth

If Earth stopped spinning all at once, it would be enormously catastrophic for much of the planet’s surface. Though we don’t feel it, we’re all moving along with the planet as it rotates; at the equator, this works out to around 1,000 miles per hour. Stop the planet suddenly, and everything sitting on top of it would go flying eastward. Imagine people, houses, trees, boulders and more being launched sideways at hundreds of miles an hour. In the aftermath, high speed winds, still rotating nearly as fast as the planet, would scour the surface clean.

If the slowdown happened more gradually, the effects would still be dramatic, but would unfold over a longer period of time. The first thing we might notice is that the Sun no longer travels across the sky over the course of a day. The apparent motion of the Sun comes from Earth’s rotation, so if the planet were stationary, it would cause a single day to last half a year long (though we could look forward to some very long-lasting sunsets).

Without the 24-hour days we’re used to, biological circadian rhythms would be thrown entirely out of whack. The rhythmic cellular processes that tell our bodies when to sleep and when to wake depend in part on regular changes in sunlight to function. Many creatures on Earth, from bees to trees, rely on circadian rhythms to carry out their lives. Changing these cycles could upend normal behavior patterns.

Atmospheric patterns on Earth are also tied to the planet’s rotation. If the planet stopped spinning, it would greatly change the way air currents move (once the 1,000 mph winds had died down). The wind patterns we see today play a significant role in driving rainfall and temperatures around the globe. Any changes to air currents could result in deserts blooming where forests currently stand, for example, or frozen tundra becoming habitable. We’re already seeing something similar, albeit on a much smaller scale, as climate change alters global weather patterns. The results could be catastrophic for organisms that depend on specific environments.

An Earth with no spin would also mean the end of hurricanes. The massive rotating storms are created by Coriolis forces that derive from the planet’s rotation. Winds pulled into the low pressure area of a growing storm are spun counterclockwise in the northern hemisphere and clockwise in the southern hemisphere, resulting in the spiraling lines and central eye that define a hurricane. This process is one reason the storms can grow so powerful — so cutting them out might be one of the rare benefits of halting the planet’s spin.

But a motionless planet would also likely mean the end of our magnetic field. Though scientists are still unclear on the exact mechanisms, it’s thought that the magnetic field is created by the movements of Earth’s liquid metal core. Scientists call this a dynamo, and the end result is a web of invisible magnetic field lines arcing around the planet. The effects of losing that field would be far worse than just no longer being able to navigate by compass. Earth’s magnetic field protects us from cosmic rays and electromagnetic storms from the Sun, among other things. It’s definitely something we’d want to hang on to.

The planets of eternal day

As far as we know, there aren’t any planets out there that don’t rotate at all. The processes that form planets and other celestial bodies naturally result in rotation, meaning that all worlds spin from the outset. But there are some planets that appear to not rotate, something astronomers refer to as tidal locking.

These are worlds that show the same face to their star at all times, resulting in permanent night and day sides. Gravitational interactions between planets and their stars can gradually slow a planet’s rotation rate down until it exactly matches its orbital period.

The Moon is a good example of tidal locking. We only see one side of the Moon, no matter where it is in the sky or what phase it’s in, because it’s tidally locked to Earth. The same situation likely occurs on many exoplanets, especially those close to their stars where the gravitational pull is stronger.

Though these planets might seem like extreme places — frozen on one side, baked on the other — some scientists have suggested life might still find a way there. Some astronomers think extraterrestrial life could find a happy medium in the twilight zone of tidally locked worlds, near to where day turns to night. Others have theorized that atmospheric circulation might keep some tidally locked worlds temperate all over, if enough heat could be spread around the planet efficiently.

Earth isn’t likely to ever get tidally locked to the Sun — we’re too far away for that to happen. And, though our planet’s rotation is slowing down ever so slightly (a day gets about 1.7 milliseconds longer every century), our planet should never stop spinning completely. That’s something to be thankful for.

Featured image: danm12/Shutterstock


Provided by Astronomy Magazine

Once-a-week Insulin Treatment Could Be Game-changing For Patients With Diabetes (Medicine)

Treating people with Type 2 diabetes with a new once-a-week injectable insulin therapy proved to be safe and as effective as daily insulin injections, according to the results of two international clinical trials published online today in Diabetes Care. The studies suggest that the once-weekly treatment could provide a convenient alternative to the burden of daily insulin shots for diabetes patients.

Starting and maintaining insulin treatment remain a challenge for millions of patients worldwide with Type 2 diabetes. Fear of injections and the inconvenience and burden of injectable therapy contribute to the barriers against insulin therapy initiation and adherence. The effectiveness and safety of ongoing insulin treatment are also highly dependent on other factors, such as the accuracy of dosages, timing, and glycemic targets. Health care providers believe that reducing the frequency of treatment administration with advances, such as the once-weekly insulin used in these phase 2 trials, may decrease the reluctance to initiate insulin therapy while improving long-term adherence, glucose control, and ultimately, patient well-being.

Ildiko Lingvay, M.D., M.P.H., M.S.C.S. © UTSW

“Insulin, which has been the foundation of diabetes treatment for 100 years, is an effective glucose-lowering agent and is safe when used at the correct dose,” says Ildiko Lingvay, M.D., M.P.H., M.S.C.S., a professor of internal medicine and population and data sciences at UT Southwestern. “Insulin treatment is burdensome, requires frequent injections, and continues to carry a certain stigma. The development of an effective and safe insulin that can be administered once a week is a huge advance in the field.”

Lingvay, who is a consultant for Novo Nordisk, is the lead author of one of the studies, which involved 205 patients from seven countries (the U.S., Croatia, Germany, Hungary, Poland, Slovakia, and Spain). The clinical trial consisted of a two-week screening period, 16 weeks of treatment, and a five-week follow-up to evaluate three different ways to adjust and optimize the insulin dose and determine which one presented the best balance between effectively lowering glucose while minimizing low-glucose events.

She also is an author of the second study that included 154 patients from five countries (the U.S., Canada, the Czech Republic, Germany, and Italy). This trial followed the same 23-week time frame and evaluated practical aspects of insulin use as well as the best ways to transition from a daily regimen to the new weekly insulin injections. The researchers determined that starting with a higher first dose – called a loading dose – allowed patients to reach their optimal glucose target faster.

“These two studies served as the steppingstones for a large phase 3 clinical trial program that is currently ongoing at UT Southwestern and other sites, which is designed  to evaluate the efficacy of once-weekly insulin administration in patients with either Type 1 or Type 2 diabetes,” Lingvay says. “A weekly insulin is a game-changer that will decrease the treatment burden for patients while also improving compliance. This treatment will also decrease the burden on those who care for patients with diabetes requiring insulin. For example, for patients who need help injecting, those living in long-term care facilities, and those with memory problems, a once-weekly insulin will facilitate treatment and decrease the burden on the care providers.”

Novo Nordisk was the sponsor of both studies.


Reference: Harpreet S. Bajaj, Richard M. Bergenstal, Andreas Christoffersen, Melanie J. Davies, Amoolya Gowda, Joakim Isendahl, Ildiko Lingvay, Peter A. Senior, Robert J. Silver, Roberto Trevisan, Julio Rosenstock, “Switching to Once-Weekly Insulin Icodec Versus Once-Daily Insulin Glargine U100 in Type 2 Diabetes Inadequately Controlled on Daily Basal Insulin: A Phase 2 Randomized Controlled Trial”, Diabetes Care 2021 Apr; dc202877.https://doi.org/10.2337/dc20-2877


Provided by UT Southwestern Medical Center


About UT Southwestern Medical Center

UT Southwestern, one of the premier academic medical centers in the nation, integrates pioneering biomedical research with exceptional clinical care and education. The institution’s faculty has received six Nobel Prizes, and includes 23 members of the National Academy of Sciences, 17 members of the National Academy of Medicine, and 13 Howard Hughes Medical Institute Investigators. The full-time faculty of more than 2,800 is responsible for groundbreaking medical advances and is committed to translating science-driven research quickly to new clinical treatments. UT Southwestern physicians provide care in about 80 specialties to more than 105,000 hospitalized patients, nearly 370,000 emergency room cases, and oversee approximately 3 million outpatient visits a year.

Search for Biomarkers of Injury Severity to Assist Patients With Spinal Cord Trauma (Medicine)

A continuation of ongoing effort by Kazan Federal University and its partners saw light in Brain Sciences.

The research is conducted by Kazan University’s Open Lab Gene and Cell Technologies (Center for Precision and Regenerative Medicine, Institute of Fundamental Medicine and Biology) and Republic Clinical Hospital of Kazan. Lead Research Associate Yana Mukhamedshina serves as project head.

Spinal cord injury mechanisms include primary and secondary injury factors. Primary injury is mechanical damage to the nervous tissue and vasculature with immediate cell death and hemorrhage. Secondary damage leads to significant destructive changes in the nervous tissue due to the development of excitotoxicity, death of neurons and glial cells, inflammatory reactions, and the formation of a glial scar, which prevents the restoration of nerve connections. It should be noted that secondary trauma during this period leads to more serious clinical consequences than the original primary trauma. In this regard, there is an urgent need to develop a panel of diagnostic biomarkers to determine the severity of injury. Therefore, over the past two decades, there has been a growing interest in the development of new, reliable and practical tools for diagnosing the degree of spinal cord injury and predicting the outcome of the disease.

This paper demonstrates the importance of measuring serum cytokine concentrations as a quick and affordable means of accurately classifying the severity of spinal cord injury in patients, eliminating the risks and complications associated with the use of repeated cerebrospinal fluid sampling. But more research is needed to integrate those findings into the universal standard of care for spinal cord injury screening and diagnosis.

The need for predictive biomarkers is multifaceted. First, health care decisions will become more personalized and tailored to each case, which will minimize ineffective interventions and facilitate patient follow-up. Second, such tools would be useful in the provision of medical care for patients with spinal cord injury in developing countries that lack modern medical resources. Third, it will significantly accelerate research into spinal cord injury at both the preclinical and clinical levels.

Results will allow the development of a test system for assessing the prognostic course of traumatic spinal cord injury, as well as recommendations and suggestions for the use of the most effective therapy option. They will also contribute to the development of new early biomarkers of neurodegenerative diseases.

Featured image: The research is conducted by Kazan University’s Open Lab Gene and Cell Technologies (Center for Precision and Regenerative Medicine, Institute of Fundamental Medicine and Biology) and Republic Clinical Hospital of Kazan. Lead Research Associate Yana Mukhamedshina serves as project head. © Kazan Federal University


Reference: Ogurcov, S.; Shulman, I.; Garanina, E.; Sabirov, D.; Baichurina, I.; Kuznetcov, M.; Masgutova, G.; Kostennikov, A.; Rizvanov, A.; James, V.; Mukhamedshina, Y. Blood Serum Cytokines in Patients with Subacute Spinal Cord Injury: A Pilot Study to Search for Biomarkers of Injury Severity. Brain Sci. 2021, 11, 322. https://doi.org/10.3390/brainsci11030322 https://www.mdpi.com/2076-3425/11/3/322


Provided by Kazan Federal University