New findings from NASA’s OSIRIS-REx mission suggest that the interior of the asteroid Bennu could be weaker and less dense than its outer layers—like a crème-filled chocolate egg flying though space.
The results appear in a study published in the journal Science Advances and led by the University of Colorado Boulder’s OSIRIS-REx team, including professors Daniel Scheeres and Jay McMahon. The findings could give scientists new insights into the evolution of the solar system’s asteroids—how bodies like Bennu transform over millions of years or more.
OSIRIS-REx rendezvoused with Bennu, an asteroid orbiting the sun more than 200 million miles from Earth, in late 2018. Since then, the spacecraft, built by Colorado-based Lockheed Martin, has studied the object in more detail than any other asteroid in the history of space exploration.
So far, however, one question has remained elusive: What’s Bennu like on the inside?
Scheeres, McMahon and their colleagues on the mission’s radio science team now think that they have an answer—or at least part of one. Using OSIRIS-REx’s own navigational instruments and other tools, the group spent nearly two years mapping out the ebbs and flows of Bennu’s gravity field. Think of it like taking an X-ray of a chunk of space debris with an average width about the height of the Empire State Building.
“If you can measure the gravity field with enough precision, that places hard constraints on where the mass is located, even if you can’t see it directly,” said Andrew French, a coauthor of the new study and a former graduate student at CU Boulder, now at NASA’s Jet Propulsion Laboratory (JPL).
What the team has found may also spell trouble for Bennu. The asteroid’s core appears to be weaker than its exterior, a fact that could put its survival at risk in the not-too-distant future.
“You could imagine maybe in a million years or less the whole thing flying apart,” said Scheeres, a distinguished professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences.
Evolution of asteroids
Of course, that’s part of the fun of studying asteroids. Scheeres explained that Bennu belongs to a class of smaller bodies that scientists call “rubble pile” asteroids—which, as their name suggests, resemble loosely held-together mounds of debris.
Asteroids also change over time more than people think.
“None of them have sat out there unchanging since the dawn of the solar system,” Scheeres said. “They’re being changed by things like sunlight affecting how they spin and collisions with other asteroids.”
To study how Bennu and other similar asteroids may change, however, he and his colleagues needed to take a peek inside.
This is where the team got lucky. When OSIRIS-REx first arrived at Bennu, the spacecraft spotted something unusual: Over and over again, tiny bits of material, some just the size of marbles, seemed to pop off the asteroid and into space. In many cases, those particles circled Bennu before falling back down to the surface. Members of the mission’s radio science team at JPL were able to witness how the body’s gravity worked first-hand—a bit like the apocryphal story of Isaac Newton inferring the existence of gravity after observing an apple falling on his head.
“It was a little like someone was on the surface of the asteroid and throwing these marbles up so they could be tracked,” Scheeres said. “Our colleagues could infer the gravity field in the trajectories those particles took.”
In the new study, Scheeres and his colleagues combined those records of Bennu’s gravity at work with data from OSIRIS-REx itself—precise measurements of how the asteroid tugged on the spacecraft over a period of months. They discovered something surprising: Before the mission began, many scientists had assumed that Bennu would have a homogenous interior. As Scheeres put it, “a pile of rocks is a pile of rocks.”
But the gravity field measurements suggested something different. To explain those patterns, certain chunks of Bennu’s interior would likely need to be more tightly packed together than others. And some of the least dense spots in the asteroid seemed to lie around the distinct bulge at its equator and at its very core.
“It’s as if there is a void at its center, within which you could fit a couple of football fields,” Scheeres said.
Now, thanks to laser altimetry data and high-resolution imagery from OSIRIS-REx, we can take a tour of Bennu’s remarkable terrain. Credit: NASA’s Goddard Space Flight Center
The asteroid’s spin may be responsible for that void. Scientists know that the asteroid is spinning faster and faster over time. That building momentum could, Scheeres said, be slowly pushing material away from the asteroid’s center and toward its surface. Bennu, in other words, may be in the process of spinning itself into pieces.
“If its core has a low density, it’s going to be easier to pull the entire asteroid apart,” Scheeres said.
For the scientist, the new findings are bittersweet: After measuring Bennu’s gravity field, Scheeres and his team have mostly wrapped up their work on the OSIRIS-REx mission.
Their results have contributed to the mission’s sample analysis plan—currently in development. The returned sample will be analyzed to determine the cohesion between grains—a key physical property that affects the mass distribution observed in their study.
“We were hoping to find out what happened to this asteroid over time, which can give us better insight into how all of these small asteroids are changing over millions, hundreds of millions or even billions of years,” Scheeres said. “Our findings exceeded our expectations.”
Read Asteroid Bennu Secrets Unlocked by NASA’s OSIRIS-REx Ahead of Historic Heist for more on this and related research.
“Heterogeneous mass distribution of the rubble-pile asteroid (101955) Bennu” by D. J. Scheeres, A. S. French, P. Tricarico, S. R. Chesley, Y. Takahashi, D. Farnocchia, J. W. McMahon, D. N. Brack, A. B. Davis, R.-L. Ballouz, E. R. Jawin, B. Rozitis, J. P. Emery, A. J. Ryan, R. S. Park, B. P. Rush, N. Mastrodemos, B. M. Kennedy, J. Bellerose, D. P. Lubey, D. Velez, A. T. Vaughan, J. M. Leonard, J. Geeraert, B. Page, P. Antreasian, E. Mazarico, K. Getzandanner, D. Rowlands, M. C. Moreau, J. Small, D. E. Highsmith, S. Goossens, E. E. Palmer, J. R. Weirich, R. W. Gaskell, O. S. Barnouin, M. G. Daly, J. A. Seabrook, M. M. Al Asad, L. C. Philpott, C. L. Johnson, C. M. Hartzell, V. E. Hamilton, P. Michel, K. J. Walsh, M. C. Nolan and D. S. Lauretta, 8 October 2020, Science Advances.
The University of Arizona leads science operations for OSIRIS-REx. NASA’s Goddard Space Flight Center in Maryland manages the overall mission.
Other coauthors on the new study include researchers at the Jet Propulsion Laboratory, Smithsonian Institution, The Open University, Northern Arizona University, KinetX Aerospace, Inc., NASA Goddard Space Flight Center, University of Maryland, Johns Hopkins University, York University, University of British Columbia, Southwest Research Institute, Université Côte d’Azur and University of Arizona.
The iconic Arezipo laboratory radio telescope collapses after the cable breaks – haveeruonline
A large radio telescope in Puerto Rico played a key role in astronomical discoveries Tuesday, officials said. The, Is popular as the backdrop for a major show in “Golden Eye” and other Hollywood hits closed after a sub cable was broken and shut down since August On the reflection dish.
A major cable broke in early November, and the National Science Foundation announced plans to shut down the radio telescope a few weeks later because the damage was so severe.
Many scientists and Puerto Ricans mourned the news, some tearing up during interviews. Puerto Rico-based meteorologist Deborah Marterell tweeted early Tuesday morning: “Friends, it is with deep sadness that I inform you that the Arecibo monitoring site has now collapsed.”
It was the world’s second largest radio telescope and had been in operation for more than half a century.
Powered by the National Science Foundation through the University of Central Florida, the iconic lab is made up of a fixed dish antenna 1,000 feet wide, which is built on a bowl-like depression 450 feet above the radio from three support towers suspended from three support towers.
For 57 years, the laboratory has played a key role in observing the composition and behavior of the Earth’s upper atmosphere using deep space targets, bodies in the solar system, and powerful light rays.
Prior to its collapse, the laboratory had withstood hurricanes and earthquakes and played central roles in films such as “Golden Eye” and “Contact”.
Bill Harwood contributed to this report.
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'The blob': Scientists confirm discovery of a completely new undersea species – SaltWire Network
Deep in the dark, murky waters of our oceans, a gelatinous blob, shaped like a dislodged human molar, floats along the seabed.
Thanks to its love for extreme depths and remote oceanic corners, no one had ever seen the blob, or even knew it existed, until a team of scientists accidentally discovered it during a deep-sea dive off the coast of Puerto Rico in 2015, with help from an underwater, remotely-operated vehicle called ‘Deep Discover.’
Five years on, in a paper published this month, scientists with the
National Oceanic and Atmospheric Administration (NOAA) have confirmed that the blob is an entirely new species of undersea creature,
– a never-before-seen species of jelly-like ctenophore. It’s also the first time that researchers have discovered a species using high-definition video footage only.
“It’s unique because we were able to describe a new species based entirely on high-definition video,”
NOAA marine biologist Allen Collins in a release.
“We don’t have the same microscopes as we would in a lab, but the video can give us enough information to understand the morphology in detail, such as the location of their reproductive parts and other aspects.”
Ctenophores, also known as comb jellies, have bulbous, balloon-like bodies, from which protrude two tentacle-like strings, known as cilia. There are between 100 and 150 species of comb jellies, according to the NOAA, and despite their name, they are not at all related to jellyfish. Ctenophores, the group explains, are carnivorous, and many are highly efficient predators that eat small arthropods and many kinds of larvae.
Three different specimens were filmed by the vehicle at depths around 3,900 metres, in an underwater area called the Arecibo Amphitheater, which lies within a trench known as the Guajataca Canyon, off Puerto Rico.
One of the animals appeared to use its tentacles to touch the seabed, scientists said.
“It was a beautiful and unique organism,” oceanographer Mike Ford was quoted as saying in a release.
“It moved like a hot air balloon attached to the seafloor on two lines, maintaining a specific altitude above the seafloor. Whether it’s attached to the seabed, we’re not sure. We did not observe direct attachment during the dive, but it seems like the organism touches the seafloor.”
Identifying a new species solely via photographic and video evidence has often yielded contentious results, the scientists explained in their paper, as natural classification “relies heavily” on the physical specimen samples preserved in museums “to serve as references to which other material can be compared.”
“Indeed, the idea of using photographic evidence to establish new species has been highly contentious in recent decades.”
In this case, however, the team was able to avoid any pushback due to the high-definition quality of the footage they recorded of the three observed specimens. The team hopes to collect real-life specimens on future dives, but fears it may be decades before they run into the species again.
“Even if we had the equipment, there would have been very little time to process the animal because gelatinous animals don’t preserve very well,”
“Ctenophores are even worse than jellyfish in this regard.”
Copyright Postmedia Network Inc., 2020
China lands on moon in mission to collect samples from surface – Al Jazeera English
If the Chang’e-5 mission is successful, China will become third country after US and Russia to collect lunar material.
China successfully landed a spacecraft on the moon’s surface late on Tuesday in the first mission to retrieve lunar surface samples in 40 years, said the country’s National Space Administration.
The space agency said the probe had successfully landed on the near side of the moon and sent back images.
China launched its Chang’e-5 probe which is not manned from the southern province of Hainan on November 24. The mission, named after the mythical Chinese goddess of the moon, aims to collect lunar material to help scientists learn more about the moon’s origins and the solar system more generally.
Hua Chunying, a spokesperson for the Ministry of Foreign Affairs, tweeted that the landing was a “historic step” adding that it would also benefit “international cooperation and the peaceful use of space.”
The mission will attempt to collect two kilogrammes (4.4 pounds) of samples in an area that has yet to be explored on an enormous lava plain known as Oceanus Procellarum, or “Ocean of Storms” and if completed as planned, would make China the third nation to have retrieved lunar samples after the United States and Russia.
— Hua Chunying 华春莹 (@SpokespersonCHN) December 2, 2020
We have a *new* lunar lander!
The Chinese #Change5 lander touched down at 43.1°N, 51.8°W at 15:11 UTC today, December 1.
Here is a wee 🧵 of some maps I made of the landing site region, with major features labelled, starting at 1:300,000 scale (~160 km field of view): pic.twitter.com/hsDuEvSAuG
— Paul Byrne (@ThePlanetaryGuy) December 1, 2020
The lander vehicle is expected to start drilling into the ground with a robotic arm to collect the lunar material in about two days, according to state media.
The samples will then be lifted into orbit and transferred to a return capsule for the return to Earth, where it is expected to land on land in China’s Inner Mongolia region.
If the mission succeeds it will be the first time scientists have secured samples of lunar rocks since Russia (then the Soviet Union) brought material back in the 1970s.
China sent its first astronaut into space in 2003 and made its first lunar landing 10 years later. In January last year, the Chang’e-4 probe touched down on the far side of the moon, the first space probe from any nation to do so and in July it launched a spacecraft to Mars to search for water.
Xiaomi announces the Mi 11 ahead of tipped January launch; to feature the new Snapdragon 888 – Notebookcheck.net
Quebec to announce decision on holiday gatherings Dec. 11, Legault says – Montreal Gazette
The iconic Arezipo laboratory radio telescope collapses after the cable breaks – haveeruonline
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