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Celestial Object Past Pluto Looks Like A Snowman: NASA

It's neither a comet nor an asteroid, according to Stern, but rather "a primordial planetesimal."

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NASA, Pluto
This image made available by NASA on Jan. 2, 2019, shows images with separate color and detail information, and a composited image of both, showing Ultima Thule, about 1 billion miles beyond Pluto. VOA

A NASA spacecraft 4 billion miles from Earth yielded its first close-up pictures Wednesday of the most distant celestial object ever explored, depicting what looks like a reddish snowman.

Ultima Thule, as the small, icy object has been dubbed, was found to consist of two fused-together spheres, one of them three times bigger than the other, extending about 21 miles (33 kilometers) in length.

NASA’s New Horizons, the spacecraft that sent back pictures of Pluto 3-plus years ago, swept past the ancient, mysterious object early on New Year’s Day. It is 1 billion miles (1.6 billion kilometers) beyond Pluto.

On Tuesday, based on early, fuzzy images taken the day before, scientists said Ultima Thule resembled a bowling pin. But when better, closer pictures arrived, a new consensus emerged Wednesday.

“The bowling pin is gone. It’s a snowman!” lead scientist Alan Stern informed the world from Johns Hopkins University’s Applied Physics Laboratory , home to Mission Control. The bowling pin image is “so 2018,” joked Stern, who is with the Southwest Research Institute.

NASA, earth
New Horizons project scientist Hal Weaver, of the Johns Hopkins University Applied Physics Laboratory, speaks about new data received from the New Horizons spacecraft during a press conference after the spacecraft completed a flyby of Ultima Thule, Jan. 1, 2019. VOA

The celestial body was nicknamed Ultima Thule — meaning “beyond the known world” — before scientists could say for sure whether it was one object or two. With the arrival of the photos, they are now calling the bigger sphere Ultima and the smaller one Thule.

Thule is estimated to be 9 miles (14 kilometers) across, while Ultima is thought to be 12 miles (19 kilometers).

Scientist Jeff Moore of NASA’s Ames Research Center said the two spheres formed when icy, pebble-size pieces coalesced in space billions of years ago. Then the spheres slowly spiraled closer to each other until they gently touched — as slowly as parking a car here on Earth at just a mile or two per hour — and stuck together.

Despite the slender connection point, the two lobes are “soundly bound” together, according to Moore.

 

Pluto, NASA, new horizons
This illustration provided by NASA shows the New Horizons spacecraft. NASA launched the probe in 2006; it’s about the size of a baby grand piano. VOA

Scientists have ascertained that the object takes about 15 hours to make a full rotation. If it were spinning fast — say, one rotation every three or four hours — the two spheres would rip apart.

Stern noted that the team has received less than 1 percent of all the data stored aboard New Horizons. It will take nearly two years to get it all.

The two-lobed object is what is known as a “contact binary.” It is the first contact binary NASA has ever explored. Having formed 4.5 billion years ago, when the solar system taking shape, it is also the most primitive object seen up close like this.

About the size of a city, Ultima Thule has a mottled appearance and is the color of dull brick, probably because of the effects of radiation bombarding the icy surface, with brighter and darker regions.

Both spheres are similarly red, while the barely perceptible neck connecting the two lobes is noticeably less red, probably because of particles falling down the steep slopes into that area.

Pluto, NASA, new horizons
New Horizons team members are seen during a press conference prior to the flyby of Ultima Thule by the New Horizons spacecraft, Dec. 31, 2018, at Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland. VOA

So far, no moons or rings have been detected. And scientists said there were no obvious impact craters in the latest photos but a few apparent “divots” and suggestions of hills and ridges. But better images should yield definitive answers in the days and weeks ahead.

Clues about the surface composition of Ultima Thule should start rolling in by Thursday. Scientists believe the icy exterior is probably a mix of water, methane and nitrogen, among other things.

The snowman picture was taken a half-hour before the spacecraft’s closest approach early Tuesday, from a distance of about 18,000 miles (28,000 kilometers).

Ultima Thule is an exquisite time machine — the most primitive object ever seen close up — that should provide clues to the origins of our solar system.

Also Read: NASA’s New Horizon Set Out To Make History

It’s neither a comet nor an asteroid, according to Stern, but rather “a primordial planetesimal.” Unlike comets and other objects that have been altered by the sun over time, Ultima Thule is in its pure, original state: It’s been in the deep-freeze Kuiper Belt on the fringes of our solar system from the beginning.

“This thing was born somewhere between 99 percent and 99.9 percent of the way back to T-zero (liftoff) in our solar system, really amazing,” Stern said. He added: “We’ve never seen anything like this before. It’s not fish or fowl. It’s something that’s completely different.”

Still, he said, when all the data comes in, “there are going to be mysteries of Ultima Thule that we can’t figure out.” (VOA)

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NASA Probe Makes New Discoveries on Asteroid Bennu

As a result, Bennu's rotation period is decreasing by about a second every 100 years, the scientists explained

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Asteroid
This Nov. 16, 2018, image provide by NASA shows the asteroid Bennu. NASA

NASA’s first asteroid-sampling mission OSIRIS-REx has observed particle plumes erupting from the surface of Bennu, an asteroid the size of the pyramid at Giza.

The Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) spacecraft, which began orbiting Bennu on December 31, first discovered the particle plumes on January 6, followed by additional particle plumes over the last two months.

While some of the particles were slow-moving, the others were found orbiting Bennu, like small satellites.

Bennu’s entire surface was also found to be rough and dense with boulders, contrary to the Earth-based observations, which showed a smooth surface with a few large boulders.

This means that the sample collection part of the mission will have to be adjusted to make sure that OSIRIS-REx can touch down and collect a sample, said NASA while presenting the discoveries at the 50th Lunar and Planetary Conference in Houston.

“The discovery of plumes is one of the biggest surprises of my scientific career,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson.

NASA
This artist’s rendering made available by NASA in July 2016 shows the mapping of the near-Earth asteroid Bennu by the OSIRIS-REx spacecraft. VOA

“And the rugged terrain went against all of our predictions. Bennu is already surprising us, and our exciting journey there is just getting started,” Lauretta added.

Further, the team observed a change in the spin rate of Bennu as a result of what is known as the Yarkovsky-O’Keefe-Radzievskii-Paddack (YORP) effect.

The uneven heating and cooling of Bennu as it rotates in sunlight is causing the asteroid to increase its rotation speed.

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As a result, Bennu’s rotation period is decreasing by about a second every 100 years, the scientists explained.

OSIRIS-REx launched in 2016 to explore Bennu, the smallest body ever orbited by spacecraft, is expected to return a sample of the asteroid to Earth in 2023.

The findings will allow researchers to learn more about the origins of our solar system, the sources of water and organic molecules on Earth, the resources in near-Earth space, as well as improve our understanding of asteroids that could impact Earth. (IANS)