Published: Sat, January 05, 2019
Research | By Sheri Schwartz

NASA spacecraft sends images of icy object past Pluto

NASA spacecraft sends images of icy object past Pluto

The NASA scientists announced this on Monday that the asteroid looked like that of a snowman.

Operating on autopilot, New Horizons was out of radio contact with controllers at Johns Hopkins University's Applied Physics Laboratory from late Monday afternoon until late Tuesday morning.

The close approach came a half-hour into the new year, and three years after New Horizons' unprecedented swing past Pluto. The next step for NASA will be to download and analyze the data captured, a process which could take years.

Among the images the scientists are hoping to receive are "higher resolution views" and pictures taken when the sun is at a better angle for viewing Ultima Thule.

Though Ultima Thule formed a long time ago, it remains pristine, seemingly unmarked by craters. They named the larger region Ultima and the smaller one Thule.

Mission organizers have been criticized for calling the object by a name that Nazis used for the mythical birthplace of the Aryan race.

"That image is so 2018", said Stern.

Instead, they focused on what the new images told them about planetary science. The new images revealed that the object is in fact a contact binary, consisting of two spheres that measure 31 km (19 mi) from end to end.

Additionally, the New Horizons team can now definitely say that-just as the images taken with the Hubble Space Telescope several years ago tentatively predicted-Ultima Thule's hue is a toasty brownish-red. It is reddish in color, probably from the radioactive decay of organic compounds on its icy surface. By contrast, he suggested, scientists did not know for sure whether other two-lobe bodies - most notably the rubber ducky-like Comet 67P/Churyumov-Gerasimenko - were two objects that came together or one larger body that had eroded into its current shape.

Ultima's current rotation rate, estimated at about 15 hours for a complete turn, isn't fast enough to fling the two balls apart, Moore said.

Moore said it appears the two spheres came together gently, at speeds of perhaps 1 or 2 miles per hour - not in some violent collision in space. He joked: "If you had a collision with another vehicle at those speeds you may not even bother to fill out the insurance forms". The two objects were slowly pulled together by gravity, creating the "bilobed" object with a distinct "neck". The probe will now study the makeup of Ultima Thule's atmosphere and terrain for further clues about how solar system and planets form.

Its mission now totaling $800 million, the baby grand piano-sized New Horizons will keep hurtling toward the edge of the solar system, observing Kuiper Belt Objects, or KBOs, from afar, and taking cosmic particle measurements. A single body is more likely, they noted. He said Ultima Thule was selected as 2014 MU69's informal nickname because its ancient meaning provided a "wonderful meme for exploration".

By week's end, "Ultima Thule is going to be a completely different world, compared to what we're seeing now", Weaver noted. That's why it already holds such lessons about the formation of the planets. "What we're looking at is basically the first planetesimals", Moore said.

The object is so old and pristine that it's essentially like going back in time to the beginning of our solar system.

"I didn't imagine that it could happen", May said.

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