January 25, 2021

On the border of the Solar System | Science

On the border of the Solar System | Science

The space probe New Horizons He has successfully flown over Ultima Thule, the farthest celestial body that has ever been visited. His encounter with this object on the outskirts of the solar system occurred at the stroke of midnight on December 31. A few hours after the historic maneuver, the ship sent its first signals, which took six hours to travel at the speed of light more than 6,600 million kilometers that separate it from Earth. Finally the message was received by a NASA deep-space antenna on the outskirts of Madrid after 4:30 p.m., Spanish time.

"The probe is in perfect condition, we just got the most distant flyby," said Alice Bowman, the mission's chief of operations, amid applause and shouts of jubilation at the Applied Physics Laboratory at Johns Hopkins University (USA). , where is the control center. Now the scientific data will begin to arrive "to understand the origin of our solar system," he added.

Ultima Thule is a world in miniature, the furthest and the oldest that a space probe has visited. This elongated object discovered in 2014 is one of thousands of asteroids and up to a billion comets that make up the Kuiper belt.

The NASA spacecraft – the fastest ever launched into space – has passed by Ultima at 18 kilometers per second, a fleeting encounter during which its cameras have tried to portray the geographical features of this body from a distance of 2,000 kilometers, three times closer to what happened on Pluto getting spectacular views. Thanks to this mission the dwarf planet ceased to be a small fuzzy ball observed by telescopes and became a complex world with glaciers, water and organic compounds where there may be an ocean under the ice.

Actual image of Ultima Thule (left) and a diagram with its axis of rotation.enlarge photo
Actual image of Ultima Thule (left) and a diagram with its axis of rotation.

The last available images, taken during the approach to Ultima, show an elongated body, shaped like a bolus, "35 kilometers long and 15 kilometers wide", explained Alan Stern, chief scientist of the mission, during a round of press this afternoon. Stern has explained that it is not yet known if it is a single body with two lobes or two separate objects. "Tomorrow we will know the answer", explained Stern, since the team expects to receive the first images of the flyby tonight, process them and publish them tomorrow. The probe took about 900 images of their encounter and send them to Earth for the next two years, as explained in a tweet Bowman, who is the first woman to occupy the post of chief of operations of a space mission at Johns Hopkins . Higher resolution images will arrive in February.

Just a few hours after the flyby, New Horizons It was already almost half a million kilometers from the newly discovered little world and it was further into the Kuiper belt, where it is possible that it could visit at least one more asteroid in the coming years.

Ultima Thule is a time capsule. It is made of the original materials with which the Solar System began to form more than 4,000 million years ago and has hardly been modified since then. Their study can clarify the origin of our star system and clarify the role that these bodies of the Kuiper belt play in diverting comets from their trajectories and bring them closer to the core of the solar system, a process that could sow life on our planet through impacts of these bodies, as explained to this newspaper Adriana Ocampo, one of those responsible for the mission.

A few hours before, another NASA spacecraft, Osiris-RexHe also made history to put into orbit of the asteroid Bennu, about 110 million kilometers from our planet, as confirmed by NASA on December 31. The probe has become the first to orbit an object as small as this one, barely 500 meters in diameter. It will also be the one that establishes the closest orbit to an overflight height of just one kilometer and a half. Your ultimate goal will be to land on the surface, suck a sample of land and send it back to Earth in 2023. This body is especially interesting because it has a small chance of hitting the Earth (0.037%).


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