New images of Ultima Thule, the small chunk of primordial debris NASA’s New Horizons probe zoomed past on New Year’s Day, came into much sharper focus on Wednesday, revealing a snowman-shaped object made up of two smaller, roughly spherical bodies that gently collided and stuck together during the birth of the Solar System 4.5 billion years ago.
“We think what we’re looking at is perhaps the most primitive object that has yet been seen by any spacecraft and may represent a class of objects which are the oldest and most primitive objects that can be seen anywhere in the present Solar System,” said Jeff Moore, a New Horizons co-investigator.
Like a time machine of sorts, Moore said New Horizons “has brought us back to the very beginning of Solar System history, to a place where we can observe the most primordial building blocks of the planets.”
Since its discovery by the Hubble Space Telescope in 2014, Ultima Thule has been little more than a dim speck of light in even the most powerful instruments. By measuring how Ultima blocked out the light of a star while passing in front as viewed from Earth, researchers concluded it was an elongated body ...