Scientists redraw the models of New Horizons
Published : Saturday, 9 February, 2019 at 5:07 PM Count : 638
When New Horizons dipped in close to the distant object MU69, also known as Ultima Thule, just after midnight on New Year’s Day, it captured humanity’s first clear look at an object in the Kuiper Belt more than four billion miles from home.
The incredible images confirmed some predictions and dispelled others, revealing MU69 to be a snowman-shaped world with a rusty red hue that spins end-over-end like a propeller, daily Mail reports.
And, with New Horizons’ last look before pressing on with its mission, things have gotten even stranger.
A new image sequence from the spacecraft’s departing view of MU69 shows it isn’t actually made up of spheroidal segments, as first thought – instead, its two lobes are flat like pancakes.
‘This really is an incredible image sequence, taken by a spacecraft exploring a small world four billion miles away from Earth,’ said mission Principal Investigator Alan Stern, of Southwest Research Institute.
‘Nothing quite like this has ever been captured in imagery.’
On Twitter, Berkeley planetary astronomer Alex Parker commented that the unusual space rock is ‘pretty pancake-like,’ with one of its lobes resembling Saturn’s flat moon, Atlas.
New Horizons captured the last-look images on Jan. 1 at 12:42 a.m. EST, when it was 5,494 miles (8,862 kilometers) beyond the Kuiper Belt object.
Stars can be seen ‘blinking out’ in the background of an animation created from several images stitched together as New Horizons flew by.
And, the new view is quite unlike anything scientists expected.
‘We had an impression of Ultimate Thule based on the limited number of images returned in the days around the flyby, but seeing more data has significantly changed our view,’ Stern said.
‘It would be closer to reality to say Ultimate Thule’s shape is flatter, like a pancake.
‘But more importantly, the new images are creating scientific puzzles about how such an object could even be formed. We’ve never seen something like this orbiting the sun.’
MU69 exists in an arrangement known as a contact binary – and, it’s now the first a spacecraft has ever explored.
The scientists say the two lobes of MU69 came together in a 'gentle' accretion process, with two objects bound together by each other's gravity.
Stars can be seen ‘blinking out’ in the background of an animation created from several images stitched together as New Horizons flew by
The primitive world was 'born' this way, and did not evolve or deform through external processes to take on the strange shape, the team explains.
'New Horizons is like a time machine, taking us back to the birth of the solar system,' said Jeff Moore, New Horizons Geology and Geophysics team lead, at the beginning of January.
'We are seeing a physical representation of the beginning of planetary formation, frozen in time,' Moore says.
'Studying Ultima Thule is helping us understand how planets form — both those in our own solar system and those orbiting other stars in our galaxy.'
Thanks to the close observations, we now know the small, oddly shaped world is 'two objects conjoined,' Stern says.
'That bowling pin is gone,' the leader of the New Horizons joked, in reference to the first blurry images sent home after the flyby. 'It’s a snowman, if anything at all.'
Based on the New Horizons observations so far, the scientists say Ultima has a ‘very regular’ rotation period, at about 15 hours.