New Data: Ultima Thule Surprisingly Flat
Explanation:
Ultima Thule is not the object humanity thought that it was last month.
When the robotic
New Horizons spacecraft zoomed past the distant asteroid
Ultima Thule (officially
2014 MU69)
in early January,
early images showed
two circular lobes
that when most simply extrapolated to 3D were thought to be, roughly, spheres.
However, analyses of newly beamed-back images -- including
many taken soon after closest approach --
shows eclipsed stars re-appearing
sooner than expected.
The only explanation possible is that this 30-km long
Kuiper belt object
has a different 3D shape than believed only a few weeks ago.
Specifically, as shown in the
featured illustration, it now appears that the larger lobe -- Ultima -- is more
similar to a fluffy
pancake than a sphere, while
the smaller lobe -- Thule -- resembles a dented walnut.
The remaining uncertainty in the outlines are shown by the dashed blue lines.
The new shape information indicates that gravity -- which
contracts more massive bodies into spheres --
played perhaps less of a role in contouring the lobes of
Ultima
Thule than previously thought.
The
New Horizons spacecraft continued on to Ultima Thule after
passing Pluto in mid-2015.
New data and images are still being received.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
