Scientists working on the New Horizon’s project have been looking for a suitable object to study in the Kuiper belt ever since the launch in 2006. Ultima Thule was discovered only in 2014 and the Hubble Space Telescope was recruited to track its trajectory. Interestingly enough, in 2017, Ultima Thule blocked three background stars (known as an ‘occultation’) on its journey tumbling through the Kuiper belt region. Data from five different telescopes gave strong indications that Ultima Thule was an odd shaped object with two uneven lobes.
The object’s strange shape has now been confirmed by data during the close fly-by and shows that Ultima Thule is bowling-pin shaped* and rotates on a similar axis as a plane’s propeller. Its size is about 35 by 15 km. The shape was mainly determined by following the object’s shadows, rotation and trajectory, in much the same way as ‘Oumuamua’s shape was found (see previous post).
Regarding its shape, there is some speculation as to whether the object is one continuous body or, in fact, a contact binary. This is where two objects have come in to contact with one another through gravitational attraction and merely touch; but eventually fuse and coalesce. Either way, this could shed light on how planets form, through the accumulation of rocky material.
Another great discovery at the far reaches of our ever-mystifying Solar System!
*when I first saw images of Ultima Thule, it looked more like peanuts in their husk than a bowling-pin (as reported by most Media agencies!), and thus, I refer to it here as the Giant Peanut in Space
New high resolution image of Ultima Thule: