The New Horizons probe in London has sent its best picture to the small, icy Last Thule, which was passing the New Year.
The image is acquired when the NASA spacecraft is only 6,700 km from its purpose, which scientists believe that two bodies are slightly merging – giving the appearance of a snowman.
Surface details are now much clearer.
New Horizons data returns very slowly over the next 20 months.
This is partly related to the long distance (6.5 billion kilometers apart), but it is also limited by the low power of the probe transmitter and the size (and availability) of the receiving antennas here on Earth. All this makes the prices of the iceberg.
The new image is obtained with New Horizons' wide-angle Multicolor Visible Imaging Camera (MVIC) and delivers a resolution of 135m per pixel. There is another version of this scene taken at an even higher resolution than the Long Distance Probe (LORRI), but this is still not connected downstream from the probe.
When the best close-ups are available (no distance of 3500 km), they should have a resolution of about 35 m per pixel.
But even in the latest MVIC observations, the new detail is fascinating. Ultima Thule's topography is now sufficiently sharpened to see the defined outlines of a number of pits, especially on the day / night boundary, or terminator. On a scale the total length of a snowman is about 33 km.
Researchers will have to determine whether the holes are impact craters or cavities created by some other process – for example leakage of volatile materials.
Ultima Thule, a conglomerate of ice and dust, runs around the Sun in a sparsely populated and low-energy environment, known as the Kaiper belt.
The ability to collide with other objects should therefore be extremely low, but then this snowman was most likely created at the very beginning of the solar system and had time to get at least a few scars.
Several factors make Ultima Thule and the area in which it moves are so interesting to scientists.
One is that the sun is so weak in this region that temperatures are about 30-40 degrees above absolute zero – the coldest atoms and molecules can be obtained. As a result, chemical reactions are blocked. This means that Ultima is in such a deep freeze that it is probably totally preserved in the state in which it was formed.
Another factor is that Ultima is small (about 33 km in the longest dimension), and this means that there is no "geological engine" type, which in the larger objects will recast its composition.
The third factor is only the nature of the environment. He is very calm in the Keiper belt.
Unlike the Inner Solar System, there may be very few collisions between objects. Kaiper's belly did not move.
Professor Alan Stern, Principal Investigator at New Horizons, said, "Everything we will learn about Ultima – from its composition to geology, the way it was originally assembled, whether it has satellites and atmosphere, and such things – will teach us the initial conditions of formation in the Solar System that all the other objects that we went out on and on, flying and landing can not tell us because either they are big and they are developing or they are hot Ultima is unique.