Astronomy Picture of the Day—20190202

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2019 February 2

UltimaThule from New Horizons

ImageCredit: NASA, JHU's APL, SwRI; Color Processing: Thomas Appéré

Explanation:How do distant asteroids differ from those near the Sun? To help find out, NASAsent the robotic New Horizons spacecraft past the classical Kuiper belt object2014 MU69, nicknamed Ultima Thule, the farthest asteroid yet visited by a humanspacecraft. Zooming past the 30-km long space rock on January 1, the featuredimage is the highest resolution picture of Ultima Thule's surface beamed backso far. Ultima Thuli does look different than imaged asteroids of the innerSolar System, as it shows unusual surface texture, relatively few obviouscraters, and nearly spherical lobes. Its shape is hypothesized to have formedfrom the coalescence of early Solar System rubble in into two objects -- Ultimaand Thule -- which then spiraled together and stuck. Research will continueinto understanding the origin of different surface regions on Ultima Thule,whether it has a thin atmosphere, how it obtained its red color, and what thisnew knowledge of the ancient Solar System tells us about the formation of ourEarth.