Contributing to Our Understanding of Our Solar System
While our solar system is seemingly well understood, with an inventory of a single star, planets, their moons, dwarf planets like Pluto and Ceres, and smaller bodies like asteroids, trans-Neptunian objects, and the outer solar system Kuiper Belt objects, discoveries continue to be made. For example, HST observations of the distant object, Ultima Thule, later studied by New Horizons and discovery of ever more distant significant objects such as Farout.
Within the solar system, Hubble has contributed to our understanding of planetary atmospheres, including characterizing atmospheric circulation and tracking turbulent storms and auroras of Jupiter, Saturn, Neptune and Uranus. Astronomers using Hubble have observed and monitored violent dust storms on Mars, and have even captured, in a rare observation, some hints at the atmosphere of Venus. Some of the main features of the surface of Pluto were modeled from early Hubble observations.
A Diversity of Moons
Hubble resolution also has enabled the studies of the moons of solar system planets, revealing water plumes on Europa, showing conjunctions of Jupiter’s moons as they orbit the large planet, and cataloging new moons, including the discovery of four of Pluto’s moons and determining the general shape of two of them. The features of Saturn’s hazy moon, Titan, were extensively observed by Hubble in preparation for the Cassini spacecraft visit and studies of that part of our solar system.
The Outskirts of the Solar System
In the outer solar system, Hubble observations of dwarf planets such as Pluto, Makemake, 2007 OR10, and Quaoar suggested the appearance of major surface features, as well as the discovery that most dwarf planets have moons. Discoveries and studies of comets have revealed these objects are complex in composition, often exhibiting tails and other jet-like features as they near the Sun in their long, elliptical orbits. Astronomers have observed many of these objects breaking into multiple pieces and spinning as they hurtle inward in the solar system. Researchers studied a previously discovered object called ‘Oumuamua with Hubble, and they speculate that the object’s origin is from outside the solar system.
Studies of solar system objects inform us about the formation of the Earth and Moon, atmospheres and climate, and they also can aid in the understanding of planets around other stellar objects.