It’s been a rough week for NASA missions. Earlier this week we covered news that Kepler, the planet-hunting telescope that revolutionized our understanding of extrasolar planets, has finally run out of fuel. Now it’s time to say goodbye to Dawn, our first probe to examine the mysteries of Ceres and Vesta.
The probe and the space telescope had completely different missions. Kepler looked for the faintest clues that would hint at the existence of other planets; Dawn visited two of the oldest bodies in the solar system examining clues to their formation and evolution. At Vesta, Dawn found the Rheasilvia and Veneneia impact craters — remnants of impacts so massive, they’re responsible for the remnants of Vesta we’ve found on Earth. 5-6 percent of all the meteors on Earth are believed to have come from one of these impacts.
Ceres and Vesta
At Ceres, Dawn confirmed that the dwarf planet is differentiated, with a rocky core and icy mantle. This is an important step in planetary evolution and marks a distinct difference between objects like Ceres and Vesta, as opposed to asteroids. Dawn found Ceres ‘bright spots’ — a completely unexpected feature — as well as organic compounds known as tholins on the surface of the planet.
I’ve always had a soft spot for Ceres because of what it and the rest of the asteroid belt collectively represent. Once thought to be the remnants of a destroyed planet, we now know that the asteroid belt is the last remnant of the building blocks our solar system coalesced from. The largest asteroids, like Pallas, Ceres, Vesta, and Psyche, are each distinct, with their own unique compositions, structures, differentiation, and orbits. Psyche is thought to be the exposed iron core of a former protoplanet. These frozen, scarred rocks are the remnants of our own solar system that weren’t flung out into space, sucked into the depths of gas giants, or agglomerated into the rocky worlds of the inner solar system. Thanks to Dawn, we know that Ceres is volcanically active, with dozens of old cryovolcanos and one newer one, Ahuna Mons, found across the surface.
Dawn provided far more data on both Vesta and Ceres than was previously known, demonstrating that even in the most ancient corners of the solar system contain surprises and unexpected finds.
Another sincere thank you to the NASA team behind Dawn. Our knowledge of the universe would be much poorer absent your dedication.
Now Read: Organic Molecules on Ceres Are More Abundant Than Previously Thought, Meteor Diamonds Confirm Protoplanets Once Existed in Our Solar System, and A cryovolcano might be erupting right now on Ceres, as you read this