In just a few days, NASA's Dawn spacecraft will begin its first science orbit around dwarf planet Ceres. There, it will take unprecedented measurements and photographs, unlike anything we've seen before.
These measurements will tell us all we've ever wanted to know about Ceres, its features and its history.
In honor of the mission, here are the five main things you need to know about Dawn and Ceres.
Dawn is a history-making mission.
Before Ceres, Dawn spent time in orbit around asteroid Vesta in 2011. It spent 14 months there, gathering valuable scientific data, much of that still under research by scientists. Not only did we get our first photos of Vesta, but we also learned that Vesta could be one of the last of the celestial bodies that formed our solar system's rocky planets.
Last month, Dawn began orbiting Ceres, making it the first spacecraft to ever orbit two planetary bodies and the first to visit Vesta and Ceres. Because it reached Ceres faster than NASA's New Horizons mission reached Pluto, Dawn also became the first spacecraft to study a dwarf planet up close.
Ceres has bright spots on its surface and we don't know what they are.
Initial photos sent back from Dawn of Ceres have shown a consistent feature on the surface of the dwarf planet: a series of unexplained bright spots. NASA even combined photos of Ceres, which shows the bright spots move as the dwarf planet rotates. These spots remain a mystery, baffling scientists who did not expect to see them.
Of course, there are theories about what these spots are, but until Dawn studies Ceres in detail, we don't know what these spots are. The most common theory is that these spots are signs of cryovolcanic activity, which would indicate active icy plumes on Ceres surface. If this proves correct, we'll have evidence of water on Ceres, which is, obviously, a very big deal.
Ceres is unique.
Ceres is the largest object in the asteroid belt, which lies between the orbits of Mars and Jupiter. It is also the only dwarf planet in the inner solar system, as well as the only object in the asteroid belt that has its own gravity. Why it's so different from other bodies in that region of space is unknown, but here's hoping Dawn's data can shed light on Ceres' many mysteries.
Dawn's mission is to teach us new things about the history of our solar system.
Dawn isn't just visiting planetary bodies, such as Vesta and Ceres, for fun. There's much we can learn from the information Dawn collects during its mission, including learning more about how our solar system formed. During its early days, the materials that would eventually make up our solar system were all over the place: some were close to the sun, some weren't. Those that drifted too far away saw their temperatures drop and became icy, while those that got closer became terrestrial.
Scientists chose Vesta and Ceres for Dawn's mission because they both originate from that time period, but are two completely different kinds of bodies. Vesta is dry and rocky, while Ceres is icy, suggesting that it has water, and even possibly possesses a weak atmosphere. Scientists hope that by studying two very different planetary bodies with the same spacecraft, we'll figure out what happened in their history that made them so different. This data could provide new insight into how our solar system formed.
The Dawn spacecraft has three instruments.
Dawn carries a total of three science instruments that it used to study Vesta and that it will use to study Ceres. There's a visible camera, which Dawn has already used to deliver our first high-resolution photos of Vesta and Ceres.
A visible and infrared mapping spectrometer will allow scientists to figure out what minerals are present on a planetary body's surface.
Dawn's gamma ray and neutron detector collects data that will let scientists figure out a planetary body's composition. This detector can reveal what lies underneath the surface of a planetary body, up to three feet deep. If Ceres is full of water, as we believe, this is the instrument that will tell us.
[Photo Credit: NASA/JPL-Caltech]