Dawn did not find actual water ice, there are signs of hydrated minerals such as hydroxyl
source of the hydrogen within Vesta’s surface appears to be hydrated minerals delivered by carbon-rich space rocks that collided with Vesta at speeds slow enough to preserve their volatile content
pitted terrain – looking much like potholes – mark where the volatiles, perhaps both hydroxyl and water, released from hydrated minerals boiled off
Hydroxyl has recently been found on the Moon in permanently shadowed craters at the lunar poles
scientists thought there might be a chance that water ice may have
around the giant asteroid’s poles
unlike Earth’s Moon, however, Vesta has no permanently shadowed polar regions
strongest signature for hydrogen actually came from regions near the equator. And there, water ice is not stable
The holes that were left as the water escaped stretch as much as 0.6 miles (1 kilometer) across and go down as deep as 700 feet (200 meters
collisions converted the hydrogen bound to the minerals into water, which evaporated
The pits look just like features seen on Mars, but while water was common on Mars, it was totally unexpected on Vesta in these high abundances
ults provide evidence that not only were hydrated materials present, but they played an important role in shaping the asteroid’s geology and the surface we see today
the first direct measurements describing the elemental composition of Vesta’s surface
elemental investigation by the instrument determined the ratios of iron to oxygen and iron to silicon in the surface materials
new findings solidly confirm the connection between Vesta and a class of meteorites found on Earth called the Howardite, Eucrite and Diogenite meteorites
have the same ratios for these elements
n, more volatile-rich fragments of other objects have been identified in these meteor
video of the Sept. 21 meteor shows what appears to be a fireball created as a small space rock breaks apart in Earth's atmosphere. Pieces of the meteor can easily be seen separating from the main body in his view
many witnesses to wonder if it was sparked by a man-made piece of space junk falling out of orbit
experts have conclusively tied the event to a naturally occurring space rock burning up in Earth's atmosphere
Veteran satellite tracker Marco Langbroe
the fireball was definitely a meteor.
sighting reports to determine the fireball's trajectory and studied videos posted by witnesses to determine how long it lasted
ack-of-the-envelope reconstruction therefore shows that this must have been a meteoric fireball, quite likely of asteroidal origin, and we definitely can exclude a satellite re-entry
meteor in space is called a meteoroid. Only when it flares up in the night sky does it become a meteor. Any remains of the object that reach the ground, meanwhile, are called meteorites
Earlier this year, a rare daytime fireball surprised U.S. observers in California and Nevada when it unleashed a sonic boom that some mistook for a small earthquake. The meteor was caused by a minivan-size asteroid and created several meteorites that NASA retrieved in a follow-up search