How high is space?

Look up, there's space. Astronomically speaking, it's right there, just outside a thin layer of atmosphere. But how far away is it? How high is space?

LADEE spacecraft finds neon in lunar atmosphere

The moon's thin atmosphere contains neon, a gas commonly used in electric signs on Earth because of its intense glow. While scientists have speculated on the presence of neon in the lunar atmosphere for decades, NASA's Lunar ...

Mercury's surprising core and landscape curiosities

(PhysOrg.com) -- On March 17, the tiny MESSENGER spacecraft completed its primary mission to orbit and observe the planet Mercury for one Earth-year. The bounty of surprises from the mission has completely altered our understanding ...

Solar storms could 'sandblast' the moon

(PhysOrg.com) -- Solar storms and associated Coronal Mass Ejections (CMEs) can significantly erode the lunar surface according to a new set of computer simulations by NASA scientists. In addition to removing a surprisingly ...

Extreme effects: Seven things you didn't know about Mercury

Pity poor Mercury. The tiny planet endures endless assaults by intense sunlight, powerful solar wind and high-speed miniature meteoroids called micrometeoroids. The planet's flimsy covering, the exosphere, nearly blends in ...

Model Helps Search for Moon Dust Fountains

(PhysOrg.com) -- In exploration, sometimes you find more than what you're looking for, including things that shouldn’t be there. As the Apollo 17 astronauts orbited over the night side of the moon, with the sun just beneath ...

Magnesium detected in MESSENGER flyby of Mercury (w/Video)

NASA's MESSENGER spacecraft served up another curveball to a University of Colorado at Boulder team after a second flyby of the hot inner planet Oct. 6 detected magnesium -- an element created inside exploding stars and which ...

page 1 from 2

Exosphere

The exosphere is the uppermost layer of Earth's atmosphere. In the exosphere, an upward travelling molecule moving fast enough to attain escape velocity can escape to space with a low chance of collisions; if it is moving below escape velocity it will be prevented from escaping from the celestial body by gravity. In either case, such a molecule is unlikely to collide with another molecule due to the exosphere's low density.

This text uses material from Wikipedia, licensed under CC BY-SA