Astronomers say they can use "galactoseismology" - the study of ripples in a galaxy's disk - to map the interior structure of galaxies and learn about dark matter.
As water piles up before a ship, so material stacks up ahead of high-mass stars moving fast through space. These cosmic bows shocks revealed the runaway stars.
NASA has called off the planned March 2016 launch of the InSight mission to Mars, following failure to repair a leaky instrument in the science payload.
Lakes around the world are warming rapidly, threatening ecosystems and water supplies, says a new study that looked at more than half of Earth's freshwater supply.
Eleanor Imster has helped write and edit EarthSky since 1995. She was an integral part of the award-winning EarthSky radio series almost since it began until it ended in 2013. She and her husband live in Tennessee, where they enjoy guitar playing and singing. They have 2 grown sons.