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Hubble Finds Dark Matter Ring in Galaxy Cluster
Dark matter emits no light, and cannot be directly observed, but scientists think that it and dark energy make up most of the mass of the universe.
Dark Energy Mystery Illuminated By Cosmic Lens
Dark energy is a mysterious quantity that makes up, along with...
night sky watching
Stuff in the sky that you can easily see this month.
Prime meridian
The world's time zones and hemispheres are divided into east a...
Wormhole
A wormhole is a theoretical passage through space-time that co...
Full Size Virgin Galactic SpaceShipTwo
SpaceShipTwo is expected to take paying customers into space a...