Follow - up studies with large telescopes on the ground revealed that the cluster is 7 billion light - years away, which means its light took 7 billion years to reach us. (sciencemag.org)
But although many planets are first discovered using telescopes on the ground, most of the spectroscopic measurements that have afforded astronomers a glimpse at their atmospheres have come from space - based observatories such as the Hubble and the Spitzer space telescopes, which operate outside the obscuring veil of Earth's own atmosphere. (scientificamerican.com)
Using radio telescopes on the ground, researchers have already devised space - based gravitational wave detectors using nature's resources: large numbers of pulsars spread throughout space that spin once every few milliseconds, sending out lighthouse - like beams of light that reach us in regular beats. (scientificamerican.com)