It is perhaps an astronomy nerd’s greatest dream – telescopes viewing space from space itself. These scopes are launched from the surface and orbit the Earth as satellites. Up there, their sight is unobstructed by any atmospheric disturbance, meaning pollution, weather and normal air turbulence, and they can therefore observe points in the sky in great detail. Getting above the atmosphere has another advantage, too: many wavelengths of radiation are simply blocked by the earth’s ionosphere, ozone layer and air, meaning the only way to “see” some kinds of non-visible light is from the vacuum of space.
What makes things even more exciting is that NASA and other organizations don’t spend millions on sending a cheap scope you can buy at any supermarket into the sky. Space telescopes are constructed with the most advanced mirror and imaging technology available.
Perhaps the king of these scopes is the Hubble. Loads of fanfare accompanied the launching of this scope and it has actually caused a minor revolution in the astronomy world. Since 1990 when the scope was placed into orbit by the space shuttle Discovery, the Hubble has produced a cornucopia of images that have been published around the world, such as its beautiful close up of the Eagle Nebula:
This didn’t occur without a setback or two – within weeks of it going online, a tiny flaw was discovered in its mirror, which led to another shuttle being dispatched to give the scope a set of “glasses” to correct its vision.
The Hubble has allowed scientists to peer farther into the galaxy than ever before. Its images of really deep-space objects have shown us galaxies billions of light years away, which has helped answer questions about the formation and the overall composition in the universe.
While this is very impressive, space telescopes remain controversial. They are very, very expensive to build and maintain and new ground-based technologies are making these telescope less competitive. Saying that the money should rather be spent at home is short-sighted, though. Sometimes, the only way to get the benefits of science is to actually invest in it, and technologies ranging from cellphones to MRI machines would never have been invented if it weren’t for discoveries made by astronomers.
Mysterious and difficult to detect, dark matter is one of the scientific puzzles space telescopes may help to solve.
Many amateur telescopes are of the refractor type and not intended to work in vacuum; learn more about them here.