Terrascope: A telescope that will make Earth's atmosphere a lens
David Kipping, the Columbia professor, plans to build a telescope using the earth's atmosphere as a lens. The earth refracts the light that enters Earth's atmosphere.
Is it possible for us to look at the end of the Universe? Yes, but to do that we need a giant telescope. The giant telescopes we currently use are costly to manufacture and maintain and limited by size. What can we do to solve this problem?
A paper published by an assistant professor of astronomy at Columbia University has a solution to this problem. He suggests a giant telescope that uses the earth's atmosphere as lens. The professor calls this device 'Terrascope'.
How telescopes work
Telescopes use a mirror or glass to magnify distant objects. The magnification depends on refraction, a property of light that helps in magnification. Refraction takes place when light passes from one medium to another. The bigger the glass (density increases) or mirror, the greater is the magnification.
But, building a big circular glass or mirror comes with its own limitations. Because of their weight they start deforming. Glasses also have a property that makes it difficult to focus the light of particular wavelengths.
Scientists found a solution for this problem: giant telescopes use a cluster of small mirrors to produce magnification. Each of these mirrors used in the telescope is controlled by computers to produce the desired magnification. These telescopes cost billions of dollars to make and are also expensive to maintain. Also, there is a limitation to how big a telescope can be.
David Kipping, the Columbia professor, plans to build a telescope using the earth's atmosphere as a lens. The earth refracts the light that enters Earth's atmosphere. Why? Because of the change in medium, from empty space to the atmosphere on earth.
A real-life example of this can be seen during sunset. The sun is visible to us even though it has actually gone down from the horizon. This happens because of refraction that causes the sun to be visible for a longer duration of time.
The Terrascope is expected to use this property of the atmosphere to observe distant celestial objects. The professor says that the device can provide a magnification of 10 to 40,000.
The concept is not ready for use and has limitations. One of the biggest is its inability to look at objects that are behind the earth. We are nowhere close to making this device; yet this might be a new way to solve the problem of gazing at distant stars.