These giant telescopes are going to change astronomy

A new wave of truly gigantic telescopes is under construction, and will give astronomers the ability to learn more about our universe than ever before.

This chart shows how a trio of telescopes set to open in the 2020s (the European Extremely Large Telescope in Chile, the Thirty Meter Telescope in Hawaii, and Chile's Giant Magellan Telescope, which just secured full funding yesterday) will absolutely dwarf all telescopes currently in existence:

(CMglee)

These telescopes will have primary mirrors 24 to 39 meters wide — more than twice as large as the biggest current telescope, in the Canary Islands, which is about 10 meters wide.

What's more, the James Webb Space Telescope, set to launch in 2018, will be nearly three times larger than the Hubble Space Telescope. Though it's smaller than ground-based telescopes, the James Webb won't have to deal with interference from Earth's atmosphere, allowing it to see distant objects with much greater clarity.

What scientists will do with these giant telescopes

The Thirty Meter Telescope, to be built in Hawaii. (Thirty Meter Telescope Corporation)

There's a reason scientists want to build such giant telescopes, both in space and on land. The bigger the mirror, the more light a telescope can collect. And the more light collected, the better astronomers can see faint objects — whether planets orbiting faraway stars or distant galaxies being born billions of years ago.

When it comes to the search for extraterrestrial life on exoplanets, these telescopes will be especially crucial. We've been able to use the Kepler Space Telescope to spot nearly 1,000 exoplanets, but we need more powerful telescopes to see them in more detail, so we can analyze their atmospheres.

The bigger the mirror, the more light a telescope can collect

"Earth-like planets are smaller and have relatively thin atmospheres — so we need to take in a lot of light to analyze them and search for potential signatures of life," says Lisa Kaltenegger, director of Cornell's Carl Sagan Institute, which aims to look for life on other planets. The James Webb and the Earth-based telescopes will both be put to use for this purpose.

These powerful telescopes will also let astronomers look back in time. Because light takes billions of years to travel from the far reaches of the visible universe to us, when we look out at galaxies there, we're literally seeing them as they were billions of years ago.

These new telescopes will be able to better resolve objects that are extremely distant — more than 13 billion light years away. The universe is believed to be 13.8 billion years old, which means these telescopes will allow astronomers to look all the way back to just a few hundred million years after the Big Bang.

During this period, which astronomers call the "dark ages," all matter was essentially just a soup of charged hydrogen atoms and free electrons, which scattered light and blocked it from traveling through space. Soon afterward, this matter started clumping together, allowing light to radiate for the first time through space. Looking back at this era could help us better understand the exotic processes that allowed all this to occur — and the universe as we know it to form.

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