Since the first time man’s eyes set upon the stars, twinkling high in the heavens above, we have had an insatiable curiosity for the inner workings of the universe. Spurred on by discovery, man has endeavored to find out all the secrets about this vast expanse of space that lies so far out of our reach.

With the commission of the world’s largest optical telescope, we may have just gotten one step closer.

The world’s biggest eye on the sky, the European Extremely Large Telescope(E-ELT) is destined to unravel mysteries and clue us in about the things beyond our solar system. Commissioned by the European Southern Observatory, it will be the largest optical telescope when finished in 2022.

The E-ELT

With a main mirror spanning about 39 meters, the telescope can detect objects in the visible light spectrum and near-infrared, opening it up to a whole new range of space debris. Its sensitivity and resolution are unmatched, making it the world’s telescope with the best vision -- 20/20 on the eye doctor visits!!

The observatory should even be able to provide insights into black holes and galaxy formation. Their ultimate goal is to find this mysterious “dark matter” that pervades the universe, and the even more mysterious “dark energy” that seems to be pushing the universe apart.

And where is this seemingly magical telescope going to be placed? You guessed it…or maybe you didn’t…Chile’s Atacama Desert! The reason for such a location is the year-round cloudless skies and clear weather. Also, since the Atacama Desert is so dry, starlight will experience less disturbance on its way down to the telescopes. Why can’t we have it in cities? They’re too polluted. All we see at night is the smoke coming out of the factories.

Optical vs. Radio

Notice that the E-ELT is the world’s largest optical telescope. Radio telescopes are much bigger. There are a few fundamental differences between these two telescopes.

The biggest difference is the way they work -- radio telescopes use large dishes to collect radio waves, and turn them into pictures. Optical telescopes use either lens or mirrors to collect light and analyze it. Optical telescopes are a lot more efficient than radio telescopes. To capture the effect of a good optical telescope, astronomers have to cover a 100 km area with radio dishes.

So why use radio telescopes, you may ask. Well, it all has to do with the electromagnetic spectrum. The electromagnetic spectrum is a set of all the different wavelengths that exist in our universe. Radio telescopes capture radio waves, while optical telescopes deal with the visible light and near-infrared waves.

So, to get a full picture of the universe, we have to use different wavelengths of radiation to capture different images. While some objects emit radio waves, others emit those of visible light, and still others emit wavelengths that we cannot capture as of now.