Giant Magellan Telescope, the world’s largest, is under construction

A
rendering of the Giant Magellan Telescope in
Chile.
GMTO
Corporation

• Construction crews have broken ground on the Giant Magellan Telescope in
  Chile.
• When complete, the telescope will have a
  light-collecting area about 80 feet in diameter — nearly the
  area of a basketball court.
• GMT’s photos will be about 10 times sharper than those
  of NASA’s Hubble Space Telescope.
• Laser-based optics will help the $1-billion telescope
  “sniff” the atmospheres of potentially habitable exoplanets.

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In astronomy, cutting-edge technology often begins with a bunch
of bulldozers, busted rocks, and dump trucks.

So it goes with the Giant Magellan Telescope (GMT), which will
the world’s largest and most powerful when it sees “first light”
in 2024. Astronomers hope to use the huge observatory to study
the ancient universe and look for signs of alien life.

Construction crews atop a Chilean mountain range broke ground for
the $1 billion project on Tuesday. The final device will weigh
more than 2 million lbs, so workers are now punching a
23-feet-deep hole in bedrock that they’ll eventually fill with
concrete to support GMT’s enormous weight.

“It will be supported by a 1,000 ton steel telescope structure
that will be housed inside a rotating enclosure that will measure
22 stories tall and 56 meters wide,” a representative for GMT
told Business Insider in an email.

Rock-breaking
kicked off GMT’s construction in August 2018.
GMTO Corporation

The GMT is being built at Las Campanas Observatory in the Atacama
Desert, one of the highest and driest regions on Earth. The site
provides astronomers with clear views of the night sky almost
year-round.

To help probe the universe, GMT will eventually have seven
27-feet-wide mirrors, each weighing close to 20 tons. Together
their light-collecting area will be about the size of a
basketball court.

The telescope will also use laser-based “adaptive optics” to
measure distortion caused by Earth’s atmosphere, correct for that
interference, and produce crisper and clearer pictures.

“The GMT mirrors will collect more light than any telescope ever
built and the resolution will be the best ever achieved,” the
project claims on its website.

One estimate suggests the images will be up to 10 times more resolute than
those of NASA’s Hubble Space Telescope.

What the Giant Magellan Telescope may discover

NASA/JPL-Caltech/R.
Hurt (SSC-Caltech)

The Giant Magellan Telescope is geared toward studying galaxies
in the deep universe, but it could play a pivotal role in
answering whether or not life on Earth is
alone in the universe — or at least refine the
likelihood of that possibility.

GMT will follow in the footsteps of NASA’s Kepler space mission,
launched in 2009, which discovered thousands of new worlds. About
50 of those are Earth-size and
may be cozy enough to support alien life.

But Kepler probed deep and narrow sections of the night sky.
NASA’s follow-on space mission, called the Transiting Exoplanet
Survey Satellite (TESS), is now
scanning 85% of the entire sky for worlds within about 200
light-years of our own (a relative stone’s throw in space). TESS
is only equipped to detect possible exoplanets, though, not study
them in detail.

Another upcoming NASA space mission, called the James Webb Space
Telescope (JWST), may be powerful enough to
sample light from an exoplanet’s atmosphere after it
launches,
perhaps in 2021. Such measurements could help verify if an
Earth-size planet has signs of biology and perhaps even
breathable air.

However, JWST may not be big enough to take detailed measurements
of an Earth-size planet. This is where GMT — expected to be about
14 times as large — could excel. Here’s how it compares to JWST
and other planned and current astronomical observatories:

A
size comparison of the Giant Magellan Telescopes to other
observatories.

Cmglee/Wikipedia
(CC BY-SA 3.0)

With its full resolving power, GMT might be able to “sniff” alien
atmospheres.

“As a planet passes in front of its star, a large telescope on
the ground, like the GMT, can use spectra to search for the
fingerprints of molecules in the planetary atmosphere,” Patrick
McCarthy, a leader of the project, previously
told Business Insider.

Spectra refers to the blend of colors in starlight. When that
light passes through a planet’s atmosphere, chemicals absorb and
remit certain parts — leaving a smoking-gun pattern of their
presence.

A mix of oxygen and methane gases similar to that of Earth’s
atmosphere, for example, could be a “fingerprint” of life’s
presence on an exoplanet.

McCarthy also said large and powerful new telescopes like GMT
might be able to deduce weather systems and surface features of
planets located trillions of miles away.

If Russian billionaire Yuri Milner has his way, we might even
send
tiny, high-speed spacecraft past the most promising planets
in the next few decades.