The black box set to revolutionize the search for life beyond Earth

Part of the VLT (Very Large Telescope) in Paranal, about
1,150 kms north of Santiago, Chile, which will search for
planets outside our solar system with help from the
Espresso spectrograph

In the world’s driest desert, an unassuming black box called
“Espresso” is about to begin a very big mission: scouring the
universe for planets like ours to find signs of life beyond

Espresso, an instrument known as a spectrograph, has a humble
appearance that belies its cutting-edge technology: it is the
most precise instrument of its kind ever built, 10 times
stronger than its most powerful predecessor.

In the Atacama desert, in northern Chile, Espresso will be
hooked up to four telescopes so big that scientists simply
named them the Very Large Telescope, or VLT. Together, they
will search the skies for exoplanets—those outside our own
solar system—looking for ones that are similar to Earth.

The Atacama is a particularly good place for this kind of
exploration. Its skies are completely cloudless most of the
year, which is why the highly respected European Southern
Observatory, which runs the VLT program, set up shop there in
the first place.

In fact, many of the world’s major telescopes are located in
the area. By 2020, the Atacama is expected to be home to about
70 percent of the world’s astronomy infrastructure.

Espresso stands for Echelle Spectrograph for Rocky Exoplanet
and Stable Spectroscopic Observations.

Partial view of a telescope at the Paranal Observatory, in
northern Chile’s Atacama desert, whose clear skies have
attracted many of the world’s major telescopes

It will analyze the light of the stars observed by the VLT,
enabling it to determine whether orbit around them, and important
information about those planets themselves: what their
atmosphere is like, whether they have oxygen, nitrogen and
carbon dioxide, and whether there is water—all essential for
supporting life.

“Espresso will be available on all four telescopes at once,
which is something that had never been done before. That means
the likelihood of finding planets similar to Earth in mass and
size, or the conditions for life, are greater,” said Italian
astronomer Gaspare Lo Curto.

Ten years of solitude

The most precise spectrograph until now, HARPS (High Accuracy
Radial Velocity Planet Searcher), could only measure planets
far larger than Earth—and less likely to harbor life.

HARPS is also located in the Atacama, at the La Silla
observatory, but is hooked up to telescopes less powerful than
the VLT.

“Espresso will be 10 times more precise than the most precise
in the world, HARPS, and will also
have the flexibility of serving each of the telescopes at the
Paranal observatory,” where the VLT program is housed, said Lo

View of the observatory in Paranal, northern Chile, where the
most precise spectrograph, known as Espresso, will work with
large telescopes to help analyze plants outside our solar

Chilean astronomer Rodrigo Herrera Camus called it a “great

Espresso “will help us answer one of the greatest questions we
have in astronomy, which is analyzing and understanding planets
outside our solar system,” he told AFP.

The new spectrograph is housed inside a giant metal cylinder
chilled to an average temperature of -150 C (-238 F)—essential
for its delicate optical instruments to do their work.

It was installed early last year beneath the base of the VLT,
which is perched atop the 2,600-meter (2,844 yards) altitude
Paranal mountain.

Espresso is currently in testing phase. But in 10 months’ time
it will officially begin its big mission—which is also a
solitary one.

To keep it cold enough and protect its instruments, astronomers
will have it under lock and key in a giant underground room
where no one will be allowed to enter for at least 10 years.

Explore further:
light for ESPRESSO—the next generation planet hunter