NASA space telescope TESS starts search for Earth-like planets

An
illustration of the Transiting Exoplanet Survey Satellite in
space.

NASA

• NASA launched a new planet-hunting space telescope in
  April using a SpaceX rocket.
• The Transiting Exoplanet Survey Satellite (TESS),
  as the spacecraft is called, could discover thousands of worlds
  fairly close to Earth.
• Scientists also expect to find about 50 small, rocky
  planets that may be habitable to
  alien life.
• TESS began its two-year mission to hunt for exoplanets
  on July 25 and may reel in its first candidates for new worlds
  this week.

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NASA
launched its most powerful planet-hunting telescope to date
on April 18, but it’s taken the spacecraft months of maneuvering
to reach a crucial sweet spot.

On July 25,
TESS — short for Transiting Exoplanet Survey Satellite —
finally slipped into a unique orbit between Earth and the moon.
The telescope is now starting to
scan 85% of the night sky, stare down distant solar systems,
and hunt for small, rocky, Earth-like planets.

The two-year observation of about 200,000 stars may potentially
reveal thousands of new planets within about 200 light-years of
Earth — a cosmic stone’s throw away from our world.

“[W]e know there are more planets than stars in our universe,”
Paul Hertz, NASA’s director of astrophysics, said in a press release about TESS. “I
look forward to the strange, fantastic worlds we’re bound to
discover.”

Sara Seager, the deputy science director for TESS
and an astrophysicist at MIT, told Business Insider that it may
not take TESS long to find its first planet candidates.

“The first science orbit of data (13.7 days) is coming down
tomorrow and the TESS Science Team will begin planet hunting soon
after that,” Seager said in an email on Monday.

Seager and others expect to find dozens of Earth-like worlds in
the coming years, perhaps doubling scientists’ inventory of

potentially habitable exoplanets.

The research may also lead to the first looks at the
atmospheres of small, rocky alien worlds, and maybe — just
maybe — the first indirect evidence that extraterrestrial life
could exist beyond our solar system.

Why TESS is NASA’s most powerful search yet for alien Earths

The
Transiting Exoplanet Survey Satellite at Kennedy Space Center in
Florida before launch.

NASA

After SpaceX launched TESS, the car-size spacecraft spent more
than two months winding out to an orbit between Earth in the
moon. Researchers then checked out the spacecraft (and took some
photos of a passing comet)
remotely before officially kicking off observations.

In many ways, TESS is an extension to the biggest boon in NASA’s
search for exoplanets, called the Kepler space telescope.

Kepler launched in March 2009 and stared at a small patch of
space for more than three years. This enabled the telescope to
record very subtle dips in the brightness of stars — a telltale
sign that a planet is passing in front.

In two multi-year missions, Kepler has found nearly 4,000 planets. This led scientists to an
astonishing realization: There could be about 2 trillion planets
in our
Milky Way galaxy alone, or some 10 per star.

Kepler also found about 50 rocky, Earth-size worlds that may be
habitable. A Google artificial intelligence algorithm has since
sifted through the data and possibly
detected even more.

But Kepler is on its last leg, as it has
nearly run out of fuel (though it did recently wake up from a potentially
deadly nap to beam back new data).

TESS will use a technique to find planets that’s similar to
Kepler’s approach, yet it will be an eminently more powerful
mission. If Kepler’s search area was like a shotgun blast, then
that of TESS is an exploding grenade or bomb.

The
TESS exoplanet search zone compared to that of the Kepler
Mission.

Zach
Berta-Thompson/NASA

TESS will conduct its hunt by taking pictures of a different
sector of the sky every 27 days. All of the sectors overlap,
enough in some parts to provide about a year’s worth of transit
observations.

The spacecraft will use its unique vantage in space and four
cameras to stitch together a huge map of about 200,000 stars —
about 33% more than Kepler studied. The observation area for TESS
will also be about 350 times as large as Kepler’s and about 15
times as close.

“TESS will discover thousands of planets and is further specially
designed to find a pool of small planets transiting small stars,”
a website for the project explains.

Researchers working on TESS expect to find at least 50 rocky,
Earth-size worlds for scientists to scrutinize — about double
what Kepler has found. However, TESS is likely find many more
than that, as it is viewing more stars (and Kepler defied its
creators’ predictions).

However, Seager said it’s “anyone’s guess” when TESS’ first newly
discovered worlds will be confirmed.

“Finding planet candidates is just the first step in a lengthy
follow-up process to discriminate between actual planets,” she
said.

That follow-up has to account for other factors that could skew
the data, such as two-star systems or any peculiarities with the
spacecraft’s cameras.

Once TESS’ discoveries are confirmed, however, they could prove
vital to the work of NASA’s upcoming and powerful James Webb
Space Telescope (JWST), which is scheduled to launch after March 2021.

The next-generation observatory will rival the abilities of the
Hubble Space Telescope and will be the largest observatory ever
launched into space. JWST will take pictures in infrared light,
which is invisible to human eyes yet perfect for studying planets
through clouds of gas and dust
in space that typically obscure distant worlds.

How TESS may lead to the discovery of life beyond the solar
system

NASA

TESS’ fresh catalog of nearby and likely Earth-size alien worlds
will give JWST many compelling targets to study in detail.

JWST might even
sample light from an exoplanet’s atmosphere to look for
indirect evidence of life.

The ability to study the air supply of a distant Earth-size
planet is made more possible by yet another telescope: the

Giant Magellan Telescope (GMT), one of the two largest
ground-based observatories under construction today.

Slated to open in 2023, GMT is designed to resolve details four
times finer than JWST. This may help astronomers study exoplanets
in ways what they’ve been dreaming of since the first confirmed
discovery of an alien solar system in 1992.

“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, said in a previous statement
to 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.

Artist’s representation of
the seven giant mirrors installed in the Giant Magellan
Telescope.

Giant Magellan Telescope – GMTO
Corporation

For example, if a planet’s atmosphere were to have a mix of
oxygen and methane gases — similar to Earth’s atmosphere — that
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.

With some luck, we might even be able to fly
tiny, high-speed spacecraft past the most promising planets
to get a closer look.