BrainStuff Classics: How Do We Find Planets That Might Harbor Life?

Ross 128 b is an Earth-sized planet only 11 light years away that might have the right conditions to sustain life as we know it. Learn how scientists are studying it in this classic episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff production of I Heart Radio. Hey
brain Stuff Lauren Vogel bomb here with a classic episode
from our archives. Part of what makes the search for
extraterrestrial life so difficult is that we only know about
the kind of life that developed on Earth, and detecting
planets that are vaguely like Earth is really hard. But

(00:24):
today's episode has to do with just such a planet
confirmed to be earthlike. Hey brain Stuff, Lauren Vogel bomb Here,
a very special alien world has been discovered on our
galactic doorstep, and it may have the secret sauce that
allows life as we know it to exist on its surface.
Enter Ross B, an Earth sized exoplanet that likely orbits

(00:48):
its star in the habitable zone. What makes this exoplanet
discovery so exciting is that it's located only eleven light
years away. Plus it's red dwarf star appears to be inactive.
That means that this newly discuss word world may not
face the radioactive ravages that other EXE planets likely endure,
thereby boosting its habitable potential. Astronomers detected Ross one B

(01:09):
using the European Southern Observatories High accuracy radial velocity planet
searcher A. K. A. Harps at the Lascia Observatory in Chile.
They measured the slight wobbles of the star caused by
the orbiting exoplanet. In a study published in the journal
Astronomy and Astrophysics, the researchers calculated the exo planet's mass
and orbital period. A year on Ross one B is

(01:31):
slightly less than ten Earth days, so the distance at
which it whips around its star is very close. But
as the red dwarf is so tiny and cool, the
exoplanet receives a similar amount of solar heating as our
planet receives from the Sun. Red dwarfs are the most
common type of star in our galaxy, and many are
known to possess planetary systems. The closest star to our
Solar system, Proximates Centauri, is a red dwarf, and in

(01:54):
astronomers made the historic discovery of a small Earth sized
exo planet in its orbit. That world, called Proxima B,
is the closest habitable zone exo planet to us, and
may even have a temperate atmosphere that could support an
alien ecosystem. However, Proxima Centauri is a violent star that
regularly erupts with powerful flares and pumps out X ray
and ultra violet radiation, which tend to be deadly to

(02:17):
life as we know it. If life could evolve on
Proxima B, and that's a big if, the planet would
need a very powerful magnetosphere, a global magnetic field, to
deflect those powerful stellar winds and thus prevent its atmosphere
from being stripped away and to prevent any life forms
from being irradiated. Ross, on the other hand, lives next
to an inactive red dwarf star one that isn't blasting

(02:39):
local space with a massive dose of radiation. In fact,
according to an E s O statement, Ross one is
the quietest nearby star to host such a temperate exo planet.
Despite being twenty times closer to its star than Earth
is to the Sun, Ross only receives thirty eight percent
more radiation. If it does have an atmosphere, life might
have had an opportunity to gain a foothold without getting fried.

(03:03):
Although radiation may not be a problem, orbiting so close
to a red dwarf star presents a unique situation for
habitable zone exoplanets like Ross. For example, researchers expect that
the planet is tidally locked. Tidal locking occurs when a
planet orbits close to its star, like the Moon is
tidally locked with Earth. That's the reason why we only

(03:23):
ever see one side of the Moon facing Us as
it orbits the planet. Exoplanets with compact orbits are also
expected to become tidally locked with their stars. One hemisphere
is perpetually facing the star and the other hemisphere is
always facing away. But this wouldn't necessarily be a death sentence.
With the right atmosphere or proportion of land masses two oceans,

(03:44):
heat from the star could be distributed from the planet's
warm daylight side to the cool side in perpetual darkness.
For now, However, though Ross is an exciting discovery, there's
no way of knowing if the nearby world even possesses
an atmosphere, let alone whether that hypothetical atmo sphere has
the right chemical balance for life to thrive. In July,
the air CBO radio telescope in Puerto Rico detected a

(04:06):
mysterious low frequency signal emanating from the Ross system. Although
there was some excitement for the possibility of a CETI
like alien radio signal, astronomers think that this is the
least likely explanation, favoring the detection of an as yet
unexplained stellar phenomenon or a rogue signal from an orbiting satellite.
When the next generation of ground and space based telescopes

(04:28):
go online, such as the E S O S Extremely
Large Telescope and NASA's James Webb Space Telescope us B,
will become a prime target for astronomers to look for
the spectroscopic clues of chemicals that could be produced by
an alien biosphere. Telescopes like the Extremely Large Telescope will
be on the lookout for water, a substance that is
essential in its liquid form for all life as we

(04:50):
know it, but also possible bio markers like dioxygen, ozone, methane,
and carbon dioxide, which could betray the presence of a
habitable or even possibly inhabited atmosphere, though of course, individually,
none of these chemicals would provide definite proof for life.
Today's episode was written by Ian O'Neill and produced by

(05:11):
Tristan McNeil and Tyler Clang. For more on this and
lots of other far out topics, visit How Stuff Works
Dot com brain Stuff is production of I heart Radio.
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