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

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<v Speaker 1>Welcome to brain Stuff production of I Heart Radio. Hey

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<v Speaker 1>brain Stuff Lauren Vogel bomb here with a classic episode

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<v Speaker 1>from our archives. Part of what makes the search for

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<v Speaker 1>extraterrestrial life so difficult is that we only know about

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<v Speaker 1>the kind of life that developed on Earth, and detecting

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<v Speaker 1>planets that are vaguely like Earth is really hard. But

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<v Speaker 1>today's episode has to do with just such a planet

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<v Speaker 1>confirmed to be earthlike. Hey brain Stuff, Lauren Vogel bomb Here,

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<v Speaker 1>a very special alien world has been discovered on our

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<v Speaker 1>galactic doorstep, and it may have the secret sauce that

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<v Speaker 1>allows life as we know it to exist on its surface.

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<v Speaker 1>Enter Ross B, an Earth sized exoplanet that likely orbits

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<v Speaker 1>its star in the habitable zone. What makes this exoplanet

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<v Speaker 1>discovery so exciting is that it's located only eleven light

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<v Speaker 1>years away. Plus it's red dwarf star appears to be inactive.

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<v Speaker 1>That means that this newly discuss word world may not

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<v Speaker 1>face the radioactive ravages that other EXE planets likely endure,

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<v Speaker 1>thereby boosting its habitable potential. Astronomers detected Ross one B

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<v Speaker 1>using the European Southern Observatories High accuracy radial velocity planet

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<v Speaker 1>searcher A. K. A. Harps at the Lascia Observatory in Chile.

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<v Speaker 1>They measured the slight wobbles of the star caused by

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<v Speaker 1>the orbiting exoplanet. In a study published in the journal

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<v Speaker 1>Astronomy and Astrophysics, the researchers calculated the exo planet's mass

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<v Speaker 1>and orbital period. A year on Ross one B is

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<v Speaker 1>slightly less than ten Earth days, so the distance at

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<v Speaker 1>which it whips around its star is very close. But

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<v Speaker 1>as the red dwarf is so tiny and cool, the

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<v Speaker 1>exoplanet receives a similar amount of solar heating as our

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<v Speaker 1>planet receives from the Sun. Red dwarfs are the most

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<v Speaker 1>common type of star in our galaxy, and many are

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<v Speaker 1>known to possess planetary systems. The closest star to our

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<v Speaker 1>Solar system, Proximates Centauri, is a red dwarf, and in

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<v Speaker 1>astronomers made the historic discovery of a small Earth sized

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<v Speaker 1>exo planet in its orbit. That world, called Proxima B,

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<v Speaker 1>is the closest habitable zone exo planet to us, and

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<v Speaker 1>may even have a temperate atmosphere that could support an

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<v Speaker 1>alien ecosystem. However, Proxima Centauri is a violent star that

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<v Speaker 1>regularly erupts with powerful flares and pumps out X ray

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<v Speaker 1>and ultra violet radiation, which tend to be deadly to

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<v Speaker 1>life as we know it. If life could evolve on

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<v Speaker 1>Proxima B, and that's a big if, the planet would

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<v Speaker 1>need a very powerful magnetosphere, a global magnetic field, to

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<v Speaker 1>deflect those powerful stellar winds and thus prevent its atmosphere

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<v Speaker 1>from being stripped away and to prevent any life forms

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<v Speaker 1>from being irradiated. Ross, on the other hand, lives next

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<v Speaker 1>to an inactive red dwarf star one that isn't blasting

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<v Speaker 1>local space with a massive dose of radiation. In fact,

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<v Speaker 1>according to an E s O statement, Ross one is

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<v Speaker 1>the quietest nearby star to host such a temperate exo planet.

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<v Speaker 1>Despite being twenty times closer to its star than Earth

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<v Speaker 1>is to the Sun, Ross only receives thirty eight percent

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<v Speaker 1>more radiation. If it does have an atmosphere, life might

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<v Speaker 1>have had an opportunity to gain a foothold without getting fried.

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<v Speaker 1>Although radiation may not be a problem, orbiting so close

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<v Speaker 1>to a red dwarf star presents a unique situation for

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<v Speaker 1>habitable zone exoplanets like Ross. For example, researchers expect that

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<v Speaker 1>the planet is tidally locked. Tidal locking occurs when a

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<v Speaker 1>planet orbits close to its star, like the Moon is

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<v Speaker 1>tidally locked with Earth. That's the reason why we only

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<v Speaker 1>ever see one side of the Moon facing Us as

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<v Speaker 1>it orbits the planet. Exoplanets with compact orbits are also

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<v Speaker 1>expected to become tidally locked with their stars. One hemisphere

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<v Speaker 1>is perpetually facing the star and the other hemisphere is

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<v Speaker 1>always facing away. But this wouldn't necessarily be a death sentence.

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<v Speaker 1>With the right atmosphere or proportion of land masses two oceans,

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<v Speaker 1>heat from the star could be distributed from the planet's

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<v Speaker 1>warm daylight side to the cool side in perpetual darkness.

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<v Speaker 1>For now, However, though Ross is an exciting discovery, there's

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<v Speaker 1>no way of knowing if the nearby world even possesses

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<v Speaker 1>an atmosphere, let alone whether that hypothetical atmo sphere has

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<v Speaker 1>the right chemical balance for life to thrive. In July,

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<v Speaker 1>the air CBO radio telescope in Puerto Rico detected a

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<v Speaker 1>mysterious low frequency signal emanating from the Ross system. Although

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<v Speaker 1>there was some excitement for the possibility of a CETI

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<v Speaker 1>like alien radio signal, astronomers think that this is the

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<v Speaker 1>least likely explanation, favoring the detection of an as yet

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<v Speaker 1>unexplained stellar phenomenon or a rogue signal from an orbiting satellite.

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<v Speaker 1>When the next generation of ground and space based telescopes

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<v Speaker 1>go online, such as the E S O S Extremely

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<v Speaker 1>Large Telescope and NASA's James Webb Space Telescope us B,

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<v Speaker 1>will become a prime target for astronomers to look for

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<v Speaker 1>the spectroscopic clues of chemicals that could be produced by

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<v Speaker 1>an alien biosphere. Telescopes like the Extremely Large Telescope will

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<v Speaker 1>be on the lookout for water, a substance that is

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<v Speaker 1>essential in its liquid form for all life as we

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<v Speaker 1>know it, but also possible bio markers like dioxygen, ozone, methane,

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<v Speaker 1>and carbon dioxide, which could betray the presence of a

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<v Speaker 1>habitable or even possibly inhabited atmosphere, though of course, individually,

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<v Speaker 1>none of these chemicals would provide definite proof for life.

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<v Speaker 1>Today's episode was written by Ian O'Neill and produced by

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<v Speaker 1>Tristan McNeil and Tyler Clang. For more on this and

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<v Speaker 1>lots of other far out topics, visit How Stuff Works

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<v Speaker 1>Dot com brain Stuff is production of I heart Radio.

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