Odds of Finding Alien Life Boosted by Billions of Habitable Worlds
A new estimate of the number of habitable
planets orbiting the most common type of stars in our galaxy could have
huge consequences for the search for life.
According to a recent study, tens of
billions of planets around red dwarfs
are likely capable of containing liquid water, dramatically increasing the
potential to find signs of life somewhere other than Earth.
Red dwarfs are stars that are fainter, cooler and less massive than the sun.
These stars, which typically also live longer than Class G stars like the sun,
are thought to make up about 80 percent of the stars in the Milky Way,
astronomers have said.
A second look
Red dwarfs generally have not been
considered viable candidates for hosting habitable
planets. Since red dwarfs are small and dim, the habitable zone surrounding them — the
region where an orbiting planet's surface water can remain liquid — is
relatively close to them. "The habitable zone would be very, very
small. Consequently, the chances that you would actually find any planet at the
right distance from the sun to be attractive to life was likely to be small,
too," said Seth Shostak, a senior astronomer at the Search for Extraterrestrial Intelligence Institute in
Mountain View, Calif. [The Strangest Alien Planets]
But the study, based on data from the European Space Agency's HARPS
spectrograph in Chile, used a sample of 102 red dwarfs to estimate that 41
percent of the dim stars might be hiding planets in their habitable zone.
"The number of habitats might increase by a factor of 8 or 10," Shostak told SPACE.com.
Difficult
environments
One of the largest concerns about
planets circling red dwarfs is radiation. A red dwarf's habitable zone is
generally closer to it than Mercury is to our sun, so a planet there would
receive a strong shock of particles when storms erupted on the red dwarf.
"They could essentially give everything on the surface that's exposed to the
sky ... a heavy dose of radiation," Shostak said. "It could be fatal."
However, if the alien planet had a magnetic field, this could provide some protection. So, too, could an ocean of
water. Life that evolved beneath an ocean might be shielded from the brunt of the radiation. More Here...
http://news.yahoo.com/odds-finding-alien-life-boosted-billions-habitable-worlds-122420222.html
A new estimate of the number of habitable
planets orbiting the most common type of stars in our galaxy could have
huge consequences for the search for life.
According to a recent study, tens of
billions of planets around red dwarfs
are likely capable of containing liquid water, dramatically increasing the
potential to find signs of life somewhere other than Earth.
Red dwarfs are stars that are fainter, cooler and less massive than the sun.
These stars, which typically also live longer than Class G stars like the sun,
are thought to make up about 80 percent of the stars in the Milky Way,
astronomers have said.
A second look
Red dwarfs generally have not been
considered viable candidates for hosting habitable
planets. Since red dwarfs are small and dim, the habitable zone surrounding them — the
region where an orbiting planet's surface water can remain liquid — is
relatively close to them. "The habitable zone would be very, very
small. Consequently, the chances that you would actually find any planet at the
right distance from the sun to be attractive to life was likely to be small,
too," said Seth Shostak, a senior astronomer at the Search for Extraterrestrial Intelligence Institute in
Mountain View, Calif. [The Strangest Alien Planets]
But the study, based on data from the European Space Agency's HARPS
spectrograph in Chile, used a sample of 102 red dwarfs to estimate that 41
percent of the dim stars might be hiding planets in their habitable zone.
"The number of habitats might increase by a factor of 8 or 10," Shostak told SPACE.com.
Difficult
environments
One of the largest concerns about
planets circling red dwarfs is radiation. A red dwarf's habitable zone is
generally closer to it than Mercury is to our sun, so a planet there would
receive a strong shock of particles when storms erupted on the red dwarf.
"They could essentially give everything on the surface that's exposed to the
sky ... a heavy dose of radiation," Shostak said. "It could be fatal."
However, if the alien planet had a magnetic field, this could provide some protection. So, too, could an ocean of
water. Life that evolved beneath an ocean might be shielded from the brunt of the radiation. More Here...
http://news.yahoo.com/odds-finding-alien-life-boosted-billions-habitable-worlds-122420222.html