Scientists discover Earth-like
planet orbiting star closest to our sun
An Earth-like
planet has been discovered orbiting the star closest to our
sun.
The planet is only a bit bigger than Earth and, like
Earth, is rocky, and it's the right distance from its star
to support liquid on the surface.
USA
TODAY
An Earth-size planet that could boast water, even an
ocean, has been found circling the star nearest our sun,
hinting that the conditions for life could exist next door.
Researchers have identified a plethora of planets outside
our solar system that both resemble Earth in size and dwell
in the “habitable zone,” where liquid water is possible. But
no other Earth-like planet outside our solar system is as
close to humans and their observatories as this new world,
making it the best possible hunting ground for living
organisms.
The find, reported in a study
published Wednesday in Nature, has scientists reaching for
superlatives. “An absolutely amazing discovery,” says
Victoria Meadows of the University of Washington. “This will
be the most accessible, closest planet in the habitable zone
to our solar system.” “The excitement is that it’s around
the closest star to our sun,” says Rory Barnes, also of the
University of Washington, adding that it’s “exciting, too,
to realize perhaps the next star over has a planet with life
on it.” Announced after a search by astronomers from around
the world, the new planet circles a small star called
Proxima Centauri. That star, though invisible to the naked
eye, is only 4.2 light-years — about 25 trillion
miles — from Earth, making it our nearest stellar neighbor.
The specs of the new planet, called Proxima b, sound much
like Earth’s. It is 1.3 times the mass of the Earth or
bigger. It is probably rocky, like Earth, and not a
Jupiter-like ball of gas. And it’s just the right distance
from its star that it would be warm enough for liquid water
to pool on the surface, assuming the planet has an
atmosphere. Of course, it may not have an atmosphere, a
prerequisite for life. Tipping the odds against life a bit,
Proxima b’s star blasts it with far more high-energy
radiation than our planet receives from the sun. All the
same, the planet may still be hospitably wet, Meadows says,
depending on how and where it formed billions of years ago
and how its star behaved during the planet’s infancy.
Picking out the planet has taken some of the most powerful
telescopes in the scientific arsenal. The first signals of a
world orbiting Proxima Centauri were recorded more than a
decade ago, and more such signals have continued to trickle
in – but never enough to be convincing. So astronomers
recruited multiple telescopes to stare at the star earlier
this year. The intensive observations confirmed that the
star quivers slightly, the result of a slight perturbation
induced by its small planet. That quiver translates into
barely detectable changes in the light streaming from the
star. Other planets outside our solar system have been
announced with fanfare, only to quietly fade away when they
couldn’t be confirmed. But “the fact that we have been able
to see a signal over so many years tells us that there
really is a bona fide planet,” says study co-author Richard
Nelson of Britain’s Queen Mary University of London. “If
you’ve got one in your backyard, it tells you that through
the galaxy there are going to be many, many of these types
of planets.” To determine whether organisms thrive on
Proxima b, scientists will need to take a picture of the
planet itself. Analysis could reveal molecules that would be
telltale signs of life. No existing instrument could snap
such pictures. But such technology is under design, and the
new discovery will likely galvanize construction of
observatories that could take a portrait of this new world.
The planet is even close enough that perhaps someday robots
could reach it. A space mission to reach exoplanets won’t be
ready until the “coming centuries,” says David Armstrong of
Britain’s University of Warwick. “But the first one we’ll
send it to will be this.”
http://www.usatoday.com/story/tech/2016/08/24/scientists-discover-earth-like-planet-orbiting-star-closest-our-sun/89258306/