A NEW PLANET FOUND
THE NEW PLANET IS A PROPOS 36 LIGHT-YEARS AWAY AND COULD BE ONE OF THE MOST EARTHLIKE WORLDS YET
It is believed that the Radial velocity is a planet-hunting method
that looks for wobbles in a star's light, which can specify the gravitational
tugs of orbiting worlds.The HARPS data demonstrate that the planet is 3.6 times
the mass of Earth, and the new world orbits its parent star at just the right
distance for water to be liquid on the planet's surface—a trait scientists
believe is crucial for life as we know it."The distance is exactly the
limit where you want to be to have liquid water," said study leader Lisa Kaltenegger
of the Harvard-Smithsonian Center for Astrophysics and the Max Planck Institute
for Astronomy."If you scale it to our system, it's a bit further out than Venus
is to our sun." At that distance, the planet likely receives a bit more
solar energy from its star than Earth does from the sun. (Explore an interactive solar
system.)
But Kaltenegger and colleagues calculated that a cloud cover
of at least 50 percent would reproduce enough of the energy back into space to avoid
over-heating. On average, Earth has 60 percent cloud cover, so partly cloudy
skies on HD85512b are "not out of the question," she said.
Of course, clouds of water vapor depend on the presence of an atmosphere
similar to Earth's, something that can't be detected on such distant planets
with current instruments.
Models of planet formation predict that planets with more than ten
times Earth's mass should have atmospheres dominated by hydrogen and helium,
Kaltenegger said. Less massive worlds—including HD85512b—are more likely to
have Earthlike atmospheres, made mostly of nitrogen and oxygen.
The newly detected planet is the second rock-strewn world outside
our solar system to be confirmed in its star's habitable zone, the region
around a star which is neither too hot and nor too cold for liquid water. The
other one known as, planet Gliese 581d, was previously discovered using the same
instrument. Another shows potential planet, Gliese 581g, was
discovered in 2010 and dubbed the most Earthlike planet yet. But
controversy backdrop the claim, where some experts declaring that the entire
planet is actually a data glitch.
Manfred Cuntz,
director of the astronomy program at the University of Texas, Arlington, noted
that more information is required before anyone can consider whether aliens are
wandering around the newfound planet."It's not their fault no extra
information [about the planet's atmosphere] is available right now," Cuntz
said of the research team. "It looks like this is a strong candidate, in
principle."In addition to size and location, HD85512b has two other points
in its goodwill for potentially harboring life, Cuntz said. The planet's orbit
is almost circular, which would provide a constant climate, and its parent
star, HD85512, is older—and therefore less active—than our sun, which would
lower the likelihood of electromagnetic storms destructive for the planet's
atmosphere. Not only that, but in principle, the age of the system—5.6 billion
years—"gives life a chance to originate and develop," he said. By
contrast, our own solar system is thought to be about 4.6 billion years old.
