Closest Earth-like planet 'stroll across park'

[Buster's Uncle]

Closest Earth-like planet 'stroll across park'
By MARCIA DUNN | Associated Press – 10 hrs ago.. .

 
CAPE CANAVERAL, Fla. (AP) — Earth-like worlds may be closer and more plentiful than anyone imagined.
 
Astronomers reported Wednesday that the nearest Earth-like planet may be just 13 light-years away — or some 77 trillion miles. That planet hasn't been found yet, but should be there based on the team's study of red dwarf stars.
 
Galactically speaking, that's right next door.
 
If our Milky Way galaxy were shrunk to the size of the United States, the distance between Earth and its closest Earth-like neighbor would be the span of New York's Central Park, said Harvard University graduate student Courtney Dressing, the study's lead author.
 
"The nearest Earth-like planet is simply a stroll across the park away," she said at a news conference in Cambridge, Mass.
 
Small, cool red dwarfs are the most common stars in our galaxy, numbering at least 75 billion.
 
The Harvard-Smithsonian Center for Astrophysics team estimates 6 percent of red dwarf stars have Earth-like planets. To qualify, the planet must be roughly the size of Earth and get as much light from its star, as Earth does from the sun.
 
This high rate of occurrence should simplify the search for extraterrestrial life.
 
As the report's co-author, David Charbonneau, noted, he's an astronomer, but hopes to become a biologist if that search succeeds.
 
These planetary candidates are quite different than Earth because of the differences between their red dwarf stars and the sun, Charbonneau told reporters.
 
Because the red dwarfs are so much smaller, potentially habitable planets would need to orbit much closer than the Earth does to the sun. They likely would be rocky, the astronomers said, but different types of atmospheres could lead to different types of life.
 
Red dwarf stars also can be old — far older than our sun — which means their planets could be much older than Earth and their potential life forms much more evolved.
 
Our solar system is 4.5 billion years old, for instance, while some red dwarf stars are 12 billion years old. One of these target planets could be 12 billion years old as well, the scientists said.
 
Future spacecraft should be able to locate these planets and provide environmental clues.
 
California Institute of Technology astronomer John Johnson, who was not involved in the study, called the proximity of the nearest Earth-like planet "extraordinarily exciting."
 
"It's right within reach," Johnson said, and future efforts will put scientists "hot on the trail of finding life elsewhere in the galaxy."
 
These newest findings are based on data from NASA's Kepler space telescope, launched in 2009. They will be published in "The Astrophysical Journal."

http://news.yahoo.com/closest-earth-planet-stroll-across-park-174405856.html

[Buster's Uncle]

Scientists: 4.5 Billion Earth-Like Planets in the Galaxy
By Mark Whittington | Yahoo! Contributor Network – 19 hrs ago.. .

 

According to a new study quoted in Space.com, the Milky Way Galaxy may have as many as 4.5 billion Earthlike planets, some within a close distance of Earth, as interstellar gulfs go, within 13 light-years.
 
Earth-like planets circle red dwarf stars

Space.com reports that the study, to be published in The Astrophysical Journal, is based on analysis of data derived from the Kepler Space Telescope. Kepler, which is dedicated to discovering exoplanets, has found 2,740 candidates for planets circling other stars since March 2009. The study suggests that red dwarf stars that Kepler has examined are smaller and cooler than previously thought. Worlds that had previously been thought to be too large and too hot to maintain life have been "downsized" to a degree that many of them are now considered rocky worlds of the approximate size of Earth. Also since their parent stars are considered cooler, many exoplanets thought to be circling too close to such stars may now be in the habitable zone where liquid water can exist and thus life may be present.
 
4.5 billion Earths in our galaxy

Space.com goes further to state that according to the data from Kepler, roughly 60 percent of red dwarves have planets smaller than Neptune, the smallest gas giant in our solar system. It was determined that roughly 6 percent of the red dwarves in the Milky Way Galaxy have Earth-like planets, hence the figure of 4.5 billion.
 
Red dwarves

According to Universe Today, a red dwarf star ranges from less than half to 7.5 percent of the mass of the sun. A red dwarf puts out between 10 percent and 1/10000 the energy of the sun. Red dwarves consume themselves at far less the rate of a yellow star such as the sun and therefore a considerably older. Thus the habitable zone for such a star is much closer to it than that of the sun, where Earth is located. The closest star to Earth besides the sun is a red dwarf, Proxima Centauri.
 
Visiting Earth-like worlds

The idea that another Earth might be within 13 light-years is beguiling to scientists. Thus far, no technology exists that could propel a probe to any star system outside our own for any amount of time less than centuries. However Space.com reports that NASA has embarked on a research and development program that might, some decades hence, create something resembling warp drive as depicted in science fiction such as "Star Trek." It could be that people alive today will see one or more of these new Earths with their own eyes.
 

http://news.yahoo.com/scientists-4-5-billion-earth-planets-galaxy-205700623.html