Science

gliese 581, gliese 581 c, gliese exoplanet
Zina Deretsky/National Science Foundation/NASA
The orbits of planets in the Gliese 581 system are compared to those of our own solar system.

Scientists Reach New Milestone with the Discovery of Earth-like Exoplanet

October 13, 2010 11:00 AM
by Anita Gutierrez-Folch
The recent discovery of a rocky Earth-like planet with an atmospheric temperature that could support the development of life is a breakthrough. But it is just one of many recent findings that support the possibility of life in space.

A Window to the Future

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The search for an Earth-like planet capable of sustaining life has kept astronomers busy for decades. It took a leap in late September with the discovery of Gliese 581 g, an exoplanet which orbits a red dwarf star located 20 light years from Earth.

By combing previous astronomical data, Steven Vogt of the University of California, Santa Cruz, and Paul Butler of the Carnegie Institution in Washington, D.C., were able to use a 10-meter Keck I telescope located in Hawaii to locate a rocky planet with the potential to harbor water, and therefore life.

As Pennsylvania State University astronomer James Kasting explains, the importance of this newly found planet lies in its solid surface, its mass compared to that of the Earth, and its position with relation to the star it orbits. Gliese 581 g, which has a 37-day orbit, is located at enough distance from its star as to prevent its atmosphere from being too hot to sustain water, yet close enough to prevent it from freezing.
“You're smack dab in the middle of the habitable zone, so that's perfect,” Kasting notes. Gliese 581 g also has a relatively low mass—between 3.1 and 4.3 times that of Earth—which suggests a rocky structure and a relatively hospitable surface potentially capable of hosting life.

Despite the fact that scientists will not be able to probe the atmosphere of Gliese 581 g, its discovery is an astronomical breakthrough, suggesting that planets such as this one may be common and within reach of scientific instruments precise enough to find them. According to researchers Gordon Moore and Greg Laughlin, the pace of discovery of such exoplanets gives room to suggest that the first habitable, Earth-like planet could be discovered soon, even as early as May 2011.

Background: Recent Astronomical Breakthroughs

The discovery of habitable Earth-like planets, a long-time goal for scientists, is a lengthy process in which every step counts. Recent years have brought a series of breakthrough discoveries that bring us closer to the discovery of other habitable planets in space.

In March 2008, NASA discovered methane in the atmosphere of HD 189733 b, a planet in another solar system located 63 light years away from Earth. Even though the scorching atmosphere on this planet would make life on it impossible, this discovery opened the doors for the future detection of smaller, cooler planets that could offer an habitable atmosphere similar to that of Earth.

In June of the same year, a team of European astronomers amazed scientists around the world with their discovery of a rare trio of “super-Earths” orbiting HD 40307, a sun-like star 42 located light years from Earth. These rocky planets have up to 10 times the mass of Earth and, as scientists suggested, could have the ability to maintain enough warmth to support life for 35 percent longer than our planet.

In March 2009, NASA scientists paved the way for a 2020 expedition to Jupiter’s moons, Titan and Europa, in hopes of finding new clues in their search for life in space. Within the same tear, Samuel P. Kounaves of Tufts University and his team managed to discover alkaline soil on Mars, a feature that would enable plant growth on the Red Planet. These encouraging findings have given scientists a more solid basis on which to found their hopes for the discovery of other habitable planets in space.

In March 2009, NASA scientists paved the way for a 2020 expedition to Jupiter’s moons, Titan and Europa, in hopes of finding new clues in their search for life in space. Within the same tear, Tufts University professor Samuel P. Kounaves and his team managed to discover alkaline soil on Mars, a feature that would enable plant growth on the Red Planet. These encouraging findings have given scientists a more solid basis on which to found their hopes for the discovery of other habitable planets in space.

In January 2010, NASA announced that its Kepler’s Mission had discovered five new extra-solar planets. Even tough these planets, labeled “roasters,” had extreme surface temperatures due to their proximity to the stars they orbited and their short orbit time span, their discovery allowed scientists to be optimistic about the potential detection of Earth-like habitable planets in a not too distant future.

Reference: Astronomy

The findingDulcinea Web Guide to Astronomy offers a concise background to the science of Astronomy, together with links to astronomy history and news, telescope-buying tips, and how to find the constellations or join an astronomy club.
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