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October 8th, 2010

Newly Discovered ‘Goldilocks’ Planet Has Potential for Life


Scientists are always on the lookout for planets with the right conditions for liquid water and life. Now, American astronomers have discovered Gliese 581g, a planet 20 light years away that is the perfect distance from its sun and therefore not too hot and not too cold -— just like porridge Goldilocks found at the home of the Three Bears.

An artist’s rendering shows the newly discovered planet Gliese 581g in the foreground with its parent star in the background.

Scientists Steven Vogt of the University of California and R. Paul Butler of the Carnegie Institution of Washington announced their discovery September 28.

“This is really the first ‘Goldilocks’ planet, the first planet that is roughly the right size and just at the right distance to have liquid water on the surface,” Butler told reporters.

Vogt and Butler found the planet by studying the light from its parent star.  Shifts in the light are caused by gravity from masses (planets) orbiting the star.

Similar to Earth

Similar to the Earth’s rotation around the sun, the Goldilocks planet circles its own red star, known as Gliese 581 (pronounced GLEE-za).  Actually, several planets orbit Gilese 581. The previous five planets found around Gliese 581 were named b to f, making the latest discovery Gliese 581g.

Through complicated calculations, scientists think the surface temperature on Gliese 581g averages about 20 degrees -—similar to Antarctica in the summer -— but an atmosphere could make it much warmer.

Gliese 581g is about 1.4 times as big as Earth, and weighs between three and four times as much.  Unlike our planet, which spins on an axis, Gliese 581g is locked into orbit with one side facing its sun, so one side is always day and the other always night.  It completes a full orbit in 37 days -– so its year is a little longer than our month.

Life needs liquid water

Astronomer Vogt told reporters, “Personally, given the ubiquity and propensity of life to flourish wherever it can, I would say that the chances for life on this planet are 100 percent. I have almost no doubt about it.”

The planet doesn’t have days and nights, Vogt went on, and therefore has very stable temperatures.  If there is water on the planet, it could house chemical reactions necessary for the formation of protein and bacteria that could eventually evolve into more complex life.  “If life can evolve, it’s going to have billions and billions of years to adapt to the surface,” Vogt said.

“Given the ubiquity of water, it seems probable that this thing actually has liquid water. On the surface of the Earth, everywhere you have liquid water you have life,” Vogt added.

Life on other planets?

Scientist Stephen Hawking has warned against seeking alien life, since he believes it’s likely life exists on other planets.”

Scientists still argue about whether the right conditions will result in life.  Paul Davies, a physicist at Arizona State University says that he is struck by how complex even a simple microbe is. He believes life’s origin may be, in effect, a miracle — not technically supernatural, but a one-shot deal.

“I would not be very surprised if the solar system contains the only life in the observable universe,” he writes at the end of his book “The Eerie Silence.”

On the other side of the debate is professor Harold Morowitz, who studies the origin of life at George Mason University. Morowitz sees a connection between the periodic table of elements and the metabolic pathways of every organism.

Recently, physicist and cosmologist Stephen Hawking warned against seeking out alien life. In a series for the Discovery Channel, Hawking said it was “perfectly rational” to assume life exists elsewhere.

However, he believes that if we discover intelligent life, it might not go well for humans.  “If aliens visit us, the outcome would be much as when Columbus landed in America, which didn’t turn out well for the Native Americans,” he said.

Light years away

A drawing shows what solar sails might look like on a satellite. Solar sails are powered by the sun and might someday be a way to speed up space travel.

Even if life exists on the “Goldilocks” planet, it will be a long time until humans make contact because the galaxy is 120 trillion miles away.  Even the current fastest traveling spacecraft, Voyager 1, now leaving the solar system at a speed of about 39,000 miles per hour, would need more than 300,000 years to travel that far.

“The distances are vast, the challenges are extraordinary,” explains Marc Rayman who works on space travel for the Jet Propulsion Laboratory.

“I don’t have any doubt that humankind will eventually have the technology to send spacecraft that distance,” he said, adding, “I have no idea how it will be done.”

–Compiled by Natalie Friedman for NewsHour Extra

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