An astronomer ranks her top 10 places to search for extraterrestrials.

The truth may be out there, but without a good guidebook, you may never find it.

Researchers probing the universe for signs of extraterrestrial intelligence got their treasure map this week. It came in the form of a list of 10 stars likely to be at the center of planetary systems that could support life.

Margaret Turnbull, an astronomer at the Carnegie Institution, picked her top 10 from a catalogue of 17,129 potentially life-supporting solar systems that she assisted in compiling in 2003.

“What I needed to do was think about the characteristics of the sun that make it such a great host for us,” Turnbull said. “We’ve had this planet with liquid water on it for billions of years, long enough to have life evolved to the point where it’s got civilization and radio telescopes and is capable of communicating between the stars.”

Turnbull evaluated the candidate stars based primarily on their ages, sizes and chemical make-ups: A star had to be old enough to have developed complex, at least three billion years old. The stars chosen are all relatively small in mass—less than one and a half times the mass of our sun—so that they may survive long enough to allow life to evolve; larger stars tend to burn out quicker. The stars also need to have high levels of iron in their atmospheres, which indicates that the nebulae in which they were formed contains sufficient amounts of heavy metals necessary to foster planets.

While Turnbull has no way of knowing what the planets in her top solar systems actually look like, she is confident that they could, under the right circumstances, sustain life. She expects, however, that extraterrestrial life may first be found in our own solar system. The planet Mars and Jupiter’s moon, Europa, are frequently mentioned as potential hosts of organisms, the latter due to its large oceans of water.

“It’s probable that [Europa] has hydrothermal activity at the bottom of the oceans, just like ours do,” said Turnbull. “Those hydrothermal vents could very well support all kinds of life forms, maybe even big animal life forms like what we see around the vents at the bottom of our oceans.”

Dimitar Sasselov, director of the Harvard-Smithsonian Center for Planetary Astrophysics, called Turnbull’s work “timely.”

“It is important to revisit our lists of best nearby neighborhoods every few years and see what has changed in our knowledge about them,” he said via e-mail. “Great habitable places are hard to find in the universe.”

At the moment though, astrobiologists are finding NASA to be an uninhabitable place, Turnbull said. On January 14th, President Bush promised to send a man to Mars by 2020, but he did not allocate sufficient funds in his 2007 budget to make this financially possible. NASA has scrambled to divert money from, among other places, its Astrobiology Institute. As part of the shake-up at the space agency, G. Scott Hubbard, the director of the NASA Ames Research Center, where the Astrobiology Institute is based, left at the end of January to join the SETI Institute.

While the 2007 budget is still pending approval in Congress, scientists who study life in outer space may come up short.

Originally published February 27, 2006

Tags

Share this Stumbleupon Reddit Email + More

Now on SEEDMAGAZINE.COM

  • Ideas

    I Tried Almost Everything Else

    John Rinn, snowboarder, skateboarder, and “genomic origamist,” on why we should dumpster-dive in our genomes and the inspiration of a middle-distance runner.

  • Ideas

    Going, Going, Gone

    The second most common element in the universe is increasingly rare on Earth—except, for now, in America.

  • Ideas

    Earth-like Planets Aren’t Rare

    Renowned planetary scientist James Kasting on the odds of finding another Earth-like planet and the power of science fiction.

The Seed Salon

Video: conversations with leading scientists and thinkers on fundamental issues and ideas at the edge of science and culture.

Are We Beyond the Two Cultures?

Video: Seed revisits the questions C.P. Snow raised about science and the humanities 50 years by asking six great thinkers, Where are we now?

Saved by Science

Audio slideshow: Justine Cooper's large-format photographs of the collections behind the walls of the American Museum of Natural History.

The Universe in 2009

In 2009, we are celebrating curiosity and creativity with a dynamic look at the very best ideas that give us reason for optimism.

Revolutionary Minds
The Interpreters

In this installment of Revolutionary Minds, five people who use the new tools of science to educate, illuminate, and engage.

The Seed Design Series

Leading scientists, designers, and architects on ideas like the personal genome, brain visualization, generative architecture, and collective design.

The Seed State of Science

Seed examines the radical changes within science itself by assessing the evolving role of scientists and the shifting dimensions of scientific practice.

A Place for Science

On the trail of the haunts, homes, and posts of knowledge, from the laboratory to the field.

Portfolio

Witness the science. Stunning photographic portfolios from the pages of Seed magazine.

SEEDMAGAZINE.COM by Seed Media Group. ©2005-2015 Seed Media Group LLC. All Rights Reserved.

Sites by Seed Media Group: Seed Media Group | ScienceBlogs | Research Blogging | SEEDMAGAZINE.COM