Day 83: Kepler and ‘Blood Falls;’ lookin’ for life in all the wild places

Blood Falls at Taylor Glacier in Antarctica. Photo by Peter West/ NSF; ©Copyright Arizona Board of Regents.

Just a taste ... That center panel is Kepler's whole field of view, including millions of stars. Details below! Credit: NASA/Ames/JPL-Caltech

What does Antarctica have to do with a mission to search for Earth-like planets around other stars?

Maybe not much, usually. But yesterday, NASA’s Kepler mission sent back its first images of the patch of the Milky Way where it will stare for the next three-plus years, hunting for planets in the habitable zones around other stars. And today, Arizona State University issued a press release about researchers who discovered microbes in “Blood Falls,” Antarctica. The little beasties are hidden in briny liquid in a cold, dark, oxygen-poor environment — a “most unexpected setting to be teeming with life.”

Finding life on Earth that thrives in unexpected conditions is exciting enough, but it also might help us know what clues to look for on on other planets — for example, the planets Kepler will find, 13,000 light years away.

The Antarctica study was led by Jill Mikucki, an apparently cold-loving geobiologist at Dartmouth College in New Hampshire. Mikucki and her team sampled Blood Falls, a water-fall-like feature at the edge of the glacier that flows irregularly, but often has a strikingly bright red appearance in stark contrast to the icy background.

Image courtesy of Benjamin Urmston

Taylor Glacier is an outlet glacier of the East Antarctic Ice Sheet. The lack of light underneath makes the process of photosynthesis improbable, causing researchers to wonder how organisms found below the glacier could survive.

The research, which appears in the journal Science, suggests that over the past 1.5 million years, the microbes have adapted to manipulate sulfur and iron compounds. Instead of using sunlight for food and energy like photosynthesizing plants do, the microbes get their energy by converting iron from one form to another.

Genetic analysis suggests that the microorganisms are more similar to those found in an ocean than on land, but capable of surviving without the food and light sources available in the open ocean. The researchers are proposing that the ancestors of the microbes probably lived in the ocean many millions of years ago. When the floor of the surrounding landscape arose more than 1.5 million years ago, a pool of seawater from the fjord that penetrated the area was trapped. The pool was eventually capped by the flow of the glacier.

The briny pond “is a unique sort of time capsule from a period in Earth’s history,” Mikucki said. “I don’t know of another environment quite like this on Earth.” If you want to know more about her discovery, the full press release is here (thanks, Eurekalert!) and you can see the abstract in Science, though they’ll ask you to pay to see the whole paper. 

Moving on — er, out! — to a region of the Milky Way that includes the constellations Cygnus and Lyra …

In one of its first images, released yesterday, the Kepler spacecraft revealed an eight-billion-year-old cluster of stars 13,000 light-years from Earth, called NGC 6791. The area pictured is 0.2 percent of Kepler’s full field of view, and shows hundreds of stars in the constellation Lyra. 

Image credit: NASA/Ames/JPL-Caltech

The image has been color-coded so that brighter stars appear white, and fainter stars, red. It’s a 60-second exposure, taken on April 8, 2009, one day after the spacecraft’s dust cover was cast off. 

Kepler is trailing Earth in orbit, where it’s clear of Earth’s artificial lights. The $500 million mission will spend its life surveying more than 100,000 sun-like stars in the Cygnus-Lyra region of our galaxy.  Its telescope is specially designed to detect the periodic dimming of stars that planets cause as they pass by. Once it detects them, it can collect clues about the planets’ orbits and atmospheres (where chemical traces could indicate the possibility of life).

Astronomers estimate that if even one percent of stars host Earth-like planets, there would be a million Earths in the Milky Way alone. If that’s true, hundreds of Earths should exist in Kepler’s focus population of 100,000 stars. 

So, ya wanna see that whole field of view again?

Image credit: NASA/Ames/JPL-Caltech

NGC 6791 and a star with a known planet, called TrES-2, are outlined here. TrES-2 is a hot Jupiter-like planet known to cross in front of, or transit, its star every 2.5 days. Kepler will hunt for transiting planets that are as small as Earth. 

I blogged about Kepler when it first lifted off, on March 6. And for the most extensive information (and more first-light photos), check out the press release at NASA.