Tag: extra-terrestrial life

The Search for a New Earth

This NASA video updates us on the search for Earth-like planets around other stars. It overviews what’s been found, and outlines some upcoming missions.

The key to finding a planet hospitable to life (as we know it) is finding one with water at the surface. We’ve found large waterworlds that are too large and hot, with “thick, steamy atmosphere[s]”.

We’ve also found Earth-sized planets but they’re, mostly, too close to their stars to support liquid water, and it’s hard to tell what their atmospheres are like because they’re so far away. One of NASA’s upcoming missions, one will look at the light reflected off Earth-sized planets to determine the composition of atmospheres: the technique is called transit spectroscopy, and is based on detecting the emission spectra of the gasses in the atmosphere.

ᔥ Science@NASA ↬ Pale Blue Blog

Gypsum on Mars

Suspected gypsum vein on Mars. Image taken by the Opportunity Rover. Image credit: NASA/JPL-Caltech/Cornell/ASU.

NASA thinks their rover has found veins of gypsum on Mars. If they have, it will be an excellent indication that there was once standing water on Mars — gypsum is usually precipitated in evaporating lakes — and will excite the search for life on Mars.

What gypsum veins on Earth look like: white gypsum veins from Somerset, UK. Image by Ashley Dace. (via Wikipedia)

Beyond Interstellar Space: Finding Earth-Like Planets

Artist's rendering of Keppler 22b, a planet 600 light years away that is in the habitable zone of its solar system. Image credit: NASA/Ames/JPL-Caltech.

The Voyager 1 spacecraft is rapidly approaching the space between the stars, where the Sun’s solar wind is pushed back by the interstellar magnetic cloud.

Voyager approaches interstellar space -- an artist's rendition. Image credit: NASA/Ames/JPL-Caltech

How far will it go? The spacecraft have enough power to last until 2020, when it will be about 20 billion kilometers from the Sun (it’s now about 17.8 billion km away). In 40,000 years it will drift “within 1.6 light years … of AC+79 3888, a star in the constellation of Camelopardalis” that’s about 17.6 light years away.

Consider the 40,000 years it will take Voyager to travel 17.6 light years, and the distance to Keppler 22-b, a recently discovered “Earth-like” planet that’s about 600 light years away.

Keppler 22b's orbit and size compared to Earth's. Image via NASA/Ames/JPL-Caltech.

Keppler 22-b is in the liquid water zone of it’s solar system: far enough away from its sun that water on its surface will not just boil away from the heat, yet close enough that the water does not just freeze solid instead. Liquid water is a key necessity for all life as we know it.

Signs of Water on Mars?

Water is necessary for life as we know it, which is why the search for life on other planets and moons in the solar system has been focused first of all on finding water. NASA now reports signs of water on Mars. Salty water perhaps, and even now there is no direct evidence that it is water and not some other fluid, but this is the first evidence of there being liquid water on Mars today.

The video above explains, and the BBC has a good article.