There are a lot of apps out there. But how many of them might help you save the world from total destruction?

Using the Asteroid Data Hunter app — which is free, and can be used on any desktop or laptop computer — amateur astronomers can analyze images from their back yard telescopes; and if something unexpected shows up, the app offers a way to report it to the Minor Planet Center at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.

The app is based on an algorithm developed in partnership with Planetary Resources of Redmond, Wash., as part of NASA's Asteroid Grand Challenge. Download the app at www.topcoder.com/asteroids.

Critter can survive anything

When we talk about "extreme" animals, the tardigrade takes the cake: Also known as the water bear, the tardigrade is a microscopic critter (just 1.5 mm across, at most!) that can withstand just about anything. The water bear is the clear star of the American Natural History Museum's latest exhibit, "Life at the Limits," which features plants, animals, bacteria and fungi that survive in some of Earth's weirdest conditions.

Rover completes Mars marathon

How long does it take to complete a marathon on Mars? About 11 years and two months if you've got six wheels and a solar-powered battery.

NASA's rover Opportunity crossed the Olympic marathon mark, putting 26.219 miles on its odometer during its 3,968th Martian day. (A Martian day, or sol, is about 39 minutes and 35 seconds longer than an Earth day.) "This is the first time any human enterprise has exceeded the distance of a marathon on the surface of another world," said John Callas, Opportunity's project manager at the Jet Propulsion Laboratory.

Hominids may have coexisted

An ancient hominid known as Little Foot may have lived at roughly the same time as Lucy, another famous human forebear, a study has found.

Discovered in South Africa in the 1990s, Little Foot (named for his tiny feet) was first thought to be about 4 million years old. Now, researchers have concluded Little Foot is 3.67 million years old, about half a million years older than Lucy. If accurate, the new research published in the journal Nature suggests that there may have been many different species of Australopithecus inhabiting a far greater range in Africa than previously thought.

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