Astronomers’ New Tricks for Finding Alien Life

What’s the Latest Development?

Astronomers at the European Southern Observatory have come up with some clever tricks to know if there is life on one of the thousands of recently discovered exoplanets, i.e. planets outside our solar system. One technique, called Earthshine, looks at how starlight refracts from a planet onto its moon. In Earth’s case, the planet’s surface reflects sunlight back at the moon but that light is altered by vegetation, the presence of water and our atmosphere. By measuring the light refracted from an alien moon, we might know if life-sustaining chemical elements are present on an alien planet. 

What’s the Big Idea?

Another trick measures light polarization, or how vibrations of light waves change as they pass through different chemical elements. In our case, sunlight vibrates outward toward the Earth in all directions but after passing through Earth’s clouds, water and vegetation, the light vibrates in distinct directions which scientists could compare to alien planets. Other potential sources of alien life could be discovered by SETI’s radio antennae, which is now asking citizen-scientists to analyze its data, or the Mars Rover currently on its way to look for ancient microbial life beneath the surface of the red planet. 

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