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Living in Circles

June 10, 2015

If ET exists, he probably lives in a solar system that has a lot of planets. That’s the implication of a discovery that astronomers have made about the number of planets in a system and the shapes of the planets’ orbits.

Astronomers have found so many planets orbiting other stars that they’re beginning to see some patterns. One of those patterns emerged from an analysis of more than 400 planets. Scientists found that all the known planets with highly stretched-out orbits reside in solar systems with only one or two planets. In contrast, solar systems with three, four, five, or six planets feature more circular orbits instead.

That’s important, because planets on circular orbits can be good homes for life. After all, we live on a planet whose orbit is nearly circular. As a result of that orbit, Earth’s distance from the Sun doesn’t change much during the course of a year, giving our planet a stable climate.

Circular orbits in other planetary systems could also set the stage for intelligent life — if a planet is the right distance from its star. In contrast, a planet on a highly elliptical orbit can get too hot when it’s closest to its sun and too cold when it’s farthest away — hardly an ideal environment for life as we know it.

So if intelligent beings exist elsewhere in the universe, they probably see other planets in their sky — just as we see Venus, Jupiter, and others in ours.

We’ll have more about exoplanets tomorrow.


Script by Ken Croswell, Copyright 2015

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