The issue: Maybe this truly is ‘the beginning of an era’

One astronomer called it “the beginning of an era.”

SCIENTISTS AT the Harvard-Smithsonian Center have identified the smallest, most Earth-size planets yet found outside our solar system.

The discoveries were made by the Kepler space telescope, on a par with the Hubble as one of mankind’s most remarkable scientific instruments for the exploration of space. Since its launch in 2009, Kepler has found 28 planets and identified 2,326 candidate planets waiting to be confirmed.

Not only are the two most recent discoveries Earth-size, they orbit a star, Kepler-20, that is remarkably like our sun. The smaller of the two planets, Kepler20-e, is 87 percent the size of Earth; the other, Kepler20-f, is 3 percent larger. And the planets appear to be rock, rather than the inhospitable gas and liquid of larger planets.

Unfortunately, for the chances of life and habitability, the two planets are well within the Goldilocks zone and have surface temperatures of 1,400 to 700 degrees. The 20-e planet has an orbit of 6.1 days; 20-f of 19.6 days, but even it is 20 times closer to its star than the Earth is to the sun.

Kepler-20 is 950 light years away in the direction of the constellation Lyra. Distance in space isn’t what it used to be. The spacecraft Dawn took off in 2007 and is now 1.7 billion miles away studying the asteroid Vesta even as the craft is preparing to go even deeper into space. But, still, a light year is 6 trillion miles.

FROM 1,200 B.C. when the Babylonians began systematically cataloging heavenly bodies, no one had seen, or been able to prove, the existence of an extra-solar planet — until 1996. At first we discovered mostly gas giants on the order of Jupiter, but then found planets that were smaller and smaller until earlier this month astronomers hit upon a planet with a just-right surface temperature of 72 degrees. However, at 2.4 times the size of Earth, it is likely mostly gas and liquid.

We have gone from 3,000 years to less than 30 days in the search for an Earth twin. That indicates that we are making progress and maybe this truly is “the beginning of an era.”

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