Earth 2.0



Guest List:

  • David Latham, Astronomer at the Harvard-Smithsonian Center for Astrophysics,
  • Dimitar Sasselov, Professor of Astronomy at Harvard University, director of the Harvard Origins of Life Initiative,
  • Jason Wright, Professor of Astronomy at Penn State, expert in the search for advanced extraterrestrial civilizations,
  • Sarah Rugheimer, PhD student at Harvard University studying the atmospheres of exoplanets.

With hundreds of Earth-like planets discovered over the past few years, it’s fair to say we’re on the verge of finding alien life. Two new programs at NASA hope to find and analyze thousands more of these exoplanets, as they’re called.  Scientists working on the Transiting Exoplanet Surveying Satellite (TESS) and the James Webb Space Telescope say there’s a very real chance of finding extraterrestrial life within the next two decades. So, if we’re about to meet our extraterrestrial neighbors, let’s get to work on some opening lines. What if we’re really not alone?

What’s the news?

The search for exoplanets is heating up — they’ve found 700 exoplanets in the last six months.
Some of them are very strange: There’s Kepler-421b, which has a year that lasts 704 days, the longest on record for a small ‘transiting’ planet. Then there’s a gas giant  that orbits 20,000 times further away from its star than Earth is from the Sun. It takes tens of thousands of our years to go around once.

They’ve found a planet turning around a star in a binary-star system, and another planet in the so-called ‘Goldilocks’ or habitable zone that’s rocky like the Earth but 17 times more massive. For a (growing) list of the most extreme exoplanets, look here.

The big news is that the Milky Way alone contains by NASA’s estimate as many as 100 billion other planets, 10% of which might be in the right zone. This makes it all the likelier that there’s life out there, as astronomers have long suspected. All it took was someone to look using the right equipment.

All this sets up the flashy NASA announcement that we will find alien life in next twenty years. Is that plausible? is the question.

What’s next?

There are two planned telescopic/observational projects that are going to change the exoplanet search fundamentally.

TESS (the Transiting Exoplanet Survey Satellite) will launch in 2017. It’s run out of MIT, with funding from Google. And its mission will be to perform a “whole-sky survey” — covering 400 times more sky than Kepler has — looking at the brightest stars for transiting exoplanets.

Then the James Webb Space Telescope (really the next Hubble) will serve as the big eye in the sky for the foreseeable future after a delayed launch in 2018. It will launch in 2018, with ‘remote sensing’ infrared sight that will allow astronomers on the ground to look for chemical patterns coming off of planets that suggest life.

There’s still a long way to go for positive proof, though — the necessary rocketry and observation technology isn’t even on the books yet.


The search right now is limited to looking for planets at the right size and in the right neighborhood with respect to their star: that ‘habitable zone’.

The astronomer Christopher McKay says we need to look, when we have better instruments, for six components that, found together, are ‘certainly damn interesting’: oxygen, “temperature, water, sunlight, nitrogen, and nothing that will kill” everything. Life like ours depends on the climate control that comes from water, too; astrobiologists are highlighting the importance of a water ocean.

The worries

Stephen Hawking wants us to lay off the search for alien life:

“I imagine they might exist in massive ships, having used up all the resources from their home planet. Such advanced aliens would perhaps become nomads, looking to conquer and colonise whatever planets they can reach… If aliens ever visit us, I think the outcome would be much as when Christopher Columbus first landed in America, which didn’t turn out very well for the American Indians.”

Nick Bostrom says any proof of advanced life anywhere is bad news. The Fermi Paradox implies little communicating life in our neighborhood. That could be because of one of two “Great Filters”:

a) The advent of life is surprisingly rare, and we’re precious!; or
b) All life keeps wiping itself out past a certain point of development, due to machine superintelligence or environmental collapse.

Back to earth: there are now and ever will be funding troubles. Shifting away from SETI and going to what Latham called the long-cut way — “searching for abodes” — made this work more palatable as pure science and less sci-fi. SETI got Senator Proxmire’s “Golden Fleece” award for government spending.

Still, NASA has had to team up with the Canadian and European space agencies to launch the $8.8 billion James Webb telescope. Sarah Seager says the exoplanet search is the test of

whether or not we as a society still believe in building marvelous things and in bearing the costs and disappointments that invariably attend such projects. It is a question uniquely addressed to Americans, for if we do not build the James Webb Space Telescope, no one else will.

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