Up@dawn 2.0

Thursday, August 25, 2016

What's so special about another Earth

Charlottesville, Va. — Yesterday, the European Southern Observatory announced that astronomers have detected a planet the size of Earth orbiting our nearest star, Proxima Centauri. We discover hundreds of “exoplanets” every year, but this one is different: It orbits its star at just the right distance so that, in theory, it’s possible it could sustain life. This detection of a “goldilocks” planet so close to our own marks a significant achievement for exoplanet astronomy, the young field devoted to the search for and study of planets orbiting stars other than our sun.

The European Southern Observatory’s news release explains that Proxima Centauri, unlike the other two stars in its system, is a red dwarf, smaller and cooler than our sun. Although liquid water, that all-important life sustaining substance, might exist on the surface of this planet, its 11-day orbit and strong radiation would create a climate very different from Earth’s. Standing on the surface, one would see not the familiar blue sky; more likely, it would be an alien red.

The astronomers are of course well aware of these dissimilarities. Why, then, do they still insist on categorizing this planet as Earthlike? Some fantasize that “another earth” could be a celestial refuge if we end up destroying our own. Another answer is that detecting a planet like ours capable of hosting life brings us one step closer to answering the ultimate question of whether or not we are alone in the universe — the end of our “cosmic loneliness,” as the science reporter Dennis Overbye wrote in this paper.

But today’s announcement will not readily lead to contact with an intelligent alien. This discovery, more than offering a connection between life-forms, is much more about us connecting with what Earth is, as a place and as our home.

Exoplanet astronomy flourished with the 2009 launch of Kepler, a space telescope dedicated to finding exoplanets. At the time, I was a graduate student at MIT studying the anthropology and history of science, in particular the men and women studying planets as close as Mars and as distant as the exoplanets Kepler was rapidly finding. What drove them? Exoplanets are rather insignificant astronomical objects, but I learned how these scientists transformed planets into places and in so doing have populated the cosmos with hundreds of meaningful worlds.

In this community, the ideal is the Earthlike exoplanet. As an exoplanet graduate student once told me, “In the end, we want to find other Earths. We want to find something similar to us.”

In 2008, a group of astronomers reflected on the philosophical implications of such a discovery, writing that it would tempt us “with wild dreams of flight,” and we would “refocus our energies to hasten the day when our descendants might dare to try to bridge the gulf between two inhabited worlds.” The cover of the current issue of New Scientist offers a beautiful, welcoming artist’s rendering of the newly discovered planet orbiting Proxima Centauri. “We’ve found an Earthlike planet around our nearest star,” the cover asks. “Should we go there?”
Dreams of interstellar journeys or contacting alien life overshadow a less sensational but equally meaningful aspect of this discovery: Amid all of the fantastical configurations in the universe, we most desire to connect with a rather unremarkable ball of rock, ice and gas, for the simple but powerful reason that it reminds us of our home. To even claim the existence of an Earthlike planet is also to claim, rightly or wrongly, that we know and understand our planet. Despite a changing climate and an unsettled population, there is some essence of our planet that we can recognize and point to, saying, “that is us.”
When I spoke with astronomers about methods for detecting Earth’s twin, I was struck that what they were searching for was Earth at its most pristine. One reason the search for an Earthlike planet is so compelling is that it is unexpectedly nostalgic. It propagates an imagination of Earth as an ideal, edenic home. This is a planetary home simpler than the one we grapple with on a daily basis; a home that we might fantasize was the planet of our youth.

Describing how exolanet astronomy connects us to our past, an astronomer described for me why her field matters. “People always want to know where we came from, where we really came from,” she said. “Other planets are a big part of answering that question.”

As they say, you can’t go home again. The discovery of the exoplanet orbiting Proxima Centauri will be closely studied in the coming years. I suspect we’ll find a fascinating world, if starkly different from Earth. That doesn’t make the discovery any less exciting or important. But it does remind us that Earth is special. As we peer deeper and with greater acuity into the universe, we are simultaneously forced to appreciate the complexity of all worlds, including our own. nyt

-Lisa Messeri (@lmesseri), an assistant professor of science, technology and society at the University of Virginia, is the author of “Placing Outer Space: An Earthly Ethnography of Other Worlds.”
Postscript. Reality-check: by present propulsion technology, Proxima Centauri is NOT in close proximity. It's 80,000 years away. If that Russian billionaire figures out how to boost those iPhone-size probes to a fifth of the speed of light they'll get there in 20 years. This is less about us getting there, than about us getting excited about our great-great...grandchildren getting there, and in order for that to happen we have to get excited about sustaining this planet, here and now. An Exoplanet Too Far


  1. Gus Simpson10:42 PM CDT

    When we look up at the sky, we aren't just seeing distant lights. We are seeing us. There is a lovely diagram showing that the most prominent elements in our bodies are also the most prominent in stars. We are made of starstuff.

    The search for life elsewhere in the Cosmos might make some feel small and insignificant, but I think it beautifully reveals our symbiosis with it. One of the most mesmerizing things about this discovery is how it allows us to envision Earth as it is - a mote of dust suspended in a sunbeam. Our problems have no bearing in the Cosmic expanse. It's humbling.

  2. H3
    In hearing about this new planet, it gives me hope that one day humans may venture out into the universe and take up residence on a similar planet where we would not have to wear special suits or breathing equipment, where we could survive as we do now on Earth. It also makes me question on why humans were placed specifically on this Earth and in this star system instead of on some other Earthlike planet in another star system. What is us human's mission here? Is it to explore our surrounding world and universe or just merely to continue to exist? My hopes are that one day we find the answers to these questions and i believe that as we continue to find new worlds and investigate what is truly in our universe we may come closer to this answer even though it may take a vast number of years.

  3. Kaite Berry H0111:31 AM CDT

    So excited for this new discovery. Every day we work we strive towards more knowledge and experience, and we've gained a huge piece of that knowledge. This one planet tells us so much data and information, whether or not we use it. So proud of all the scientists who came together to find a planet so similar to ours so far away.

    I'm super excited to see what the cosmos has out there and I just hope that I'm still here to see some of the great discoveries!!

  4. Does the universe end? If so, where does it end? Instead, perhaps it is an infinite space of stars, planets, galaxies, light, time...
    When I look up at the sky, I feel so small that it's spectacularly mind-boggling. There are innumerable possibilities and we have barely scraped the surface. However, with every new discovery, comes a magnitude of vital information to better understand the cosmos.