Exoplanet hunt and SETI

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Profile Spencer

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Message 1612290 - Posted: 11 Dec 2014, 17:08:49 UTC

http://www.space.com/27953-five-billion-years-solitude-author-interview.html

Interesting summary and Q&A about a new book that explores the approach used in the hunt for exoplanets being key to SETI.

If the link doesn't work, the article can be found on space.com and is titled, "In 'Five Billion Years of Solitude,' Author Lee Billings Searches for E.T."

Your thoughts?

Keep on crunching..
Spencer
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Message 1612758 - Posted: 12 Dec 2014, 11:18:45 UTC

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Profile William Rothamel
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Message 1612829 - Posted: 12 Dec 2014, 15:30:55 UTC - in response to Message 1612290.  

I couldn't discern any viewpoint or new ideas from what I read.
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Message 1612847 - Posted: 12 Dec 2014, 16:50:39 UTC - in response to Message 1612829.  

As I read it, his central theme is the discussion around different approaches for searching for exoplanets that might harbour (intelligent) life. He explains the different schools of thought or approaches with hunting for exoplanets:

1.) Searching for "Earth-Sun" analogs - which is expensive and would require further investment in our ability to detect them.
2.) Searching for "Super Earths, orbiting M Dwarf stars", which is easier and less expensive to do.

Since we only know of life on #1, he advocates continued investment to develop the tools required to find those kinds of exoplanets. The challenge is doing that with available resources.. when the easier option is the search for more of the #2 type.

Hope this summarizes well enough. Here's the core of the text on this topic, definitely worth a closer read, as it relates to SETI and where might be best to aim our radio telescopes to listen for ET:

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Space.com: You talked to a lot of scientists looking for exoplanets; what are their hopes for the next 20 or 30 years for the field?

Billings: It's interesting to look at the spectrum of opinion that exists about where we should go in the future. Because there are a lot of different paths we could take.

You have folks like David Charbonneau at Harvard, who makes the very reasonable, pragmatic argument that we should no longer pay much attention, in the near-term future anyway, to Earth-sun analogs, and we should instead focus the vast majority of our efforts on finding and studying super-Earths around M dwarfs.

[Editor's Note: Super-Earths are planets slightly larger than Earth but significantly smaller than gas giants like Neptune. M dwarf stars are significantly cooler and smaller than stars like our sun but are still hot enough to create habitable climates for orbiting planets. Super-Earths have been found in the habitable zones of their M dwarf stars (a region where the planet could have a surface temperature suitable for life).]

[Focusing on super-Earths around M dwarfs] makes a lot of sense from the viewpoint of having a flat or declining budget and just not being able to really push the envelope. It is easier to go out and study these systems. Finding and studying an Earth-twin around a sun-like star is much harder. So hard, in fact, that we haven’t done it yet. People forget in all the excitement over the recent explosion in exoplanet discovery rates that we still have not found any planet the size or mass of Earth in the habitable zone of a sun-like star.

All that said, I would bet against a strict focus on M dwarf super-Earths being a viable long-term strategy in the search for life beyond the solar system.

Space.com: Why would you bet against that? If M dwarf super-Earths are easier (hence, cheaper) to find, why not go after them as hard as we can?

Billings: I’m worried about the habitability of these planets, and I’m not alone in those worries.I'm not saying M dwarf super-Earths wouldn't be habitable, they just have a big unknown factor. We have no examples of super-Earths in our own solar system. We don't orbit an M dwarf. There are good reasons to think those planets have very different histories and environments than our own. So if your goal is to go find habitable planets, then to pin your hopes on this thing that's so different from your actual experience is pretty risky. Even though it's seen as the safe option because it's so easily achievable.

I think you could actually make the argument that it's riskier [compared] to an Earth-sized planet around a sun-like star, because we could easily have so much more trouble interpreting what we see, if we are fortunate enough to actually see [the super-Earth] atmospheres in the near future.

In one of the chapters of the book, I describe an important meeting that was organized by Sara Seager, a planetary scientist at MIT, called "The Next 40 Years of Exoplanets." At the meeting there was a great confrontation between David Charbonneau, who is all about M dwarf super-Earths and transit studies, and Geoff Marcy, who is kind of the dean of exoplanet detection and studies in America. Marcy said, 'No, we need to go for a bigger sample, we need to go for Earths around suns, we need to go for direct imaging, and we also need to do that with [technology] that ultimately give you the kind of high-resolution imagery that you need to answer important questions about a faraway planet's environment.' And so it's this great kind of tension. And I'm definitely more in that latter camp. I personally think it makes more sense [to look for Earth-sun analogs]. It also costs a lot more money. It's expensive. So you need more political weight to do that.

Space.com: I feel like the tone of the book is both very excited about what scientists are going to discover in the near future, but there's also feelings of frustration, and a fear that maybe the people asking the questions today won't be alive to learn the answers. Am I just focusing too much on the melancholy aspects?

Billings: No, that’s an accurate takeaway from the book. You have to remember, I started the project when the near-future of exoplanet studies was relatively bright, certainly brighter than it is right now. I began it back in 2007 before the financial collapse and the government bailouts and all that. People were still talking about launching a Terrestrial Planet Finder, a space telescope that could seek out and image Earths around a representative sample of nearby stars, sometime in the next decade or so, certainly in the 2020s. Now, no one at NASA really talks about doing that until sometime in the 2030s at the absolute earliest. The way things are going, this sort of thing could easily be deferred until the 2050s, or simply become nothing more than a frozen, half-remembered dream. Watching all that potential and momentum crumble and drain away was shocking and saddening.

But, you know, things are still very bright. The fact that the James Webb [Space Telescope] is going to be going up in 2018 and that we're going to try to use it to access and study the atmospheres of a handful of transiting M dwarf super-Earths is really, really exciting, and that's great.

I just think we should keep pushing and that we shouldn't settle. So as great as this amazing golden age is for all of astronomy, it could go away in the future without sustained support and public interest, and sound policy planning and execution. We need to keep pushing. We can't just settle for “good enough.” I think that this quest for extraterrestrial life, whether within or beyond the solar system, is so profound and exciting and important that it can actually sustain a lot of other investment and development in many other areas of space science. Because I feel like it's something that everyone has interest in.

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Cheers,
Spencer
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Message boards : SETI@home Science : Exoplanet hunt and SETI


 
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