Earth's sister in the crosshairs

Apr 20, 2012

Earth’s sister is out there, somewhere, and scientists searching for planets that may support life believe they are closing in on finding just that.

“Maybe this year, maybe next — before 2014,” predicted Harvard astronomer Dimitar Sasselov, head of Harvard’s Origins of Life Initiative and co-investigator on the planet-finding .

Sasselov’s prediction may seem bold to those who have not been following the avalanche of new findings in the search for planets circling other stars. From the barest trickle in the mid-1990s, the discovery of extrasolar planets, or exoplanets, has rapidly increased as astronomers have developed new techniques and deployed new instruments, including the 2009 launch of Kepler, specifically designed to find planets around other stars.

The telescope already has located more than 2,300 candidate planets, of which 61 have been confirmed as actual planets. Researchers using other telescopes have confirmed hundreds more. The emerging picture is of a universe not only rich in planets, but one with millions circling in their stars’ “Goldilocks Zone,” an orbit not too hot and not too cold where liquid water could support the conditions of life. The most interesting of the planets found in stars’ habitable zones are called “super-Earths,” the rocky or water-covered bodies with a mass of up to 10 times that of Earth.

Sasselov explores the emerging science surrounding super-Earths in a book released this year called “The Life of Super-Earths: How the Hunt for Alien Worlds and Artificial Cells will Revolutionize Life on Our Planet.”

In an interview, Sasselov said the idea for the book came from his work on the Origins of Life Initiative and the undergraduate class he co-teaches with Andrew Knoll, Fisher Professor of Natural History and professor of Earth and planetary sciences. The class, “Life as a Planetary Phenomenon,” has grown each year, nearing 400 students this year. The initiative, the class, and the book all examine life and its place in the universe from the perspective of two disciplines that are not normally considered complementary: astronomy and biology.

The book, aimed at the general public and students without a science background, gives a brief history of the investigations that brought exoplanet and origins-of-life research to where they are today and provides a broad outline of the idea that life is part of the natural evolution of planets under certain conditions.

“From that cosmic perspective, one can look at life as a process that can occur in specific conditions in the universe with specific chemistry,” Sasselov said.

Harvard scientists have played a key role in the search for planets around other stars and have done important work concerning the molecules of life and the formation of early cells. Together, experts in the two fields are seeking to understand the geochemical processes and environmental conditions under which life arises in the universe.

Sasselov talks about this new union of biology and astronomy in his book, saying that for the first time researchers are understanding that life, rather than being a rare cosmic accident, layered onto a planet but apart from its physical processes, might actually be part of a continuous process of planet formation and evolution. In this new understanding, life is a natural — and perhaps common — outgrowth of geology, chemistry, and other processes, linked rather than separate.

“We always thought of life as being this odd phenomenon that is on the Earth rather than of the planet,” Sasselov said.

One dramatic example of life as a planetary phenomenon occurred here on Earth billions of years ago when single-celled organisms developed photosynthesis, consuming carbon dioxide in the atmosphere and giving off oxygen to create the atmosphere that we know today.

Astronomers can help biologists by sharing findings from space, Sasselov said. Using advanced techniques, they can determine the composition of ’ atmospheres. Once sister Earths are found, their atmospheres can be examined and those results given to biologists to further inform their search for the conditions under which life began.

By extending his search for new planets to include the search for life, Sasselov said he has refreshed his own work. The new focus has forced him to learn more about biology and chemistry and given him new perspectives on old problems.

“Astronomy didn’t care much about biology. For me, it’s been a great career reinvigoration,” Sasselov said. “You can question a lot of different things when you look at something from a new perspective.”

Explore further: How baryon acoustic oscillation reveals the expansion of the universe

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dogbert
1.4 / 5 (7) Apr 20, 2012
From that cosmic perspective, one can look at life as a process that can occur in specific conditions in the universe with specific chemistry, Sasselov said.


You can say that, you can write a book about it and you can even teach a college level course about it, but the fact remains that we have no (zero, nada) evidence for live beyond this solar system.

I think most people want there to be abundant life in the universe, but wanting it does not cause it to be true.

The search for life is exciting, but presenting our desires as inevitability is not scientific.
kevinrtrs
1.7 / 5 (11) Apr 20, 2012
In this new understanding, life is a natural and perhaps common outgrowth of geology, chemistry, and other processes, linked rather than separate.

One dramatic example of life as a planetary phenomenon occurred here on Earth billions of years ago when single-celled organisms developed photosynthesis, consuming carbon dioxide in the atmosphere and giving off oxygen to create the atmosphere that we know today.

So what they're saying is that life will just spontaneously erupt, given the right conditions. This in strict contradiction to what we actually observe right here on earth. Scientists have now been searching for many decades for ways that this eruption of life can occur but have yet to find any. So for them to stretch the imagination this far is to simply fall into science fiction.
All current biological research clearly point to life having been designed and manufactured; it does NOT arise spontaneously from bare, unassisted chemical interactions.
Birger
5 / 5 (6) Apr 20, 2012
All current biological research clearly point to life having been designed and manufactured


Nope it doesn't. Creationists tend to be sloppy with the truth. See concept of "RNA World" et cetera.
SoylentGrin
5 / 5 (3) Apr 20, 2012
we have no (zero, nada) evidence for live beyond this solar system.


30 years ago, people were saying the same thing about life beyond Earth. Hell, they were saying there is no evidence for *planets* beyond the Solar System.
Now, we have growing evidence for life on Mars, and possibly Encedalus and Europa, as well as catalogs of exosolar planets.
The article says it's only a matter of time before we find a planet out there that is like Earth, not that we have found it already.

Given the number and type of planets we're racking up, and so quickly, to think that Earth still occupies a unique special place in the Universe (or even the galaxy) is rather medieval.
dogbert
1.7 / 5 (7) Apr 20, 2012
SoylentGrin,
The article says it's only a matter of time before we find a planet out there that is like Earth, not that we have found it already.

Given the number and type of planets we're racking up, and so quickly, to think that Earth still occupies a unique special place in the Universe (or even the galaxy) is rather medieval.


To be earth like, a planet must not only be similar in size and composition and inhabit a zone where liquid water is possible, it must have life to give it an earth like atmosphere. A candidate planet with a methane/ammonia atmosphere is decidedly not earth like.

There is currently no indication that life exists anywhere except in this solar system. I hope the universe teems with life. But no human being has any reason to suspect that life exists anywhere else unless we discover life somewhere else.

Assigning a positive probability with zero evidence is not logical.
Lurker2358
1 / 5 (4) Apr 20, 2012
dogbert:

They don't get it.

If you had a super-Earth, and even if it had exactly the same average composition as Earth, there would be serious problems for life.

For starters, the core would be too hot, and obtain critical mass from Uranium and other isotopes, and the planet would probably blow itself apart...but even if that didn't happen, it would take at least 10 times longer for the planet to cool than for earth..

Next, even if you somehow had an Earth-like atmosphere, if it was same composition vs same composition, it would be about 4 atmospheres pressure at the surface.

Not to mention the surface gravity would be so strong most plants wouldn't be able to live, not to mention humans.

Between the atmosphere and the gravity, erosion would be immensely strong and would beat mountains flat in a fraction of the time on Earth. The planet would be a featureless marble, which is a problem, because on Earth weather is caused in part by topography.

...continued...
perrycomo
4.4 / 5 (7) Apr 21, 2012
kevinrtrs .

Do you mean there is a big super daddy designer up in the sky ? Sitting on his throne and now and then working in his lab , to create millions of different sorts of bacteria , viruses or frogs ? And not only for planet earth but for billions of planets in the universe. Why don't you wash the dirt from your eyes and ears? And by the way why should the big daddy in the sky not be a very big and huge mammy in the sky with very big hands ?
Au-Pu
3.9 / 5 (7) Apr 21, 2012
Dogbert, life, where possible, is inevitable but your problemis that it does not have to be anything even remotely like life on Earth.

kevinrtrs you deserve seperate space because you are the greatest argument I have ever encountered against so called creationism/intelligent design. Please keep up the good work?

lurker2358 nonsense. Even our limited experience here on earth shows us time and time again that life is adaptable. Life will adapt to different or changing circu,stances. I think some fellow named Darwin might have written a few words about it. Your negativity almost places you with kevinrtrs, I didn't say it did only almost.
dogbert
1.8 / 5 (5) Apr 21, 2012
Au-Pu,
Dogbert, life, where possible, is inevitable but your problemis that it does not have to be anything even remotely like life on Earth.


I have not sought to define the nature of life elsewhere and agree that if it exists, it may be very different from here. You continue to miss the point on two fronts:
1) The article talks about sister earths. A planet or planets similar to this planet must have similar life processes in order to have a similar atmosphere.
2) You plainly state that life is inevitable. This statement is based purely on desire and fantasy. There is no evidence whatsoever that life exists anywhere but in this solar system and we do not know how it came to exist here. Spontaneous generation of life was discredited many years ago. We simply do not know the answers to these questions. Lacking that knowledge, we cannot rationally talk about the inevitability of life.
bewertow
5 / 5 (1) Apr 25, 2012
All current biological research clearly point to life having been designed and manufactured; it does NOT arise spontaneously from bare, unassisted chemical interactions.


[citation needed]

If ALL research points to this, I'm sure you can find a citation, right?
CardacianNeverid
5 / 5 (1) Apr 25, 2012
But no human being has any reason to suspect that life exists anywhere else -dogTard

There are extremely good reasons to SUSPECT that alien life exists. All you need is some knowledge of physics, chemistry, thermodynamics, planetary abundances, available timescales and a logical mind.

You plainly state that life is inevitable. This statement is based purely on desire and fantasy -dogTard

See above. Why is dogbert so dogmatic? Was it inevitable?

Spontaneous generation of life was discredited many years ago -dogTard

WTF? What do you mean by 'spontaneous', doggie-doo?

Lacking that knowledge, we cannot rationally talk about the inevitability of life -dogTard

Yes we can - again see above, as we do have plenty of knowledge and no roadblocks to say otherwise.