Notes from the wider 'Verse: Who needs terraforming? by 06K64

GENERAL DISCUSSIONS

Notes from the wider 'Verse: Who needs terraforming?

POSTED BY: 06K64
UPDATED: Monday, October 4, 2010 04:53
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Thursday, September 30, 2010 2:51 PM

http://news.yahoo.com/s/ap/20100929/ap_on_sc/us_sci_new_earths

Could 'Goldilocks' planet be just right for life?

By SETH BORENSTEIN, AP Science Writer Seth Borenstein, Ap Science Writer – Wed Sep 29, 7:19 pm ET
WASHINGTON – Astronomers say they have for the first time spotted a planet beyond our own in what is sometimes called the Goldilocks zone for life: Not too hot, not too cold. Juuuust right.

Not too far from its star, not too close. So it could contain liquid water. The planet itself is neither too big nor too small for the proper surface, gravity and atmosphere.

It's just right. Just like Earth.

"This really is the first Goldilocks planet," said co-discoverer R. Paul Butler of the Carnegie Institution of Washington.

[Related: Seven best places to sleep under the stars]

The new planet sits smack in the middle of what astronomers refer to as the habitable zone, unlike any of the nearly 500 other planets astronomers have found outside our solar system. And it is in our galactic neighborhood, suggesting that plenty of Earth-like planets circle other stars.

Finding a planet that could potentially support life is a major step toward answering the timeless question: Are we alone?

Scientists have jumped the gun before on proclaiming that planets outside our solar system were habitable only to have them turn out to be not quite so conducive to life. But this one is so clearly in the right zone that five outside astronomers told The Associated Press it seems to be the real thing.

"This is the first one I'm truly excited about," said Penn State University's Jim Kasting. He said this planet is a "pretty prime candidate" for harboring life.

Life on other planets doesn't mean E.T. Even a simple single-cell bacteria or the equivalent of shower mold would shake perceptions about the uniqueness of life on Earth.

But there are still many unanswered questions about this strange planet. It is about three times the mass of Earth, slightly larger in width and much closer to its star — 14 million miles away versus 93 million. It's so close to its version of the sun that it orbits every 37 days. And it doesn't rotate much, so one side is almost always bright, the other dark.

Temperatures can be as hot as 160 degrees or as frigid as 25 degrees below zero, but in between — in the land of constant sunrise — it would be "shirt-sleeve weather," said co-discoverer Steven Vogt of the University of California at Santa Cruz.

It's unknown whether water actually exists on the planet, and what kind of atmosphere it has. But because conditions are ideal for liquid water, and because there always seems to be life on Earth where there is water, Vogt believes "that chances for life on this planet are 100 percent."

The astronomers' findings are being published in Astrophysical Journal and were announced by the National Science Foundation on Wednesday.

The planet circles a star called Gliese 581. It's about 120 trillion miles away, so it would take several generations for a spaceship to get there. It may seem like a long distance, but in the scheme of the vast universe, this planet is "like right in our face, right next door to us," Vogt said in an interview.

That close proximity and the way it was found so early in astronomers' search for habitable planets hints to scientists that planets like Earth are probably not that rare.

Vogt and Butler ran some calculations, with giant fudge factors built in, and figured that as much as one out of five to 10 stars in the universe have planets that are Earth-sized and in the habitable zone.

With an estimated 200 billion stars in the universe, that means maybe 40 billion planets that have the potential for life, Vogt said. However, Ohio State University's Scott Gaudi cautioned that is too speculative about how common these planets are.

Vogt and Butler used ground-based telescopes to track the star's precise movements over 11 years and watch for wobbles that indicate planets are circling it. The newly discovered planet is actually the sixth found circling Gliese 581. Two looked promising for habitability for a while, another turned out to be too hot and the fifth is likely too cold. This sixth one bracketed right in the sweet spot in between, Vogt said.

With the star designated "a," its sixth planet is called Gliese 581g.

"It's not a very interesting name and it's a beautiful planet," Vogt said. Unofficially, he's named it after his wife: "I call it Zarmina's World."

The star Gliese 581 is a dwarf, about one-third the strength of our sun. Because of that, it can't be seen without a telescope from Earth, although it is in the Libra constellation, Vogt said.

But if you were standing on this new planet, you could easily see our sun, Butler said.

The low-energy dwarf star will live on for billions of years, much longer than our sun, he said. And that just increases the likelihood of life developing on the planet, the discoverers said.

"It's pretty hard to stop life once you give it the right conditions," Vogt said.

(Or, for the more science-y among us:

http://www.nasa.gov/topics/universe/features/gliese_581_feature.html )

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Friday, October 1, 2010 5:36 AM

BYTEMITE

Yep, they found Gliese 581c and Gliese 581d a couple years ago. They're like three or four planets in that solar system they think could be habitable or potentially support life. It is ultra cool.

>_> I'd go.

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Friday, October 1, 2010 6:03 AM

ZEEK

Quote:
Originally posted by 06K64:
Vogt believes "that chances for life on this planet are 100 percent."

I don't see how he can say that. That seems like such a stretch. I don't know how much they know about the planet, but that article didn't say anything about water or an atmosphere. Even with those I'd think it would only be a stepping stone for us to try to understand how life forms. We may find that it's a crazy freak occurrence like lightning striking the exact right grouping of molecules to create a single cell which needs to be in the right environment to survive and multiply. It could be like 1 in a trillion habitable planets win the life lottery for all we seem to know at this point.

Granted my knowledge comes from my understanding of tv shows and junk, but I haven't seen a definitive explanation for how life began. Without that how can someone be 100% certain that life would spring into existence on another planet?

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Friday, October 1, 2010 10:28 AM

CYBERSNARK

Life is likely on Zarmina because it's in the area where liquid water will form, it's rocky, and because it has enough gravity to allow for an atmosphere. If it has an atmosphere, liquid water, carbon (which it does almost by definition), and energy, it has the ingredients necessary to form amino acids --bonded carbon-based molecules.

(The planet is tide-locked [one face always toward the sun, one face always dark], so if it has an atmosphere, the sunward side would heat up and hot air would convect to the dark side, even as cold air gets pulled sunward. Add some moisture in the air, and you get hemisphere-wide electrical cyclones that make Katrina look like a sunshower --more than enough energy to spark chemical reactions.)

The most basic requirement of life is to convey information --on Earth, we use DNA, constructed from animo acids. Every living thing on Earth is a melody of four notes (adenine, cytosine, thymine, guanine), arranged in different ways. Once these four amino acids materialize and react, what follows is inevitable.

Cut'n'pasting from some of my writing notes:

Most life in the galaxy would tend to be carbon/water-based (like humans). This is because (1) carbon is one of the most plentiful bonding substances in the observable universe (so most reactions end up carbon-based by default), (2) carbon bonds are flexible, allowing for "dynamic" life that can evolve and diversify, (3) carbon-based biomes (i.e., plants) support an oxygen-rich atmosphere, meaning that a sentient species on these worlds can master fire and develop recognizable technology. In other atmospheres, life functions too slowly, or fire cannot burn (leaving many life-forms at a developmental plateau).

Note that, when it first formed, Earth's atmosphere was mostly carbon monoxide and carbon dioxide. The first life on the planet developed in ways that took advantage of that (manipulating CO2 atoms to create energy, producing O2 only as a byproduct) --they were so successful that the atmosphere became mostly oxygen, and new life-forms developed to take advantage of that. Oxygen is unstable (it dissolves into other gasses), so it must constantly be replenished into the atmosphere: if a planet has an oxygen atmosphere, it pretty much guarantees life (because it means that something has to be actively breathing).

Chlorine-rich atmospheres are highly toxic and corrosive, and preclude open flame. Dynamic life is possible on these worlds, but with no fire to develop advanced toolmaking, civilization would plateau at a pre-industrial level.

Nitrogen-rich planets will be mostly desert (insufficient surface water to break down atmospheric nitrogen). Any "water" on the surface would be nitric acid and nitrates, and the atmosphere would be reactive (meaning fire can burn).

Ammonia-based life can only arise on frigid planets (usually a Jovian moon or around a dwarf star). The environment will be corrosive, and fire will not burn. Any life-forms from here will have very slow metabolisms.

Sulfuric Acid-based life-forms could be found on very hot planets --meaning they'd be close to a star. This requires hydrogen and oxygen, which in turn require a massive, metallic planet --meaning very heavy gravity (to prevent the hydrogen-rich atmosphere from being blown away by the star). The atmosphere would be too corrosive and hot for surface metals to form. On the other hand, this world would have enough oxygen to have fire (plus hydrogen, so fire would actually burn far brighter and hotter than on Earth), and life based on sulfuric acid would support earth-like levels of dynamism, possibly leading to intelligence.

Sulfur dioxide-based life can survive on colder (i.e., human-comfortable) worlds. The sulfur-dioxide/nitrogen atmosphere would stifle flame, and sulfur-dioxide breathers would tend to be sluggish and slow to evolve.

Silicon-based life evolves and metabolizes slowly (silicone compounds are more stable than carbon ones), so it requires a very hot/corrosive environment, full of an acid-like solvent (to soften the silicones, allowing mutation to take place). Silicone "respiration" would leave solid byproducts, meaning that a silicon-based lifeform would constantly be extruding anything from fine powders to large chunks of carbon. The rubbery, starfish-like Horta from Star Trek is actually a fairly accurate reflection of what a silicon-based lifeform could look like.

Crystalline life is carbon-based (crystals are formed from carbon), and arizes in highly-pressurized environments, like deep within a planetary crust or mantle, or on the surface of a neutron star (or in a controlled laboratory). The atomic structure of the crystal would have to be a spin-ice, with different molecular structures used to convey information akin to DNA (a molecule with four carbon atoms versus a molecule with five carbon atoms --note that Earthican DNA only has four variables, so life doesn't need much. Two notes might be enough).

Many carbon-based life-forms have different chirality (humans possess "left-handed" amino-acids. A handful of Earth species have "right-handed" versions), but this has no effect on gross biology. Most carbon-based life also makes use of biogenic silica, but this is collected from the environment and not an integral part of their biochemistry (just because something might have silicon cells within it doesn't make it silicon-based).

As for humanoid bodies, they actually make a deceptive amount of sense; they're complex enough to handle most natural environments, but simple enough that our brains can operate them (consider how much of a centipede's "brain" is dedicated entirely to coordinating its legs).

All our internal organs are clustered in a specific area (shaped vaguely like a tube because it's the most efficient form for a digestive tract --the other organs can be positioned however they "want," so the digestive tract has to take precedence). All of our sensory apparatus are grouped together on a freely-moving bulb (meaning that we can scan our environment without moving our whole body), which also houses one end of the digestive tract (so that food doesn't leave our gaze before we eat it), and the one organ specifically dedicated to running these sensors and interpreting data. We evolved from four legged beings (with limbs spaced at the front and back to better support our bodies), four legs being the perfect number for stability, flexibility, and simplicity (fewer legs impair rapid movement, more legs take more brainpower to coordinate). These ancestors learned to walk upright (raising the end with our head so that we could scan further away), and our forelimbs evolved into convenient manipulators (close enough to our heads that we could see them, and positioned to reach [i.e., protect] our entire torso and head as needed --shoulders at the side means that we can reach behind us to protect our back). Walking on our heels means that our legs can rest straight --not very good for running, but very energy-efficient at rest or for carrying weight (suggesting that carryin' stuff and standin' around was an evolutionary factor

). A vertically-positioned body is also compact --we can stand close together and turn around in only as much space as we take to stand, with no worries about counterbalancing tails or swinging heads.

-----
We applied the cortical electrodes but were unable to get a neural reaction from either patient.

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Saturday, October 2, 2010 12:37 PM

LEMMING

Nice summing up, but the biologist in me winced at the DNA nucleotide bases being described as amino acids. DNA of course (via mRNA, tRNA and ribosomal RNA as the site of the process) *codes* for amino acids. Each triplet (codon) of DNA bases can code for one of the 20 normal amino acids which build up into peptides and proteins via the transcription process (some amino acids have more than one codon, other codons represent "start" or "stop" for transcription)....

:-)

Yep, the latest developments in exoplanet study are facinating, mainly for what they hint at might still be there to discover - if we've only just found the first, imagine how many more there may be with even better situations for producing life on the carbon/liquid water based model.

Nick

The Signal < www.serenityfirefly.com>

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Sunday, October 3, 2010 10:39 AM

CYBERSNARK

I stand corrected. Point was, though, that it's just chemistry on a physical basis; if there's chemical reactions, there can be life.

Also, io9 has an interview with the guy who discovered it.
http://io9.com/5653433/the-astrophysicist-who-discovered-zarmina-descr
ibes-life-on-second-earth

Quote:
People thought there'd be hellacious winds. But there have been 3D climate models of tidally locked planets and calculations show there would be high altitude winds like jet streams on our planet. But according to these models, the maximum winds on the surface would be 30-40 miles per hour on the hot side. On the dark side, winds would be 0-10 miles per hour. It would be quite pleasant. The winds would carry heat from the hot side to the cold side in the high altitudes and then the cold winds would come back down over the poles. The winds would circulate on a large scale like on Earth and that would even out the temperature somewhat. Some of that depends on whether it's covered by oceans or continents.

So I stand corrected on the weather, as well.

-----
We applied the cortical electrodes but were unable to get a neural reaction from either patient.

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Sunday, October 3, 2010 10:57 AM

FREMDFIRMA

Even more interesting - chances are, one or more of em is inhabited.

Remember, we caught what seemed to be a coherent, artificial signal coming from that same region.

http://www.dailymail.co.uk/sciencetech/article-1316538/Gliese-581g-mys
tery-Scientist-spotted-mysterious-pulse-light-direction-newEarth-planet-year.html

Which means, we're probably not alone out here...

And that kinda scares me since our "leaders" are just the type to start a conflict for no other reason than they'd be different.

-Frem

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Sunday, October 3, 2010 11:02 AM

LEMMING

Oh no argument there: it seems increacingly clear that even here on Earth That Is, just when we think we've found the most inhospitable environments on the planet, the carbon/DNA/water model allows life not just to exist but often to flourish (e.g. ocean smokers possibly even being a candidate for the origin of this pattern)

So it is not unreasonable to make the assumption that if there are chemicals whose physical characteristics are amenable to the required processes and and a medium (not necessarily water) in which to react with each other, then life may actually be almost inevitable. That's an exciting possibility.

Nick

www.serenityfirefly.com>

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Sunday, October 3, 2010 12:24 PM

AURAPTOR

America loves a winner!

How soon until the Drake equation is ultimately proven ?

"Small moves, Ellie. Small moves."

"The modern definition of 'racist' is someone who is winning an argument with a liberal."

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Sunday, October 3, 2010 1:35 PM

CYBERSNARK

The Drake Equation can't be "proven," it can just (in theory) be solved. Unfortunately, that can't happen until we know several orders of magnitude more about. . . well, pretty much everything.

(The Drake Equation is pretty much useless, really, since it's just a string of undefined variables. At the moment, the most we could possibly do is speculate on most of them --accurate answers would take a complete cartographical scan of this galaxy at least.)

-----
We applied the cortical electrodes but were unable to get a neural reaction from either patient.

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Sunday, October 3, 2010 2:22 PM

AURAPTOR

America loves a winner!

The Drake Equation seems like something that'll never be fully solved, as we may never know all the #'s for the different variables.

Point being, will we make 'contact ' - ever ?

I wonder if 500 years is enough time for us to know, given our technological advances.

"The modern definition of 'racist' is someone who is winning an argument with a liberal."

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Monday, October 4, 2010 4:07 AM

RAHLMACLAREN

"Damn yokels, can't even tell a transport ship ain't got no guns on it." - Jayne Cobb

Quote:
Cybersnark wrote:

...accurate answers would take a complete cartographical scan of this galaxy at least.

I know, let's send the Google Earth Guys!

--------------------------------------------------
Find here the Serenity you seek. -Tara Maclay

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Monday, October 4, 2010 4:44 AM

BORIS

I think I need terraforming...all my bits are starting to disintergrate.

Rose S

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Monday, October 4, 2010 4:53 AM

ZEEK

Quote:
Originally posted by Cybersnark:
I stand corrected. Point was, though, that it's just chemistry on a physical basis; if there's chemical reactions, there can be life.

See right there you made a much better statement than "100% chance". "Can be" is what we seem to know at this point. Saying there "will be" life is just hyperbole IMO.

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