Saturday, December 22, 2007

Terrestrial Planets Forming in the Subaru!


© Lynette R. Cook, for Gemini Observatory.
In the Pleiades (known as Subaru in Japanese - yes, the car company is named for it), astronomers have discovered evidence of terrestrial planets forming, or having recently formed, around two young (100 - 400 million years old) stars in the Pleiades cluster.
"This is the first clear evidence for planet formation in the Pleiades, and the results we are presenting may well be the first observational evidence that terrestrial planets like those in our solar system are quite common," said Joseph Rhee, a UCLA postdoctoral scholar in astronomy and lead author of the research (UCLA, par. 3).
The Pleiades is a young open cluster 400 light years away. Some scientists feel that our Sun was formed in an open cluster as well; stars in an open cluster tend to wander from the "nest" as they age. So, we may see the beginnings of home worlds for future Subaruians (Pleiadians?).

Reference:

UCLA News Results. "Planets found forming in Pleiades star cluster." SpaceFlight Now. 15 November 2007. 22 December 2007. <http://spaceflightnow.com/news/n0711/15pleiades/>

Thursday, December 20, 2007

Christmas on Omicron Persei 8

During this time of year, my thoughts turn philosophically, sentimentally deeper toward several things: family, the past, spirituality and, of course, life on other planets.

For family, this time of year means additional sentimental thoughts partly because, for the Northern hemisphere, the weather is growing colder, and the nights darker and longer, and so our hearts instinctively look to shorten the distances between loved ones to increase warmth, security, and hope.

For the past, at this time of year, with the New Year approaching, it is a time that we begin to realize that another year has gone, and we begin to look back and take stock of what has happened - sometimes with happiness, sometimes with new knowledge realized, sometimes with anger, sometimes with regret, and sometimes with sadness. If used right, it is a time of extra growth.

For spirituality, this season has strong, and many times somewhat similar, religious meanings for many of the world's theologies. This is in large part because, again for the Northern hemisphere, the Winter solstice brings not only the longest night of the year, but the knowledge that the days will now begin to lengthen again - the Sun returns, and with it renewed warmth and energy filled life. It is the promise of Spring. It is the promise of rebirth, renewal, and resurrection that we rejoice in and are thankful for. It is the promise of death conquered. And connected with looking back to the year that was, and looking close to loved ones, it is a time of year to be thankful yet again for the blessings that loved ones, that love, brings (though for those struggling with a bad year, with abandonment, it can be a very dark time of year indeed).

Of course, too often all of this is ruined by crass commercialism, by the pressures and stresses of false and shallow meanings that have been attached to the season. But that is a topic for other blogs.

For life on other planets, I wonder how they would treat a solstice on their planet? To be high level sentient does one have to be a pattern seeker, to look for the meaning and/or reasons for the patterns? If so, then such sentient beings would see the pattern of solstice and equinox as even our distant ancestors did (from even before Stonehenge) and work to apply a meaning or reason to the pattern (for to find meaning or reason is to find purpose and to be able to make predictions, and maybe even gain some control over - or at least the illusion/delusion of some control).

This, of course, depends on many factors which would affect the severity, or the placidness, of annual weather patterns. Is the planet in a very circular orbit, or a somewhat elliptical one? Is the planet close to its star, and thus with a very short year? Is the planet actually a large habitable moon circling a gas giant? Is there a virtually non-existent tilt to its axis or it is a large tilt? And what of these combined?

If, for instance, the planet is in a very circular orbit, at a close orbit (a red dwarf, for instance, would have a habitable zone much closer to it than a normal G-type star like our own Sun), and with virtually no tilt to its axis, such a planet may have very little differences between its seasons - and seasons that come and go quickly (smaller orbit means, usually, a shorter year). If a longest night is very quickly followed by a longest day (weeks later, i.e.), would there be as much imperative to celebrate the return of the sun's dominance in the sky?

For a planet-moon circling a gas giant, the sun could disappear for days at a time before returning to a "regular" schedule.

Or if the planet-moon is phase locked with its parent gas giant planet, then for the time it is behind the planet there would be, for the far side of the planet-moon there would be constant darkness until the planet-moon came out from behind the gas giant; but then the sun would rise and stay in the sky as it slowly arcs to the opposite horizon as the planet-moon orbits in front of the gas giant. On such a world, a short winter may cover the entire globe while in the shadow of the gas giant, and summer cover the entire globe while in front of the gas giant with extremely short springs and fall at the point the planet-moon is over the terminator line of the gas giant (the line where day and night on the gas giant meet, where one begins and the other ends). Maybe the world's sentient race would view their world as more of a unity than we view our own as on Earth the Northern and Southern hemispheres experience direct opposite seasons at the same time, while on this hypothetical world, both hemispheres experience the same season at the same time.

Anyway, back to the long day and long night, a primitive sentient mind may see that as a mighty heroic epic struggle between day and night. Though if a non-aggressive sentient species, say a slow moving herbivore species on a cool planet, maybe the day and night would represent a sort of "wheel of fortune" - first good luck (sun, warmth, plants taking full advantage) and then bad luck (days long darkness, worsening cold, plants folding up waiting for the sun)?

Additionally, there would be no solstice like we have - there would be no gradual shortening of the night - just one long night, and then one long day, each individual night as long as the night before, separated by an equally long day. Essentially, they would be in eternal equinox. Spring would be morning, summer would be the day, fall would be the evening, and winter would be the night - if you wanted to give them seasons. It may be more accurate to say such a world would have no real seasons at all, only the kind of "seasons" any day-night cycle would have.

If, instead, the planet-moon did have a noticeable tilt to its axis, and a non-circular orbit around its parent gas giant planet, which itself had a non-circular orbit around the central sun, or if the parent planet had a noticeable tilt to its axis with the planet-moon orbiting directly over the parent planet's equator, then the planet-moon, while still retaining non-changing lengths to its day and nights, would gain true seasons. The sun would arc over the sky differently through out the parent planet's year - while the planet-moon's year is the time it takes to orbit around the gas giant, the gas giant has its own year as it orbits its sun.

On such a world, a season would not be different parts of the planet-moon's year, but would be seen year to year. A number of years would be Spring, while another number of years would be Summer, and so forth, repeating itself. What a different kind of zodiac such a world would have! In some ways, it would be similar to a Chinese zodiac calendar (the year of the horse, the year of the dog, etc), except each zodiac would cover a span of years. Their zodiac could contain a zodiac within a zodiac within a zodiac.

Solstice on such a world may not represent so much the return of day, since it is possible that the day and nights would not change in length from year to year, but could represent the point where Winter is half over and thus the return of Spring begins. And maybe, just maybe, the celebration would be a whole year (for the planet-moon).

Of course, this is supposing that all higher level sentient beings feel, in an emotive sense, for in some ways spirituality, and especially sentimentality, depends upon emotion more (at least at times) than reason. Is emotion necessary to higher level of sentience? It seems on Earth, at least, the higher the level of sentience, the more emotion the creature seems to have.

But this is a topic for a future blog.

Comments? Feel free to comment on any post in this blog. Please feel free to disagree with me (just do so respectfully please - even if you think I sin in any or all of my opinions, please recall, if you are Christian, Jesus' attitude toward the adulteress: while he was against what she did, he did not condemn her, and turned away those who would stone her).

Happy Holidays to you and yours (and even to Lrrr, Ruler of Omicron Persei 8, and his wife Nd-Nd. And what the heck, to Robot Santa too!*).

* If Lrrr, Nd-Nd, and Robot Santa mean nothing to you, you need to run, not walk, to the TV and catch an episode of Futurama.

Wednesday, December 19, 2007

Hazy red sunset on an extrasolar planet...


© NASA, ESA, & G. Bacon (STScI)
From a 11 December 2007 press release from the NASA/ESA Hubble Space Telescope reported by SpaceRef.com

A team of astronomers have used the NASA/ESA Hubble Space Telescope to detect, for the first time, strong evidence of hazes in the atmosphere of a planet orbiting a distant star. The discovery comes after extensive observations made recently with Hubble's Advanced Camera for Surveys (ACS).

The team, led by Frederic Pont from the Geneva University Observatory in Switzerland, used Hubble's ACS to make the first detection of hazes in the atmosphere of the giant planet. "One of the long-term goals of studying extrasolar planets is to measure the atmosphere of an Earth-like planet, this present result is a step in this direction" says Pont. "HD 189733b is the first extrasolar planet for which we are piecing together a complete idea of what it really looks like."

The exciting aspect of this is, of course, the increased possibility that astronomers may, within years, measure the atmosphere of a planet that bears life - and life will leave its mark on any atmosphere. While not cold, hard, definitive proof of life (even then, some folk would just refuse to accept), it would be exciting evidence.

For a "Hubblecast" video of this new find, and more info on "hot Jupiters," visit <http://www.spacetelescope.org/videos/vodcast/heic0720a.m4v>

Reference:

"Hazy Red Sunset on Extrasolar Planet." SpaceRef. com. 11 December 2007. 19 December 2007. <http://www.spaceref.com/news/viewpr.html?pid=24244>

"Heic0720: Hazy Red Sunset on Extrasolar Planet." News and Photo Releases. The European Homepage for the NASA/ESA Hubble Space Telescope. <http://www.spacetelescope.org/news/html/heic0720.html>

Sunday, December 16, 2007

Alien Safari!


© NASA, JPL
Alien Safari, from NASA's JPL can help you "Discover some of the most extreme organisms on our planet, and find out what they are telling astrobiologists about the search for life beyond Earth" (Alien Safari, par. 1).

The Safari includes the weird methane-ice worms found deep 80 miles off the coast of Louisiana. Life finds a way yet again! Though, to be fair, this doesn't necessarily mean that life can originate everywhere, just that life, once established, is tenacious and difficult to get rid of (you can, unfortunately, eliminate individual species easily, but getting rid of life entirely is extremely difficult). So it may bode well for terraformers more than for those searching for alien life. However, I still bet on life being rather common in solar systems.

Alien Safari destinations:
  • Living Without Sunlight
  • Highest Radiation Dose
  • Most Acidic
  • Farthest Underground
  • Strangest Habitat
  • Hottest
Reference:

"Alien Safari." Planet Quest. Jet Propulsion Laboratory. 16 December 2007. <http://planetquest.jpl.nasa.gov/AlienSafari_launch_page.html>

Keep Track of New Worlds: PlanetQuest 2.0

PRESS RELEASE
Date Released: Thursday, November 29, 2007
Source: Jet Propulsion Laboratory

More than 260 planets have already been discovered orbiting other stars, and new ones are found almost every month. Having trouble keeping track? Help is on the way.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., has revamped its award-winning PlanetQuest website with improved tools to help users stay on top of the latest discoveries, at http://planetquest.jpl.nasa.gov.

PlanetQuest 2.0 features include:
  • The Visual New Worlds Atlas: A continuously updated database of extrasolar planets, with star images, planet system visualizations, and graphics comparing other planets to those in our own solar system.

  • Desktop planet counter: Install this widget for your PC or Mac and keep up with the current tally of newly-discovered planets.

  • Enhanced multimedia gallery: Games, movies and simulations immerse you in the world of interstellar exploration.

  • Map of planet hunters: Interactive global view of scientists and techniques involved in searching for another Earth.

JPL is part of NASA's ongoing program of searching for planets around other stars, particularly those that might be Earthlike and potentially hospitable to life.

JPL is a division of the California Institute of Technology in Pasadena.

Reference:

"Keep Track of New Worlds: PlanetQuest 2.0." SpaceRef. 30 November 2007. 16 December 2007. <http://www.spaceref.com/news/viewpr.nl.html?pid=24145>

Tuesday, December 11, 2007

Once In A Blue Moon: Earth's Moon Even More Rare?

Yet more evidence suggests that a moon like ours is rare. Oh, moons are found aplenty around planets, but they tend to be rather small in comparison to the planet they orbit, and most of them are captured. Our Moon, however, was not captured, and is very large in comparison to the Earth. The ratio of the difference in size is so small that some astronomers propose calling the Earth-Moon system a double planet system.


Around 4.5 billion years ago, a large Mars-sized planet collided with the Earth in such away that part of the Earth's mantle was thrown into space. The Mars-sized impactor was absorbed by the Earth, it's iron core joining the Earth's. It also increased the Earth's spin. Most of the section of mantle that was thrown into space coalesced quickly into the Moon (may have taken as little as a year). The rest of the debris that was "kicked up" by the collision, and which did not coalesced, continued to circle the sun for millions of years before gravity and solar radiation cleaned it up.

Again, why is this important information, and included in this blog?

Well, as reported before in this blog (Astronomers Say Moons Like Ours Are Uncommon - How Important is That?), some scientists feel that the Moon was essential to the origin of life on the Earth due to the tidal mixing which helped to mix, mainly from erosion caused by the tides, chemicals from the soil with the oceans, creating the chemical soup from which life arose. This is especially true for the young Earth when the Moon was closer and had a much more dramatic effect on the tides. Only 1/3 of the today's tidal effects is attributed to the Sun, the rest to our Moon.

In the original report, it was stated that maybe only 5 to 10% of planets would a moon like Earth's. However, a new report by Nadya Gorlova of the University of Florida in the November 2007 issue of The Astrophysical Journal, states that the percentage may even be smaller: 1 in 400. As reported by Physics News:

Using the cryogenically-cooled infrared orbiting Spitzer Space Telescope, Gorlova and her colleagues surveyed the 30-million-year old star cluster NGC 2547. They selected this cluster because of its age. The planetary building process usually ends by approximately 50 million years, making the odds of a giant impact unlikely to occur outside this window. The other advantage of NGC 2547 is that it is old enough for the material left out from the original cloud of
which solar systems formed to dissipate (this takes about 3-10 million years). By focusing on radiation at a wavelength of about 8 microns, they could detect the heat they would expect from dust at a distance of about one astronomical unit (1 AU) from a solar-type star. The NGC 2547 cluster was previously surveyed spectroscopically, so they could cross-check to make sure that the emission they detected was not due to gas (which would be evident by spectral emission lines). Out of about 400 stars in the NGC 2547 cluster, they found only one that showed evidence of dust from a massive impact.
What needs to be kept in mind are 1) this is just one sampling. There may be other factors at play here that, for instance, may have sped up the cleaning of debris after the collision, or otherwise minimized the debris; 2) statistically, an average is not found everywhere - that is, if 1 out of 10 planets, on average, form a Moon like Earth's, you would find some regions where the percentage was higher, and some regions where it was lower; 3) even without the Moon, enough mixing may still occur for life to begin (albeit maybe would've taken longer); and 4) there may be other situations such as a habitable moon orbiting a gas giant - where the tidal effects from the gas giant would be strong enough to mix chemicals on the young terrestrial moon.

Reference:

PHYSICS NEWS UPDATE. The American Institute of Physics Bulletin of Physics News. Number 849 December 5, 2007 by Phillip F. Schewe and Jason S. Bardi <www.aip.org/pnu>

Saturday, December 8, 2007

Life on Water Worlds

No, not the movie of the same name.

Some planets may very well be true water worlds - totally covered in water. Though some, like Gliese 581 C (a "super-earth" 50% larger than the Earth 20.5 light-years away) may have dense water - maybe a thin layer of liquid water on top of compressed water. What sort of life would arise there? Think about it - no dry land, or extremely rare dry land that is easily flooded by storms or tides. Life transitioning to land would not happen, at least not large roaming life which needs territory to grow and thrive on (digression: could high level stationary sentient life ever evolve, I wonder?).

On Earth, life developed limbs and walked out of the seas - large tracts of land allowed for evolution to proceed in that direction. On a planet covered with one giant ocean, that direction would be blocked, unless the poles were cold enough to keep up the continued production of ice floes - then there could be an evolutionary path for living on ice floes part or full-time. Otherwise, any evolutionary development of limbs would go in the direction of underwater ambulation. But how useful is underwater ambulation? As useful as fins on land? And so, over millenia, higher sentient life would evolve totally adapted to the oceans. I don't think they would have just fins - hard to build and use tools without some means of griping and manipulating the physical environment.

That is not to say intelligent life needs a means to physically manipulate the environment, but that the ability to manipulate the environment does allow for greater evolution and progress of the brain, or at least to make it much easier for it to happen.

Maybe on some water world planet, a species of sentient life has evolved that can not manipulate the environment, but they have survived for millenia and so have slowly evolved to be able to do high order abstract thinking - their art, culture, science, and theology would all be based on communication - their only tool left to them; they would manipulate the mental environment. Art would be, for those that communicate via sound, vocal music and oral literature. Science would be based largely on observation and mental experiments (of the kind that Einstein made famous, but that the Greeks did to an extent as well) since they could do little experimenting (some, probably, but not much). They would not less likely to physically explore space, as they would not be able to leave their planet (water is extremely heavy, especially compared to air, lifting a craft full of water out into space would be extremely difficult -albeit not impossible - to do. In addition, making space suits for exploration, especially that of dry surfaces, would be extremely problematic as well). Would they be more likely to become telepathic then? To astrally project themselves? Or is that too "newagey?"

For a large planet with several times greater gravity, a thick ocean may have "normal" water at the top, but definitely, for a thick ocean, water that would become denser quickly the deeper one went - water become plastic, or even solid. We have a slight inkling of that here on Earth - mountain climbers know the air gets thinner as they climb, it is a danger if ignored. For our water world aliens, something similar may be in play.

Depending upon their evolutionary track, if they evolved as deep sea creatures, rising up to the surface may be dangerous - especially if they can not work with tools to create devices to help them breath or deal with the pressure change. Even sea creatures on Earth have ranges - some that live closer to the surface can dive rather deep, but they don't live in the depths. Other deep living creatures tend to stay in the depths, only coming near or to the surface when they are sick or dying (like giant squid) - near the surface is not a friendly environment for them to linger in.

Another thought - would, after millenia, creatures evolve to be like our flying fish? Would the air be conquered there as it has long been here as well by flying creatures? They would have to be creatures that feel at home surrounded by oceans, who do not need land to survive. Probably most likely flying fish like creatures, though maybe one some planets, the flying fish make the evolutionary steps toward fish that fly more than they are fish, and develop lungs and end up spending their lives either floating on the surface (when resting, for instance) and flying.

There are some sea birds on Earth that can live far out at sea, and may spend much of their life out at sea. Such birds tend to glide or soar more than the powered flight. This is because they can take advantage of the wind deflected by waves, and or by ground effect which reduces drag.

Because of convergent evolution (where unrelated species tend to develop similar characteristics due to their sharing similar environments, and due to the fact that the same physical laws apply to all species in the same environment) we can make educated guesses that creatures on other planets will tend to try to be efficient in adapting to their environments just like Earth life. If deflected wind and the ground effect is still in effect on this alien water world, then flying creatures there will glide more than they would use powered flight since the latter uses more energy.

Would these fully pelagic sea bird like creatures be the ones to most likely to become tool makers? They would have, possibly, develop feet (webbed most likely), which could have an opposable digit to help them grip prey (like modern Earth birds) and which could eventually evolve to manipulate tools (as a previous blog entry has noted, some birds, crows most notably, are known to create and use tools, and may be as smart, or even smarter, than a chimpanzee).

Or would the creatures be more like flying fish, or half-bird/half-fish - able to live under water (maybe to nest and breed) as well as live on the water surface and fly over it (to more easily hunt for food - flying through air is faster than flying through water - less dense, less drag).

Though one drawback (to sentient beings) is that on a water planet it would be hard to work with metals - to melt, smelt, and other wise work with metal to create structures and devices that would allow them to eventually explore the stars. Mining ore would be more problematic as well. Water is heavier than air, more dense - it takes more energy to move through it, and probably more difficult to shore up tunnels (not only would they have the weight of the stone above, but the pressure of the water on top bearing down). Light has a harder time penetrating water than it does gaseous atmospheres (sound, however, could travel great distances under water). Working with electricity would be harder. Building telescopes to view the heavens would be harder (though maybe on a planet with rare land, a species that could tolerate the air for short periods could build telescopes on such land - or the avian species, which would have a higher ability to tolerate the air).

On a larger planet, covered with water, how would that affect territorial issues? Would such creatures tend to be more nomadic - especially if they never develop the ability to farm, there is no need to settle down and build cities. Are cities necessary for advancement? Do cities help speed up advancement of civilization, and if they do help (which it does seem like they did for humans), are they the only way? Could nomadic species find their own way to help quickly spur on advancements in civilization? Without natural barriers like mountains, oceans, ice fields, deserts, and large rivers are to humans, would their be less isolation between groups and thus a more "we are one" sort of sentiment develop? Or would groups still develop, some adapting to more colder regions, for instance? (but would this still, in the end, create fewer insulated, insular groups than is the case on Earth?) Would this create a species that would be less xenophobic?

What theology would exist for such creatures? For those on planets with rare land - would the inhospitable land be their version of hell? Or for deep dwelling sentient species, which can not bear being near the lower pressure regions in the upper regions of the sea, would the upper, more lighted, and more dynamic regions be more like hell and heaven more like the darker, heavier, and calmer pressured regions? Would they think all planets are ocean, and that heaven would be a calm ocean? They probably would have some tectonic activity - underwater volcanoes - as well as deep, dark trenches that could play roles in primitive theologies. And for the water bird sentient species, how would their primitive ancestors first think of the world, theologically (I suppose they would love the O.T. verses that describe God as a mother hen).

Two digressions:

1. Would a water world be less susceptible to extinction level events from meteor impacts (no dust to throw up into the air to create a long lasting year round winter that kills off the plant life, no cracking open part of the crust and letting out lava, etc)?

2. There is an article in DVICE.com about the Focus 21 France, a hovercraft prototype that would use the ground effect to achieve helicopter speeds. It would have to fly close to the water to take advantage of the ground effect (a height equal to twice the wingspan or less). I thought that maybe that is how water world sentient species would fly, at least for their earlier flights. Sort of like sub-orbital or low earth orbits for us.

References:

"Astronomers Find First Earth-like Planet in Habitable Zone." ESO. 25 April 2007. 9 December 2007. <http://www.eso.org/public/outreach/press-rel/pr-2007/pr-22-07.html>

White, Charlie. "Focus 21 France uses ground effect to zip above the waves" DVICE.com. 3 December 2007. 9 December 2007. <http://dvice.com/archives/2007/12/focus_21_france.php>

Friday, December 7, 2007

Terraforming Mars

Astrobiology Magazine has a neat (OK, neat for space geeks) online interactive program that allows you to "Build a Virtual World" by playing around with many different environmental factors, from reflected sunlight (albedo) to the amount of methane in the atmosphere - it then tells you how much of Mars would be habitable under the conditions you set.

The Genesis Project

Reference:

"The Genesis Project." Astrobiology Magazine. 7 December 2007. <http://www.astrobio.net/news/terraform.php>

Sunday, December 2, 2007

Wait a Minute - What About the Asteroid Belt?


"Dark Matter" © DigitalBlasphemy.com
In three previous posts, "Planets, Planets Everywhere," "Young Sun-like Star Already Parent," as well as The Introduction to this blog, we learn that planets seem rather common-place: they form readily. All you need is debris or dust circling a star, gravity, and time (a million to several million years). Planets even are reborn around pulsars - regenerated from the blasted debris of the star's original planets (planets destroyed by the enormous supernova explosion that preceded the star becoming a pulsar).

And this got me to thinking - how come the rocky and dusty debris of the asteroid belt has never coalesced into a planet or dwarf planet? Possibly the tidal influence of Jupiter? If anyone has any input on this matter, it would be gratefully received.

Young Sun-like Star Already a Parent?

The Spitzer Space Telescope has discovered a young Sun-like star, UX Tau A, may already be a parent, even though it is only 1 million years old! Within the thick dust disk surrounding the star is a gap - a gap indicative of the sweeping action of a planet (or planets); planets that form out of primordial dust disks tend to clear a path through the disk. A process called photoevaporation can also clear away some of the disk from the star outward some distance, but since there is a thick ring of dust close to the star, then the gap, then another thick ring of dust - photoevaporation cannot be the cause.

If this is the case, then it is yet more evidence that stars and planets are a common combo, like peanut butter and jam, ham and eggs, or like Homer and doughnuts.

Reference:

Jet Propulsion Laboratory. "Youthful Star Sprouts Planets Early." SpaceRef. 29 November 2007. 2 December 2007. <http://www.spaceref.com/news/viewpr.nl.html?pid=24132>

NASA's Astrobiology Roadmap

In 2003, NASA, through the input of more than 200 scientists and technicians, finalized an Astrobiology Roadmap to outline and prioritize research and exploration pathways. The Roadmap has six goals:

Goal 1: Understand the nature and distribution of habitable environments in the Universe

Goal 2: Explore for past or present habitable environments, prebiotic chemistry and signs of life elsewhere in our Solar System.

Goal 3: Understand how life emerges from cosmic and planetary precursors

Goal 4: Understand how past life on Earth interacted with its changing planetary and Solar System environment

Goal 5: Understand the evolutionary mechanisms and environmental limits of life

Goal 6: Understand the principles that will shape the future of life, both on Earth and beyond

Goal 7: Determine how to recognize signatures of life on other worlds and on early Earth

I will be returning to this topic from time to time, especially Goal 3, which actually speaks of developing a study of universal biology.

The Roadmap can be found at <http://astrobiology.arc.nasa.gov/roadmap/index.html>, with a PDF version at <http://astrobiology.arc.nasa.gov/roadmap/AB%20RoadmapBrochure.pdf> (as of 2 December 2007).