Pat Rawlings/SAIC
An artist's rendering of the recently discovered planet.
Bill Marsh/The New York Times
Posted on 09/21/2004 3:38:18 PM PDT by neverdem
Like most New Yorkers, I have real estate fever. Even though I hate moving, I can't travel anywhere without wondering what it would be like to live there. I can't walk down a street in Oaxaca or the East Village without window shopping for apartments and evaluating the restaurant scene and the availability of playgrounds.
It doesn't stop there. Roll a sleeping bag out under the sky in a place like Mesa Verde, 7,000 feet up in the Colorado Rockies, on a summer evening and you will wake up at midnight with your nose in the Milky Way. There are roughly 200 billion stars in the Milky Way and somewhere around that number of galaxies in the observable universe. Surely there must be some prime real estate out there somewhere, perhaps with neighbors.
These are hopeful times for those inclined to view the universe as generous and nurturing, who like to think the prospects of life elsewhere are good. As of early September, the official count of verified extrasolar planets stood at 111, according to a list kept by the International Astronomical Union at www.ciw.edu/boss/IAU/div3/wgesp/planets.shtml.
But the numbers change weekly. What began as a trickle of discoveries of strange unlivable planets a decade ago has become a torrent of new ones looking friendlier and friendlier to life.
One recent discovery orbits Gliese 436, a dim star slightly less than half the mass of the Sun, known as a red dwarf. It was announced earlier this month that Gliese 436 has a planet only about 20 times the mass of Earth, about the size of Neptune in our own system.
Circling its parent star every 2.6 days at a distance of about 2.6 million miles, this new planet would be unlivable, like all the other much bigger exoplanets already discovered - except for one circumstance that can't be ruled out or in, yet. And here is where the chain of speculation and dreams begins.
The planet is so close to its star, astronomers calculate, that tidal forces have locked it into keeping the same face toward the star, the way the moon keeps the same face toward Earth as it rotates. That means that one side of the planet is perpetually blowtorched while the other is in an eternal deep freeze. But in the twilight zone, between the two sides, where Gliese 436 looms like an orange clown face forever on the horizon, there is a thread of a chance, some astronomers say, that the temperature could be in the Goldilocks range, neither too hot nor too cold, of liquid water -the sine qua non of Life As We Know It.
I have begun to imagine a kind of ring world on Gliese 436 b, as this planet is now unpoetically known, a dusky narrow scrum of hungry green, a sort of Alaskan summer bog strip crawling with ingenious critters hemmed between ice and desert, building their narrow little cities straddling a canal full of extraterrestrial bass, with windows pointed sunward, full of clever mirrors.
It's interesting to ponder the psychology and cosmology of creatures who live in perpetual twilight. Is it always dawn or always sunset on Gliese 436 b? Would they know about stars?
Of course this is a long shot. Forget about cities and life. A few alien bacteria in a mud puddle someplace would change science. Even the possible existence of liquid water someplace would have astrobiologists and science writers doing handstands, but that thread hangs on the nature of the planet's atmosphere. If it's too thick, heat from the illuminated side would be conducted around to the dark side and the whole place would be stifling.
If the atmosphere is thin or nonexistent, astronomers concede, some more grudgingly than others, it's not impossible that some piece of the twilight zone could remain lukewarm. But nobody really knows what Gliese 436 b is like, whether it is made of rock and iron, like the Earth, or ice and snow like Neptune, nor what the dynamics of its atmosphere might be, whether, for example, water would evaporate away from the light and fall as snow on the cold side.
And it's worse than that. Red dwarfs like Gliese 436 are prone to giant flares and sunspots, so its planet and anything on it would have to endure variations in sunshine as well as radiation showers.
It's way too soon for sober folks to get excited about the possibility of life at Gliese 436 or any other particular putative dust speck in the sky. But odds are increasingly in favor of the idea that one of these days, some newly discovered planet will have the "Goldilocks" properties that will make it a good bet for an enterprising real estate agent.
The newly discovered planets were all detected indirectly, mainly by looking for the wobbles their gravity induces in the motions of their stars, and so the race is on at observatories around the world to get pictures. Because they create the biggest wobble, the first exoplanets were gaseous giants like Jupiter orbiting close to their stars, too hot and dense for any life that we know about. But as they have looked longer and more sensitively, astronomers are beginning to find friendlier looking systems.
Gliese 436 b is only one of three new planets recently discovered that are significantly smaller, about the size of Neptune. One of them, known as 55 Cancri e, is part of a four-planet system that is the closest thing astronomers have found yet to our own solar system.
These discoveries have moved the game into a whole new realm, unexpectedly quickly, said Dr. Geoff Marcy, an astronomer and longtime planet hunter at the University of California, Berkeley.
When he and his collaborator, Dr. Paul Butler of the Carnegie Institution, were starting out in the early 1990's, Dr. Marcy said, "people literally looked down at their shoes in embarrassment when we told them that we were trying to detect planets." Hunting for planets around other stars, he said, considered was akin to searching for U.F.O.'s.
Now it's mainstream astronomy and a growing chunk of NASA's budget.
The next big milestone, astronomers say, will be the detection of Earth-size planets, although that will require going to space. NASA has planned a series of missions, including Kepler, scheduled for 2007, the Space Interferometry Mission, scheduled for 2009, and a pair of spacecraft known as Terrestrial Planet Finders about a decade from now to identify and study habitable planets.
Closer to home, the Spirit and Opportunity rovers seem to have confirmed the presence of water sometime in the past on Mars. Last week, scientists from the University of Colorado concluded from analyzing data from the Mars Global Surveyor and the Mars Odyssey spacecraft that Opportunity's landing site had once been an ocean as big as the Baltic Sea.
Scientists think there are oceans under the ice on Jupiter's moon Europa, and hydrocarbons raining down onto the slushy surface of Saturn's moon Titan, into which the Huygens probe will descend this winter.
Nobody knows if there ever was or is life in any of these places. Scientists have found life everywhere on Earth that they have looked, from the driest and the coldest to the hottest and wettest of places, but the odds of life off Earth are incomputable under the best conditions we can imagine or hope for.
Scientists don't know how life originated on Earth, after all. No less a light than Francis Crick, co-discoverer of the structure of DNA, suggested in an article in 1973 in Icarus, a planetary science journal, along with the chemist Dr. Leslie Orgel, that extraterrestrials could have spread life throughout the stars in the form of spores or genetic material encapsulated in small meteorites, an idea that goes all the way back to the Greek philosopher Anaxagoras.
Nor are scientists absolutely sure they even know how to recognize life that is too far removed from the one example we know - ourselves and our kin - based on the chemistry of DNA. In the search for extraterrestrial life, as Dr. Jill Tarter, a radio astronomer at the SETI Institute in Mountain View, Calif., once pointed out, "No. 2 is still the most important number in the process."
The question of life has recently come to occupy a central position not just in the space program but in physics and cosmology, traditionally the most bloodless of sports, requiring a depressingly vast and abstract perspective on the cosmos. Cosmologists have found to their astonishment that life and the universe are strangely and deeply connected. Life As We Know It seems to depend on the miraculous and improbable juggling of the numerical values of a few atomic and astronomical constants - like the relative masses of elementary particles or the strength of the "dark energy" accelerating the universe outward. Twiddle these control knobs on nature's console a little bit and the galaxies evaporate before stars and life have a chance to evolve, or atoms fall apart.
What this means is being debated fiercely these days by some of the smartest physicists in the world. Do we live in a lucky universe? Or are there zillions of different possible universes and we live in one with laws that happen to be conducive to life, the way that fish live on a planet that is warm enough to have liquid water?
"We live where we can live," say the proponents of the latter view. But others, following the example of Albert Einstein, say that we don't know anything about physics yet and that we if we work hard enough, we will understand why God had to make the universe the way it is.
Now I am not generally known for my optimism. I think the world is getting worse and more dangerous, despite the onward march of science. And I don't expect to hear the end of the debate about the alleged fine-tuning of the laws of nature, which seems to me to be as much about philosophy and personality as it is about science.
What seems indisputably clear is that our knowledge of the universe is dwarfed by our ignorance.
So I find myself bullish on the universe, so to speak. Almost everything is still possible. I think it is likely that astronomers will find Earthlike planets in my lifetime and probably long before anybody lands on Mars. We might live to see it as a little dot in the newspapers or on television, and to start thinking about sending a space probe there, knowing it will be a voyage that would last generations.
We might find out where it is that we can live. As it happens, my family and I just finished moving into a new apartment. By the time we get an answer back, I might be ready to move again.
Pat Rawlings/SAIC
An artist's rendering of the recently discovered planet.
Bill Marsh/The New York Times
ping
European Southern Observatory
A team of European and American astronomers think they may have taken the first portrait of a planet orbiting around another star. It is a dim point near a star called 2M1207, about 230 light-years away in the constellation Hydra. If it is a planet, said the astronomers led by Dr. Gael Chauvin of the European Southern Observatory, it is about five times as big as Jupiter.
If I were incarcerated in New York, or within 1,000 miles thereof, I'd spend every waking moment thinking about moving, too.
"...incarcerated in New York..."
LOL!!
If you look at something that is 30,000 light years away,
you see it the way it looked 30,000 years ago.
Kind of like those Amy Kellogg Fox News reports from Arab countries.
I was born in Brooklyn, but over the years I've thanked my parents repeatedly for having the foresight to move us out west - when I was all of two months old.
I'm sure I've seen that frigid dark side on my X girlfriend.
I don't know who is in neverdem's ping list so I'm making sure you get pinged.
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