Seriously Searching for Life in the Universe

The Curiosity rover is still taking photos and analyzing rocks on Mars.

The more data we get about about Mars, the more it looks like there might be life there. Then again, there might not.

If critters live on Mars, they almost certainly won't be like the familiar movie monsters. I'll be pleasantly surprised if we find a microscopic Martian.

Another week's gone by, and we still haven't found extraterrestrial life. (February 1, 2013) The continuing search was in the news, though:

1. SETI: "Hardly Surprising"
   • Technology, Life, the Universe, and Billions of Years
   • Listening for Drums?
2. Looking for Life

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Considering the cultural legacy of films like "Frankenstein Meets the Space Monster," and the flying saucer craze of the late 1940s, I'd better explain what I mean by "extraterrestrial life."

Cargo Cults, Movies, and Me

I don't expect groovy space aliens to come from the stars and solve all our problems. That sort of thing makes entertaining movies, like "The Day the Earth Stood Still," and "Close Encounters of the Third Kind." What I've seen and read of folks who take the 'space alien missionaries' thing seriously encourages me to think that the belief is a sort of cargo cult, with imagined space aliens taking the place of real pilots and missionaries of an earlier generation.

Aside from being highly improbable, that attitude toward extraterrestrial intelligence strikes me being as a sort of idolatry: treating a creature as if it's God. That's a very bad idea: and strictly against the rules. (Catechism of the Catholic Church, 2112-2114)

At another extreme, there's the alien invader. H. G. Wells' "The War of the Worlds" made sense, given what folks knew in the late 19th century. Movies like "Plan 9 From Outer Space," not so much.

Finally, some folks seem to think that there can't be life anywhere except on Earth. Maybe that's so: but as a Catholic, I'm not allowed to say so. The Catholic Church ruled that we must not deny the possibility of other worlds, when the issue came up: over seven centuries ago. (January 29, 2012)

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1. SETI: "Hardly Surprising"

"No Alien Signals Detected in Kepler SETI Search"
Ian O'Neill, Alien Life & Exoplanets, Discover News (February 7, 2012)

"In an effort to search for intelligent extraterrestrials, SETI astronomers have completed their first 'directed' search. Unfortunately, it turned up no evidence of transmitting aliens. But that's hardly surprising.

"This non-discovery is a result in itself - the SETI team can now place important limits on the likelihood of finding a sufficiently advanced alien race in the Milky Way. Generating a powerful radio signal requires a lot of energy, so the team point out that they will most likely detect a civilization capable of generating an isotropic signal (i.e. a radio transmission that is emitted in all directions)...."

As Ian O'Neill said, not picking up radio signals from space aliens is "hardly surprising." He made some good points, but left out what I see as a major flaw in most systematic searches for intelligent life elsewhere in the universe.

We use modulated radio transmissions for long distance communication. Our signals could reach other stars, and it's reasonable to assume that we could pick up incoming signals - if there were any.

I think it's reasonable to try listening for radio signals from the stars. It's a moderately low-cost way to 'listen' for evidence of another civilization. But I also think that if there are other people out there, who are "sufficiently advanced," they won't be using radio for long distance communication.

Technology, Life, the Universe, and Billions of Years

As I've said before, this creation is old, about 13,730,000,000 years; the Solar system has been around for about has been around for about a third of that time; and critters lived on Earth for upwards of 3,500,000,000 years. (June 10, 2012) Then 1,000,000 or so years ago, our ancestors started learning how to use fire without killing themselves. (January 27, 2013)

Compared to how long we've used radio, a million years is a long time. Compared to how long Earth has supported life, not so much.

If not-human people who had been using radio only a half-million years ago live in our 'neighborhood,' my guess is that they still know about radio: but don't use it for communication. Not routinely, anyway.

Listening for Drums?

Let's take the hypothetical case of folks who are a human as I am, living on a remote cluster of Pacific islands. These (fictional) folks don't know about the world beyond their little archipelago.

Some of them think there might be other islands: and that maybe other people live on those islands. It's a radical idea, but worth testing.

These hypothetical islanders use drums to signal each other. It's 'obvious' that it's a practical means of long-distance communications: and one that "sufficiently advanced" civilizations might use.

After several attempts, rowing out until they could barely see their island home, and listening for days: they detected no alien drums. With a dish antenna, and the right equipment, they could pick up satellite television: but that's technology they don't have, and never heard of.

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2. Looking for Life

"Kepler Data Suggest Earth-size Planets May Be Next Door"
Kepler, Mission News, NASA (February 6, 2013)

"Using publicly available data from NASA’s Kepler space telescope, astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) estimate that six percent of red dwarf stars in the galaxy have Earth-size planets in the "habitable zone," the range of distances from a star where the surface temperature of an orbiting planet might be suitable for liquid water.

"The majority of the sun's closest stellar neighbors are red dwarfs. Researchers now believe that an Earth-size planet with a moderate temperature may be just 13 light-years away.

" 'We don't know if life could exist on a planet orbiting a red dwarf, but the findings pique my curiosity and leave me wondering if the cosmic cradles of life are more diverse than we humans have imagined,' said Natalie Batalha, Kepler mission scientist, NASA's Ames Research Center in Moffett Field, Calif.

"The research team analyzed 95 planet candidates in the Kepler catalog orbiting 64 red dwarf stars. Most of these candidates aren't the right size or temperature to be considered Earth-like, as defined by the size relative to Earth and the distance from the host star. However, three candidates are both temperate and smaller than twice the size of Earth...."

The habitable zone of red dwarfs, where a planet could have an atmosphere like Earth's and liquid water, is tiny compared with our star's. The odds of a planet being in that zone is smaller than with stars as bright as ours. But there are a whole lot more red dwarfs than our comparatively bright star.

Opinion about whether or not life could exist on a planet circling a red dwarf have shifted over the decades.

Some scientists have pointed out that a planet close enough to a red dwarf would probably have one side always facing the star, like our moon and Earth. That would leave one side of the planet in permanent light, the other in perpetual night: quite possible frozen on one side and torrid on the other. Quite a few red dwarfs have flares, like our sun's: which would periodically expose 'habitable' planets to extreme radiation.

Other scientist have suggested ways that life could exist, even under those conditions - and point out that not all red dwarfs are flare-prone.

I'm inclined to agree with the 'could exist' set: particularly since I ran into a book about the possibility of extraterrestrial life that very came close to demonstrating that life can't exist on Earth.

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