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I’m halfway through Paul Davies’s book The Eerie Silence, about the Search for Extraterrestrial Intelligence (SETI) project and the wider scientific and philosophical issues involved. One of the ways of investigating the probability of extraterrestrial life is to look at the vexed question of the probability of life on earth, and chapter 2 of the book is entitled, “Life: Freak side-show or cosmic imperative?”

Was there a high probability that any life, let alone intelligent life, would develop on earth? The answer is: we haven’t a clue. And that’s because we still have almost no understanding about how life developed on this planet in the first place; and we don’t even know if it started here anyway – it may have started on Mars and migrated on materials that got dispersed into the solar system and then fell to earth.

We simply don’t know how life began. As Charles Darwin said:

We might as well speculate about the origin of matter.

This lack of knowledge isn’t reflected in the ‘cosmic imperative’ mood of the scientific and journalistic moment. Many thinking people, in other words, believe that given the vastness of the universe the emergence of life must be almost inevitable. Alan Boss of the Carnegie Institution in Washington declared in 2009:

If you have a habitable world and let it evolve for a few billion years then inevitably some sort of life will form on it… It would be impossible to stop life growing on these habitable planets… There could be one hundred billion trillion Earth-like planets in space, making it inevitable that extraterrestrial life exists’ [25-26].

The flaw in this probability argument is obvious even to a non-scientist like myself. Boss uses the word ‘evolve’: if you let a habitable world ‘evolve’ then life is bound to emerge. That would be true if we had any evidence that a ‘world’ evolves. But we don’t. Life evolves, once it is started – we know that. But we can’t use an assumption about the progress of evolution within life as an argument that life itself, at its beginnings, is the result of a pre-life evolutionary process. We have no idea what such a process might involve, or any evidence that it took place, or any indication of what the probability of it taking place might be.

George Whitesides, Professor of Chemistry at Harvard University, gives the alternative view, which Paul Davies himself accepts. First of all he seems sceptical:

How remarkable is life? The answer is: very. Those of us who deal in networks of chemical reactions know of nothing like it… How could a chemical sludge become a rose, even with billions of years to try? … We (or at least I) do not understand. It is not impossible, but it seems very, very improbable [31].

But it’s not so much scepticism as a humble awareness of the impossibility of speaking about a high probability of life emerging when we know so little about what would or would not make it probable in the first place.

How likely is it that a newly formed planet, with surface conditions that support liquid water, will give rise to life? We have, at this time, no clue, and no convincing way of estimating. From what we know, the answer falls somewhere between ‘impossibly unlikely’ and ‘absolutely inevitable’. We cannot calculate the odds of the spontaneous emergence of cellular life on a plausible prebiotic earth in any satisfying and convincing way’ [31].

All we know is that it has happened at least once.

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A few months ago I wrote about the possibility of discovering alien intelligence, and the whole SETI project. New research suggests that the planets close enough for us to investigate have environments that would be extremely inhospitable to life – at least to life as we know it.

Sophie Borland writes about Howard Smith’s recent findings.

Still waiting for little green men to make contact? Don’t hold your breath. A leading astronomer has concluded there probably aren’t any aliens out there – meaning we are entirely alone in the universe.

Even though there may be tens of thousands of other distant planets similar in size to Earth, the conditions on them are likely to be too hostile to support life-forms such as ET.

Dr Howard Smith, a senior astrophysicist at Harvard University, believes there is very little hope of discovering aliens and, even if we did, it would be almost impossible to make contact.

So far astronomers have discovered a total of 500 planets in distant solar systems – known as extrasolar systems – although they believe billions of others exist. But Dr Smith points out that many of these planets are either too close to their sun or too far away, meaning their surface temperatures are so extreme they could not support life.

Others have unusual orbits which cause vast temperature variations making it impossible for water to exist as a liquid – an essential element for life. Dr Smith said: ‘We have found that most other planets and solar systems are wildly different from our own. They are very hostile to life as we know it.’

‘The new information we are getting suggests we could effectively be alone in the universe. There are very few solar systems or planets like ours. It means it is highly unlikely there are any planets with intelligent life close enough for us to make contact.’

Not everyone agrees.

Only last month Professor Stephen Hawking said the fact that there are billions of galaxies out there made it perfectly rational to assume there were other life-forms in the universe.

Researchers from the University of London have recently suggested that aliens could be living on as many as 40,000 other planets.

But Dr Smith suggests that such estimates are optimistic.

He said: ‘Any hope of contact has to be limited to a relatively tiny bubble of space around the Earth, reaching maybe 1,250 light years out from our planet, where aliens might be able to pick up our signals or send us their own. But communicating would still take decades or centuries.’

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If you thought that the whole point of science fiction was to transport you into a world of the improbable, the impossible, and the utterly fantastical – think again. NASA has stepped into the debate about what makes good science fiction, and the answer is: good science.

The best science fiction takes us to the very edge of what is currently known and currently possible, it draws out the unforseen implications of this present knowledge, it stretches the boundaries and speculates about where we might be in a year or a millennium, but it doesn’t throw aside reason and create a world of nonsense or sheer fantasy. To put it another way, good science fiction is prophetic, it helps us see where we might be going – scientifically, technologically, even morally and politically. And it helps us see where we might not want to go.

How has NASA got involved? By joining with the Science & Entertainment exchange to compile a list of the best and worst science fiction movies of all time. Wenn.com writes:

NASA scientists have named John Cusack’s blockbuster 2012 as the most “absurd” sci-fi film of all time.

Experts at the National Aeronautics and Space Administration (NASA) and Science and Entertainment Exchange have put together a list of the least plausible science fiction movies ever made, and the big budget 2009 picture came top.

The film, which depicted Earth besieged by natural disasters, featured ahead of two more ‘end-of-the-world’ movies – 2003’s The Core and 1998’s Armageddon.

Donald Yeomans, head of NASA’s Near-Earth Asteroid Rendezvous mission, says of 2012, “It’s absurd. The film-makers took advantage of public worries about the so-called end of the world as apparently predicted by the Mayans of Central America, whose calendar ends on December 21, 2012.

“The agency is getting so many questions from people terrified that the world is going to end in 2012 that we have had to put up a special website to challenge the myths. We have never had to do this before.”

Staff at the organization also compiled a list of the top 10 most realistic sci-fi films, with 1997’s Gattaca, starring Ethan Hawke and Uma Thurman as space agency workers, winning the highest praise from the scientists. NASA experts also named dinosaur movie Jurassic Park and Jodie Foster’s Contact among the most realistic sci-fi films.

I’d agree with this. Part of the fascination with these three films is the idea that this could really happen, this could really be round the corner. Gattaca: a genetic underclass is created in the near future and denied certain rights and privileges. Jurassic Park: fossilised DNA is used to recreate the dinosaurs. Contact: we listen for signs of intelligent life beyond our solar system, and one day we finally hear something [but ignore the crazy mystical ending].

Here are the two lists.

The worst sci-fi movies of all time:

1. 2012 (2009

2. The Core (2003)

3. Armageddon (1998)

4. Volcano (1997)

5. Chain Reaction (1996)

6. The 6th Day (2000)

7. What the #$*! Do We (K)now!? (2004)

The most realistic sci-fi movies of all time:

1. Gattaca (1997)

2. Contact (1997)

3. Metropolis (1927)

4. The Day The Earth Stood Still (1951)

5. Woman in the Moon (1929)

6. The Thing from Another World (1951)

7. Jurassic Park (1993)

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VLA radio telescopes by stephenhanafin.

I’m dying to read Paul Davies’s new book The Eerie Silence: Are We Alone in the Universe? I know it’s a bit cheeky just pasting the the blurb from Amazon here for a book I haven’t read, but it does summarise the fascination of the whole SETI project:

On April 8, 1960, a young American astronomer, Frank Drake, turned a radio telescope toward the star Tau Ceti and listened for several hours to see if he could detect any artificial radio signals. With this modest start began a worldwide project of potentially momentous significance. Known as SETI — Search for Extraterrestrial Intelligence — it is an amalgam of science, technology, adventure, curiosity and a bold vision of humanity’s destiny. Drake has said that SETI is really a search for ourselves — who we are and what our place might be in the grand cosmic scheme of things. Yet with one tantalizing exception, SETI has produced only negative results. After millions of hours spent eavesdropping on the cosmos astronomers have detected only the eerie sound of silence. What does that mean? Are we in fact alone in the vastness of the universe? Is ET out there, but not sending any messages our way? Might we be surrounded by messages we simply don’t recognize? Is SETI a waste of time and money, or should we press ahead with new and more sensitive antennas? Or look somewhere else? And if a signal were to be received, what then? How would we — or even should we — respond?

Bryan Appleyard had an article in the Times recently about Jill Tarter, who is the scientist on whom Jodie Foster’s character in Contact was based. He writes about Drake’s work:

He came up with the Drake Equation, a way of calculating the number of intelligent civilisations in the Milky Way, our galaxy. To solve the equation most of the terms have to be guessed. But making, he says, reasonable assumptions, Drake reckons there are 10,000 alien civilisations in our galaxy.

“I’m not being super-pessimistic or super-optimistic when I say that.”

Unfortunately, 50 years on and in spite of the odd wow moment, Seti has found none of them.

In the institute the equation is everywhere — on T-shirts, posters and even on a plaque at reception. It ties together everything they do, which means not just scanning the skies but investigating Mars and meteors, planets and protozoa.

Only a small proportion of this place is actually devoted to Seti proper, the rest is a specialist science operation. But everything feeds into the equation. And all the other projects bring in money in the form of research grants, primarily from the nearby Nasa Ames Research Center.

The equation seems to say life is out there, probably in abundance, that the Milky Way is more like a cocktail party than a desert. So where the hell are they all?

The scientist Enrico Fermi once said that if we hadn’t heard from the aliens, they weren’t there. The universe is so old — 13.7 billion years — that a single intelligence would have had time to colonise the galaxy. At the institute they step round this. Nobody here doubts there is life out there. “I bet everybody a couple of Starbucks that we’ll find ET within a couple of dozen years,” says the gleeful and buoyant Seth Shostak, senior astronomer at the institute.

“I cannot imagine a scenario in which life on Earth is unique,” says Mark Showalter, expert on planetary rings and discoverer of three new moons and three new rings, principal investigator.

All say the real miracle would not be ET but the complete absence of intelligent life. “If there are aliens out there,” says Shostak, “that’s miraculous; if there aren’t, that’s a miracle.”

No aliens would mean that in our entire galaxy — 100,000 light years across (for perspective, the moon is 1.3 light seconds from Earth), 1,000 light years thick, 100 billion stars, countless planets — and in the entire universe, 170 billion galaxies, 14 billion years old, humans were a one-off. Would that make us feel special or lonely? It should certainly make us feel weird.

For me, the alien questions go hand-in-hand with the early hominid questions – hence my fascination with them both. Is there something unique about human intelligence, imagination, creativity and freedom? Were we ‘alone/unique’ even in the time of the Neandertals (and the two other possible contemporaneous hominids: more posts to follow)? Are we alone now?

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With my love for circles, tangents, prehistoric art, and monumental gestures, I can’t resist linking to these images of Jim Denevan’s enormous desert art project – which also happens to be the largest artwork ever made, dwarfing Christo’s wrapped buildings and even the greatest of the anonymous crop circles (if they are human art rather than a form of alien communication…)

All the images I can find are in copyright, so I can’t paste them here; but please take the time to click on the link above and look. Here are some other sand images by Denevan – but they are nothing to compare with this latest project:

Spiral I by ChibiJosh.

Sand image by Jim Denevan on Ocean Beach in San Francisco

Spiral III by ChibiJosh.

doing the denevan V by dotpolka.

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