Exoplanets expert thinks intelligent beings rare in galaxy

Here, Space.com's Mike Wall interviews astronomer Geoff Marcy on "Life on other planets?" (2/1/2011):

Leading expert weighs in

Marcy has had a hand in finding more alien planets than anyone else. He helped spot 70 of the first 100. He also found the first multiplanet system around a sun-like star, and he discovered the first planet that transits — or passes in front of — its star from our perspective on Earth

[ ... ]

Space.com: Our solar system is so young, compared to the universe. And the universe is so big. So there's been lots of time and opportunity for advanced civilizations to get started, and to try to contact us. Some people think that the fact that we seemingly haven't been contacted means that we may well bealone in the universe.

Marcy: Well, you have to fold it in. The absence of an intelligent radio or television wave from any advanced civilization represents one indication, not a proof, that maybe habitable planets that sustain Darwinian evolution for a billion years —maybe they're rare. Maybe.

Space.com: What do you reckon? Do you have a gut feeling about this?

Marcy: I do. If I had to bet — and this is now beyond science — I would say that intelligent, technological critters are rare in the Milky Way galaxy. The evidence mounts. We Homo sapiens didn't arise until some quirk of environment on the East African savannah — so quirky that the hominid paleontologists still can't tell us why the australopithecines somehow evolved big brains and had dexterity that could play piano concertos, and things that make no real honest sense in terms of Darwinian evolution.

The whole is worth reading. He thinks $billion should do the trick.

Hostility to life is norm for exoplanets, senior astrophysicist says

Artist's conception of  Kepler-10b, NASA

In “Kepler-10b - The first extrasolar system rocky planet”, British physicist David Tyler notes,

The presumption that there are millions of Earth-like planets in habitable zones is based on theory that is not supported by evidence. This point has recently been made by Howard Smith, a senior astrophysicist at Harvard. He has made the claim that "we are alone in the universe" after an analysis of the 500 planets discovered so far showed all were hostile to life.

"Dr Smith said the extreme conditions found so far on planets discovered outside out Solar System are likely to be the norm, and that the hospitable conditions on Earth could be unique.
"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," he said."

never mind rare Earths, there aren’t any spare Earths, period. Better take care of the one we got.

Exoplanets: Aren't we at risk of running out of gee whiz adjectives?

From "Rocky exoplanet milestone in hunt for Earth-like worlds" (Jason Palmer, BBC News, 10 January 11), we learn,

Astronomers have discovered the smallest planet outside our Solar System, and the first that is undoubtedly rocky like Earth.

Measurements of unprecedented precision have shown that the planet, Kepler 10b, has a diameter 1.4 times that of Earth, and a mass 4.6 times higher.

However, because it orbits its host star so closely, the planet could not harbour life.

The discovery has been hailed as "among the most profound in human history".

One can't help wondering why, actually. Well, because

"We want to know if we're alone in the galaxy, simply put - and this is one link in the chain toward getting to that objective.

"First we need to know if planets that could potentially harbour life are common, and we don't know if that's true - that's what Kepler is aiming to do."

Okay, but can we please leave the "most profounds" (the phrase is used twice in a short report) out for now?

Otherwise, what phrases will we haveleft when we find an extrasolar planet that can host life?

While we are at it, the phrase "a planetary missing link", used in the story, doesn't really work. If the conv-

NASA artist's conception of Kepler 10b

entional explanation of planet formation is correct, Kepler 10b isn't a long-sought link between one planet and another. And if we do find a planet that harbours life, it won't be a link either - any more than Earth is a "link" between Venus and Mars.

A friend writes to say,

We had total failure at finding Earth-like planets that might support our Darwinian assumption (and massive expenditure) that we are not unique in the universe. But now we've found something other than a giant-gas planet so we are less discouraged than before. But it turned out to be a solid chunk of iron at 1300 degrees orbiting a few solar radii above the star, so it isn't what we were looking for, which is discouraging again. But we'll call it "rocky" anyway and maybe our luck will return.

One hopes so. A summer planet would be nice. But not that one.

2010 Fourth giant exoplanet strains key theories on planet formation

From New Scientist, we learn that astronomers are puzzled by the four

The discovery of a fourth giant world around the star HR 8799 is straining the two leading theories of how planets form.

Planets are thought to coalesce from a dusty disc around a young star. One model, called core accretion, says that giant planets form when the dust gathers into a rocky core, which then draws in gas to form a massive atmosphere. Another, called disc instability, says that these planets collapse suddenly from sections of the disc.

HR 8799's four planets, each five to 13 times Jupiter's mass, are too far apart to be explained easily by either model, say Christian Marois of the Herzberg Institute of Astrophysics in Victoria, British Columbia, Canada, and colleagues.

Here's a vid:

 

Graphics time is much too soon for certainty on this one.

See also:

Exoplanets: The planet with 100% life has 0% existence?

Exoplanets: The recent pilgrimage to Darwin's shrine.

Does our solar system occupy a unique position in the universe or just an ordinary one?

Rare? Solar systems like ours are rare?

Astronomer argues that we can test whether Earth is fine-tuned as a science lab

Serious push to find more exoplanets

Exoplanets: Will intelligence be common or rare?

Exoplanets: The planet with 100% life has 0% existence?

A recent news story featured an astronomer whose personal feelings about the chances for life on a recently discovered planet orbiting a star other than our sun were - 100%:

Personally, given the ubiquity and propensity of life to flourish wherever it can, I would say, my own personal feeling is that the chances of life on this planet are 100 percent," said Steven Vogt, a professor of astronomy and astrophysics at the University of California, Santa Cruz, during a press briefing today.

"I have almost no doubt about it.”

He might have done with a few doubts about planet Gliese 581 g, which has a 37-day orbit around a dim, red dwarf star. The
latest story is that other astronomers can’t establish that Gliese exists.

Two weeks after one team of astronomers announced finding the habitable planet Gliese 581 g, another team says it can find no evidence of the world in its data.

Last month, a team of astronomers announced the discovery of the first alien world that could host life on its surface. Now a second team can find no evidence of the planet, casting doubt on its existence.

[ ... ]

But it might be too early to claim a definitive detection. A second team of astronomers have looked for signals of Gliese 581 g in their own data and failed to find it.

"We easily recover the four previously announced planets, "b", "c", "d", and "e". However, we do not see any evidence for a fifth planet in an orbit of 37 days," says Francesco Pepe of the Geneva Observatory in Switzerland. He presented the results on Monday at an International Astronomical Union symposium in Turin, Italy.

Although the Geneva team cannot find evidence for the new planet, they cannot exclude the possibility that Gleise 581 g exists. "We are not trying to prove the nonexistence of a planet," Pepe says. "It's really difficult to prove that something does not exist. We are just saying we do not see a significant signal that is really different from noise."

- Rachel Courtland, "First life-friendly exoplanet may not exist", 1(3 October 2010)

Well, as we, and they, all know, one cannot prove that a physical thing really does not exist. One simply reaches the point where one considers its existence too improbable to spend more time looking.

If Gliese is not found, the episode will demonstrate one important thing: Many people badly need to believe in life on other planets, and many more people are eager to hear them tell about it. The legendary caution of science stands no chance against the onslaught of such yearnings.

See also Exoplanets: The recent pilgrimage to Darwin's shrine.

Does our solar system occupy a unique position in the universe or just an ordinary one?

Rare? Solar systems like ours are rare?

Astronomer argues that we can test whether Earth is fine-tuned as a science lab

Serious push to find more exoplanets

Exoplanets: Will intelligence be common or rare?

100 per cent chance newly discovered planet has life

How do we know? Faith in faith alone, the astronomer explained:

"Personally, given the ubiquity and propensity of life to flourish wherever it can, I would say, my own personal feeling is that the chances of life on this planet are 100 percent," said Steven Vogt, a professor of astronomy and astrophysics at the University of California, Santa Cruz, during a press briefing today.

"I have almost no doubt about it."

Well, that settles it, I guess.

James M. Kushiner points out, at Mere Comments blog, re "Odds of Life on Nearby Planet '100 Percent,' Astronomer Says":

Did you hear about the astronomer, who said, get this, that the odds of life on nearby planet are 100 Percent? What was he thinking? What do astronomers know about biological life, and, besides, if the odds are 100 percent, then there are no odds--at least if I go to Arlington Race Track and find a horse that has a 100 percent chance of winning, they probably won't be taking bets on him. No odds there.

[ ... ]

I am not saying this planet could not support life. I am just wondering what are the chances that any given astronomer would peg a planet with so many unknowns or uncertainties with a probability of having life on it at 100 percent? Of course, if a news story is in play with a possible headline, I'd up those chances considerably, whatever they are.

If you want to read science, don't read the news.

Read more here. Kushiner is editor of the science and popular culture mag Salvo, pictured above.

Exoplanets: The recent pilgrimage to Darwin's shrine

At Britain's Telegraph (November 04, 2009), Tom Chivers advises that "Darwinian evolutionary theory will help find alien life, says Nasa scientist."
Charles Darwin’s theory of evolution may give pointers in the search for alien life, says a Nasa astrobiologist. Here, we learn two competing views:

And so the limits of Darwinian evolution will define the range of planets that can support life – at least Earth-like life."

but

... alien life may not be entirely Earth-like. Dr Baross said: "I'd like to point out there are many different ways for non-Earth-like life to not use light or chemical energy but use some other form like radiation energy, wave energy, or ultraviolet energy."

. And then how can we know that the way they proceed is by Darwinian evolution?

We also learn

"I think all of us really believe that rocky planets, like Earth, are going to be found at some point," said Baross.

Well, lots of people have really believed lots of things that never happened. I happen to agree with him re rocky planets, because in a galaxy the size of ours, we will doubtless find lots of things, possibly extraterrestrial life ...

I am a little more concerned about the underlying agenda in some cases. NASA could be undermining its chances via Darwin worship.

Some more exoplanet stories:

Does our solar system occupy a unique position in the universe or just an ordinary one?

Rare? Solar systems like ours are rare?

Astronomer argues that we can test whether Earth is fine-tuned as a science lab

Serious push to find more exoplanets

Exoplanets: Will intelligence be common or rare?

Hat tip The Mustard Seed.

Response to search engine query: What is this blog about?

I was asked to define it for a "deep" search engine group, Feedmil, and replied as follows:

Colliding Universes takes a critical look at cosmology, especially its many unexplained assumptions. Here’s one:

Earth is not special. There must be many planets that host life forms.

Now, what if we find 3000 exoplanets and none host life forms.

Does that suggest that Earth is special?

No, many cosmologists would say. We just haven’t looked hard enough. Find 3000 more.

It becomes obvious that their research is intended to confirm the “not special” view, and that – for both practical and philosophical reasons – it cannot be disconfirmed.

The practical reason is that they can always argue, “They’re out there somewhere.” The philosophical reason is that they are determined to believe what they want to believe.

That’s fine, but don’t call it science.

Incidentally, even if, after a search of 6000, two other planets were found that had life forms, we would know that there are three special planets, ours being one.

But don’t expect the pop science media to interpret it that way.

See also:

"Privileged planet" astronomer Guillermo Gonzalez: Dissing St. Carl Sagan in his own church

Study: Sun not special, therefore alien life should be common?


Galactic habitable zone not unique, computer sim suggests

Does our solar system occupy a unique position in the universe or just an ordinary one?

Rare? Solar systems like ours are rare?

Astronomer argues that we can test whether Earth is fine-tuned as a science lab

"Serious push to find more exoplanets

Exoplanets: Will intelligence be common or rare?

Extraterrestrial life: Immanuel Kant, meet Frank Drake and Carl Sagan

From "Looking for planets like ours", a review by Michael Brown of Alan Boss's The Crowded Universe: The Search for Living Planets:

Even if the Kepler and COROT missions do find an abundance of planets, the Kantian revolution will not be complete. The new planets might be exactly the same size as Earth and orbit their stars at the same distance, and although an astronomer might be willing to call such a thing Earth-like, most people will look for more. Does it have liquid water? Does it have a recognizable atmosphere? And, inevitably, could it — does it — support life?

Finding the answers to these questions will take decades. Kepler and COROT are merely steps along the way. In the meantime, we can take solace from Kant: "I am of the opinion that it is not particularly necessary to assert that all planets must be inhabited. However, at the same time it would be absurd to deny this claim with respect to all or even to most of them."

It took nearly 250 years to prove him mostly right the first time. With a little luck and perseverance — and, as Boss shows, a lot of work by astronomers around the world — the final step may just come a little faster.

I wonder whether Kant would regard the discovery that bacteria had once lived on Mars or might live elsewhere - if it is made - as evidence for his position.

See also:

Alfred Russel Wallace on why Mars is not habitable

See also: Boldly go, but why, exactly?Extraterrestrials:

Several million UFOs later - the state of the question

Younger astronomers less likely to believe than older ones?

So what if fossil bacteria are found on Mars? Polls show many Americans expect Star Trek!

Some scientists hope that the aliens are NOT out there!

Increase in UFO sitings in Canada - what's behind that?

Rare? Solar systems like ours are rare?

In that case, does our stock go up? On the other hand, it will be hard to get replacement parts.

Also, do we risk being tagged by the Galactic Historical Board, so we are not allowed to make any changes. Getting rid of the smallpox virus? The malaria parasite? Forbidden, if we are a rare historical artifact.

Carl Sagan, check your e-mail. According to Jeff Hecht, in New Scientist,

Our solar system is a Goldilocks among planetary systems. Conditions have to be just right for a disc of dust and gas to coalesce into such a set of neatly ordered planets, a new computer model suggests.

Similar planetary systems are likely to be a minority in the galaxy, says model developer Edward Thommes of the University of Guelph in Ontario, Canada. Even so, if only 1% of the Milky Way's hundreds of billions of stars have a terrestrial planet with a stable orbit in the habitable zone, the Earth could have plenty of company.

Honestly? I think computer models are basically race tracks without the horses.

Here's the abstract:

Science 8 August 2008:
Vol. 321. no. 5890, pp. 814 - 817
DOI:
10.1126/science.1159723
Prev Table of Contents Next

Reports Gas Disks to Gas Giants: Simulating the Birth of Planetary Systems
Edward W. Thommes,1,2* Soko Matsumura,2 Frederic A. Rasio2
The ensemble of now more than 250 discovered planetary systems displays a wide range of masses, orbits and, in multiple systems, dynamical interactions. These represent the end point of a complex sequence of events, wherein an entire protostellar disk converts itself into a small number of planetary bodies. Here, we present self-consistent numerical simulations of this process, which produce results in agreement with some of the key trends observed in the properties of the exoplanets. Analogs to our own solar system do not appear to be common, originating from disks near the boundary between barren and (giant) planet-forming.

1 University of Guelph,
Guelph, ON N1G 2W1, Canada.
2 Northwestern University, Evanston, IL
60208, USA.

See also:

Serious push to find more exoplanets

Exoplanets: Will intelligence be common or rare?

Design vs. chance: If extra-terrestrials designed a planet, could we know it was intelligently designed?

In The Design Matrix: A Consilience of Clues, Mike Gene discusses a 2005 paper by Luc Arnold of the Observatory of Haute-Provence in France, in The Astrophysical Journal.

p. 194 Arnold explains his idea thus:

... considering that artificial planet-size bodies may exist around other stars, and that such objects always transit in front of their parent star for a given remote observer, we may thus have an opportunity to detect and even characterize them by the transit method, assuming these transits are distinguishable from a simple planetary transit. These objects could be planet-size structures built by advanced civilizations, like very lightweight solar sails or giant very low density structures may be specially built for the purpose of interstellar communication by transit. (P. 194)

Arnold argues that non-spherical artificial objects such as triangles and other exotic shapes each have a specific transit lightcurve, so alien design would be detectible in principle.

Gene is a bit dubious about how soon to expect this revelation, pointing out that "we are still looking for evidence that microbes exist on other planets," never mind aliens capable of designing, say, a planetary bundt pan.*

Mike Gene's basic point, of course, is that one need not know "who" a designer is in order to detect design, and he cites Arnold because Arnold apparently doesn't think so either.

Gene also observes in the Chapter Notes (Note 3) that France is the home of the Raelians. Mi-i-ike! Do keep in mind, if you are an American, that the United States is the home of Roswell.

Here is Arnold's citation and abstract:

"Transit Lightcurve Signatures of Artificial Objects." Astrophysical Journal, 627:534-539.)

The forthcoming space missions, able to detect Earth-like planets by the transit method, will a fortiori also be able to detect the transit of artificial planet-size objects. Multiple artificial objects would produce lightcurves easily distinguishable from natural transits. If only one artificial object transits, detecting its artificial nature becomes more difficult. We discuss the case of three different objects (triangle, 2-screen, louver-like 6-screen) and show that they have a transit lightcurve distinguishable from the transit of natural planets, either spherical or oblate, although an ambiguity with the transit of a ringed planet exists in some cases. We show that transits, especially in the case of multiple artificial objects, could be used for the emission of attention-getting signals, with a sky coverage comparable to the laser pulse method. The large number of expected planets (several hundreds) to be discovered by the transit method by next space missions will allow to test these ideas.

*Yes, the bundt-pan design would so be handy, when you need your planet to section easily into structures with flat sides and curved tops ....

(Note: The image is an artifcial planet concept from The Infinity Society.)

Serious push to find more exoplanets

Pretty safe prediction: We will hear more about dozens of planets that orbit stars other than our sun. At least if this May 8 (2008) presser from NASA is any indication:

You know the planets of our solar system, each a unique world with its own distinctive appearance, size, and chemistry. Mars, with its bitter-cold, rusty red sands; Venus, a fiery world shrouded in thick clouds of sulfuric acid; sideways Uranus and its strange vertical rings. The variety is breathtaking.

Now imagine the variety that must exist in hundreds of solar systems. There may be worlds out there that make Venus seem hospitable and Uranus positively upright. Only 20 years ago, astronomers were unsure whether any such worlds existed beyond our own solar system. Now, they've found more than 280 of them, each with its own planetary "personality," each a fascinating example of what a world can be.

I wish people would quit calling these exoplanets "worlds" when no one has even remotely suggested that there might be any life there - cept what we send or bring.

What we normally mean by a "world" includes intelligent beings. You know, "Shakespeare's world" or "Nefertiti's world" or even "Sherlock Holmes's world" or, at worst, the "dinosaurs' world."

The perceiver of a world is in at least one sense its creator. I would rather not lose that concept.

A researchers hold out little hope, apparently, that the planets they will find are well suited to life. Still, we wait with interest ... And the graphic above, by artist T. Riecken, is pretty neat.

Exoplanets: Will intelligence be common or rare?

In "Intelligence: A Rare Cosmic Commodity", John D. Ruley profiles the views of Professor Andrew Watson who argues in Astrobiology that intelligent life on the exoplanets (planets orbiting stars other than the sun) is likely to be rare. Watson, who studied under James Lovelock (of the Gaia hypothesis), estimates,

the overall probability that intelligent life will evolve as the product of the probabilities of each of the necessary steps. In his model, the probability of each evolutionary step occurring in any given epoch is 10 percent or less, so the total probability that intelligent life will emerge is quite low (less than 0.01 percent over 4 billion years). Even if intelligent life eventually emerges, the model suggests its persistence will be relatively short by comparison to the lifespan of the planet on which it developed.

Given that we only know about life or intelligent life right here where we live just now, I think some of this would be better as fiction than non-fiction, but it is interesting to hear about anyway.