Whatever that is in the second picture, I'm sure it's on the menu somewhere in China.

(And let's not forget that the skinny aliens with the bulbous heads and black eyes are the product of one of Spielberg's earlier bad movies.)

If you want to postulate that winged humanoids live on other planets, I'm sure that you'll get a warm reception from the ET museum.

Or maybe not - there are some physics and biological issues to resolve before such an assertion could be called "likely"...

But it would be just as scientifically based as the fantasies and guesses on display in London.

Posted by: Michael Herdegen at October 15, 2005 2:48 PM

Michael: Exactly. One would think that Science museums would be shy of just making stuff up to put on display in this day and age. Doesn't help The Cause, does it?

I think that our world has such a wide variety of body plans amongst its animal population that any extraterrestrial alien is going to look a lot like some creature here on Earth. The alien in the picture looks a lot like a member of the spider or crab family.

In part, though, that's because we make a lot of implicit assumptions about what is inherent to living organisms based on one example. For example, maybe life on other planets isn't symmetrical. How do we know?

(Of course, this is all moot as there is no life on other planets.)

David:

Rather, there is life on at least 10,000,000,000,000,000 other planets.*

Note: Life, not necessarily sentient life.

Whether we'll ever get to see any of it is debatable.

*An essentially made-up number, of course; it all depends on how much weight you give the many variables.
However, the hypothesis that there is life on NO other planet besides Earth has only the wee, faintest bit more chance of being correct than the propostion that there is life on ALL other planets.
It's such a long shot that I'd jump at the chance to bet my life against a Krispy Kreme donut that life exists on at least one other planet in the Universe.

Posted by: Michael Herdegen at October 16, 2005 2:09 AM

Done.

Michael: Twenty years ago the SETI/Carl Sagan types proclaimed loudly that there were millions of advanced civilizations in our own galaxy. Their justification was the Drake Equation, which is only interesting in that it shows rather explicitly that we know nothing that we need to calculate the number of inhabited planets, but they went right ahead anyway. Now they are reduced to claiming that there might be hundreds, perhaps thousands, of civilizations, given that they've found nothing and it's been quite a while of looking. Seems to me that Peter Ward & collaborators are far closer to the truth than Carl Sagan & friends. But heck, so is our esteemed Mr. Cohen...

David:

Great, I love free donuts.

I just hope that I'm alive to collect when the proof is found.

b:

Closer, but not "close".

Suppose that, on average, there's only one sentient life form in any given galaxy.

Now, multiply by ten billion to get the number of such in the Universe.
Also, note that the 10*10^14 number that I gave above is only for LIFE, from slime molds on up, not just the advanced civilizations that Sagan spoke of.

Our negative contact SETI results are a continuing disappointment, but not so odd, even if advanced civilizations inhabit our galaxy.
If any of them have learned how to travel among the stars, they're just as likely to use "jungle drums" as they are radio waves - lasers and entangled particles are better bets, or something even more exotic, like space-folding or other high-dimensional communication or travel.

Posted by: Michael Herdegen at October 16, 2005 2:05 PM

Michael: We have observed 1 advanced civilization in our galaxy. Therefore let's use a Poisson "shot noise" estimate of n^0.5 for our uncertainty on that measurement. So based on what we know we can estimate there are 1+/-1 advanced civilizations per galaxy. If the truth is really even as large as 1, your multiplication gets really big. If the truth is really 0, your multiplication stays at 0.

"If any of them have learned how to travel among the stars, they're just as likely..."

Sez who? This may be fun to speculate about, but how exactly does any of this belong in a "science" museum? That was the original point, wasn't it? Don't get me wrong--looking for ET is a legit & important scientific enterprise. But anything beyond that is just fantasy.

b:

I agree with almost everything in your post.

However, for many reasons, long-faring space-travelling civilizations are more likely to communicate between planets and with spacecraft with something other than radio.
Setting aside everything that we can't yet do, that would make lasers a more likely tool than radios.

I can elaborate, if you're interested.

Posted by: Michael Herdegen at October 16, 2005 2:36 PM

Michael:

Setting aside everything that we can't yet do, that would make lasers a more likely tool than radios.

I trust you have pondered that your medieval ancestors of eight hundred years ago (a nano-instant in evolutionary time and space) would have concluded passenger pigeons were the most likely.

Look up the Fermi Paradox, dudes. If there are technological civilizations in the galaxy, the question isn't "why don't we hear them?" but "why aren't they turning our solar system in to consumer goods?". I'm confident we'd have noticed that.

Michael: You're assuming contemporaneity. Even if there were one intelligent species per galaxy, that still wouldn't give us any reason to think that there's more than one in the Universe at any given time.

Hey Peter, really, lighten up. I swear, a scientist really must have run over your puppy when you were a boy.

Has it occurred to you that most science museums are struggling financially and are turning to even the most ridiculous flights of fiction - or sci-fi - just to survive? (Although, come to think of it, the recent "angel" fad probably has much the same motive).

Or that the only real difference between that ridiculous shiny robed cherub with wings and the spindly, spiderlike alien creature is that everyone acknowledges that the latter is the product of someone's imagination, while a fair number of people actually believe in the existence of the former?

M:

Around here, I have the impression the opposite is often the case.

I love scientists. I'm just trying to keep them honest. It's kind of like with software engineers. I love them too, but I do worry when they come to think the way their fried brains work can help the rest of us solve the problems of real life. :-)

I trust you have pondered that your medieval ancestors of eight hundred years ago (a nano-instant in evolutionary time and space) would have concluded passenger pigeons were the most likely.

Yes, which is why I mention quantum entangled particles, which we can currently do, but which we are assured cannot be used for communication (ha !), and folded-space, which we cannot do.

We also cannot do faster than light travel, or even travel fast enough to be practical in visiting other star systems.
Therefore, we can predict with certainty that any civilization which CAN do either of those things will also be better at long-distance communications, and that it's unlikely that we'll overhear such commo by searching for radio traffic.

After all, Alexander G. Bell never dreamed of fiber-optics and cellphones, yet here we are.

Posted by: Michael Herdegen at October 18, 2005 3:50 AM