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Winning the E.T. Lottery
Consul writes "Space.com has a cute story about the statistical probabilities that we have been visited by an alien civilzation. He seems to make a convincing argument."
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The problem with this is that analysis like this are simply interesting reading and speculation. Nothing more. Barely science and really not past the hypothesis stage (there is no evidence he is correct).
I can find good arguments for both why or why not other worlds may have life or intelligent life.
-Sean
What are the probabilities that if ETLF(s) were to visit the earth, that there is a single thing we could/should/would do about it? This argument is mute. This guys is just looking for some short lived publisity, and even talks about it in the beginning of his artical. His points are silly at best, and down right retarded in all cases. If I have to pick three points to prove alians have never landed, all three that he used would be tied into one. While I appreciate the idea behind his artical, it was week, confusing, and misleading.
You have a quarter in your pocket and decide to flip it in the air. It lands with the heads side facing up. You repeat this procedure, and without fail the heads side is always facing up after the quarter lands. You do this ... oh ... 10,000,000 times and every time the heads side is facing up. What is the probability that on the next throw the heads side will be facing up?
... 50%
Are you ready for the answer?
The existence of intelligent life on this planet does not necessarily imply the existence of intelligent life on other plantes. Just because a quarter lands heads up 10 million times does not imply that the next toss will produce the same result.
The existence of life on any planet must be taken as an individual probability just as each individual quarter toss must be taken as an individual probability.
QED
They spice up our water/air/primordial-soup with some pre-life cake mix and then fly away. They tell all their friends to come and visit when they get the chance, you know, just to look in and see how things are going. Well, then we get visited by aliens for the next few billions years (assume they have long life spans, or collective memories).
Seems this scenario gets rid of all of his improbable probabilities.
...And instead gives the improbable scenario of aliens stopping by tens or hundreds of millions of times over the Earth's history. This would take a significant expenditure of resources, to little end (especially since the hypothetical ant-farm alien could have seeded a barren world in their own system or otherwise closer to home for convenient visiting). It would also require lots and lots of patience and dedication that would probably be more entertainingly spent elsewhere.
In summary, I'm doubtful of this scenario.
> That's 55 years in a planetary history of 4,600,000,000 years.
What about their planet's history? It's possible that they haven't been able to travel to other planets for that entire time... more like a couple thousand years? Then the ratio is more realistic. (I just love misleading journalists...)
How do you know that there are any appreciable number of space-faring civilizations that have developed in the past few thousand years. Our sun is probably a second, maybe third or more, generation star. Many billions of years have gone by. After the first few billion, one would expect life to start reaching towards our level of complexity. That makes the chance of near-by systems developing high speed space travel nearly synchronized with our own technological revolution highly unlikely. This isn't like Star Trek where hundreds of civilizations all start developing warp drive around the same time. What you are saying is just as unlikely as the point the article was trying to make. Read Contact, that one is more likely.
Don't Bogart the fish sticks
The most amazing thing I was taught as a graduate student of celestial mechanics at Yale in the 1960s was that all gravitational interactions between bodies in all dynamical systems had to be taken as instantaneous. This seemed unacceptable on two counts. In the first place, it seemed to be a form of "action at a distance". Perhaps no one has so elegantly expressed the objection to such a concept better than Sir Isaac Newton: "That one body may act upon another at a distance through a vacuum, without the mediation of any thing else, by and through which their action and force may be conveyed from one to the other, is to me so great an absurdity, that I believe no man who has in philosophical matters a competent faculty of thinking, can ever fall into it." (See Hoffman, 1983.) But mediation requires propagation, and finite bodies should be incapable of propagate at infinite speeds since that would require infinite energy. So instantaneous gravity seemed to have an element of magic to it.
The second objection was that we had all been taught that Einstein's special relativity (SR), an experimentally well established theory, proved that nothing could propagate in forward time at a speed greater than that of light in a vacuum. Indeed, as astronomers we were taught to calculate orbits using instantaneous forces; then extract the position of some body along its orbit at a time of interest, and calculate where that position would appear as seen from Earth by allowing for the finite propagation speed of light from there to here. It seemed incongruous to allow for the finite speed of light from the body to the Earth, but to take the effect of Earth's gravity on that same body as propagating from here to there instantaneously. Yet that was the required procedure to get the correct answers.
These objections were certainly not new when I raised them. They have been raised and answered thousands of times in dozens of different ways over the years since general relativity (GR) was set forth in 1916. Even today in discussions of gravity in USENET newsgroups on the Internet, the most frequently asked question and debated topic is "What is the speed of gravity?" It is only heard less often in the classroom because many teachers and most textbooks head off the question by hastily assuring students that gravitational waves propagate at the speed of light, leaving the firm impression, whether intended or not, that the question of gravity's propagation speed has already been answered.
Yet, anyone with a computer and orbit computation or numerical integration software can verify the consequences of introducing a delay into gravitational interactions. The effect on computed orbits is usually disastrous because conservation of angular momentum is destroyed. Expressed less technically by Sir Arthur Eddington, this means: "If the Sun attracts Jupiter towards its present position S, and Jupiter attracts the Sun towards its present position J, the two forces are in the same line and balance. But if the Sun attracts Jupiter toward its previous position S', and Jupiter attracts the Sun towards its previous position J', when the force of attraction started out to cross the gulf, then the two forces give a couple. This couple will tend to increase the angular momentum of the system, and, acting cumulatively, will soon cause an appreciable change of period, disagreeing with observations if the speed is at all comparable with that of light." (Eddington, 1920, p.94) See Figure 1.
www.metaresearch.org/cosmology/speed_of_gravity.a
Crazy stuff.
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