Posted on 04/10/2015 11:52:04 AM PDT by BenLurkin
The argument claiming that extraterrestrials don’t exist was actually proposed by the astronomer Michael Hart, in a paper he published in 1975. Hart supposed that if an extraterrestrial civilization arose in the galaxy it would develop interstellar travel and launch colonizing expeditions to nearby stars. These colonies would, in turn, launch their own starships spreading a wave of colonization across the galaxy.
How long would the wave take to cross the galaxy? Assuming that the starships traveled at one tenth the speed of light and that no time was lost in building new ships upon arriving at the destination, the wave, Hart surmised, could cross the galaxy in 650,000 years.
Even allowing for a modicum of time for each colony to establish itself before building more ships, the galaxy could be crossed in two million years, a miniscule interval on a cosmic or evolutionary timescale. Hart asserted that because extraterrestrials aren’t already here on Earth, none exist in our galaxy.
Hart’s argument was extended by cosmologist Frank Tipler in 1980. Tipler supposed that alien colonists would be assisted by self-reproducing robots. His conclusion was announced in the title of his paper ‘Extraterrestrial intelligent beings do not exist’.
Why is it important that Hart’s argument wasn’t really also formulated by the eminent Enrico Fermi? Because Fermi’s name lends a credibility to the argument that it might not deserve. Supporters of the search for extraterrestrial intelligence (SETI) want to search for evidence that alien civilizations exist by using radio telescopes to listen for radio messages that extraterrestrials may have transmitted into space. Interstellar signaling is vastly cheaper than a starship, and is feasible with technology we have today.
(Excerpt) Read more at universetoday.com ...
ping
“Extraterrestrial intelligent beings do not exist” or interstellar travel will never be feasible at least to much extent.
We are the interstellar species that will inhabit the universe. We are not yet around for a million years. If we continue to exist as a species we will inhabit the known universe.
2. What would an advanced civilization desire or require from the equivalent of rats, if we're lucky?
It's like dating in high school. The troglodyte rarely scores the Prom Queen. Nothing in common.
Once again... We don’t know everything there is about science- mathematically it IS possible to do faster than light travel.
From ancient records it is obvious SOMEONE was here that they talked about coming “from the heavens”
And Bob Lazar saw their gravity propulsion systems, and I believe him (seriously, I do)
The so-called Drake Equation isn't taken seriously because the name is attached to a prominent SETI pioneer. It's not taken seriously because it's nothing more than a WAG, and everyone who understands quantified science knows it.
Truly stupid arguments!
you do not know when the first intelligent beings first started the conquest of the galaxy. They could be starting just about now and will be here in 2 million year.
at 10% of the speed of light, how long would it take us to reach the next closest solar system?
We may be the first intelligent life form that will conquer the galaxy.
etc. etc.
"Mathematically" means nothing. The question is, is this physically possible. The answer to that question is no.
The difference is, that the troglodyte and prom queen pass each other all the time in the halls, and, given the intelligence of most prom queens probably have a lot of classes in common.
In your analogy, the trogs are sitting in their little enclave in the cafeteria. Somebody mentions the prom queens in movies and asserts that the odds are millions to one that they must exist. The Fermi troglodyte replies: "how come there aren't any in our school?"
We are, without a doubt, a very impatient species. Modern science is not quite 250 years old with a tremendous leap forward beginning in the first half of the 20th century. Look at where technology was just 10 years ago compared with now. We are just scratching the surface in the discovery of and study of planets circling other stars.
Yet there are many voices saying that anything other than earth is a waste of time and money to explore. Heal Gaia and ignore the rest? Not only that, a lot of so called ecologists advocate killing off 90 to 100% of us to save the earth.
Forty years.
The likelihood that we are the first intelligent life in the galaxy is astronomically small. So is the probability that no one has reached us over the course of the last few hundred thousand years. Unless... there are unknown factors which make life much less probable than the best conjectures.
what would an advanced, intelligent species want with us lowly primitives (other than, perhaps, to “serve mankind” ... for dinner)?
The Milky Way is 100,000 ly across, so traveling at 1/10 the speed of light that’s 1 million years not 650,000. Plus of course there’s the assumption of no “distractions” which doesn’t really hold water. Plus of course even if somebody went across who says they come to here. And colonization takes a lot longer than merely travel. And we don’t know when they started, if they started on this 1 million year journey 750,000 years ago they’re “almost” here... and we won’t encounter them for many times our recorded history.
The odds are overwhelmingly that they have been here for some time.
The odds are also that we would not see them unless they wanted to be seen.
Finally, if you were them, would you want to be seen by us?
Can’t get past today?
Even an ordinary, intelligent person could probably make a half decent guesstimate on the *possibility* of life elsewhere, with a limited set of variables. Comparing life elsewhere with Earth is problematic, though, because of our “extinction events”, that result in evolutionary “reboots”.
“In the past 540 million years there have been five major events when over 50% of animal species died.” And while human beings breed *a lot*, this cannot be assumed to be a common quality of intelligent animals. Humans have never had to endure an extinction event.
Another down factor are “cosmic” extinction events, like supernovas, that can sterilize a large sector of space to the point where there are no surviving microorganisms.
There is also a good theory that in a galaxy, life can only exist about 3/4ths of the way away from the galactic center. Not too near and not too far away. Like us, on a branch of a spiral, in a quiet enough part of the galaxy to thrive for a while.
In any event, assuming the life of the Milky Way galaxy is about 14 billion years, if you plot where the supernovas have been in say the last 500 million years, to eliminate them from where life is likely to be, then adjust for about 3/4ths of the way away from the galactic center, you have likely eliminated 99 out of 100 places to look.
Then you get to the intelligent life problem, basically, how long to intelligent species last before they either revert to a more primitive state, or just die out? This is the 14 billion year problem.
If intelligent species only last 100,000 years on average, they are biological “flashes in the pan”. But if they are as durable as horseshoe crabs or coelacanth fish, at 450 and 400 million years, respectively, then they have a good chance to at least make their mark in the universe.
About a 1 in 35 chance, that it. 400 million into 14 billion.
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