Positive rate From Australia, joined Sep 2001, 2143 posts, RR: 1 Posted (10 years 2 months 2 weeks 12 hours ago) and read 770 times:
I'm a little over half way through a biography about Dr. Carl Sagan- the 20th centuries greatest astronomer and astrophysicist in my opinion. I've found it to be a really interesting read and I'm quite surprised as to the depth of Dr. Sagan's knowledge. He was really the only scientist at NASA who believed in the possibility of extraterrestrial life in the universe- he even argued in the 1960's that Venus could be terraformed by humans and Mars had microorganisms, of course these theories turned out to be false but who knew that back in the 60's? He came up with the idea of fitting plaques on the Pioneer and Voyager space probes in case extra terrestrial beings ever discover them. Most of all Sagan is most remembered as the scientist who brought science into the average person's living room and explained things in such a way that even the layman could understand what he was saying. He became famous by appearing on the Johnny Carson show and later by making the series Cosmos.
Does anyone know if the Cosmos series is available on DVD or video because I can't find it anywhere??? I'd really like to see it.
Positive rate From Australia, joined Sep 2001, 2143 posts, RR: 1 Reply 2, posted (10 years 2 months 2 weeks 11 hours ago) and read 735 times:
Yes but that's irrelevant for a number of reasons. If alien beings to exist then the chances are they will be far superior than us and benevolent and they might not even be interested in us because we are so far behind them. And secondly we humans have been inadvertently sending radio messages to the stars for the past half century or more by way of televsion and radio- it all goes out into space even tv shows and radio broadcasts so they's detect that anyway.
Scotty From UK - Scotland, joined Dec 1999, 1875 posts, RR: 3 Reply 4, posted (10 years 2 months 2 weeks 10 hours ago) and read 730 times:
I was a great enthusiast of Carl Sagan. In 1981 hundreds of students and academics, together with members of the public, queued up for over two hours each day for a week to get into the Gifford Memorial Lectures at Glasgow University in Scotland as he was the guest speaker. In the end, he used three lecture rooms and a total combined audience of about 2000 each day, with video links.
I was in or near the front row at every lecture, got to talk to him for quite a long time and have a copy of his book, Cosmos, personally signed, which is one of my personal treasures.
He was controversial, visionary, and great. He helped humanity to lift its eyes beyond its own parochialism. Nobody has come along to replace him.
On the question of extraterrestrials one of his comments in particular remains a clear memory. When asked if he could PROVE that they existed, he simply replied "absence of evidence is not evidence of absence" and used exactly the same phrase again a few minutes later when asked if he believed in God.
Hartsfieldboy From United States of America, joined Sep 2001, 552 posts, RR: 1 Reply 5, posted (10 years 2 months 2 weeks ago) and read 712 times:
Why do people always think that aliens are going to be superior than us? If there is other life, most likely it will be nothing more than muck or slime. IF They happen to be intellingent life, why would they be human-like with thoughts of exploration or war or whatever? There are hundreds of thousands of different species on earth that could be similar to aliens, what makes you think they would be more like us and have technology? They would be like the 99% of all other life and not have the capacity to do anything if they encounter anything we made.
GDB From United Kingdom, joined May 2001, 12715 posts, RR: 80 Reply 6, posted (10 years 2 months 2 weeks ago) and read 706 times:
A great man of popular science (don't knock it if it helps get the funding).
As for aliens, maybe they exist, but coming for us? You need faster than light travel which I doubt is possible.
(Bad luck Star Trek fans, it aint going to happen, and if it does, it won't be anything like how that show depicts it, any more than Jules Verne was right about how we'd get to the Moon).
Unless they've evolved to a sort of post-physical body state maybe, then we won't know they are here.
But it is likely that advanced, space faring life, is very, very rare.
Earth is just the right distance from the Sun, a large Moon prevent too much tilt thus allowing stable seasons, a giant like Jupiter deflects or shields us from too much bombardment from comets.
Only a single sun, no double star system, or variable stars needed too.
In fact, without the Moon, pretty unlikely advanced animal life would have arisen at all.
That still leaves a lot of potential second Earths in our Galaxy probably, but not teeming with them.
Also, there has been plenty of time in the history of the universe for super-advanced life to evolve several times over, on a similar development timescale to us, not seen them yet have we?
Maybe it's also the natural order of things that advanced races on planets destroy themselves at around a certain point in their development, maybe before they get the ability to do star travel, unlikely as such a thing is.
Another reason for us not to have met them.
(I think you can safely conclude that I'm not in the 'UFO's are spaceships' camp).
Positive rate From Australia, joined Sep 2001, 2143 posts, RR: 1 Reply 8, posted (10 years 2 months 1 week 6 days 17 hours ago) and read 681 times:
It is estimated that the Milky Way Galaxy alone contains about 300 billion stars. Out of those 300 Billion stars Sagan estimated that going by the Drake equation there should be at least 1 million technically advanced civilistaions in our Galaxy alone, the only problem is they are probably spaced about 150-200 light years apart from each other which makes interstellar travel very very difficult. For those of you that don't know it here is the Drake Equation:
N=R*fp ne fl fi fc L
The variables represent:
N- the number of civilisations in the Milky Way Galaxy ABLE and willing TO ENGAGE IN INTERSTELLAR COMMUNICATION
R*- the rate of star formation in the galaxy (that is, the number of newborn stars that arise per year)
fp- the fraction of stars with planets
ne- the fraction of habitable planets in an average planetary system
fl- the fraction of habitable planets on which any form of life arises (microbes, mollusks, etc.)
fi- the fraction of inhabited planets on which life evolves into "intelligent" beings
fc- the fraction of alien societies that develop the technical ability to communicate with outside planetary systems, as well as the will to do so
The last, most ominous variable is L
L- the average lifespan of a technologically advanced civilization (that is, how long a typical advanced civilization survives before it dies off or self-destructs)
Tsv From Australia, joined Nov 1999, 1641 posts, RR: 5 Reply 12, posted (10 years 2 months 1 week 6 days 3 hours ago) and read 631 times:
The way Earth was destroyed in "The Hitchhiker's Guide to the Galaxy" (making way for a hyperspace bypass or whatever it was) was quite funny and is one possible way superior Aliens might get rid of us.
Positive rate From Australia, joined Sep 2001, 2143 posts, RR: 1 Reply 15, posted (10 years 2 months 1 week 5 days 16 hours ago) and read 597 times:
The thing that most worries me about the Drake equation is the variable L. This is the average lifespan of a technologically advanced civilization. While we have nukes there is always a danger that we will wipe ourselves out. We've come so close to do so numerous times in the past and we're about to do it again with Iraq. If we have nukes then the chances are if an advanced civilization does exist then they will have possessed nukes at one time or another too, so they probably went through their own version of a cold war etc. Perhaps that's the reason why SETI is not detecting any alien signals, maybe they've all annihilated themselves?? It's a possibility
Delta-flyer From United States of America, joined Jul 2001, 2676 posts, RR: 7 Reply 16, posted (10 years 2 months 1 week 5 days 16 hours ago) and read 593 times:
Interesting you should mention SETI. I just got a newsletter from them today.
Here's what they say: "On March 18-20 2003 we travel to the Arecibo radio telescope to re-observe the most promising "candidates" produced by our search so far. There is a chance that these new observations will yield the first real evidence of extraterrestrial life."
PHX-LJU From , joined Dec 1969, posts, RR: Reply 18, posted (10 years 2 months 1 week 5 days 14 hours ago) and read 582 times:
"Also, wasn't he one of the first scientists to accept "God or a higher power" in his discussions on science?"
Actually, he was an atheist -- he rejected the idea of God, at least in the traditional sense of that word. In fact, he famously stated that "The cosmos is all that is, or ever was, or ever will be." According to http://www.angelfire.com/oh3/scottspage/sagan.html, "The only remotely traditional view of God Sagan nods to is Einstein's concept that God is the sum total of the natural laws."
Positive rate From Australia, joined Sep 2001, 2143 posts, RR: 1 Reply 20, posted (10 years 2 months 1 week 5 days 12 hours ago) and read 566 times:
The Biography that I just finished reading is titled: "Carl Sagan a life", written by Keay Davidson, I'd highly recommend it to anyone with an interest in this scientist and astronomy in general. After reading it it's amazing to realize all he accomplished during his lifetime and the theories that he came up with(some which later proved to be incorrect)but interesting nonetheless.
As far as I know his only television series was "Cosmos" which aired in 1980, it's a 13 part series dealing with everything from the origin of human life to extraterrestrials and the formation of stars, planets and the human brain. The planets is another series I have on video, but it's not produced by him although still very good.
After reading his biography it's obvious that Sagan didn't believe in the existence of a GOD. To him it had to be scientifically plausible to be real. I.e the existence of a GOD can neither be proven nor disproven therefore it cannot be a rational theory. Even up until the point where he died there was no conversions, he firmly believed it was the end. He did however side with various religious groups for political purposes i.e to convey his theory of Nuclear Winter during the cold war.