Why is earth the only one?

I have just been watching the video below, the classic Carl Sagan - Pale Blue Dot video with the song "On the turning away". It's always a thought provoking piece...



I particulary refer to the first few words that Carl Sagan is saying in that interview. He says, "Hey, thats only one little world, we don't have anywhere else to go, no other planet in the solar system is a suitable home for you or me".

Why though?

May i firstly say, i have no amazing knowledge of the universe other than the many talked about theories spoken of here on ATS. A very basic backyard astronomer at best.

So my question. When we look at the Big Bang Theory, why is it that when this huge explosion happened, did just one planet as perfect to sustain life as ours, grow?

I know we haven't exactly explored all of the universe yet, so there could well be another earth out there somewhere. I just find it curious that when the Big Bang happened, and everything we see around us grew from that, surely all that came from that Big Bang would have been scattered around the universe local to us too.

Surely all the ingredients for a perfect life sustainable planet wouldn't have only ended up in one place...here?

I'm not sure i am getting my question across correctly, so i only hope you get my drift.

It's like this, say i get a dusbin full of flower seeds and blow it up thousands of feet above the ground, those seeds will scatter for miles and will grow the same wherever they land.

They will not all fall into my backyard and start growing nicely in my flower bed, but nowhere else will they?

So whatever the ingredients were that came out of the Big Bang, that have over billions of years given us this amazing planet that allows us to live....why are those ingredients not also building earth like planets nearby?

Maybe i'm looking at it all too basic? Maybe other planets are in the early stages of earth?

Just thought i'd put it to the experts.

Thanks.

CX.

[edit on 16/8/09 by CX]

Originally posted by CX
It's like this, say i get a dusbin full of flower seeds and blow it up thousands of feet above the ground, those seeds will scatter for miles and will grow the same wherever they land.

They will not all fall into my backyard and start growing nicely in my flower bed, but nowhere else will they?

[edit on 16/8/09 by CX]

Think more of a dustbin full of flower seeds being individually scattered for millions/billions of miles. Even if another does grow what are your chances of finding it?

[edit on 16-8-2009 by FAQAmerica]

reply to post by FAQAmerica


Good point.

I'm just thinking though, the Big Bang was a pretty large dustbin though.

Don't you just wish you knew exactly how big the universe was?

CX.

It is futile to try and attempt to rationalize or think how large even 1/3rd of the known universe is...our itty ibitty brains can't fathom it,we can write math but not actually imagine the scale in our minds.Needless to say.No doubt there are planets *exactly* like earth..not just kinda,but exactly.Even though the sheer amount of things that had to happen for earth to be what we currently live on no doubt it has happened many many many many times.But problem is the universe is just too darn big..imo anyway.



[edit on 16-8-2009 by Solomons]

There are 200 to 400 billion stars in our galaxy alone, plus who knows how many other galaxies and random stars scattered between them.

Even most mainstream "serious" hardcore academics will admit that statistically, there are almost certainly other planets with life on them "somewhere out there." There just don't happen to seem to be any such other planets in our solar system. Which is, after all, only 8 (or 9, if you count pluto, which some don't anymore) planets.

I think of ourselves a bit like Easter Island. Easter Island is the most "remote" (distant from any other land) inhabited island in the world. Back in the day, most Easter Islanders thought their island was the only land in the universe, surrounded by endless sea horizontally and endless sky/space vertically.

Carl Sagan said "solar system" not universe.

I think mr. Sagan believed in other earth like planets in the universe

Considering the great number of planets out in the universe and even in our galaxy, I suspect there are many, many planets that are "similar" to Earth. However, I think there are far less that are exactly Earth-like -- i.e., same atmosphere, same gravity, same protection against radiation. Heck, I think one also needs to consider the amount of daylight a planet gets...humans are set up on a 24-hour clock, and breaking that cycle causes physical and psychological problems, and it is very difficult to adapt to a different cycle.

I think finding a planet that humans would be able to "live on" without the aid of any artificial devices (gravity-assist, radiation protection, or possibly a respirator to help with breathing) will be much more difficult than simply finding one on which humans can "survive" in the most basic sense of the word.

It will be very difficult to find another planet that is "perfect" for human life simply because human life developed on Earth, and is therefore specifically suited to the atmosphere, gravity, length of day, and cosmic radiation levels.

[edit on 8/16/2009 by Soylent Green Is People]

reply to post by CX


Well, folks see enough stuff in the skies to know that Earth is not unique in having life on it.

If the media is trying to put in our heads that we are still looking for the aliens, and that "we haven't found any so there aren't any", then obviously something is mighty fishy.

Then, after going to the stage hypnotist show, and seeing some ordinary guy say some magic words and hypnotize a zillion folks at once, then that just takes all the mystery out of it... something fishy is going on indeed!

FYI, there have already been discovered 2 other possibly habitable worlds just 20 light years away.

Earth is not alone. Just the fact that 2 worlds might be habitable that close can fill in a lot of Drake's equation and prove that habitable worlds are abundant.

Dr. Sagan almost certainly was referring to our solar system, not the entire Universe. I am sure that Sagan's comments were that we cannot get anywhere else but the solar system, at least not with present technology. The closest star is 4.3 light years away, meaning it would take us centuries to get there, if we could do it at all.

As for why Earth - well, we grew up here. Our physical bodies evolved to survive on a planet like this. If life exists (or existed) on other planets, it would have evolved to thrive under the conditions of those planets. Life on Venus would have to tolerate extremely high temperatures. Life on Mars would have to survive cold and a very thin atmosphere. Each life form would be well suited for its planet of origin, and not for planets that were significantly different.

There's a good chance that there are other planets in the Universe that are somewhat similar to Earth. We don't know where they might be, nor whether any of them developed life. But whatever set of circumstances led to Earth's formation, has probably occurred many times.

Originally posted by MegaCurious
Well, folks see enough stuff in the skies to know that Earth is not unique in having life on it.

If the media is trying to put in our heads that we are still looking for the aliens, and that "we haven't found any so there aren't any", then obviously something is mighty fishy...

I haven't heard the media say that, and it's very rare to find a scientist who believes that. Most scientists believe that life is probably abundant in the universe and even in the galaxy, and most media outlets commonly report that.

I've even seen lately a lot of talk about the possibility finding life in the solar system -- recent news reports about Saturn's moons Enceladus and Titan often discuss the potential for those worlds to have life, and Europa has been in the news for several years now.

Here are a few mainstream news stories about the potential of life elsewhere:
CNN story about organic compounds on Enceladus

ABC News story about "Extremophiles"

BBC story about the possibility of life on Europa


[edit on 8/16/2009 by Soylent Green Is People]

The biggest problem in my mind to finding a planet that we can live on is not so much the physical differences ( as in a little warmer or colder ) since those can be handled fairly well with even our levels of technology. The biggest problem will be bacteria, viruses, and parasites. Since we have so much trouble with them on our little planet that we evolved on imagine what it would be like on a planet out there. We would have close to zero defense w.r.t. those little buggers.