The habitable zone

cyberhog

Religious people would say that God put the earth in the habitable zone. I'm not religious myself but I'd imagine the odds would be near-astronomical that a planet would land in just the right spot of outer space to support life. So I was wondering if atheists are not willing to entertain the possibility that the religious folks are right, how else do ye explain the earth being in just the right location to support life?

im invisible

we wouldnt be 'here' if 'here' couldn't support life, simples

endacl

Did god put your post there, op, just so I could have a giggle?

TheChizler

Well planets will always form in the vicinity of, and orbit around stars (by definition!), so it's no coincidence that the sun is nearish. Also people seem to have the perception that the Goldilocks zone is within a strict error of maybe a few kilometres, this simply isn't true. The earth's distance from the sun varies by several million kilometres over the year without a perceptible deviation in conditions.

Your question is like asking what are the chances of people being able to just build a computer from scratch, when in fact it's the result of a long and adapting design process over hundreds of years.

Maybe you need to look at this the other way around, not: what are the chances of a planet with our life on it having formed suitably in a suitable zone around a suitable star, but: what are the chances of life forming on and adapting to conditions on a planet with roughly this composition in roughly this orbit around a star that is roughly suitable.

The thing about life is that it adapts to all sorts of extreme conditions, if we got knocked into some significantly different orbit some life would in all likelihood survive and eventually thrive.

krudler

It's also amazing that we mostly live in places that aren't made of lava, or the bottom of the ocean

Zombrex

cyberhog wrote: »

Religious people would say that God put the earth in the habitable zone. I'm not religious myself but I'd imagine the odds would be near-astronomical that a planet would land in just the right spot of outer space to support life. So I was wondering if atheists are not willing to entertain the possibility that the religious folks are right, how else do ye explain the earth being in just the right location to support life?

That question is like asking how do you explain that the space in your kitchen that gets mold happens to be the exact right conditions to get mold.

The point is that the mold is there because the conditions are right, not the other way around. The mold develops in that spot because that is where it can develop

There are probably hundreds of trillions of planets in this galaxy alone. Just like looking at the entire kitchen and spotting where mold starts growing, it is not out of order to say that life started to develop where it could.

oldrnwisr

cyberhog wrote: »

Religious people would say that God put the earth in the habitable zone. I'm not religious myself but I'd imagine the odds would be near-astronomical that a planet would land in just the right spot of outer space to support life. So I was wondering if atheists are not willing to entertain the possibility that the religious folks are right, how else do ye explain the earth being in just the right location to support life?

Oh great, another fine tuning argument.

OK, as TheChizler has already explained, the variation in our orbit is quite large. The difference between perihelion (the point in our orbit when we are closest to the Sun) on 3rd January and aphelion (the point in our orbit when we are furthest from the Sun) on 4th July is approximately 5 million kilometres. So we already go way past the idea of just the right spot even in our own orbit.

Then you've got the habitable zone itself. Currently the earth is 1AU from the Sun or approximately 149.5 million kilometres. The most pessimistic estimate for the habitable zone is 0.95-1.01 AU or approximately 8.9 million kilometres. This is roughly 700 times the diameter of the earth. However, the best supported estimate we have suggests that the size of the habitable zone is 0.95-1.37 AU or almost 63 million kilometres. That's nearly as far out as Mars which is just 1.38 AU from the sun. So the idea in practical terms that we are in "just the right position" is laughable.

Now, there other things to consider with this question too.

Firstly, there is the anthropic principle which im invisible referred to. If earth weren't suitable for life then we wouldn't be here talking about it.

Secondly, you've got your cause and effect slightly backwards. It's not the planet that was adapted for life, it's that life adapted to the conditions on the planet.

Finally, as much as religious people might claim that God put the earth in the habitable zone like some kind of cosmic lego set, we actually have a reasonable idea of how our solar system formed, it's called the solar nebula hypothesis.

username123

Other posters have already answered the question clearly. Might I suggest reading a basic science book and looking up the section on formation and evolution of the solar system? It will contain factual information unlike the bible which is a work of fiction.

Dades

And nobody's even mentioned the puddle, yet!

OP, you're using logic like the puddle who thinks the hole in the ground he sits in must have been made for him, because it fits so perfectly.

pauldla

username123 wrote: »

Other posters have already answered the question clearly. Might I suggest reading a basic science book and looking up the section on formation and evolution of the solar system? It will contain factual information unlike the bible which is a work of fiction.

Indeed. Bill Bryson's A Short History of Nearly Everything is a good everyman. The OP should find Chapter 16 quite interesting.

Akrasia

This also a version of the marksman fallacy. Basically, firing an arrow randomly and then placing the target in the exact place the arrow landed and declaring that you've struck the bullseye

Given the law of entropy and the fact that everything is tending towards disorder, every single particle and photon in the universe is in it's position due to a conflation of extraordinarily unlikely events.

The fact that you are born is down to one particular sperm out of millions of competing sperm getting to fertilise one particular egg out thousands of eggs your mother had in her ovaries. That's pretty unlikely, but your existence also requires the exact same good fortune for each of your grandparents and their parents and their parents etc etc etc

This is one reason why it's a little bit silly to give 'potential' life the same status as actual life (things like banning embryonic stem cell research or the morning after pill or more controversially, early term abortions)

Every single aspect of every single part of our genetic identity and our personality and our lived experience is the result of extremely unlikely random occurances that all happened to happen in the precise order to allow you to have your experiences

Given that there are trillions of stars and trillions of planets and possibly even an infinite number of universes and opportunities for life to evolve, it is more of an inevitability that extremely unlikely things will happen.

TheChizler

Dades wrote: »

OP, you're using logic like the puddle who thinks the hole in the ground he sits in must have been made for him, because it fits so perfectly.

Or even that the banana was designed for the benefit of humans since it is easy to hold, tastes good, and fits in the mouth...

krudler

TheChizler wrote: »

Or even that the banana was designed for the benefit of humans since it is easy to hold, tastes good, and fits in the mouth...

*snigger*

Bannasidhe

Isn't it amazing that our feet are the perfect shape to fit in wellies. God designed it that way...



:rolleyes:

endacl

Bannasidhe wrote: »

Isn't it amazing that our feet are the perfect shape to fit in wellies. God designed it that way...



:rolleyes:

I though holygod had cocked it all up when I first heard of the 'wellies hypothesis'. I hadn't accounted for the whole left welly, right welly thing. To be honest, it nearly had me convinced when I got that bit figured out. Then I thought 'hold on. I don't need wellies! Like I don't need an appendix...'

T'was back to square one for me that day, I can tell you. Philosophical crisis much!

fitz0

TheChizler wrote: »

Well planets will always form in the vicinity of, and orbit around stars (by definition!),

Not true as it turns out.

http://phys.org/news/2012-11-astronomers-homeless-planet-space.html

A planet that is not orbiting a star, effectively making it homeless, has been discovered by a team of University of Montreal (UdeM) researchers working with European colleagues and data provided by the Canada-France-Hawaii Telescope (CFHT) and the European Southern Observatory's Very Large Telescope (VLT). "Although theorists had established the existence of this type of very cold and young planet, one had never been observed until today," said Étienne Artigau, an astrophysicist at UdeM. The absence of a shining star in the vicinity of this planet enabled the team to study its atmosphere in great detail. This information will in turn enable astronomers to better understand exoplanets that do orbit stars.

It's almost certain they could never support life as we know it though. This in no way detracts from the arguments made here, it's just an interesting factoid.