[Greyson]

Originally Posted by dreadgeek

MsD:

I saw this on HuffPo and I'm so looking forward to the book being released. I'm happy it'll be out before classes start again so I can lose a weekend to the book.

At any rate, one thing that Hawking states is that the discovery of extra-solar planets shows that our conceit that Earth--or even our solar system--is somehow special and a sign that there's a creator is misplaced. It's very true. Something one hears quite a bit is that *because* the Earth is in the habitable zone of our local star it shows that a divine being *must* have created the planet since what odds are there that a planet would be in the particular orbit we are in.

Here's the thing, around any star--of any size--there will be some number of stable orbits. One or more of those orbits will be in the HZ which means that it will be both warm enough and cool enough for liquid water to exist on the surface. What orbit that will be is going to be determined by the size of that star, its luminosity and its color. Stars run from Blue - Red (In descending order of heat--Blue, Blue-White, White-Yellow, Yellow, Orange-Red, Red) and from Very Bright (luminous) Supergiants to Dwarf stars (also called main sequence stars), to white dwarf stars. The HZ for any one of these stellar types will be different. Our star--which is small and relatively cool (as these things go)--has a HZ at around 80 - 100 million miles (if we find that life got started on Mars then the HZ would extend to Mars' orbit at 140 million miles). A Blue Supergiant star (which would be about the size of our entire solar system if you can imagine that) would have a very different orbit (probably beyond the Kuiper belt and Oort cloud and possibly halfway to our nearest stellar neighbor four light years from here).

An intelligent species, living on a planet orbiting a blue supergiant, would likely think that there was something special about being 2 light years from their primary star--until they developed science and built space-based telescopes and started looking for planets outside their solar system.

I'm not saying there is no god--that's not for me to say although I don't believe that there is--and neither is Hawking. But what Hawking *is* saying is that there is nothing that requires a god for the universe to work. In a universe with gravity, you're going to get stars and you're going to get planets, after that all you need are enough stars, enough planets, and enough time--all of which the universe has in abundance. There are an estimated 100 *billion* galaxies in the observable universe and each one of these galaxies has hundreds of millions of stars, astronomers are finding that planets are not all that rare--about half of all stars have them--so there are, at least hypothetically, billions upon billions of planets and some of them are going to be in the HZ of their primary so life has at least a fighting chance to get booted up and that's just a matter of time (surprisingly little time, as it turns out. Earth may have had life starting as early as 500 million years after the planet formed and cooled).
Cheers
Aj

It is not a secret that I do believe in a God, Universal Power, One that manifests and expands through every living thing. I read about this forthcoming book earlier this morning and I will be reading it. Not to dismiss his thoughts nor to burn it. There are "believers" that do not minmize "God" to be only what my mind can phantom, comprehend.