someone showed me this yesterday. I haven't read it but does he explain in there how we'll make it to the end of this century without many of us being wiped out? Maybe "within a thousand years" in just in reference to the richest humans keeping safe, the ones who'll probably make it no matter how the rest are suffering

Does he mention how losing so many species might affect things?

Maybe I should just read it, it looks very uplifting!

Seriously, why do we need humans all over the galaxy? What good are we?

Now, if I could have a body adapted to run around Mars naked, feeling comfortable in all sorts of Martian weather, enjoying the open sky and the sunshine against my skin, well maybe then emigration would be worthwhile.

Frankly, it's possible our intellectual prodigy may leave earth, either bio-engineered beings or self-reproducing mechanicals, but humans as we exist now are too fragile and not quite smart enough to thrive in non-earthly environments. In fact we're pushing the limits in arctic environments and people have lived there for thousands of years. And it's only because air, water, and food already available naturally in abundance.

As humans we are clever, but the technological society we have is fragile, and may not make it even on the planet we are best adapted to.

Scientists aren't sure if it was a meteor or a pathogen that actually wiped out the dinosaurs, or a combination of both: pathogen reduced their numbers and made them too weak to survive in the harsh conditions immediately following the meteor. That's just conjecture, IMO.

What we do know is that there have been several extinction events on Earth and there is no guarantee that another is not on the way. Some surmise that every few hundred million years the Sun enters a galactic band of dust and gas that somehow causes havoc... and we're due for it again sometime.

The question is: where do we go and how do we live there when we get there?

you can tell at one point they were molten and in these now solidified rocks is fossils of what is mostly shells, some pretty strange some pretty much like what we have today. In my opinion there has been a mass extinction that I think would go back further than the dinosaurs.

Here's a link that shows what caused each and you can drill down to see specifics of the percent of species killed off.
http://dsc.discovery.com/earth/wide-angle/mass-extinctions-timeline.html

Now that we are sentient and have the capability, it's just plain crazy not to try to colonize space. Hawking gave us a hundred years to start. There' s no telling where our technology will be at that time. But since we can do it with today's technology (admittedly at great expense), I see no reason why we should not start planning for it starting in 2100.

Since life began on earth, at least three and a half billion years ago, there hasn't been any natural disaster that would make the earth less attractive than mars, the moon, any known planet, or free space.

Clobber earth with an asteroid, freeze the earth's surface solid in ice, cover it with volcanoes and a poison atmosphere, and yet the earth is still an easy place for us to live in comparison to anywhere else.

Time is long, the universe is big, and we don't know of any other planets that humans would be comfortable on.

The earth is where we live, the earth is where we will die.

We've got as much chance of thriving in space as a dolphin has got living in a fourth floor walkup in Brooklyn.

You seem to think that people will be walking around the surface of Mars in shorts and a tee shirt, despite the -250 degree temperatures and near total lack of oxygen. Your vision is impaired.

We will live in underground habitats on Mars that have been dug out of the solid rock that we know is there. It will be more like the underground mall in Atlanta or Toronto's underground than anything your post seems to imagine.

There will be wide open spaces filled with trees, shrubs and flowers because *that* is how humans feel most comfortable. Actual food production will be by hydroponics -- Mars contains everything we need to grow as much food and natural environments as we wish, except for potassium. That we can ship from Earth until we perfect methods of mining the asteroids and the Oort cloud which contain everything we will need and more.

Daylight bulbs: http://www.amazon.com/s/ref=nb_sb_ss_i_3_12/182-7270502-2972002?url=search-alias%3Daps&field-keywords=daylight+led+bulb&x=0&y=0&sprefix=daylight+led%2Caps%2C293

Oxygen and rocket fuel:

Thanks for the link

We will not be colonizing space.

It's time to get used to being what we are, where we are, and trying to make the best of that first.

"... it is also an expression of loyalty to the earth which bore us and sustains us, the only home we shall ever know, the only paradise we ever need - if only we had eyes to see." --Ed Abbey

Hawking is right. We should not have all our eggs in one basket.

But we do. So now what?

Rather than fantasizing about running away to join the space circus, perhaps we might think about growing the fuck up and acting like responsible adults here on earth...

about both?

And not all catastrophes ought to be caused by humanity - asteroid/cometary impacts or global epidemics are also a threat.

I was a "rocket boi" in the mid-60s, just like Homer Hickam, right down to the fuel mixing and the backyard launch pad. I was going to go into aerospace engineering until I got my first look at the math required for orbital mechanics. I oppose everyone who advocates cutting the NASA budget or thinks that we should be chopping the pittance we spend on planetary exploration. I've dreamed of L5 cylinders and beanstalks, and went to see "2001" five times.

But.
But.
But.

The reality is that we have evolved and live in a deep gravity well, the resource costs of maintaining human life outside of an earth-like planetary environment is utterly prohibitive, there are no other such environments available, and we have gravely overestimated both out own ingenuity and all-in cost of the resources required. We are running out of critical resources needed just to maintain life as we know it here on Earth. We may be near the end of this cycle of civilization, a situation that is the direct result of our heedless cleverness and our inability to accept limits.

The dream of living elsewhere in the universe is a puerile fantasy, unworthy of a species that fancies itself as approaching some pinnacle of adulthood. It just plain ain't going to happen. Sorry to be so harsh - but how do you think I felt when I realized it, given my background?

But the congress cut their budget so much that it became impossible.

The point is we COULD have had lunar colonies starting in the 1970s. That we chose not to is budgetary failure, not lack of vision.

Not full colonies to expand the human presence into the cosmos.

Implying that would not be human presence, which would grow over time if access to space was not very expensive. Implying it is not enough to expand our presence at least into the inner solar system (I am skeptical about colonising other star systems due to FTL barrier, but colonising our solar system is perfectly viable with our technology).

SpaceX rockets and capsules, Atlas Phase II, factory produced Bigelow inflatable modules, fuel depots, ion thrusters, maybe nuclear powered outposts and nuclear propusion - with these things we can build human colony on the Moon or Mars for fraction of the ISS cost. If we wanted.

There were science articles about parking spacecraft in the "Lagrange points" surrounding the Earth and Moon. My classmates and I made reports about them in science class. Decades later, techie trekkie types even held "Lagrange fests" to celebrate Lagrange colonization fantasies.

John Glenn's flight and the Apollo program inspired me to go into physics and astronomy, which led to a degree in engineering and a career doing certification paperwork for a manufacturer in Asia. Heck, it's a living!