Credit: NASA
Another question is: Can we exist for a long time away from the Earth?
Our experience with the International Space Station (ISS), shows that it is possible for human beings to survive for many months in space, but that zero gravity causes a number of undesirable physiological changes such as weakening bones.
One would therefore want any long-term base for human beings to be on a planet or moon, with gravity.
By digging into the surface, one would get thermal insulation and protection from meteors and cosmic rays. The planet or moon could also serve as a source of the raw materials that would be needed if the extraterrestrial community was to be self-sustaining and independent of Earth.
What are the possible sites of a human colony in the Solar System? The most obvious is the Moon. It is close by and relatively easy to reach. We have already landed on it and driven across it in a buggy.
On the other hand, the Moon is small and without atmosphere or a magnetic field to deflect the solar radiation particles, like on Earth. There is no liquid water, but there may be ice in the craters at the north and south poles. A colony on the Moon could use this as a source of oxygen with power provided by nuclear energy or solar panels. The Moon could also be a base for travel to the rest of the Solar System.
Mars is the obvious next target. It is half as far, again, as the Earth from the Sun and so receives half the warmth. It once had a magnetic field, but it decayed four billion years ago, leaving Mars with no protection from solar radiation. This stripped Mars of most of its atmosphere, leaving it with only one per cent of the pressure of Earth's atmosphere.
However, the pressure must have been higher in the past because we see what appear to be runoff channels and dried-up lakes. Liquid water cannot exist on Mars now, as it would vaporize in the near-vacuum. This suggests that Mars had a warm and wet period during which life might have appeared either spontaneously or through panspermia.
There is no sign of life on Mars now, but if we found evidence that life had once existed, it would indicate that the probability of life developing on a suitable planet was fairly high.
NASA has sent a large number of spacecraft to Mars, starting with Mariner 4 in 1964. It has surveyed the planet with a number of orbiters, the latest being the Mars Reconnaissance Orbiter. These orbiters have revealed deep gullies and the highest mountains in the solar system.
NASA has also landed a number of probes on the surface of Mars, most recently the two Mars Rovers. These have sent back pictures of a dry desert landscape.
However, there is a large quantity of water in the form of ice in the polar regions. A colony on Mars could use this as a source of oxygen, at least.
There has been volcanic activity on Mars too. This would have brought minerals and metals to the surface which a colony could utilise.
The Moon and Mars are the most suitable sites for space colonies in the Solar System. Mercury and Venus are too hot, while Jupiter and Saturn are gas giants with no solid surface. The moons of Mars are very small and have no advantages over Mars itself.
Some of the moons of Jupiter and Saturn might be possible. In particular, Titan, a moon of Saturn, is larger and more massive than other moons and has a dense atmosphere.
The Cassini-Huygens Mission of NASA and ESA landed a probe on Titan in 2004, which sent back pictures of the surface. However, it is very cold, being so far from the Sun, and I wouldn't fancy living next to a lake of liquid methane.
what a nut!
this nutjob lives off the state,he will never speak truth to power because his kind live on the state teat.all this space travel will be paid for by the state in the form of taxes stolen from you by the barrel of a gun.these nutty professors need to get real jobs and quit wasting our time and money on this shite.
Your a nut!
Steven Hawking is a genius. He is thinking in the long term.. I don't think taxes are fair but whats 1/4 percent of our GDP. I'm sure we could take it from our defense budget and do just fine. How about bring all the troops home for every country in the world. That would equal the money we need plus some. Also what he's trying to tell you is that this "new space race" could help mankind. This is how new technology is created. Its a goal. In the long term it could benefit mankind. Just look at the computer you are using and the internet. This is what science has provided for you! You need to wake up and realize that science and research is something we should be spending our money on. Not wars and bailouts. Want to debate more? AIM steve196982
Don't think taxes are fair?
Hahah. So how are you planning on paying for your roads? Airports? Regulatory bodies? Power? Water? Defense?
We need government.
Don't feed this troll
Hmmm...this poster is probably a tin-foil-hat-wearing conspiracy-theorist offended by Prof Hawking's denigration of ufo believers as "cranks" and "weirdos"....just a thought.
I am no fan of big
I am no fan of big governments and repression and all, but I do say these lunatics whining about taxes being taken at the barrel of a gun will be the death of us all. What do they propose? Every large number of people will need government and policing and collective infrastructure. If you don't have collective governmental programs and investments and tax you live in a country like Somalia - where there's is nothing except warlords.
Nut job?
Perhaps...but then most of those 'what brought us to this dance' were or are. Hawking is simply stating what most of us that lived through the shut down of the NASA moon ventures said at the time.
Now, here we are, 35 years later, more than 6 trillion poured into the failed 'great society' with the same percentage of poor now that we had then, and believing that had we not changed direction in this country we would have a well established moon colony today and probably reaching out with manned missions to Mars.
Shalom Freedman
Its encouraging that Stephen Hawking is concerned about the future of the human race, and is not of the party of the 'trans-humanists' or those who believe the 'Singularity' is going to lead to our replacement by a more advanced kind of Intelligence. I also suspect that should we not bring disaster upon ourselves in the coming years mankind will move into space. It seems to me that humanity by its very nature seeks challenge and adventure, new worlds of exploration and creation. And the vast universe lies out there if not like a dream, than at last like a rough and rugged frontier which may give in time new worlds.
Looking in, then out
If you really want humans to go to other star systems, you may need to re-engineer humans either so they can survive on minimal provisions and oxygen (and won't get bored) or develop clones that "hatch" when the ship approaches the target, receive training and then head out. Perhaps space travel starts with the human genome.
SETI's findings
The astronomers who are engaged in the search for extraterrestrial intelligence (SETI) certainly don't believe that the project has failed as this article implies. The truth is that SETI has been impeded for a number of reasons--cost, limited telescope time, and the vastness of the universe.
In the past, most SETI searches have relied on existing radio telescopes. While this allows searches to be conducted on large instruments such as the mammoth 305 m Arecibo dish in Puerto Rico, the amount of telescope time available is necessarily restricted.
Now SETI has a brand new tool--the Allen Telescope Array. This instrument will allow a targeted SETI search to proceed 24 hours a day, 7 days a week.
I hope that everyone reading this article (and Dr. Hawking) will not prematurely designate SETI a failure. The search for ET is really just beginning.
Ellen Jackson, author
THE MYSTERIOUS UNIVERSE
LOOKING FOR LIFE IN THE UNIVERSE
Columbus/Space analogy
I don't dispute the argument that we should push into space. I do take issue with the analogy between Columbus and Space exploration. Columbus and and his backers had the objective of finding a route to India. They knew it existed. The risk was technological, not existential. Space exploration carries the additional existential risk that there is no other place that will sustain human life without cost far in excess of any surplus that could be gained. This is a problem. Thanks.