View Full Version : Hawking: Humans must leave earth

30th Nov 2006, 14:16
Errr, thatīs not order, just a suggestion...

Iīd like to see him get into space, Iīm sure Branson would do it as well for the publicity, but I canīt see the medics giving the OK and think of the PR if it killed him..... :uhoh:

Hawking: Humans must leave earth

Mankind will need to leave planet Earth to ensure the long-term survival of the species, theoretical physicist Professor Stephen Hawking has warned. And he disclosed his own ambition to go into space, and appealed to Virgin tycoon Sir Richard Branson - who is planning a "space tourism" venture - to make his dream come true.

Prof Hawking was speaking ahead of the presentation to him of Britain's highest scientific award, the Royal Society's Copley Medal, previously granted to Charles Darwin, Michael Faraday and Captain James Cook.

He told BBC Radio 4's Today programme that scientists may be within 20 years of reaching his prediction in A Brief History of Time that mankind would one day "know the mind of God" by understanding all the laws which govern the universe. He said: "The long-term survival of the human race is at risk as long as it is confined to a single planet. Sooner or later, disasters such as an asteroid collision or nuclear war could wipe us all out. But once we spread out into space and establish independent colonies, our future should be safe.

"There isn't anywhere like the Earth in the solar system, so we would have to go to another star. If we used chemical fuel rockets like the Apollo mission to the moon, the journey to the nearest star would take 50,000 years. This is obviously far too long to be practical, so science fiction has developed the idea of warp drive, which takes you instantly to your destination. Unfortunately, this would violate the scientific law which says that nothing can travel faster than light".

"However, we can still within the law, by using matter/antimatter annihilation, at least reach just below the speed of light. With that, it would be possible to reach the next star in about six years, though it wouldn't seem so long for those on board."

The science fiction series Star Trek used matter/antimatter annihilation to explain the warp drive which powers spaceships through vast distances in a short time. But some scientists believe that the radiation produced when matter and antimatter are brought together and destroy one another could be used to accelerate craft to close to the speed of light.

Prof Hawking said that his own ambition was to go into space. He said. "Maybe Richard Branson will help me."......

tony draper
30th Nov 2006, 14:27
Well we all do eventually.:rolleyes:

30th Nov 2006, 14:43
We need more "Lebensraum"...

For it is not in colonial acquisitions that we must see the solution of this problem, but exclusively in the acquisition of a territory for settlement, which will enhance the area of the mother country, and hence not only keep the new settlers in the most intimate community with the land of their origin, but secure for the total area those advantages which lie in its unified magnitude.

eastern wiseguy
30th Nov 2006, 14:59
Can I take more than 100ml's of toothpaste in my carry on?

Tricky Woo
30th Nov 2006, 15:41
So, if yer were travelling at 99% of the speed of light to alpha centuri (6 lights years) those left behind using a really powerful telescope would watch yer receding spaceship receding into the distance over a period of just over 6 years, right? But time dilation would mean those on board wouldn't experience the full six years on board.

So wots the formula, Mr ORAC? At 99% of light speed, how much internal time passes on board this space ship during its 6 year journey?


Tricky Woo
30th Nov 2006, 16:40
Never mind, Mr ORAC, a simple Lorentz transformation's not beyond yer Tricky Woo.

Here's the results for a 6 light year trip to alpha centuri with a space ship travelling at various percentages of the speed of light...

10% - Speed of light
60 years - Earth time
5 years 11 months - Ship time

25% - Speed of light
24 years - Earth time
5 years 9 months - Ship time

50% - Speed of light
12 years - Earth time
5 years 2 months - Ship time

75% - Speed of light
8 years - Earth time
3 years 11 months - Ship time

90% - Speed of light
6 years 8 months - Earth time
2 years 7 months - Ship time

95% - Speed of light
6 years 3 months - Earth time
1 years 10 months - Ship time

98% - Speed of light
6 years 1 months - Earth time
1 years 2 months - Ship time

99% - Speed of light
6 years - Earth time
10 months - Ship time

99.9% - Speed of light
6 years - Earth time
3 months - Ship time

99.99% - Speed of light
6 years - Earth time
1 months - Ship time

Seems to me to be eminently feasible, depending on how fast yer can get that spaceship to approach the speed of light. Anything less than 10% light speed, and most of the people remaining on the earth will have snuffed it by the time the "we arrived, sunny, wish yer were here" radio message gets back (add 6 years to the earth times above). But note that at 10% it'd 'only' take about 6 spaceship years to arrived, so while yer astronauts might have unfashionable haircuts, they'd be young, fit and healthy enough.

At 50% light speed, the message would be back in 18 years, which may be long, but it's more or less as long as it's going to take to build the bloody space station in total, so clearly people have the stomach for this sort of wait. Ship time drops a bit to 5 years and 2 months.

Things get interesting for the ship occupants at 98% light speed. The trip time drops to a mere 1 year and 2 months. Earth people would wait a tad over 12 years for the message (trip plus radio back) but that can't get significantly better, i.e. 12 years is as good as it'll get from now on.

There's some other equation that tells yer how much energy it'd take this spaceship to reach significant percentages of light speed. Loads, I seem to remember. However, the sweet spot seems to be around 90% of light speed. With that capability yer could have a bloody good look around our immediate neighbourhood and yer older relatives would still get to hear about it on their death beds.


Lon More
30th Nov 2006, 16:44
Some would say I left years ago

Tricky Woo
30th Nov 2006, 16:49
Hmm, Voyager 1's currently at 0.005% light speed. We might have a bit of work to do to get ourselves up to 90%.


30th Nov 2006, 16:53
Er.. shouldn't we finish trashing this place first?:hmm:

Tricky Woo
30th Nov 2006, 16:55
Yeah, no point leaving the party until all the beer's been supped.


30th Nov 2006, 17:02
That lawn mower Lonmore posted on the other thread looks as if it is capable of approaching the speed of light.

tony draper
30th Nov 2006, 17:08
This is a proscribed solar system,we are a proscribed species,they int gonna let us out there.

tony draper
30th Nov 2006, 17:14
Actually one's new calculation show we are on the entirerly wrong track with this striving for speed,what we need is some kind of drive that actually slows us down well below the speed of standing perfectly still, at the speed of being much slower than being actually motionless we drop into another universe,only its not a paralel one its actualy a square one,and distances shrink to nothing.

30th Nov 2006, 17:46
Aha! A square universe would be perfect for a lawnmower.
We could leave neat stripes all over it!
This has all become a bit surreal, time to disappear up my own black hole methinks.....

30th Nov 2006, 17:53
Time to fire up the Improbability Drive.

"Hyperspace travel is a bit like being drunk."

"What's so bad about that?"

"Ask a glass of water."

30th Nov 2006, 17:58
Whenever I read about speed in space.... out comes

Loose rivets
30th Nov 2006, 17:58
However, the sweet spot seems to be around 90% of light speed. With that capability yer could have a bloody good look around our immediate neighbourhood and yer older relatives would still get to hear about it on their death beds.

What do you calculate the time to reach c90% given say, 1.5g acceleration?

150,000,000 M/sec mean will be near enough I suppose.

Oh, and talking of Lorentz, how long will yer space-ship be while in the cruise? :8

tony draper
30th Nov 2006, 19:03
Gonna be a buggah having to hire yer starship and pay five years rental on it when you are there and back in three months.

30th Nov 2006, 19:03
Tony Blair left this planet a long time ago!!:rolleyes:

Lon More
30th Nov 2006, 19:06
Tony Blair left this planet a long time ago
Thatcher and the vegetables were never on it:\

30th Nov 2006, 19:15
Thatcher and the vegetables were never on it:\

If it hadn't been for Maggie the unions would have stopped the growing
of vegetables.

"Demarcation brothers! We're not paid to dig!!" :hmm:

Windy Militant
30th Nov 2006, 22:05
Space tourism, wonderful you queue for three days and when you finally arrive on Rigel you find your bags have gone to Altair!

I still find it ironic that English Heritage are using GPS surveying systems to catalog the Spadeadam test site, especially after the government told us that satellites had no practical use at all.

Just imagine MUSTARD shuttles blasting off from Cape Carlise with TSR 2 chase planes. Hour and a half to the Commonwealth space port at Woomera and fortyfive minutes to NewYork. :ok:

We had proper science in them days! :(

30th Nov 2006, 22:28
Right, so who's going to volunteer for the "B" Ark, then?

I have a few names in mind........:}


30th Nov 2006, 23:52
I sat parked in the car listening to Hawking this morning being interviewed on the Today programme. A truly inspiring man, humbling to see such spirit in such a wrecked body. So much to contribute, yet unable to express it adequately.

On the subject of going elsewhere, we might as well start now, fire off some DNA on voyager-style mail-shots. That has as much chance of breaking out of the solar system successfully as anything that will happen before we hand over the baton to the next big thing. Its just too far, too likely to end up in a barren system, and anyway what happens when you get there and find someone else is there already? We can't go stomping around the galaxy infringing 'alien rights' can we? Or would we treat aliens as badly as we treat our terrestrial animal brothers?
Anyway who cares, when your time is up, its up. Do we have a responsibility to our DNA? It seems to do nothing but use us for its own ends, so why make the effort to help it? It would dump us for a better replicator if it had the chance. We have become more than what our DNA would like us to be. A bit like HAL.

1st Dec 2006, 00:25
It'd be a bit of a bummer if they got to Alpha Centauri and found it had no habitable planets in its solar system.

It'd be even worse if they found a habitable planet, inhabited by large, fast and hungry carniverous critters.

"Earth to Alpha Centauri, come in please; Come in please.... Are you receiving me? Over. "
"....Still no reply Mr. President."

"Keep trying, keep trying. We blew sixty squintillion bucks on this - oh Lord what am I going to tell Congress?..."

Arm out the window
1st Dec 2006, 01:03
I think it likely our species will get itself established somewhere out there before we total ourselves here, but it ain't really that much of a biggie.
A far greater achievement would be to sort ourselves out to stabilise population growth, get clean energy happening, feed the hungry and stop killing eachother - now, that would really be something.

What does it matter if the race doesn't survive? Colonising other worlds won't do bugger all for those down here suffering now apart from taking money and resources away from them.

If we could do both things, well and good - I love a good technological achievement as much as anyone, but it doesn't make a hell of a lot of sense to me to be saying, "Well, our planet's stuffed, everyone's suffering except the filthy rich elite and we're about to be taken out by a bloody great asteroid, but by crikey, the human race is now established somewhere else to start doing it all again, so that's all OK then."

1st Dec 2006, 04:49
But who is going to feed the cats?

1st Dec 2006, 05:15
We need do nothing.

GOD will provide. HE will save us. GOD put us here on Earth and it is up to HIM to arrange the next step.
It would be ungrateful for US to abandon HIS works (which are GREAT).
The wonder of HIS works displays the firmament, for so is it written in the great BOOK (let Joseph Haydn be HIS witness).
Let it be.

1st Dec 2006, 08:38
We need do nothing.

CPTN, you are 'a very naughty boy'

Weren't you paying attention when Prof H was talking about us 'knowing the mind of God'? ;)

1st Dec 2006, 09:03
There are several problems with this high speed travel.

First is production of the tons of required anti-matter. We can manage it for the odd atom, anything above that is problematical, as is storage. Hint, don't do it next door.

Second is interstellar debris. Ignoring the oort cloud at either end, space is not as empty as it seems, and even running into the odd speck at 0.9 light would.....hurt.

Third is navigation. The view ahead shrinks to a blue speck, that behind to a dark red hole. Just hope your figures were right, star shpts will be tricky.

The Fitzgerald-Lorentz contraction should be interesting though...

(Alternate means of acceleration is a vast solar sail in two concentric rings. You fire vast terawatt lasers to push the ship from the solar system. When approaching the target system the larger outer ring is released and reflects the beam back to slow the smaller, lighter inner ring and ship as it accelerates on..)

Tricky Woo
1st Dec 2006, 09:59
It's more likely that the first trip to alpha centuri and the like will be by a Voyager-style robotic probe. More likely a series of such probes would be sent on their way to all of known planetary-system stars within (say) 10 light years. Nice thing about robots is that yer don't have to worry too much about bringing them back.

ORAC's right in that the first hurdle is producing a workable non-science fiction drive that could accelerate such a probe to a significant light-speed percentage, i.e. 50% or 90%, and then turn around and decelerate again. Not sure where NASA are these days with their nuclear-electric concept, but surely that's the way to go.

(Not sure if nuclear electric's the right jargon, and don't care so there)

Nuclear electric uses a nuclear fission reactor to generate electricity, which is then used to accelerate ions of xenon gas (or something similar) out the arse end... The ion drive's already been used on various spacecraft (i.e. DEEP SPACE 1 and SMART 1) but the electricity's been generated using solar panels. Clever and efficient, but not much cop when yer a light year away from any significant light, hence the need for a nuclear reactor. In practice, there'd probably be a combination of both nuclear reactor and solar panels.

The problems with using the current ion drives for this prupose are that the thrust levels are very low, i.e. just a fraction of a 1g. However, they can continue to accelerate for up to a year, which means that even a weeny bit of acceleration can get yer up to serious speeds if yer patient enough. NASA and ESA are working on enhancing this concept for higher accelerations (still a lot less than 1g though) and for longer intervals, i.e. years. I seem to remember that the recently cancelled JIMO was to use such an engine.

Oo oo, found it. Look for Project Prometheus on Google and Wikipedia.

Anyways, one reckons that if such a concept was worked on for a few decades, then acceleration and duration would be increased enough to get that robotic probe to another star. Even 0.1g over a 5 year period could get yer up to that 50% light speed. Trouble is that this would need sh1t loads of xenon, and a massive leap in technology. Probably many many decades away, if not centuries.

Ahh well, we can wait a bit longer. Still plenty of nooks and cranies to examine in our own backyard.


1st Dec 2006, 10:31
Interstellar Sailing Ships (http://scientium.com/specials/sotm/starship/sailships.htm#solar)

tony draper
1st Dec 2006, 11:10
Sadly can't see it ever coming off meself,the purse strings are in the hands of politicians,and there's no votes in space exploration ,the moon shots proved that,the man in the street is even less likely to show approval for some multi billion dollar enterprize that will not show any return,or even live telly pictures for 250 years,mebbee some robot shots as Mr Woo said.
Hollywood has already been there and done that,and the Hollywood universe is probably a lot more exciting than the real thing to yer average Joe.