The renowned physicist Stephen Hawking is working on a spacecraft that can travel at a fifth of the speed of light – meaning it could reach the nearest star and send back images of a suspected ‘Second Earth’ within 25 years – in a bid to save humanity.
In a speech at the Starmus Festival, Professor Hawking warned humans must soon colonise another planet if we are to survive.
One explanation for why Earth has not been contacted by an advanced civilisations from another part of the Universe is that every time ‘intelligent’ life evolves it annihilates itself with “war, disease and weapons of mass destruction”, he said.
And in addition to the chance that we will meet this fate, Professor Hawking said the planet had become too small for our burgeoning population with its “physical resources … being drained at an alarming rate”. Climate change, an asteroid strike or some other kind of cataclysmic cosmic event also pose significant threats.
The proposed spacecraft, called a Star Chip, would be just a few centimetres in size with a lightsail weighing a few grams. It would be powered by an array of lasers based on Earth that would drive the tiny probe “on a beam of light” at about 100 million miles an hour, a fifth of light speed.
“Such a system could reach Mars in less than an hour, reach Pluto in days, pass Voyager [the space probe launched in 1977] in under a week, and reach Alpha Centauri in just over 20 years,” Professor Hawking said.
“Once there, the nano craft could image any planets discovered in the system, test for magnetic fields and organic molecules, and send the data back to Earth in another laser beam.
“This tiny signal would be received by the same array of dishes that were used to transit the launch beam, and return is estimated to take about four light years.
“Importantly, the Star Chips’ trajectories may include a fly-by of Proxima b, the Earth-sized planet that is in the habitable zone of … Alpha Centauri.”
The project, called Breakthrough Star Shot, was “a real opportunity for man to make early forays into outer space, with a view to probing and weighing the possibilities of colonisation”, he said.
And he admitted: “Of course, this would not be human interstellar travel, even if it could be scaled up to a crewed vessel. It would be unable to stop.
“But it would be the moment when human culture goes interstellar, when we finally reach out into the galaxy. And if Breakthrough Star Shot should send back images of a habitable planet orbiting our closest neighbour, it could be of immense importance to the future of humanity.”
Because it is travelling so fast any pictures taken by a camera on the Space Chip would be “slightly distorted” due to the effects of special relativity, as first described by Albert Einstein. This would be the first time anything has travelled fast enough to see such effects.
“We are standing at the threshold of a new era. Human colonisation on other planets is no longer science fiction. It can be science fact,” Professor Hawking said.
He warned the need to find a new home to colonise was being driven by threats that were “too big and too numerous” to be positive about the future.
The moon and Mars were possible locations but both had limitations, the Cambridge University academic said. The moon is small, has no atmosphere or a magnetic field to deflect solar radiation. Mars has also lost its magnetic field and much of its atmosphere.
He said humans should create a base on the moon by 2020 and send people to Mars by 2025. Interstellar travel for humans might be accomplished in the next 200 to 500 years, Professor Hawking added.
In the speech, he showed flashes of his sense of humour.
Considering the prospect of a Star Chip discovering life, he said “If there are beings alive on Alpha Centauri [the solar system] today, they remain blissfully ignorant of the rise of Donald Trump.”
On the failure of an advanced alien species to contact humans, he said he preferred the explanation that while primitive life was common, intelligent life was rare. He then added: “Some would say it has yet to occur on Earth.”
Not exactly the most accurate article, but I do find myself agreeing with Stephen Hawking here. Especially on the lack of intelligent life on Earth.
Seeing current events as they are is wrecking me emotionally. So I say 'farewell' to this forum. For anyone who wonders.
I'm not too sure something a few grams can count as a space craft... or how it will feature a camera and comm equipment to return the images... or how the hell we will be accurate enough with a laser over such distances to hit something so small.
Get busy living or get busy dying... unless there’s cake.
The sail itself is probably a square kilometer or so.
I am more concerned with how it would fit the equipment to transmit data back to Earth. And how its electronics would survive interstellar radiation at those speeds.
For something like this to work out you'd need to send dozens to account for the failure rate, unless they've got some incredible tricks about shielding the thing.
Imperial528 wrote:The sail itself is probably a square kilometer or so.
I am more concerned with how it would fit the equipment to transmit data back to Earth. And how its electronics would survive interstellar radiation at those speeds.
For something like this to work out you'd need to send dozens to account for the failure rate, unless they've got some incredible tricks about shielding the thing.
As far as I can recall, they're sending a lot of the little suckers for redundancy, and they're all supposed to function as one giant phased array in the target system to send and receive data.
EDIT: okay, looking at the wiki page for this they're sending a thousand of them, and I think I'm conflating the "phased array" thing with a similar concept I read about on Atomic Rockets.
JI_Joe84 wrote:Wow its actually possible to send a space ship to another star system now, thank you science!!
Not really. The plan depends, amongst other things, on the continuation of a Moore's law-like exponential increase in laser power. A more accurate statement would be that it may be possible to send a spaceship to another star system if current technological trends continue.
The renowned physicist Stephen Hawking is working on a spacecraft that can travel at a fifth of the speed of light – meaning it could reach the nearest star and send back images of a suspected ‘Second Earth’ within 25 years – in a bid to save humanity...
This isn't new; the idea was called 'Starwisp' at least a decade ago.
And he admitted: “Of course, this would not be human interstellar travel, even if it could be scaled up to a crewed vessel. It would be unable to stop.
This suggest he hasn't quite caught up to the cutting edge in this field, I think; there seems to be a way for a light-sail craft to slow to a stop at the destination, even with a launch laser. Furthermore, a launch laser would greatly reduce the fuel requirements for a conventional interstellar drive, making it possible to use a smaller and/or faster craft.
He said humans should create a base on the moon by 2020 and send people to Mars by 2025. Interstellar travel for humans might be accomplished in the next 200 to 500 years, Professor Hawking added
Uh... those probably aren't happening on schedule. We physically don't have the hardware for a moon base by 2020 and probably not by 2025; there were plans for such things (e.g. Ares I and V), but they were scrapped or delayed or disrupted to the point where the schedule slip forces deadline slip.
Wake me up when they've got a working Alcubierre drive prototype, dammit.
Yeah, I've always taken the subtext of the Birther movement to be, "The rules don't count here! This is different! HE'S BLACK! BLACK, I SAY! ARE YOU ALL BLIND!?
- Raw Shark
Destiny and fate are for those too weak to forge their own futures. Where we are 'supposed' to be is irrelevent.
Simon_Jester wrote:This suggest he hasn't quite caught up to the cutting edge in this field, I think; there seems to be a way for a light-sail craft to slow to a stop at the destination, even with a launch laser. Furthermore, a launch laser would greatly reduce the fuel requirements for a conventional interstellar drive, making it possible to use a smaller and/or faster craft.
There are, but with how small these are, I don't think they could reliably maneuver to do so.
I expect these to go like this:
Given the tiny mass budget there's really no reason to incorporate the ability to stop in these.
Simon_Jester wrote:In the context of my reply, I was talking about the maneuverability of manned starships.
Ah, yeah, fair enough.
With these even they may be able to deploy the sail in a drag configuration so they'll be going slower at least. Would greatly reduce the relativistic contraction and distortion in the images.
Though I do wonder just how many of these drive lasers they plan to build for this, if they are indeed building them on Earth. The energy loss through the atmosphere alone will be bad enough, that on top of modern laser efficiencies mean they may need to build new power plants just to drive the arrays.
The renowned physicist Stephen Hawking is working on a spacecraft that can travel at a fifth of the speed of light – meaning it could reach the nearest star and send back images of a suspected ‘Second Earth’ within 25 years – in a bid to save humanity...
This isn't new; the idea was called 'Starwisp' at least a decade ago.
Maybe so, but the starwisp was not seriously funded. Yuri Milner put $100m into breakthrough starshot, and is hoping other sources will provide the rest of the ~$10 billion he thinks the mission requires.
And he admitted: “Of course, this would not be human interstellar travel, even if it could be scaled up to a crewed vessel. It would be unable to stop.
This suggest he hasn't quite caught up to the cutting edge in this field, I think; there seems to be a way for a light-sail craft to slow to a stop at the destination, even with a launch laser. Furthermore, a launch laser would greatly reduce the fuel requirements for a conventional interstellar drive, making it possible to use a smaller and/or faster craft.
My understanding is that someone from breakthrough starshot (not hawking) was contacted about a paper talking about slowing down a lightsail craft, but try rejected the idea because they saw the purpose of breakthrough starshot as to send an interstellar craft within the lifetime of those involved (or rather, the lifetime of Milner, Hawking for example is too old). The proposal would have required reducing the velocity of the craft, meaning that would no longer be possible.
That said, I think ten billion is unduly optimistic, but that's a rough eyeball estimate. We could develop something, but I'm not sure it'd have any chance of surviving the journey and I doubt we could build the launch infrastructure, though again, that's me intuiting things.
I guess it's just that we should be aware that this isn't "another brilliant breakthrough by multidisciplinary master scientist Stephen Hawking" the way that the popular press might make it out to be. It's more like "A bunch of people got together to implement an idea that was already floating around, and Stephen Hawking is the most prestigious person who attached his name to the project because he's one of the short list of 'media darling scientists.' "
While the idea is valid as nothing in known physics prohibits it I think they should start small. Build some prototype lightsail craft and scaled down laser station to send lightsail craft on fast flybys of Uranus, Neptune and dwarf planets in outer solar system. It would need a fraction of laser power compared to interstellar version, could be built sooner for less money and provide practical experience with lightsails. When lightsails are proven, whole system debugged then it could be scaled up to interstellar version
Sky Captain wrote:While the idea is valid as nothing in known physics prohibits it I think they should start small. Build some prototype lightsail craft and scaled down laser station to send lightsail craft on fast flybys of Uranus, Neptune and dwarf planets in outer solar system. It would need a fraction of laser power compared to interstellar version, could be built sooner for less money and provide practical experience with lightsails. When lightsails are proven, whole system debugged then it could be scaled up to interstellar version
Sky Captain wrote:While the idea is valid as nothing in known physics prohibits it I think they should start small. Build some prototype lightsail craft and scaled down laser station to send lightsail craft on fast flybys of Uranus, Neptune and dwarf planets in outer solar system. It would need a fraction of laser power compared to interstellar version, could be built sooner for less money and provide practical experience with lightsails. When lightsails are proven, whole system debugged then it could be scaled up to interstellar version
I think that's the plan.
It's difficult to get excited about something that would take decades to reach its destination- what I find more interesting is its applications for exploring the rest of the Solar system. Certainly a probe that can reach the outer planets in days instead of years would be massively useful for science, since we don't know much about the Kuiper belt. It might also answer the question about whether the Oort cloud is real or not- it all depends on whether any craft so small can carry any instruments sensitive enough to generate useful data.
