Is Finding Et Becoming A Viable Reality?

naomi24 | 07:22 Thu 14th Apr 2016 | Science

70 Answers

In an attempt to leapfrog the planets and vault into the interstellar age, a plan to send a fleet of robot spacecraft no bigger than iPhones to Alpha Centauri, the nearest star system, 4.37 light-years away, has been announced.

A rocket would deliver a “mother ship” carrying a thousand or so small probes to space. Once in orbit, the probes would unfold thin sails and then, propelled by powerful laser beams from Earth, set off across the universe.

Any returning signals would take 4 years to reach us, but it will take 20 years for the probes to reach Alpha Centauri as opposed to Voyager 1’s 70,000 years.

Exciting stuff!

http://www.nytimes.com/2016/04/13/science/alpha-centauri-breakthrough-starshot-yuri-milner-stephen-hawking.html?_r=0

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Bazile

Well - youv'e got to start somewhere don't you ?

Great oaks from little acorns , grow

jomifl

@hypo, just a tenuous line of reasoning probably best ignored.

Hypognosis

@jom

Nah, I'll happily play along with it.

Just think, this planet ticked away for (how many?) billion years without any intelligent life on it and then we emerged. The Drake equation covers this aspect with the idea of a critical time window in which an alien world must be observed, in order that the intelligent life is detectable and before the window closes when its civilisation destroys itself.

As theories go, maybe it was a bit over-burdened with 60s social commentary but it is still a valid equation term. We credit ourselves with intelligence but we still have the capacity to destroy one another.

-- answer removed --

jim360

Cost of project estimate is probably an underestimate, but it's hardly public money being "frittered away" (and anyway, there are other things we arguably "waste" more than $10 billion a year on -- this is only $10 billion or so over a couple of decades).

More to the point, this project doesn't even have to get halfway before it's achieved various technological advances. In laser technology, batteries, efficient computing, miniaturisation, very long-distance lossless signal transmission, cameras etc etc. If it goes all the way and fails (eg due to robots crashing into space junk), it still represents a new method of travelling long distances at a reasonable speed. The amount of collaboration that's going to be involved, too.

Finally, the surest way to achieve nothing is not to try. This is totally worth a shot.

naomi24

Question Author

Jim, //Finally, the surest way to achieve nothing is not to try. This is totally worth a shot. //

Absolutely!

jomifl

Given that voyager has a large parabolic dish, a transmitter powered by a nuclear reactor and can only just communicate from the edge of the solar system.… then there is the well known inverse square law..

jim360

The inverse square law applies primarily to signals that are transmitted without bias for any direction. Once you transmit a signal in a fixed direction, then it doesn't lose power or signal strength nearly so quickly. Transmission over that distance is still tricky, but far from impossible. Also, Voyager is about 50 or 60 years out of date, and maybe a hundred years or so when this proposal turns into reality.

mibn2cweus

I try to view things in the perspective of human terms. Could such as we are really be the very best that this universe has to offer? . . . so far at least.

jomifl

Jim, the problem with a beamed siignal is that you have to point it very accurately.

jomifl

Jim, at what degree of 'beam' does the inverse square law cease to apply..

jim360

It's not so much that it ceases to apply, but that it ceases to matter, at least over a certain distance. With care in the set-up, a signal can certainly be transmitted over 4 light years or so with no appreciable power loss. Essentially the point is that other effects can dominate over a certain range. It's hard to quantify without giving a specific example, but loosely it would go like this:

- The inverse square law applies in totality only to any point-like source.
- Some sources are only "point-like" if you are far enough away.
- Within a certain distance, the precise structure of the source matters.
- That is, if you are close enough to an object to see that it is not point-like, then the inverse-square power loss may be "suppressed" by more local effects.

There's no doubting that the whole project is a huge challenge, and the long distances involved don't help, but I don't think they are so obviously fatal.

jomifl

/a signal can certainly be transmitted over 4 light years or so with no appreciable power loss./

I'd like to see a proof of that assertion. It sounds like bullsh1te to me.

jim360

Well, perhaps I should say "with no disastrous power loss", as in the signal is still going to be recoverable from whatever "scraps" you end up receiving.

I can prove the assertion easily enough, I think, if I pick the right numbers in the right formula, but it really doesn't matter too much. If you point the signal in the right direction, and do everything else right, then you should be able to pick enough up to recover the information that you want to. No doubt it will be very hard to get everything right, but then that's the whole point of the research programme, no?

jomifl

If you could find a microwave frequency that wouldn't be obliterated by background noise and that didn't 'leak' at the edges and that could be aimed accurately at an antenna on earth over several thousand billion miles then I'm sure it would work perfectly. So that's 3 'Ifs' one of which is enough to make the project impracticable.
So go ahead and do the calculations if you don't think this was an April 1st spoof.