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gwardotnet t1_iu1jer8 wrote

Reply to comment by Apostastrophe in How long do you predict it will take before a probe reaches a habitable exoplanetand actually sends back footage of alien life? by sky_shrimp

Wrong. Check the distances again. Even close to the speed of light it takes forever.

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Miloshy t1_iu1k6iq wrote

How would it take forever at close to the speed of light? It’s like 4 light years away

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Real_Affect39 t1_iu1odfg wrote

Using current (or close to current) technologies, we could accelerate tiny probes to ~0.25c, meaning a 20 year mission to gather data from Proxima Centauri.

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Apostastrophe t1_iu1q1y8 wrote

You’re wrong. I know exactly the distances I’m referring to. The Centauri stars are around 4 light years away. Using laser-propelled micro probes we could accelerate them up to 20% of the speed of light. Meaning it could be a 20 year journey. The science checks out.

And with a combination of nuclear pulse propulsion, fusion and/or antimatter-catalysed fusion, which could be available within a century or so, you could even send manned vessels able to get there within a couple of generations. That’s hundreds of years, not thousands.

Close to the speed of light, the time it takes to get there is the number of light years away it is. Though you’d have to accelerate and slow down. At a constant acceleration of 1g for around a year and a constant deceleration of 1g at the half way point (not currently feasible with modern technology) you could get there within half a dozen years real time.

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pompanoJ t1_iu2n08n wrote

The last paragraph is where the thousands of years comes in.

Develop tech to send say, 100 tons at a significant fraction of the speed of light. ---- thousands of years.

Build and send out probes to every star system within 100 light years... hundreds of years.

Then you find your answer, if it is within that population.

Else? Continue sending probes and waiting increasingly long times for the answer.

But eventually, either we aren't here to send probes, or we find the answer. Moat of the Milky Way is within 50,000 light years, so some .5C probes could potentially get you the answer from most of our galaxy within 150,000 years.... if you had 100 billion probes and the requisite launchers.

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Apostastrophe t1_iu2ucx5 wrote

We don’t need to send “say 100 tonnes” at a significant fraction of the speed of light.

For that same cost we could use a launcher like SpaceX starship and send dozens of microoprobes into orbit and use Earth-side laser arrays to accelerate them to a significant two-digit percentage of the speed of light. We can do that today with currently available technology if we just make the infrastructure. None of it is outwith our current technological expertise.

The OP is asking about images of an extrasolar planet. Or of evidence of life there. Not necessarily juman boots on the ground.

If we take that, we can even do that without even leaving our solar system. With technology currently available at our development level (should we decide to build it - plans are available) we are capable of sending types of telescopes to many, many AU beyond the sun in a particular direction within a couple of decades (same time it would take to send a starshot prove to the Centauri systems) to use the sun’s gravity well as a lens to image extrasolar planets with a pixel resolution of tens of km. That’s enough to see cities.

You’re arguing over some semantics that aren’t even in question in the particular sub thread here. We can and could send probes to nearby star systems in a time measured in decades, not millennia. It’s not about 100t behemoths. It’s about micro probes using microtechnology on the probe itself and macro technology here on earth as a form of propulsion with transit time being only 5-10 times the light year distance.

We don’t know where life is. It could be next door. It doesn’t necessarily take thousands of years to get information from our closest stellar neighbours. If we want to use the “if could be so far away” the answer is infinity, not thousands of years. But the answer as to whether we can get information about planets on our local stellar group, the answer is yes, with currently available technology and within decades to hundreds of years (Ly distance divided by 0.2) for now. And within a century or two with that technological capability plus fusion, including antimatter catalysed. A large number of stars are in the hundreds of years rather than the thousands. There are almost 60,000 stars within 100 light years. Even with those pessimist figures that’s less than a thousand years to get there at current tech. Within a few centuries we’re looking at a much quicker and much more efficient probe.

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dustofdeath t1_iu1pz3o wrote

Proxima is 4.6 light years. Voyager is currently around 0.005% of that speed.

Or 92000 years to travel.

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Apostastrophe t1_iu1zk2l wrote

Voyager isn’t propelled by laser sail propulsion though. There have been papers written, showing we could send laser-solar sail probes to the Centauri stars in a timescale of decades not centuries with current technology.

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