Just microbes, I'm holding out hope for that type of find in my lifetime, and I'm late 80s.

Intelligent life, generations away.

A physical device getting somewhere like that? That will probably take thousands of years at least

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Thousands of years.

The laws of physics wont change. We aren't going to send probes and get back data any faster than light and in all likelihood much slower. Even at our best "hey we might be able to do this in our lifetime" we are looking at a probe taking 20-30 years to reach Alpha Centauri, then 4 more years for the data to get back. A Cent is only 4 light years away so even visiting a reasonable close star of 100 light years is a 750 year journey and another 100 to get back data.

Now couple that with the small likelihood of life (so far we have a sample of 1 in infinite), the number that will be sent to habitable but uninhabited worlds, the expanded size probes need to be to send back data from ever increasing distances, the costs and political realities of funding and it will be thousands of years before we see that data if ever.

Well the closest exoplanet is proxima centauri B. That's 4 light years away. Closest star is Alpha Centauri, that's 4.3 light years away. So if there's life around those at the very minimal it'd be Voyager that they ..find. Voyager is nearing 15 billion miles away. Subtract that from the relative distance 4 light years is, like 1.06(I think) trillion miles for one light year. Then do the math of 16000 mph to cover that distance, you'd have plus a return trip(if whatever was sent was at that same speed) and you've got a rough idea.

Translation, dependent on MANY ifs, A VERY long time.

A flyby mission perhaps in the next 50-100yrs.

But slowing down and landing at the other end is massively more difficult. Carrying the fuel/energy required would be a massive challenge. I doubt we would have the tech for that for at least several hundred years.

>I won't be able to see this event, but it's obviously clear that it will eventually occur.

That's not clear at all. The distances in space are enormous, and we don't even have a theoretical solution for traveling them.

Assuming technology increases at the rate it is doing and another Newton or Einstein surfaces, about 300 years or so.

Get there, not clear we can. Map the surface with a telescope? Maybe 50 years if this NASA proposal succeeds. https://youtu.be/4d0EGIt1SPc

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Thousands of years.

There are multiple very high odds factors (low probability) in your question: Finding signs of life, knowing beforehand that the planet actually has "advanced" life, getting there (acceleration+deceleration) with our tech, known physics, fuel.

Thousands of years.

Several hundred years. Presumably we'll get a lot better at viewing exoplanets over the next hundred years, so by examining their atmospheres' we'll be able to find some juicy targets. Then it is just a matter of building the probe. I believe technology will continue to be developed at a very fast rate and 200 to 300 years from now we'll have some pretty crazy tech for space exploration capable of travelling at some modest but reasonable fraction of C.

Unless some fantasy technology becomes reality like warp or wormhole which allows us to travel faster than speed of light , it's going to take thousands of years and this considering the fact everything goes perfectly fine without any collision or malfunction .

Moores law is going to peak so you may need to add a few centuries

What exactly makes it "obviously clear" that this will happen?

Not necessarily. There are ways we could send probes to Proxima Centauri or Alpha Centauri and image exoplanets with currently available technology within current lifetimes. The problem is both funding and development and whether it’s actually worth it.

You’d need a lot of infrastructure (several nuclear power stations worth of energy and a massive laser array) but it could be done. We’re just not doing it.

Isn't infinity-1 something they only use in improbability mathematics?

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And at this point it look quite improbable that there is anything out there, much less nearby. That could change, the numbers of planets known has gone from 9 to thousands in only half my lifetime, but even with 5,197 known exoplanets as of today we have 1 known with life.

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

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

Unfortunately, we will likely go extinct before the time that would take to occur.

I hate to be all doom and gloom but our prospects for long term survival on this planet aren't looking so good.

This. Voyager won't even break out of the Oort cloud for another 30,000+ years at it's current velocity of 17km/s, and it'll be long dead by then. That's if it even makes it that far, assuming it doesn't collide with anything or have its tragectory altered by passing massive objects.

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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We may archive 1% (voyager is at 0.005%) of light speed for probes in the near future.

Proxima is 4.6 light years.

460 years at that speed.

But you also need time to speed up and slow down. So ~900 years + extra to transmit data.

Even if we could achieve 90% of light speed in minutes, we would spend a eternity slowing down.

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

Or 92000 years to travel.

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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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.

125 years ago, we did not have technology for powered flight. 100 years ago, we were unaware of that the universe was larger than our home galaxy. 50 years ago, there were no personal computers in homes. Less than 30 years ago, we were unaware of any firm evidence of exoplanets.

It’s very difficult to imagine future technology and what developments will cascade exponentially. If we manage to make fusion energy work in the next 75 years, it will be a real game changer for a lot of things. Getting information back from another planet is a major technological jump, and as has been discussed, it will take a long time. Getting information back with evidence of life, or images of lifeforms is just a matter of more time for more distance as we increase the number of data points with improvements in technology.

Within 10 parsecs (33 ly) of Sol, there are about 413 stars. Most are red stars, which may be less conducive to life due to higher dynamic solar radiation and activity. Within those 413 stars, there are only 54 stars that are either G type - like Sol; K type - Orange/Red; F type – Yellow/White; or A type – Bluish/White.

I will go out on a limb and say inside of 250 years from now we will have decent data from some visitation to 15-20 planets associated with these stars. How many will show any evidence of life? It’s impossible to say.

Yes we do. Matter anti matter engine is an easy theoretical solution.

Yeah unfortunately I agree. We are far too divided as a species to prioritize something like this. I don’t think a single nation could accomplish these feats alone

We have the plans and technology to send tiny probes with massive solar sails powered by a ground based laser for acceleration today if the funding was there. It is almost certain that OPs dream will happen.

More than a thousand years. Probably more than a thousand thousand years.

There, happy now?

It's highly dependent on how fast we develop certain technologies, and can expand into space. We theoretically have the capability to build spacecraft that can last generations today (the voyager probes), and they weren't even meant to last that long, so if we did want to build a spacecraft that can tough it out, it could last a long while before breaking down.

One big problem is propulsion, in order to get to these stars within a century or so requires us to go at least 5% of the speed of light, which is no small feat. Thankfully, many scientists have devised ways it could be done, but these are speculative concepts, and aren't comparable to blueprints since nothing has quite left our imaginations (yet).

Some of the propulsion systems that are capable of this, in no real order:

Orion pulse propulsion - possibly feasible with not just current technology, but technology from the 60s. Instead of the hard problem we have with sustainably containing fusion in a compact way, why don't we set off specially designed nuclear bombs outside the ship, and use its momentum to move forward? You would need a lot of nuclear charges to get up to speed, but a lot of people back in the day worked out that it was possible. It's just a politcal dead end due to the amount of weapons grade fissile material you need, and the nuclear test ban treaty.

Then there's fission fragment - also possibly feasabile with current technology. It uses rapidly spinning discs coated in fissile fuel (spinning to prevent melting from the intense temperatures), and as the fuel undergoes fission, the 'fragments' get expelled with a magnetic nozzle at incredibly high velocities (up to 3% of the speed of light) which is pretty great and helps give a high specific impulse and overall top speed. I don't know how fast you could ultimately go and still slow back down on the other end, but I assume you'd be able to reach Proxima Centuari within a couple hundred years or so.

An indirect form of propulsion are laser sails. It uses the same principle as a light sail, using the momentum of photons to accelerate a reflective sail with a smaller spacecraft. But where sunlight drops off with distance, and gives a limited top speed (something up to a few hundred km/s. Good for interplanetary - even though you wouldn't actually max out, but not enough for interstellar), a laser can concentrate that light to such a degree that it will be able to accelerate you to up to 10-20% of the speed of light (~40-20 years to Proxima Centuari), and can have multiple relay stations to take over acceleration as the lasers will also eventually become diffuse. These can be powered by solar arrays closer to the inner solar system, and nuclear reactors further out. The only downside? You need these same stations on the other end to slow back down, or a secondary propulsion system like the ones above. But, this does save fuel overall, because instead of bringing all that fuel to accelerate and deccelerate (which requires an incredibly high mass), you only need enough to deccelerate (which is much lower).

These are all within current technological bounds, and goes to show that even if nuclear fusion never pans out in a practical way, we still have a means of accomplishing interstellar travel in a more reasonable period of time, not the tens of thousands of years commonly brought up (and only applies when talking about chemical rockets - which we'd never use if we were actually serious about an interstellar mission to another star).

Actually building and launching one of these ships is outside our capability because even if we have most or even all of the technology, we'd still need a ship spanning hundreds to meters to a few kilometers, massing hundreds of thousands to millions of tonnes, with overall power outputs exceeding the terawatts. And for that we don't currently have any industrial or manufacturing capability in space that can do that. I don't see humanity being ready to send out an interstellar probe for maybe a century, maybe up to two centuries. Depending on how practical it is to scale up space outposts, ISRU, and the like in the next few decades.

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On the bright side, we might not have to wait quite that long to get confirmation of alien life. JWST will be sensitive enough to pick out likely candidates by examining their atmospheres for things like carbon dioxide, water vapor, oxygen, and methane (really looking forward to the TRAPPIST-1 findings in this case), but probably not enough to confirm life outright. However, it will definitely let astronomers know where to look in the future. The Nancy Grace telescope will be able to directly image Jupiter sized exoplanets in somewhat better detail than now, and be a testbed for a coronagraph that can image potentially habitable Earth sized planets. PLATO and ARIEL (to be launched in 2026/29 respectively) are ESA missions to look for exoplanets, particularly Earth sized habitable zone planets, while ARIEL will follow up on known planets and will be able to also characterize their atmospheres, though I don't know how much more/less sensitive their instruments are compared to JWST.

I don’t think we can say yet whether it’s probable that any life is out there, or even close by. There could be microbes or even multicellular organisms on Titan and we wouldn’t necessarily know it yet. There could be intelligent non-technological organisms in 25% of the systems within 50 light years for all we know.

However, I agree with your assessment that sending probes returning evidence of life is likely going to take a LONG time, especially if searches in our own solar system come up dry. I’m hopeful that the Starshot or similar ventures will reach the nearest stars sometime in the next few centuries (MAYBE decades), but it could well be millennia before any definitive evidence of life on extrasolar planets is communicated back to us, if ever.

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.

Step away from the cable news. Our long term prospects have never been better in the entire history of primates.

Infinity being an infinite universe.

But in this case it should be whatever fraction of the 100 billion or so stars in the Milky Way have planets that are potentially habitable, instead of the infinity that is the whole universe. We are probably not sending probes to other galaxies for the better part of 5 billion years or so, until Andromeda comes to us.

Yeah, it is plausible that some group is already vetting the data on a spectral analysis of an exoplanet atmosphere that reveals the presence of life. Or maybe that moment is a decade away. Or 10 decades.

But I think we all believe that moment is indeed just a matter of time and telescopes.

I have it on good authority that it will be picked up by a race of sentient machines, repaired, given an artificial intelligence, and returned to earth.

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It is a huge leap to go from 0.005% to 1% of the speed of light.

I'm of the mind that thousands of years is an optimistic estimate, but minimally realistic.

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.

Good point. I think that quantum computing will be an absolute game changer in technology once it is more mainstream.

Think of the problems we are unable to solve today. They will take seconds to solve.

“Quantum computing is a new generation of technology that involves a type of computer 158 million times faster than the most sophisticated supercomputer we have in the world today. It is a device so powerful that it could do in four minutes what it would take a traditional supercomputer 10,000 years to accomplish”

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Accelerating is easier - solar sails or lasers for example. But slowing down is a problem.

That keeps getting repeated but…

We will have been replaced by the cephalopods or dolphin

That's a BIG leap, from "it's technically possible to do if only the funding was there" to "it will almost certainly happen.

The problem with Europa is that it is 15 kilometers thick and the water it encases is under extremely high pressure. We could maybe observe microbes in the water it ejects into space through geological activity but we are nowhere near technologically advanced enough to uncover whats beneath the ice.

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>Given the exponential rate at which space exploration is advancing

Hold on a second. Do we really believe this? I think the landing on the moon was highly politically driven, and not by science/engineering etc.

And how long ago is that now?

I refrain from even ballparking when anything will happen space related.

Actually, we do, for the closest ones. Nuclear pulse propulsion. Basically, throwing thermonuclear bombs out the ass-end of the spacecraft and using them to generate thrust.

That gets you to about 10 or 12% the speed of light at the top end. If you're just interested in doing a fast flyby of the closest stars, that would get you to them in just X / .10 or X / .12 years, where X = distance in light years.

So for example, Alpha Centauri is 4.37 light years, so we could fly a probe through that system between 4.37 / .12 = 36.4 years to 4.37 / .10 = 43.7 years after launch.

We know that we can build space probes that are capable of lasting that long. The two Voyager spacecraft were launched in 1977, and are still operating. That's 45 years. Because of the huge amounts of payload that NPP allows for, we can have backups of backups of backups, and plenty of power generation.

But that's the maximum possible delta V, so if you want to actually slow down and explore the system over time, you're limited to using half that for acceleration, and the other half to decelerate at your destination, so you'll need between 72.8 years and 87.4 years before arrival. Conventional Plutonium powered RTGs won't be sufficient, but Americium ones would work, combined with a nuclear reactor activated to supply extra power to the systems during the exploration phase.

That's a problem for humans, though, because even a young, new engineer fresh out of school at launch is going to be 97 when the probe arrives. We don't really have will for multigenerational projects.

So there would have to be a compelling secondary mission for something like this. Measuring the parallax on nearby stars to refine our distance estimates would be a good one, and perhaps also super-dee-duper long baseline interferometric radio telescope observations would be another.

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Of course, there are two things I've ignored so far.

First is cost. This would be a hugely expensive undertaking. Would we want to spend the money to do something like this? There'd have to be a really compelling reason to do so.

Second is that it's literally illegal. The 1963 Limited Test Ban Treaty forbids any and all nuclear explosions in space regardless of the reason for them. At least, it does for nations that have signed and ratified the treaty. Both the US and Russia have done so.

China has not.

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>I don’t think we can say yet whether it’s probable that any life is out there, or even close by.

The problem with this is its never ending. A hundred years from now with colonies on Mars someone is going to say the same thing about that little niche over there on Mars that hasn't been explored to their satisfaction.

Life on Earth has left no doubts its here. It has produced rocks in volume (limestones), its changed the atmosphere and entire chemical makeup of the surface and oceans. If life isn't thriving across the surface of a world it wont last in geologic terms. Life isn't going to hold on under some rock for any length of time, being localized like that is to fragile. And there is no evidence that anything on Mars or Titan isn't the result of normal non-life initiated chemical reactions. As much as we want it to be life isn't common.

>The problem with this is its never ending. A hundred years from now with colonies on Mars someone is going to say the same thing about that little niche over there on Mars that hasn't been explored to their satisfaction.

That's right. However, the more we explore a planet without uncovering any signs of life, the more confidently we can say there probably isn't life there. I'm personally not holding my breath for finding evidence of life on Mars or any other body in our solar system for that matter. There's no evidence yet that I find very convincing.

But it's a large leap from that to claiming with any certainty that there IS no life on any body in our solar system other than Earth. It may seem like we've explored our solar system quite a bit, but we really haven't - not in the detail that would be required to rule out the existence of microbes. To use a common analogy, that's like taking a bucket of water out of a large lake, looking at it with a magnifying glass, and claiming there's no fish living there.

>As much as we want it to be life isn't common.

I'd agree that life as we know it is definitely not common, in the sense that it probably occurs on a small minority of all rocky bodies (most of which don't have any water or atmosphere, so it's hard to imagine any life arising or existing for any geological length of time there). We don't yet know exactly how uncommon it is. Does it arise on 25% of terrestrial planets or moons with liquid water in the habitable zone? 1%? 0.00001% Does it arise in 25% of star systems with terrestrial planets in the habitable zone? 1%? 0.00001%? We don't have sufficient information to rule out any of these possibilities, as far as I know. We can't even analyze the atmospheres, much less the surfaces and soil chemistries, of any extrasolar planets in much detail (or at all, in the case of soil chemistries).

I understand the motivation to tentatively conclude in the negative, so as not to be disappointed. I have a Ph.D. in chemistry and it's still difficult for me to imagine a probable series of steps to life on Earth, so it wouldn't surprise me if less than 1 in 1000 star systems had life. But it's ok (and indeed more accurate) to say that we just don't know how common life is yet.

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I recall when new computers with faster chips were a serious issue for consumers. After a number of years of this improvement, I thought, "Yeah, a faster computer...like I will spot the difference." The slow part of my computing (then) was the idiot operating the keyboard.

I get that quantum computing is a major jump, but it's not clear to me what that will change for the masses. All one hears in the media is about encryption, although I am sure there is much more.

Solar sails will not work well in interstellar space. As for lasers, far from Earth (or wherever the laser is located), the beam will be spreading out from diffraction -- at which point its power is subject to an inverse-square-law dependence.

You only need to accelerate once, you won't really slow down after that.

Well they could break existing encryption almost instantly. But they will also be able to make algorithms that are completely unbreakable.

Then interesting thing for me will be that once they surpass normal supercomputers (they are not faster yet. About one year away) there will be a time that certain folks can crack what the masses are using very easily.

The first real use will be in big data and AI. You won’t see much of a benefit but google and Amazon will know even more about you. Lol.

After that it will start solving some of the really hard physics issues and with that we may see real advances in the space race and then eventually consumer goods.

Gonna be a good 20 years until we see things hit mainstream but once it does. Look out.

As to the original post, when we send spacecraft to other plaetary systems, we will need pretty serious AI, or something close, to manage the probes, drones and other devices for data collection and analysis. Although I really have no idea, I assume quantum computing will play a big part in that overall success with no human involvement in decision processes to complate the tasks.

Step 1 would be not extincting ourselves in the next 200 years, and that's far from a sure thing.

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