Wouldn't a fantasy imply they have nothing to show? Aeon R engines are being built and tested. And not getting to orbit on the first launch is far from a bad thing in spaceflight, very few rockets work the first time. They made it past Max-Q, even past MECO and stage separation, Falcon 1 didn't get that far during its maiden launch.

Assuming I'm reading your comment correctly, we have found plenty of gas giants in the habitable zone, more than the number of terrestrial and super-Earth sized planets even. One notable example is Mu Arae b, over 1.6x more massive than Jupiter and could certainly hold onto a larger moon. It's orbiting an G-type star older than the sun about 50 ly away.

Well the "proof it works for us" is part of why our searches for life (and habitable planets) center on life lthat functions like our own. It's easier to detect and confirm carbon based, oxygen breathing, water drinking lifeforms (especially at a distance) than looking for exotic life that doesn't use those things. As noted in the comments by greypowerOz, there is other reasoning besides that, oxygen is great for metabolic processes and complex life, but other respiratory gases like hydrogen has been considered.

If you're looking for other forms of life, you're really looking for chemical disequilibriums, an abundance of certain elements (like oxygen, and methane) that on their own, would dissipate quickly, and so need some process like life to sustain that abundance. However, false positives are possible, and natural processes could create these same disequilibriums under the right conditions, and look like life. So that's a big thing we need to keep in mind when looking for biosigniatures, especially ones different from life like on Earth.

I know you weren't, that was just from what I pasted. My main opinion was that sending out signals isn't something we need to be really worried about.

I agree though, we have come far, when Frank Drake made the first SETI like experiment in 1960, we hadn't been to the Moon, and had barely begun space travel. Now we know of thousands of planets, have the tools to look for signs of life, and are approaching a future we're we're expanding across the solar system.

That kind of thing is only applicable for very distant galaxies. It's unlikely to affect us for most of the universe's future existence. There may come a time when the only stars visible are the ones in the Milky way, and that the rest of the universe would be unobservable, but if I'm remembering it right, that won't be until the universe is already down to it's last stars.

I'm going to copy paste another reply I had to a similar comment below, but in any case, if the Voyager probes are found by a civilization in any reasonalby short amount of time, they were on their way here anyway. The probes are barely 100 AU from Earth, it's a rounding error compared to a single light year, and by the time the Voyagers reach any significant distance of light years, it would be hundreds of thousands of years from now.

But if you're also worried about signals, it's pretty unlikely that the systems we've sent messages to have civilizations in the first place. The rationale that certain systems may have life doesn't mean it would have a civilization, so our efforts in METI are really unlikely to stumble across someone.

Our location is also already known by any reasonably advanced civilization. In the last couple decades, we've already found thousands of planets across thousands of light years. Our technology is getting good enough that we can start to look for biosigniatures, and there are even concepts like the solar gravitational lens, that could allow us to not only image, but map entire planets as if we had probes in the system (possibly even allowing us to spot city lights and other technosigniatures). And that's with technology we have now, or can develop in the next couple decades. A civilization capable of just ubiquitous interplanetary travel could easily map their section of the galaxy, and have, on record, every planet with life, and every planet with a possible or known civilization. That will include us. And that's not getting into civilizations capable of interstellar travel.

Acting like we're doomed because of a few messages is misguided fear at best, and concern trolling at worst. If there are other civilizations out there, close enough to reach us, they already know we're here. We don't need to send out messages for them to know that. So we have nothing to lose and everything to gain by attempting contact, because if someone is willing to respond, I'd wager they're helpful in the first place.

Interstellar travel is hard anyway. It can take decades or centuries to reach distant stars, even with the best technology, so the idea that a civilization might attack others isn't really a cause for concern. If there was anyone malicious out there, I refer back to my second point, in that they already know we're here, so as morbid as it is, there's nothing we can do about it. But seeing as life has been around for bilions of years, and our civilization has been allowed to exist up to now doesn't look to me as though there are murderous civilizations out there rabidly wiping out any life.

That's a bit extreme, but any probes we have past Mars should still be around, and we have more than just Voyager traveling outside the solar system (New Horizons, Pioneer, etc).

I personally think we'll still be around in a billion years. Or at least some distant descendents of ours, that can trace themselves back to humanity. Once we can settle other planets, something that should be possible in this century, it would be just about impossible for us to go extinct, so our chances of still existing in some way millions of years and more from now go way up.

A couple things here

1. it's pretty unlikely that the systems we've sent messages to have civilizations in the first place. The rationale that certain systems may have life doesn't mean it would have a civilization, so our efforts in METI are really unlikely to stumble across someone.

2. Our location is already known by any reasonably advanced civilization. In the last couple decades, we've already found thousands of planets across thousands of light years. Our technology is getting good enough that we can start to look for biosigniatures, and there are even concepts like the solar gravitational lens, that could allow us to not only image, but map entire planets as if we had probes in the system (possibly even allowing us to spot city lights and other technosigniatures). And that's with technology we have now, or can develop in the next couple decades. A civilization capable of just ubiquitous interplanetary travel could easily map their section of the galaxy, and have, on record, every planet with life, and every planet with a possible or known civilization. That will include us. And that's not getting into civilizations capable of interstellar travel.

Acting like we're doomed because of a few messages is misguided fear at best, and concern trolling at worst. If there are other civilizations out there, close enough to reach us, they already know we're here. We don't need to send out messages for them to know that. So we have nothing to lose and everything to gain by attempting contact, because if someone is willing to respond, I'd wager they're helpful in the first place.

Interstellar travel is hard anyway. It can take decades or centuries to reach distant stars, even with the best technology, so the idea that a civilization might attack others isn't really a cause for concern. If there was anyone malicious out there, I refer back to my second point, in that they already know we're here, so as morbid as it is, there's nothing we can do about it. But seeing as life has been around for bilions of years, and our civilization has been allowed to exist up to now doesn't look to me as though there are murderous civilizations out there rabidly wiping out any life.

The golden records are more symbolic than anything. If they traveled any meangingful distance before being found (i.e. many light years), it would be hundreds of thousands of years from now, so having our location on it isn't really all that bad, because by then we'd either be extinct (hopefully not), or so advanced that they pose no threat.

If they stumble across the record in any meaningful time (within the next few human lifetimes), well, the Voyagers would be within several hundred AU from Earth, and so they were on their way here anyway.

As for decoding it, I refer to the other responses here. We tried not to do anything obtuse, and used concepts any technological civilization should have and know about. I think it could be decoded well enough by another species.

Presumably, if we have the ability to disaaemble entire planets, we more than have the capability to work around any orbital dynamic differences it brings.

Over long enough timescales (geologic, not human), you'd probably notice some changes in the paths of the inner planets, but I doubt you would see anything wildly different, and the outer planets would be mostly unaffected since they outmass Mercury significantly, and are much farther away from the Sun.

In order to keep a more stable Dyson Swarm though, free from most collision risk, those future engineers would probably aim to disaaemble every inner planet, stray asteroid, and the belt for materials. The gas giants would be last due to their mass, and because they're far away so their gravitational influence can be better mitigated with advanced technology.

This isn't something that would happen over a few thousand years or something like that, mind you. If we decide to work our way up to a Dyson Swarm, it could very easily be the project of a million years or more, starting with enourmous clouds of habitats and solar arrays slowly surrounding the planets and their Lagrange points as we need them, before they grow outward to independently orbit the Sun. Both because we won't have the population or industry to use all that excess energy and habitation space immediately, but also because it will take a long time to mine out entire planets out in the first place. It would be a very different world than the one we're used to now.

Well, we have some polar satellites, and those go 'up/down,' but for the most part, all planets are roughly in the same disc, so that's where we aim our spacecraft. Juno had to move along that path to reach Jupiter, but its orbit is polar, and highly elliptical.

But spacecraft don't go straight, their trajectories curve, and it takes less energy to follow the path of Earth's rotation/orbit than it takes to go perpendicular to it.

Yes. Humanity has only been traveling to space for less than a century. And 80,000 years or so to Proxma is only if you rely on chemical rockets, but even just fission based propulsion can cut it down to under 10,000 years. And that's on the pessimistic side of things, it's quite possible we could reach other stars in under a millennia, or close to a century, with nuclear technology fairly close to what we have today.

The big thing holding us back is infrastructure and manufacturing in space that has the capacity to construct the likes of an interstellar vessel. For that to be possible, we need low cost, frequent transportation to orbit. And we're steadily moving towards that already. This century is likely going to be a transition period from spaceflight as a highly specialized and risky field, to a widespread place of work, still specialized and risky, but not as much as today.

But bottom line, I don't believe we'll be limited in the solar system, or on Earth. In any case, there's a lot we can do here. And it'll be quite some time before we exhaust everything, by which point, interstellar travel may be as difficult as putting together an interplanetary mission now.

Earth has had life for over 3-4 billion years. The galaxy is only around ~100,000 light years across or so, and the furthest light we can see is no older than that. Additionally, the nearest galaxies are millions of light years away, and what we're seeing is those galaxies from that long ago. Any life on those worlds on planets about as old as Earth would be nearly as evolved as life here, so it would be about as visible.

However, what we can see with telescopes are macro scale things, stars, galaxies, nebula, etc. Smaller scale objects like planets are much more difficult to spot, and signs of life are even harder. For all we know, Proxima b (a mere 4.2 light years away) does in fact have life, but we don't have any way of confirming it because our instruments aren't sensitive enough. Now apply that to stars dozens of light years away, or even in other galaxies. We're only barely able to find planets within our own galaxy, though our techniques are getting steadily better, but we have no way of doing the same for potential planets outside the galaxy.

One caveat to that though is that the reason we can't spot life on Proxima b is because it doesn't transit, and we can't use our only available method for searching exoplanet atmospheres without one, whereas with the TRAPPIST 1 planets, they do transit, so studying their atmospheres is possible, though still tricky. It will likely be a further generation or two of telescopes, and the ability to directly image Earth sized planets (circumventing the need for transits) before we can really detect and confirm signs of life in all but the most specific cases.

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.

It's not about pop culture or just random probability measurements, It's really the fact that life made it here, so why can't it elsewhere? 3-4+ billion years of life, how can Earth be the only example? Because in spite of the universe being deadly and destructive as you say, life exists anyway. So either life here got improbably lucky where everything else was simply killed, or the universe may just be a little more conducive to life than you think.

But to be honest, basing the assumption on what we know so far about exoplanets isn't the greatest evidence for or against extraterrestial life. We've only been searching for planets over a few short decades, our instruments have only very recently become sensitive enough to analyze the atmospheres of Earth sized planets, and even with JWST online, it may be years more before they're advanced enough to confirm life, not just find candidates. We simply don't have enough data yet.