if the thing we have labeled "life" on this one planet, this one context on this one planet we use an example, exists anywhere else, and if this thing we can barely define in our own species as "intelligence", which we base entirely on one species as the default example of, has somehow arisen from that "life" somewhere else, and this "intelligence" uses anything like the same concepts as ours that would be able to recognize anything remotely similar to our concepts and symbols we use in our "intelligence" and they have some concept of responding to the electromagnetic spectrum that interact with this "intelligence", and they exist on any of these planets that has the possibility of ever detecting Earth, then sure, they may be watching.
This feels like way too cynical of a take. Intelligence in this context means the ability to develop the tools necessary to detect other unusual planets.
Anything at that level of development will of course be aware of the electromagnetic spectrum, just as how we can't see in the infrared and have developed tools to do it for us, or how we've become aware of gravitational waves and are refining our tools for listening to them.
They don't even have to be based on the same chemistry. The only conditions on them would be that they are slightly more advanced than us to be able to do exoplanet atmospheric spectroscopy en masse. Earth would really stand out for being oxygen rich without the temperatures to explain some sort of extreme activity.
GP didn’t strike me as cynical, only more of a call to broaden our expectations!
> Intelligence in this context means the ability to develop the tools necessary to detect other unusual planets.
What if instead of attempting to detect planets, they just spam the universe with their space-hardened eggs, and hope that eventually they’ll smack into something habitable? Seems a lot more productive than analyzing incoming UV rays for thousands of years, then spending who knows how long to figure out how to get to the ones we suspect are interesting.
We are concerned with disseminating our discoveries and keeping in touch with the folks back home. But a non-hierarchical intelligence (by whatever hand-wavey metric you want to use for “intelligence”) might be more concerned with simply existing in as many places in which it can survive in as possible, whether Mom and Dad know about it or not.
This isn’t science fiction: I’d estimate there’s 1e10 spore-producing mushrooms on Earth on any given day. (That’s only a couple steps away from a wild-ass guess, but hear me out.) One mushroom can produce over a billion spores per day, 1e9. That’s 1e19 “eggs” every single day, and that number hasn’t changed significantly for thousands of years. It’s a staggering number.
This is science fiction: Imagine mushrooms are aliens who originally came from a planet with a more turbulent atmosphere, one which promotes more ejections of tiny spores into space. Imagine that their spores are drastically more long-lived and more spaceworthy (the Earth ones already do pretty well).
This isn’t science fiction: Mushrooms (well, fungi) have a symbiotic relationship with an overwhelming majority of plants. They are crucial to forests; there’s a viable hypothesis that forests only exist because mushrooms “decided” to farm trees. That decision, if the hypothesis is correct, played a huge role in the development of humans and therefore big telescopes.
Even if they’re native earthlings (they probably are), could they represent an intelligence whose comprehension of their environment, existential goals, mode of communication, etc. is too far outside of what we are used to in order to recognize them as being intelligent?
To bring it back around to what GP wrote, fungi do pay attention to humans, an analogue for “watching” us. They “hear” our footsteps and send hyphae to investigate, because we often track tasty things from our shoes onto their rooftops. If we cannot even speculatively judge a homegrown lifeform’s intelligence, why do we think we’ll stumble across an alien species that makes more sense to us? Those odds seem even less in our favor.
Your mushroom overlords have taken notice of your words and shall ensure you a particularly cushy spot in the dirt mines after their peaceful takeover of Earth is completed.
I am writing to confirm that this was indeed my goal, and I am definitely not a Vermont forest mycelial mat that figured out how to use a RaspberryPi someone dropped on me, gauging the humans’ response to the idea of said peaceful takeover.
But seriously, limiting ourselves to light speed here is somewhat... disappointing.
If the speed of light really is something that can't be worked around with warp drives, etc., then who cares if there are aliens or not. They will never be interacted with in any meaningful way, except for maybe the hyper-rich folks on those generation ships.
> More than 1,700 stars could have seen Earth in the past 5,000 years.
The most interesting observational period for observing Earth would be the beginning of the industrial period right up to the banning of CFCs and other detectable, non-naturally occurring organic compounds. The spectra would have been a dead giveaway that we're here.
Here's hoping JWST can spot CFCs or similar in extrasolar spectra.
With our current technology, could we make a useful radio link to a planet 11 light years away? If so, about when would that have become possible? Last 20 years? My gut says it's still not possible we'd have trouble picking anything out of the noise and the power requirements would take more energy than we manipulate as electricity.
"Look at it this way: the sun to that system barely emits enough energy to make that planet visible to our technology.
So, if that planet wanted to send us data, they would have to send as much energy as gets reflected by that planet in our direction.
Since you said "as advanced as ours": We're not capable of producing that much power. Not even remotely. So they're not capable of doing that, either. A star is amazingly powerful.
Let's look at this way. The estimated power of the sun is something like 1026 W."
If I understand correctly, it's not the light reflected off the exoplanet that we detect, it's the slight dimming of the stars light as the exoplanet transitions between the star and our telescope.
I'm not sure what this has to do with a communications link though. It's not like we need as much energy as a star, we can use a directional link like a laser. Sure it'd still need to be massive but while I don't have the math in front of me, it seems like something we could build.
You are talking about detecting planets as they revolve around the star. As you said, if the planet rotates on an axis that "blocks" a tiny, tiny fraction of the star as we observe it, we see the dimming (that goes away as the planet passes) and can assume a planet and some parameters.
You are also right that the conversation is about COMMUNICATION:
1. You either dim the star with a Dyson swarm, or
2. You pulse more power than the star outputs as background noise briefly
Why can't you use a laser with a relatively high power? Should be easier to differentiate that from background and star light? Or something more exotic like sweeping wavelengths.
Hum... All the other answers on that thread are variations of "yes, we could, here's an example of how" with the examples varying from one widely impractical idea to "here is how we do something similar by accident today, we just have to control it".
If we had to overpower the Sun to communicate, we wouldn't use radio on Earth either.
Having followed that answer for years and read quite a bit, I am fairly certain that the "yes, but" answers are wrong. It's as simple as "you can't see a flashlight when it's being flicked on and off behind a lighthouse lamp". I am very interested in the topic.
If we had to emit light just like a flashlight vs a lighthouse, aka roughly equivalent wavelengths, you'd be right, however we only have to beat the sun in a single wavelength. An extreme uv laser is probably the easiest option there. We also only need to beat the sun's output in a single pinpoint (in cosmic scale)
Also to damage the example a bit, we can easily detect a flashlight shining from behind a lighthouse. Our eyes are just logarithmic and suck at detecting smaller absolute differences like that.
Isaac Arthur does a good video on this topic and talks about some of the specifics of such a beacon starting at around 14 minutes https://youtu.be/DHoOjIEcRV8?t=829
I haven't read enough on the subject to know the answer to that question, so here's another one. How do we know that ET uses radio for communication? They might've moved onto something else. Tachyons or gravitational waves might make good candidates but those are just the ones we know about. For those two we do have instruments sensitive enough to detect potential WOW signals, just not a lot of will for them to be used for that purpose.
A massive object flying at a substantial fraction of the speed of light would be better for communication over very long range. Sure, the overall latency would be greater, but a massive object doesn't suffer from the inverse-square law if you know where you want to send it, and doesn't need a larger antenna to make it more directional. If it's some kind of programmable or even intelligent machine, then it could adapt to the evolution of conditions at its destination upon arrival, and engage in many iterations of short distance communications before sending data homeward.
It's like why we sent human envoys during the era when communication speeds were limited by horses and ships.
ET has probably given up on long range radio for their local comms, just as we have. The bulk of our comms go through waveguides (electrical cables and optical fibers). Even our radio comms have relatively short range, and are designed to be virtually indistinguishable from noise. It's as if we've wrapped ourselves in a primitive Dyson sphere.
Out of all the physical phenomena we know about, EM (various aspects of it, radio or lasers or whatever) is the best way to transmit information across space.
Tachyons are fictional, there's no reason to assume they exist. Gravitational waves require exceptionally large amounts of energy to generate; we can't transmit with them, and for a more advanced civilization which does have that capability, using the same amount of energy for a focused/directional EM transmission would be much easier to detect; because gravitational waves (unlike EM) radiate equally in all directions but EM can be directed to a particular recipient. Neutrinos are similar to EM but worse, as their transmission/power characteristics are pretty much the same but it's very difficult to detect them.
It may be possible to use gravitational waves to transmit signals, although gravity is hugely more challenging to manipulate than electromagnetism because it's purely attractive and interacts much less strongly with matter, making this very unlikely in my opinion. Another theoretically plausible but very unlikely signal carrier could be neutrinos. 'Tachyon' is a name used to refer to any theoretical particle which travels faster than the speed of light; as far as I'm aware all current experimental evidence rules out the existence of tachyons.
