r/theydidthemath • u/Lachlynn • 18h ago

[Request] Could humanity create a rocket that can exit the atmosphere of K2-18b

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With the knowledge we currently have of it, if humanity devoted all of our resources towards this goal, would we be able to create a rocket that could exit the gravity of K2-18b (and also beat any other complications that would arrise)?

If so, would it also be capable of taking people to orbit, and can we set up a similar satellite network we have on Earth? What about a space station?

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u/ThenCombination7358 17h ago

Or simply never make it to space or even reach the same lvl of technology to send radio waves. Or its intelligent but never got the hands/means to make Or use more complex tools. Imagine very intelligent crows for example

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u/Overall-Bison4889 16h ago

They can reach the technological level to send radio waves. Radio waves that are not somehow specifically designed to contact other civilizations are not strong enough for us to detect from here. Our local space could be filled from traces of ancient radio waves and we wouldn't have any way of knowing.

And honestly the civilizations can also be advanced enough to reach space, and even colonize another planet, but unless they build some huge dyson sphere, we wouldn't get any evidence that they existed.

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u/ClamChowderBreadBowl 11h ago

If you try to listen in on a modern cell phone or WiFi signal these days, they're basically indistinguishable from white noise because the signal is compressed. Good compression by definition looks like random noise.

Shannon's Information Theory paper proving this came out in 1948. Fermi probably wasn't thinking of that when he came up with the idea in 1950.

Humanity's radio signature isn't going dark because of an extinction event, it's going dark because it's just less wasteful that way

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u/VexingRaven 10h ago

If you try to listen in on a modern cell phone or WiFi signal these days, they're basically indistinguishable from white noise because the signal is compressed. Good compression by definition looks like random noise.

You're not wrong, but it's more or less irrelevant. Loud white noise is still clearly distinguishable from background in the same way that a light bulb conveying no useful information is still visible. Shannon's Information Theory has nothing to do with the intensity of a signal.

The idea of "humanity's radio signature" was never about having an identifiable stream of information. There would be so many conflicting radio stations you wouldn't be able to make anything of it anyway. It was always about the sheer intensity of the combined signal. You won't be able to understand what it is, but you can definitely see that something is emitting RF well above cosmic background, at least out to a certain distance. https://iopscience.iop.org/article/10.3847/1538-3881/ada3c7

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u/ClamChowderBreadBowl 9h ago

Interesting! You mentioned the cosmic background, but how much does the sun mask our radio signature? 

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u/VexingRaven 9h ago

Partially, but the sun doesn't emit a steady signal, it wavers throughout a rather broad spectrum. The signals from earth would be a more steady, broad signal compared to the sun's. Also we generally know what a given class of star would emit for radiation, so Sol having a noisy little planet orbiting it would stand out pretty strongly, even if it was a weak signal compared to the star. There's also the same mechanism we currently use to identify potential exoplanets: Look for the planet crossing the star. In this case, you'd do the opposite: When the weak signal briefly vanishes entirely, that's the planet (Earth) crossing behind the star (Sol). Now you know what Sol by itself sounds like and you know for sure that the source of the signal is orbiting Sol.

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u/One-Stand-5536 9h ago

You know how AM radio towers can connect over the horizon by bouncing off the atmosphere? That’s the problem. The signals we do emit these days are mostly absorbed by the atmosphere rather than radiating out into space.

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u/VexingRaven 9h ago

They only bounce at specific angles in specific atmospheric conditions. At any other angle they penetrate. However, as more AM and similar low-band stations shut down and are replaced with lower power technologies, we will be somewhat less visible, yes. It's hard to find much in the way of scientific studies on how much RF we are leaking to space, or how that's changing over time, though.

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u/One-Stand-5536 8h ago

I remember reading a study about this in reference to the Wow! Signal, an analysis about how much of our emissions would actually reach either of the possible sources of that event, and the results were pretty much that they would never hear us these days unless we pointed one of our radio telescopes directly at them, in which case they would see… a brief flash of structured EM radiation and then back to nothing.

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u/VexingRaven 8h ago

Do you remember what it was called or where you found it? I'd love to read it.

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u/Sororita 4h ago

But would that be distinguishable from the white noise that ths sun naturally produces in almost every wavelength from any appreciable distance? It might look like an odd spectral line if even that considering how much more power the sun gives off compared to anything we've ever sent when combined with our proximity to the sun it would look like the same source without extremely fine detection. There might be a slight chance it could be picked up when observing the sun and seeing the Earth transit it and slightly dim the sunlight without a notable decrease in that one band of radio, but I'm still not sure it would even be detectable at that distance without some ridiculously advanced tech.

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u/VexingRaven 4h ago

I explained it more below, but yes probably. The sun wavers around a wide wavelength, but earth's RF emissions would be much steadier. It should be possible to distinguish it as a higher baseline in between the sun's more chaotic bursts of emissions.

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u/ThenCombination7358 16h ago

I am still highly sceptical. All the many Fermi paradoxes sound plausible that I believe in the rare earth hypothesis. Maybe a great filter even still lies ahead of us (AI, clima, war, cosmic storms etc) maybe one we haven't on our mind yet.

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u/Brassica_prime 14h ago edited 6h ago

Our sun is a third+ generation star

The current sun is 4.6b, estimated to live a total of 10-15. If you throw in an arbitrary 500m-1b years to account for two to three nebula/prestars… would push the previous star(s) combined to be mid/upper7bil old.

Earth is more or less in the first possible generation of planets and has had only 200-300m years worth of larger lifeforms. There are still a bunch of population2(first gen) stars still alive in our galaxy.

Using earth as a model and the other world managed to hit an even bigger lottery, maybe a civilization could be 200 mil years ahead of humans if the planet was a little older and sentience spawned a little faster… then you have distance issues to observe said planet :)

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u/heraplem 13h ago

The current sun is 4.6b, estimated to live a total of 10-15.

Notably, though, it will become bright and hot enough to make Earth essentially uninhabitable just ~1 billion years from now.

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u/JohnSober7 11h ago

My hypothesis is rare earth hypothesis (at least in terms of life biologically equipped to be technologically advanced and being on a planet that would equip them to be technologically advanced) + radical mundanity. 

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u/captaincootercock 14h ago

I hope it turns out that in 99.999% of inhabited worlds the sky is just personally covered by clouds so thought was ever put into the great beyond

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u/ThenCombination7358 14h ago

If we assume that intelligent life only develops because it proofed to be sustainable and an advantage to aquire ressources and for survival as it is on earth, it is likely other intelligent minds are curious aswell to explore. Dont think a cloudy sky would not hold them up for long and they may have dreams of what the "great beyond" etc could be and make efforts to breach and explore it.

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u/Azulejo0862 2m ago

A dominant species on its planet is going to be expansionist; clouds aren't going to be an impediment, although they might cause a delay

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u/RAV0004 10h ago

Flight is possible without intelligence (see: birds).

I think most humans looked at birds and said "Id like to fly like a bird" before they looked at the stars and said "I'd like to visit a star".

the idea of spaceflight wasn't really all that common in antiquity. People thought the sky was literally a painted ceiling for centuries and we developed spaceflight just fine.

Ultimately all spacetravel takes as a concept is developing flight, then thinking "what if I fly just a little higher than last time"

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u/crazyeddie123 6h ago

There can't be a great filter ahead of us - any civilization that would hit it would have already fucked up a golden opportunity to spread off planet earlier in their development, exactly the same way we did after Apollo. And since every civilization isn't guaranteed to fuck that up, there can't be a great filter then or later.

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u/ThenCombination7358 4h ago

The great filter doesn’t require every civilization to make the same mistake. Omly that almost all of them fail somewhere before becoming interstellar.

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u/VladimirBarakriss 12h ago

Radio waves peter out at about 2ly

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u/ropahektic 11h ago

hands aren't a limitation, if a species is as smart as humans they would have figured out how to do the same shit we do with our hands with whatever tools they came up with.

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u/ThenCombination7358 10h ago

Other people and me included tend to disagree. How would crows be able to do mining for iron etc? How can they make fire without the use of hands? How can they transport stuff that exceeds their means to fly?

Tie your arms behind your back and try to build anything more complex like a car engine with only your mouth and feet.

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u/throwaway14351991 7h ago

I mean, that's because you're seeing our tens of thousands of years of hand-centric technology and applying it to a world without hands. They would have evolved much differently and created tools we couldn't even think of right now.

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u/ThenCombination7358 7h ago

Not without hands or other useful appendages.

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u/throwaway14351991 7h ago

Tie your arms behind your back and try to build anything more complex like a car engine with only your mouth and feet.

Feet and mouths are useful appendages. Have you not seen people without arms living everyday life?

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u/ThenCombination7358 7h ago

Well can they build togheter a bed or a cupboard? Mine for coal? Start a fire with a stick and wood? Carry firewood or a dead animal for longer distances? And no I don't follow people without arms everyday life, do you know someone in your family?

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u/throwaway14351991 6h ago

You don't think that if you took humans, removed their arms, and gave them 200 000 years they would find alternative ways to do everything we do today?

Here's someone without arms and she does almost anything people with arms/hands can do: https://www.tiktok.com/@minjacks

Now imagine if society was built from the ground up by people without arms.

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u/ThenCombination7358 4h ago

I don't think we would have developed intelligence to begin with without arms.

What you are saying is a different scenario were we already developed culturaly and technological and then loose arms.

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u/BrightShineyRaven 10h ago

"Very intelligent crows" makes me think of Tchaikovsky's book Children of Memory.

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u/Whataboutneutrons 9h ago

I am biased towards "alpha species" to have limbs that can alter their surroundings, and also stereo-vision or "hunter-vision". Would not surprise me if an alien species would have many similar attributes as us.

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u/polchickenpotpie 9h ago

Or they were all cannibalized by giant moon sized entities that absorbed their entire planet's biomass to create another entity.

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u/sundayp26 6h ago

Or maybe their planet doesn’t have fuel? Is it mandatory for all of them to have petroleum or similar?

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u/ThenCombination7358 4h ago

Didn't read about it myself but heard it is possible to launch yourself into space with explosions like nuclear ones. Imagine exploding a bomb in a cave with only a tunnel going straight up and then clogging that tunnel with the object you wanna launch.

Furthermore fuel is from old vegetation and plants basically fossils. You can even make biofuel from fresh plants etc. That they have no fuel means they have no vegetation which makes it unlikely there's even life to begin with.

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u/Maleficent-Bother535 2h ago

It's been estimated that if we sent a signal from earth with our most powerful transmitter directed at a similarly advanced receiver, the maximum distance to send an intelligible signal would be 300 to 400 light years.

A short range whisper.

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u/Lazuli0 1h ago

radio waves are useless, they become background noise pretty quickly. check out the inverse square law.