I think this is more like 'impatience paradox'. With our current technology we have extremely little chance of detecting any intelligent life.considering the formidable obstacles created by one single barrier - the distance measured in light years. Once we have ,at least, a few hundred thousands of years of observations AND NOT just 50, we will be able to talk about the Fermi paradox.

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What's not well known is that, during the Apollo 15 mission, Lunar Module Pilot James Irwin almost added his own name to the list.

He had undetected and severe coronary artery disease and developed bigeminy while on the way to the Moon. If he wasn't in the pure oxygen and zero-G environment of the Apollo Command Module, that would have had a good chance to progress to full on fibrillation and zero blood pressure.

The coronary artery disease was only detected two years later when he had a major heart attack (at the age of 43!) and was given an emergency triple bypass.

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that was part of the idea the big crunch. The thing is once the Big Bang was theorised, people tried to figure it out. The Big Crunch stipulates that eventually gravity of all the material in the universe will pull everything together and basically return everything to the conditions right before the big bang, ending the universe in a crunch.

So, let's try and make a predictions out of this hypothesis, how would it work? and what would we expect to see in the universe that would affirm it?

Well, the idea is that the moment the Big Bang happens, everything is thrown in all directions and begins to slow down, much like with a rock that you throw, the moment a propelant is spent it slows down, because there's something that resists it – i.e. gravity. So, what we should be seeing is that galaxies away from us should be slowing down, or starting to even reverse their direction of travel (but that would be typical of a much older universe). And that's exactly what scientists were looking for.

But guess what they found? The universe isn't slowing down, it's actually accelerating. I'm talking that since that first observation, about fourty years of further observations confirm the same findings. There are areas of uncertainty there, but the evidence that the universe does not slow down is rather consistent.

But to your other point, we are still trying to figure out reality. How big is the universe really? how is it shaped – i.e. is it flat or is it curving (our current observations say it's flat), so on and so forth, and there are more and more scientists that stipulate that there are more universes out there that we can't see or interact with, at least not yet. I think they didn't make any workable prediction that one can measure and draw any conclusions from, but you're not alone in this. Still, our understanding of the universe is incomplete, and is evolving. It's just based on theories that correlated with observation and science.

Then we have a big torch to carry.

Mars does absolutely nothing to ensure the survival of the human race. At best, you're condemning a bunch of colonists to a terrible death if something happens to mothership Earth. (or, much more likely, some petty squabble on Earth leaves the colonists to fend for themselves)

I know Elon said it all those years ago and then everyone else jumped on the bandwagon. But, it's a quite facile take on the issue that's more about wish fulfillment than reality.

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We will never know. It’d be nice to think they would. Apollo-Soyuz happened in the 70’s, and that would have taken a lot of co-operation and co-ordination between US and Russian space agency staff. I imagine most of them could put the politics aside and appreciate each others achievements in the field.

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‘Cool worlds’ ‘The history of the universe’ ‘pbs eons’ ‘pbs space time’

There are lots of possible answers. It could be that intelligent life is pretty rare, so that even if there was a species out there building dyson spheres or doing other crazy things in a far distant star system we wouldn't be able to detect them. Or maybe there is a sociological explanation, like civilizations tend to be unstable and collapse in on themselves before they can become type 1.5 civilizations. Or maybe most intelligent species are trapped in their solar systems or their home planet, that interstellar colonization will never be economically feasible.

At the beginning, there were no atoms, because densities were too high for atoms to exist. It was some weird quantum soup of particles.

Also, not sure where you are going with knowing the size of hydrogen atom. You can't simply pack those as tight as possible. As you pack those hydrogen atoms more and more tight, at some point protons will capture electrons, turn into neutrons (and release neutrino in the process). This is how neutron stars form. Neutron stars are about densest you can get matter before it collapses into a black hole.

Where is that from? Is it Last Chance to See?

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Americans already leaving rubbish up there… go back and pick up your shit.

One hydrogen atom occupies approximately 6 x 10^(-31) m^(3). Nearly all of that volume is empty space. But then the volume occupied by every atom is overwhelmingly empty space.

The hydrogen nucleus, a single proton at the center, is about 1.7 femtometers wide (1.7 x 10^(-15) m). While the spherical electron cloud surrounding it (which contain one solitary electron) has a Bohr radius of approximately 50 picometers (5 x 10^(-11) m).

Cat Stevens start singing somewhere off in the distance ...

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Been reading too much sci-fi fantasy or playing video games eh, get some sleep pal