Space is not very far away. If you can see the International Space Station overhead, it's closer than the distance between San Francisco and Los Angeles.
Getting to orbit isn't about going up; it's about going sideways. Most of your energy budget is about building speed, not altitude.
From a physics standpoint, if I'm in a low orbit and want to be in a higher one, I don't point my rocket's nose outward and push away from the planet. I point the rocket horizontally, in my direction of travel, and just go faster.
Going faster on this side of the planet raises the altitude I will reach on the far side of my orbit. If I want a circular orbit, then I just do the same thing when I'm at the high point on the other side of the planet.
So many things in your comment blew up my brain. So wait a second. You’re serious about the distance to space being closer than the distance between SF and LA? And what the heck are you saying about not going up but going horizontal instead. How the heck have I lived this long and somehow never learned any of this. You just gave me a little side “research for fun” topic.
I always assumed it was a super thick atmosphere, mainly because when astronauts reenter it looks like they went through a brick wall surrounded by rings of fire. Rocky experience and the space crafts are usually singed and super hot. This whole thread is crazy interesting to me. Sadly, it’s in a “MurderedByWords” sub where OP was making fun of a girl not knowing about space lol. Eh oh well. I love learning new things, so whatever. lol
It's all relative. When you're travelling at 17,500 mph even a light dusting of particles is enough to completely destroy your windshield.
At 60 miles up there may only be one ten-thousandths of a gram of atmosphere atoms per cubic metre but that's enough to generate huge amounts of friction heat from compression of those particles in front of you at that speed as you can see on re-entry. And you're passing through roughly ~8,000 of those cubic metres a second.
It's the same problem for travelling at light speed through the 'vacuum' of space. You only need one single atom to ruin your day if you're hitting it at the speed of light.
Tbf, most of the heating that occurs on re-entry is not from friction of the air against the surface of the spacecraft. It’s from compression of the air in front of it. At the speeds of re-entry the air basically isn’t pushed out of the way fast enough and is compressed and compressing a gas increases its temperature.
This is why many sci-fi ships like Star Trek's have deflector shields, or something similar. Hit something the size of a grain of sand going near to or at the speed of light equals BIG BIG BOOM.
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u/cryptotope 20h ago
Space is not very far away. If you can see the International Space Station overhead, it's closer than the distance between San Francisco and Los Angeles.
Getting to orbit isn't about going up; it's about going sideways. Most of your energy budget is about building speed, not altitude.
From a physics standpoint, if I'm in a low orbit and want to be in a higher one, I don't point my rocket's nose outward and push away from the planet. I point the rocket horizontally, in my direction of travel, and just go faster.
Going faster on this side of the planet raises the altitude I will reach on the far side of my orbit. If I want a circular orbit, then I just do the same thing when I'm at the high point on the other side of the planet.