Let’s imagine we’re in a rocket ship in a circular orbit, and we want to go back to earth. You might think you need to point towards the ground and turn your engine on, but remember how we got up here–we’re in orbit because we’re going sideways very fast. The most efficient way to come down is to point backward along our orbit and slow ourselves down, to lower the height at the opposite side.
What happens if we do point straight downward? Well, we would start going downward, but because we aren’t pointing straight backward, we aren’t actually reducing our speed, only changing the direction of the orbit. It would take much more energy to come back to earth this way, and because we aren’t actually reducing our speed, it would be much more dangerous, because we would be entering the atmosphere faster than if we had pointed backwards instead.
In a worst case scenario, we would run out of fuel before re-entering the atmosphere. This is very bad, because as we fall towards the earth, we start moving faster. Remember how moving faster at the lowest point in an orbit increases the height of the highest point? If we don’t hit the atmosphere, the top of our orbit will end up even higher than it was before!
A lot of people think that to get to orbit, you just have to go up, but actually you need to go sideways.
Imagine throwing a ball that leaves a visual trail behind it. You throw it straight up, it comes straight back down and just leaves a vertical line. Throw it across the room, and it makes an arc. Take it outside, throw it really hard, and it makes a bigger arc. Zoom the camera out, and throw it so hard it goes over the horizon. It leaves a pretty long arc right? If you throw it hard enough, that arc goes farther and farther past the horizon until it misses the ground entirely and comes right back around to you. That’s an orbit!
But that’s only part of it. You see, any time you impart force on an object in orbit, you only change its trajectory, not its current position. Since your arm is now the lowest part in the ball’s orbit, you can never raise that point above where your arm is. But you can affect the other side of its orbit–the faster you throw the ball, the higher the opposite side of the orbit gets. Let’s head up to the highest point in the ball’s orbit, and give it another push. Again, that doesn’t affect its current position, but it does affect its trajectory. Making the ball go faster forward increases height at the opposite side of its orbit, so if we push it with the right amount of force, we can make its orbit circular!
Now you know enough to get a rocket to space! Well, kind of. You also need to know about fuel and the tyranny of the rocket equation, but that can wait until you play Kerbal Space Program or get a job at NASA
I remember early 2020, there was a small push to bring capes back, before something else took over every discussion. Something about blue jays or crows or something
I never actually thought about how tea was discovered, and my new headcanon is that some weird person was just drinking hot water, some leaves fell in their cup, and they were too lazy to just get some clean water
Yeah, I’m reminded of the Ohio chemical attack last year. CNN had a story about it… Underneath seven other stories about Taylor Swift’s new boyfriend or whatever.
If you’re a professional ecologist, then you should know full well that even if a cat is perfectly sedentary and kills nothing, and is neutered, they can still get and spread diseases, they can still get run over, and they can still be attacked and killed by other outdoor animals
30% of bird deaths is still a lot of bird deaths. I would much prefer if cats were only responsible for 40 small animal extinctions rather than the 60 or so that they’ve caused so far
A properly built hammock is sturdy enough that it isn’t gonna fall down, and because the middle of it dips down with your weight, the sides come up sort of like a bowl and hold you in. Sleeping on your back isn’t actually that bad, and once you get used to it, you figure out how to spin slightly to one side or the other for comfort.
For reference, I was sleeping in a travel hammock meant for camping every night for about a year, I weighed over 200 lbs at the time, and even after the canvas started to tear at the seam, it never actually failed. The only reason I got rid of it is because the tear started to grow over the course of about a week.
Edit: also, for safety, I had a couple old comforters under it to cushion a potential fall, and an old pillow underneath my head for more protection. Never ended up actually needing them, but it’s an option
Legitimately the best sleep I ever got was when I had a hammock. It takes a bit of adjustment, but once you’re used to it, it’s so easy to wake up. I haven’t felt fully rested since I replaced my hammock with a bed