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Toss up : a coworker who I would have counted as quite intelligent said we haven't been to the moon because "it's impossible to launch a rocket to the moon and land on it because rockets go in a straight line. Trying to time the shot of the rocket, and get to the moon at the exact moment when the moon gets to the right spot would be astronomically impossible. The odds of pulling that off at the speed you would be traveling and the distance you travel... Well the odds are effectively zero."
"Also you can't catch up to the moon because the moon is traveling faster then our rockets can go "
Either that or a prochoice individual who voted for Trump....
How does this person think guided missiles work? "Well the plane moved so we missed."
"Also you can’t catch up to the moon because the moon is traveling faster then our rockets can go "
- Not true so discussion over right there
- Even if its angular velocity was faster than a rocket its radial velocity is nearly 0 so all you would have to do to intercept it is to lead it. No different than shooting a moving target at long ranges.
Okay im curious. What about shooting something into the sun is very hard?
The earth has a lot of angular momentum, in fact the planets combined have more than the sun and planet formation may actually be necessary to "bleed off" angular momentum from protostellar discs for star formation, but I digress. So if you were to aim directly at the sun you'd miss it wildly as the tangential motion of the earth would be added to your motion. Even worse it would miss the sun, go around it, and orbit back to where you came from. A bad thing if you were trying to toss, say, radioactive waste into the sun. To hit the sun you have to bleed off all of that angular momentum by using rockets (very expensive) or do what NASA usually does and use gravity assists swinging by planets to gain or lose energy. The Parker solar probe had to do a bunch of swings past Venus to lose enough angular momentum to get close to the sun.
I was assuming rockets were an option like going to the moon. Cost wasnt something i thought we were factoring in thats not really a factor in just trying to send a space ship at the sun and having it get there. It doesnt have to be moving fast (relatively) to get there so you just need good aim and to keep it on track.
Cost should be its own problem separate from the objective. Assume 0 costs, how hard would it be?
It requires a LOT of energy to counter the earth's orbital motion. Hitting the moon is different because the moon is traveling with the earth and you are going outwards. Energy is always part of the equation since orbital mechanics is all about energy. You can't ignore it by saying "Assume 0 costs, how hard would it be?" then we could just say it can approach the speed of light since we are ignoring any energy costs.
"It doesnt have to be moving fast"
But you will be moving fast, you are starting at an angular speed of 30km/s. The Apollo missions with their massive engines reached 11 km/s. Now think of someone wanting to dump hundreds of tons of nuclear waste into the sun and the energy that would require.
Maybe this explains it better:
How does this person think things like ICBMs work? They just go straight up and away from the earth and can't turn?
When he used both arguments in the same conversation. I shrugged and stopped talking. Nothing to gain by continuing the conversation
No, you must go back and tell him that the moon moves at a very predictable rate and once you get close enough it will even pull you in.
Also I'm pretty sure the ISS moves a lot faster than the moon but we still manage to dock spacecraft with it. I'm pretty sure it's a bit smaller than the moon and docking can require higher precision than landing on a surface. Even Boeing managed to do it.
The first argument is more or less understandable (still wrong): you can't just propel yourself upwards at your earliest convenience to reach the moon, you have to play around with orbital mechanics.
If your friend's idea of a moon-worthy vessel is an unsteerable rocket with infinite fuel and a chair strapped to it... well the odds are effectively zero.The second argument? bro, last time I checked the moon was still orbiting Earth
The friend should play Kerbal Space Program. It will be a fun way to show that yes, it's really hard, but it is possible to play around with orbital mechanics and get to the moon.
And then it will show that an unsteerable rocket with infinite fuel and a chair strapped to it is also possible, just really really hard.
I imagine the latter isn't too hard, you just have to get it right just before leaving the atmosphere (quick saves help); however, isn't landing (not crashing nor rolling around) on the Mün without steering straight up impossible?
Though I can see some rocket landing on a planet with an atmosphere...
Depends if you're trying to get to the moon, or get to the moon safely.
... so, when are we launching?