4 ms·

This comes up on HN every year but I re-read it every time. My idea is just figure out a way to nudge earth towards the sun and inertia will do the rest, slowl

by ck2 10y ago

This comes up on HN every year but I re-read it every time. My idea is just figure out a way to nudge earth towards the sun and inertia will do the rest, slowly but surely, so a vote for their #10 Or settle for wiping out all human life on earth and earth will survive just fine without us. Picking a US President that will use nuclear weapons might be a dangerous starting point to investigate.

Smaug123 10y ago
I didn't bother to search HN for the title, just the link, and this is the first time this particular variant of the link (https) has been posted. Sorry; I wouldn't have posted it if I'd realised it had appeared multiple times before.
- golergka 10y ago
  Nothing to be sorry about: a lot of HN readers (invluding me) are seeing it for the first time. And I will upvote this next time I see it, too.
wlesieutre 10y ago
> My idea is just figure out a way to nudge earth towards the sun and inertia will do the rest, slowly but surely, so a vote for their #10 I don't think you can. Even if you could give the whole Earth a push toward the sun, it has enough orbital velocity (~30,000 m/sec) that it'll miss and keep on going around. You might turn its orbit into a slightly different ellipse. Say we want to straight up (down?) launch a probe into the sun. It's a hard thing to do because it has to shed all of that orbital speed to get its velocity vector pointed in the right direction (at which point it can fall in on its own). If you only get rid of most of it, you'll fall into a long elliptical orbit. You could potentially dump some energy with a gravitational assist off of Venus (transfer some of our momentum into speeding up its orbit while slowing ours down), but there's still the matter of getting the Earth to Venus for that to work. And at that point maybe you just want to stick to #9. I haven't played enough KSP to be sure of all that, but that's my understanding of the orbital mechanics.
- jacquesm 10y ago
  If you wait for a while (8 billion years, give or take) the Sun will expand enough to meet the Earth, and presumably that will happen long before any drag effects will cause the reverse to happen.
- abecedarius 10y ago
  It's straightforward: throw the moon off in the direction of Earth's motion around the sun. The Earth has 81 moon-masses, so you'd have to throw the moon 81 times faster: still less than 1% of the speed of light. That'd take considerable energy, but the sun outputs 3.846×10^26 W, so we'd only need 17 years of total solar output. It'd be a lot easier to just roast the Earth's surface, it's true. (I haven't read the original post in a long time, but had thought about it myself before.)
- TeMPOraL 10y ago
  > You could potentially dump some energy with a gravitational assist off of Venus (transfer some of our momentum into speeding up its orbit while slowing ours down) I've heard that a hard turn around Jupiter is even better. I remember Scott Manley dropping a probe into Kerbol via Jool gravity assist in one video[0]. Actually, now I want to make a simulation with Earth doing Jupiter flybys. What's good for that nowadays? Universe Sandbox? [0] - https://www.youtube.com/watch?v=uNS6VKNXY6s https://www.youtube.com/watch?v=uNS6VKNXY6s
  - deciplex 10y ago
    Scott Manley also made a trip to Minmus using only the starting Career parts. Just because he did a thing doesn't mean it's the optimal way to do that thing :-) (In fact, it's probably a better indicator against, heh.)
TeMPOraL 10y ago
> Or settle for wiping out all human life on earth and earth will survive just fine without us. Picking a US President that will use nuclear weapons might be a dangerous starting point to investigate. This may be very dangerous. When you take antibiotics, you need to do the full course, 'lest some bacteria survive. Similarly, if the nuclear destruction isn't complete enough, the surviving humans will repopulate the planet and continue to trouble it for millennia to come. When planning an apocalypse, one needs to be sure it can be carried out to the end.
- mikeash 10y ago
  That's an excellent point. If you think humans are bad, nuclear-resistant humans are worse.
stcredzero 10y ago
My idea is just figure out a way to nudge earth towards the sun and inertia will do the rest ARRGH! This is about as big a misunderstanding as not knowing the difference between sending a rocket to space vs. getting to orbit: https://www.youtube.com/watch?v=uNS6VKNXY6s https://www.youtube.com/watch?v=uNS6VKNXY6s tl;dr -- the Earth is whizzing around the Sun at a really high speed. You'd have to cancel most of that velocity to get a spacecraft to get anywhere near the Sun. It would actually be less energy to send the Earth to Jupiter than to drop it into the Sun. You've repeatedly re-read this article, but never delved into basic orbital mechanics all that time!? I'm going to have to remember this in my chronicles of "Stuff I've actually seen posted in comments on HN."
vinceguidry 10y ago
Small amounts of force applied in any direction will not set the Earth into a collision course with the Sun. An intuitive explanation for why can be found in the game Osmos. www.osmos-game.com The short reason is that inertia is the entire reason the Earth is orbiting the Sun right now, you have to overcome that inertia rather than generate more of it. When you're playing Osmos during the orbital sections, a little bit of playing around reveals that the best way to reduce your orbit is to thrust in the same direction you're currently moving in. To increase your orbit, you thrust in the opposite direction. Thrusting towards or away from the 'star' alters your orbit somewhat but doesn't really change how far away from the star you are on average. After awhile you figure out the right way to finesse your way into orbits that carry you on a trajectory to eat smaller bodies. With that skill comes the dying off of the fantasy of being able to easily dispatch the Earth in this fashion. Inertia doesn't work that way.

by ck2 10y ago

Smaug123 10y ago

I didn't bother to search HN for the title, just the link, and this is the first time this particular variant of the link (https) has been posted. Sorry; I wouldn't have posted it if I'd realised it had appeared multiple times before.

golergka 10y ago
Nothing to be sorry about: a lot of HN readers (invluding me) are seeing it for the first time. And I will upvote this next time I see it, too.

wlesieutre 10y ago

> My idea is just figure out a way to nudge earth towards the sun and inertia will do the rest, slowly but surely, so a vote for their #10 I don't think you can. Even if you could give the whole Earth a push toward the sun, it has enough orbital velocity (~30,000 m/sec) that it'll miss and keep on going around. You might turn its orbit into a slightly different ellipse. Say we want to straight up (down?) launch a probe into the sun. It's a hard thing to do because it has to shed all of that orbital speed to get its velocity vector pointed in the right direction (at which point it can fall in on its own). If you only get rid of most of it, you'll fall into a long elliptical orbit. You could potentially dump some energy with a gravitational assist off of Venus (transfer some of our momentum into speeding up its orbit while slowing ours down), but there's still the matter of getting the Earth to Venus for that to work. And at that point maybe you just want to stick to #9. I haven't played enough KSP to be sure of all that, but that's my understanding of the orbital mechanics.

jacquesm 10y ago
If you wait for a while (8 billion years, give or take) the Sun will expand enough to meet the Earth, and presumably that will happen long before any drag effects will cause the reverse to happen.
abecedarius 10y ago
It's straightforward: throw the moon off in the direction of Earth's motion around the sun. The Earth has 81 moon-masses, so you'd have to throw the moon 81 times faster: still less than 1% of the speed of light. That'd take considerable energy, but the sun outputs 3.846×10^26 W, so we'd only need 17 years of total solar output. It'd be a lot easier to just roast the Earth's surface, it's true. (I haven't read the original post in a long time, but had thought about it myself before.)
TeMPOraL 10y ago
> You could potentially dump some energy with a gravitational assist off of Venus (transfer some of our momentum into speeding up its orbit while slowing ours down) I've heard that a hard turn around Jupiter is even better. I remember Scott Manley dropping a probe into Kerbol via Jool gravity assist in one video[0]. Actually, now I want to make a simulation with Earth doing Jupiter flybys. What's good for that nowadays? Universe Sandbox? [0] - https://www.youtube.com/watch?v=uNS6VKNXY6s https://www.youtube.com/watch?v=uNS6VKNXY6s
- deciplex 10y ago
  Scott Manley also made a trip to Minmus using only the starting Career parts. Just because he did a thing doesn't mean it's the optimal way to do that thing :-) (In fact, it's probably a better indicator against, heh.)

TeMPOraL 10y ago

> Or settle for wiping out all human life on earth and earth will survive just fine without us. Picking a US President that will use nuclear weapons might be a dangerous starting point to investigate. This may be very dangerous. When you take antibiotics, you need to do the full course, 'lest some bacteria survive. Similarly, if the nuclear destruction isn't complete enough, the surviving humans will repopulate the planet and continue to trouble it for millennia to come. When planning an apocalypse, one needs to be sure it can be carried out to the end.

mikeash 10y ago
That's an excellent point. If you think humans are bad, nuclear-resistant humans are worse.

stcredzero 10y ago

My idea is just figure out a way to nudge earth towards the sun and inertia will do the rest ARRGH! This is about as big a misunderstanding as not knowing the difference between sending a rocket to space vs. getting to orbit: https://www.youtube.com/watch?v=uNS6VKNXY6s https://www.youtube.com/watch?v=uNS6VKNXY6s tl;dr -- the Earth is whizzing around the Sun at a really high speed. You'd have to cancel most of that velocity to get a spacecraft to get anywhere near the Sun. It would actually be less energy to send the Earth to Jupiter than to drop it into the Sun. You've repeatedly re-read this article, but never delved into basic orbital mechanics all that time!? I'm going to have to remember this in my chronicles of "Stuff I've actually seen posted in comments on HN."

vinceguidry 10y ago

Small amounts of force applied in any direction will not set the Earth into a collision course with the Sun. An intuitive explanation for why can be found in the game Osmos. www.osmos-game.com The short reason is that inertia is the entire reason the Earth is orbiting the Sun right now, you have to overcome that inertia rather than generate more of it. When you're playing Osmos during the orbital sections, a little bit of playing around reveals that the best way to reduce your orbit is to thrust in the same direction you're currently moving in. To increase your orbit, you thrust in the opposite direction. Thrusting towards or away from the 'star' alters your orbit somewhat but doesn't really change how far away from the star you are on average. After awhile you figure out the right way to finesse your way into orbits that carry you on a trajectory to eat smaller bodies. With that skill comes the dying off of the fantasy of being able to easily dispatch the Earth in this fashion. Inertia doesn't work that way.