"It’s Easier to Leave the Solar System Than to Reach the Sun"

[maynard]

“I’m always amused when someone says, ‘Shoot X or so-and-so into the sun,’” says Rand Simberg, a space consultant and an engineer. “Because they have no idea how hard that is to do.”

discuss.

 

[Printimus]

You ever played Kerbal Space Program? There's some science to the theory above. It is incredibly hard to hit the sun.

 

[DirectorGunner]

hmmm... that doesn't make sense to me.. why? The sun wobbles due to planetary pull but.. wny is it so hard? Wouldn't you be more likely to hit an asteroid on the way out of the system then being stopped by something on the way to the sun? I must ponder this

 

[NaffNaffBobFace]

Wouldn't you be more likely to hit an asteroid on the way out of the system then being stopped by something on the way to the sun? I must ponder this

You probably already know this, but were you aware that the Asteroid belt, the nearest asteroid field in the solar system, has hundreds of thousands of miles between each 'roid?

Scientists are more likely to send spacecraft via asteroids if they can find on on the way to where it is going :slight_smile:

Info starts at 1:44

 

[NaffNaffBobFace]

Found a video on how hard it would be to shoot nuclear waste into the sun which covers the same concepts:

 

[Thalstan]

This seems to cover it pretty well

https://space.stackexchange.com/questions/3612/calculating-solar-system-escape-and-and-sun-dive-delta-v-from-lower-earth-orbit

 

[Sraika]

neat, i hadn't considered that. I suppose it makes sense. i'm gonna have to pull out KSP again and experiment.

 

[FZD]

For those too lazy to follow the links, here is a TL;DR:

1. When you launch into space and plop out of earths gravity, you'll already have an incredible amount of kinetic energy tangential to the sun, which gravity will alter the direction of that kinetic energy. This'll lead you to have a stable orbit around the sun. (Simply put, you exit a body that has stable orbit around a star, chances are you now also have a stable orbit around that star.)
2. To approach the sun, you need to reduce that kinetic energy along the tangent enough to achieve sub-orbit. To get further away from the sun, increase your kinetic energy along the tangent.
3. The closer you are to a body, the more work you have to do. Just like exiting earths gravity, you'll have to spend most fuel right at the beginning, but it'll gets easier the further away you get.