So, getting to the sun is actually really hard, the earth is moving around the sun at ~30km/sec. For comparison, a satelite in low earth orbit is only moving about 8km sec.
30km/sec is a LOT of velocity change, and you'd need to cancel practically all of it to actually fall into the Sun.
Let me put it another way. If it is comparatively cheap to get to any of the other planets. Couldn't we just go to Neptune and stop our orbital velocity from there where it's only 5kms?
How about exiting planetary orbits retrograde? It seems like larger planets would have escape velocities that are larger than their orbital velocity. Why couldn't our space barge leave Jupiter's orbit on a trajectory that would intersect with the sun?
> Couldn't we just go to Neptune and stop our orbital velocity from there where it's only 5kms?
Yes. This is a bi-elliptic transfer, it's a standard technique, and another thread claims it would save about 40% of the required dV.
> How about exiting planetary orbits retrograde? It seems like larger planets would have escape velocities that are larger than their orbital velocity. Why couldn't our space barge leave Jupiter's orbit on a trajectory that would intersect with the sun?
It could. That's a gravity assist, and it's the only practical way to go just about anywhere with current technology (all our interplanetary probes do that).
(There are arguments against using either with nuclear waste, but I don't think the page is seriously talking about that)
If you're interested in this stuff, definitely play Kerbal Space Program.
30km/sec is a LOT of velocity change, and you'd need to cancel practically all of it to actually fall into the Sun.
Way harder than getting to any of the planets.