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Why the sun is a poor dumping ground for nuclear waste (2010)

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Re: Why the sun is a poor dumping ground for nuclear waste (2010)

#91

Post by washadjeffmad »

mynameishere wrote: post #18
apalmer wrote: post #2

Its generally not worth it to give smart answers to dumb questions. I guess its a pet peeve of the author though.

I would argue it's a waste not because it's stupid, but because it's just extraordinarily trite: http://www.reddit.com/search?q=nuclear+waste+sun&restrict_sr... ...variations include "why can't we put garbage in the sun", "why can we put nuclear waste in volcanoes", etc. It's a great question coming from a 6-year-old, but if an adult asks it, he's simply not the kind of person who will spend one second in critical th…

You're right of course, we're free to determine how to spend our time. And you thought it worth yours to search for reddit discussions to post here to illustrate why you felt this topic not worth your time, perhaps as a lone beacon to guide future generations who might be tempted towards the folly of exploring questions which have answers you already know.

Discussing good explanations for a topic, no matter how common, is not a waste for anyone who is interested, especially any curious people who might currently be lacking the tools to solve it themselves. I don't believe any of us comes fully equipped.

Re: Why the sun is a poor dumping ground for nuclear waste (2010)

#92

Post by [deleted] »

cpeterso wrote: post #48
aqme28 wrote: post #24

I always thought the biggest reason was that if a rocket carrying nuclear waste exploded in our atmosphere, it would be catastrophic. It's a lot less risky to just bury it underground and pray it never leaks.

Or bury the nuclear waste in oceanic trenches. It is out of the way and future generations won't stumble upon it when humans forget where they buried all this stuff.

[deleted]

Re: Why the sun is a poor dumping ground for nuclear waste (2010)

#93

Post by sbov »

cpeterso wrote: post #48
aqme28 wrote: post #24

I always thought the biggest reason was that if a rocket carrying nuclear waste exploded in our atmosphere, it would be catastrophic. It's a lot less risky to just bury it underground and pray it never leaks.

Or bury the nuclear waste in oceanic trenches. It is out of the way and future generations won't stumble upon it when humans forget where they buried all this stuff.

Do we know enough about our oceans to know that there would be no harm from this?

Re: Why the sun is a poor dumping ground for nuclear waste (2010)

#94

Post by maxerickson »

acadien wrote: post #84
maxerickson wrote: post #53

Earlier quoted context omitted.

The author always says "an acceleration", which is the same thing as delta-v. I have no idea how particular it is to phrase it that way, but it isn't confused.

The author says multiple times: "an acceleration of [X] km/s is required", maybe they meant to imply that the magnitude of the change of the velocity?

Accelerating at some rate km/ss for a period of s results in km/s. So the net result of "an acceleration" can be expressed as a velocity.

(what it comes down to is that "an" is an indefinite article and always modifies a noun and km/ss is described by the verb acceleration. Yay English.)

Re: Why the sun is a poor dumping ground for nuclear waste (2010)

#95

Post by mindcruzer »

sbov wrote: post #93
cpeterso wrote: post #48

Earlier quoted context omitted.

Or bury the nuclear waste in oceanic trenches. It is out of the way and future generations won't stumble upon it when humans forget where they buried all this stuff.

Do we know enough about our oceans to know that there would be no harm from this?

No

Re: Why the sun is a poor dumping ground for nuclear waste (2010)

#96

Post by fleitz »

Crito wrote: post #31
fleitz wrote: post #5

This is why you'd use gravity braking to do the work for you... You just have to change direction, not slow yourself down, as long as your path intersects the sun you're done... we have sent spacecraft to the sun... it's not beyond our technical capabilities. Basically, it's like flying into a banked curve... as long as you're pointed at the Sun when you exit the curve you're going to hit the sun with out needing to…

> "If it was difficult to hit things with large gravitational forces we wouldn't see very many comets in the night sky..." The difficulty does not come from the mass of the Sun. It comes from Earth's velocity around it. The waste starts out with that velocity as well. Basically the waste is already in a stable orbit around the sun, and getting it out of that is difficult.

It's not in a stable orbit around the sun...

If it has velocity to escape earth's gravity then it does not match earth and will eventually go somewhere else.

If it does not it will fall back.

Only at a Lagrange point will it not deviate from earth.

Given that it is not heading to earth we simply point it at an appropriate trajectory to intercept the moon and/or another planet using that planet to perform aforementioned "banked curve" which directs it to the sun at increased or decreased velocity.

The primary cost of shipping stuff to the sun is escaping earth, once you do that the additional fuel required to reach the sun is nowhere near the amount of fuel required to slow from 30 km/sec to zero.

Basically all we need to do is reach the moon... from there gravity does the work for us with the correct trajectory and a small amount of fuel to correct the trajectory.

Re: Why the sun is a poor dumping ground for nuclear waste (2010)

#97

Post by nothrabannosir »

tomphoolery wrote: post #69

This article just ruined every Star Trek episode for me where they fly a ship into a star.

To be fair, the problem here is that the waste is already in orbit (by virtue of being part of earth). His point is that if you want to hit the sun: don't orbit it. To stop an orbit around the sun is a hell of a job.

But if you're not orbiting in the first place: no problem.

Re: Why the sun is a poor dumping ground for nuclear waste (2010)

#98

Post by tempestn »

geophile wrote: post #58

Why does it have to be the sun? Why not just perpendicular to the sun/earth plane?

You'd still be in orbit, and would still cross the plane at regular intervals, so you wouldn't "get rid of it", as with flying out of the solar system or into the sun.

Re: Why the sun is a poor dumping ground for nuclear waste (2010)

#100

Post by dalke »

Terr_ wrote: post #90
kllrnohj wrote: post #82

Earlier quoted context omitted.

Because if the orbital velocity is intact you will perputally miss hitting the sun. The only way you can hit a thing you are orbiting is to remove all the orbital velocity (well, remove enough of the orbital velocity such that your orbit drops low enough to scrape the surface anyway).

The sun's pretty big... And if you're worried about overshooting, you could probably lose a lot of velocity just braking against the solar wind.

While the solar wind gets stronger closer to the sun, it's an r-square law that balances the r-squared force of gravity. Fun fact: If a solar sail could be in a fixed position at Mercury orbit then it could also be in fixed position a Neptune orbit.

Quoting from http://en.wikipedia.org/wiki/Solar_sail, the "total force exerted on an 800 by 800 meter solar sail, for example, is about 5 newtons (1.1 lbf) at Earth's distance from the Sun".

The Orion space capsule is ~25 sq meters. I'll round that up to 100 sq meters (I'm being generous), giving a breaking force of 5/64 N on the waste barge.

The capsule mass is 20 tons. Assuming the waste barge were the same mass (I'm being generous) gives a solar gravitational force in Earth orbit of 120 newtons. This far exceeds the push from solar wind, even with wildly optimistic numbers. (Note: there's some 50,000 tons of high-level nuclear waste in the US.)

So no, you couldn't lose a lot of velocity just braking against the solar wind. Not unless you've also developed effective solar sail technology.

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