Sun as final storage for radwaste?

For the discussion of the sciences. Physics problems, chemistry equations, biology weirdness, it all goes here.

Moderators: gmalivuk, Moderators General, Prelates

xPoKeFaNx
Posts: 1
Joined: Tue Feb 26, 2013 9:35 pm UTC

Sun as final storage for radwaste?

Postby xPoKeFaNx » Thu Feb 28, 2013 8:26 am UTC

Dear Randall, dear forums,

would it be a good idea to send our radwaste into the sun? Might be even easier than sending stuff to mars because sun's gravity would probably take care of guidance and acceleration for most of the route. Maybe our spacecraft could just deposit some containers far enough away from earth's gravity and maybe even decelerate them a bit. Would we need to monitor the remainder of their transport? Should we care whether the containers are being damaged on their way?

How often could we do it, especially with respect to earth's weight and orbit? Just in case mankind tends to continue producing radwaste and ponders if one more delivery would be ok.

Yours, xPoKeFaNx

User avatar
gmalivuk
GNU Terry Pratchett
Posts: 26822
Joined: Wed Feb 28, 2007 6:02 pm UTC
Location: Here and There
Contact:

Re: Sun as final storage for radwaste?

Postby gmalivuk » Thu Feb 28, 2013 10:39 pm UTC

xPoKeFaNx wrote:Might be even easier than sending stuff to mars because sun's gravity would probably take care of guidance and acceleration for most of the route. Maybe our spacecraft could just deposit some containers far enough away from earth's gravity and maybe even decelerate them a bit.
If you want to decelerate them enough to fall into the sun, you'd have to do so by about 30km/s. If you decelerate them by less than this, they'll just end up continuing to orbit the sun, albeit in a more elliptical path than Earth's.

Sending them out to Mars, on the other hand, would only require about 1.5km/s of velocity change, once stuff is out of Earth's gravity well.
Unless stated otherwise, I do not care whether a statement, by itself, constitutes a persuasive political argument. I care whether it's true.
---
If this post has math that doesn't work for you, use TeX the World for Firefox or Chrome

(he/him/his)

User avatar
Tass
Posts: 1909
Joined: Tue Nov 11, 2008 2:21 pm UTC
Location: Niels Bohr Institute, Copenhagen.

Re: Sun as final storage for radwaste?

Postby Tass » Thu Feb 28, 2013 11:06 pm UTC

And to elaborate on gmalivuks answer in case you didn't know: Deceleration in space is just as hard to do as acceleration since there is noting to push against. The sun is actually one of the hardest places in the solar system to get to.

User avatar
ahammel
My Little Cabbage
Posts: 2135
Joined: Mon Jan 30, 2012 12:46 am UTC
Location: Vancouver BC
Contact:

Re: Sun as final storage for radwaste?

Postby ahammel » Thu Feb 28, 2013 11:23 pm UTC

Tass wrote:The sun is actually one of the hardest places in the solar system to get to.
I did not know that. Cool.
He/Him/His/Alex
God damn these electric sex pants!

screen317
Posts: 252
Joined: Mon May 16, 2011 7:46 pm UTC

Re: Sun as final storage for radwaste?

Postby screen317 » Thu Feb 28, 2013 11:32 pm UTC

What is the purpose of deceleration? Why is it so difficult to get to the Sun?

User avatar
Sizik
Posts: 1260
Joined: Wed Aug 27, 2008 3:48 am UTC

Re: Sun as final storage for radwaste?

Postby Sizik » Thu Feb 28, 2013 11:36 pm UTC

Because if you have any sideways* velocity, you're likely going to end up orbiting the sun instead of hitting it.

*Sideways being perpendicular to the line from the object to the sun.
she/they
gmalivuk wrote:
King Author wrote:If space (rather, distance) is an illusion, it'd be possible for one meta-me to experience both body's sensory inputs.
Yes. And if wishes were horses, wishing wells would fill up very quickly with drowned horses.

screen317
Posts: 252
Joined: Mon May 16, 2011 7:46 pm UTC

Re: Sun as final storage for radwaste?

Postby screen317 » Thu Feb 28, 2013 11:44 pm UTC

What I'm unclear about is why this effect is specific to the Sun. Can we really not throw a small target at the Sun with good enough accuracy to fall into the Sun?

User avatar
Sizik
Posts: 1260
Joined: Wed Aug 27, 2008 3:48 am UTC

Re: Sun as final storage for radwaste?

Postby Sizik » Thu Feb 28, 2013 11:48 pm UTC

Because

gmalivuk wrote:If you want to decelerate them enough to fall into the sun, you'd have to do so by about 30km/s. If you decelerate them by less than this, they'll just end up continuing to orbit the sun, albeit in a more elliptical path than Earth's.
she/they
gmalivuk wrote:
King Author wrote:If space (rather, distance) is an illusion, it'd be possible for one meta-me to experience both body's sensory inputs.
Yes. And if wishes were horses, wishing wells would fill up very quickly with drowned horses.

screen317
Posts: 252
Joined: Mon May 16, 2011 7:46 pm UTC

Re: Sun as final storage for radwaste?

Postby screen317 » Thu Feb 28, 2013 11:53 pm UTC

Sizik wrote:Because

gmalivuk wrote:If you want to decelerate them enough to fall into the sun, you'd have to do so by about 30km/s. If you decelerate them by less than this, they'll just end up continuing to orbit the sun, albeit in a more elliptical path than Earth's.
This is what I don't understand. If cargo is headed directly in the direction of the center of the Sun, why is deceleration necessary? Is the inaccuracy of launched crafts really that high?

User avatar
Tass
Posts: 1909
Joined: Tue Nov 11, 2008 2:21 pm UTC
Location: Niels Bohr Institute, Copenhagen.

Re: Sun as final storage for radwaste?

Postby Tass » Thu Feb 28, 2013 11:56 pm UTC

screen317 wrote:What I'm unclear about is why this effect is specific to the Sun. Can we really not throw a small target at the Sun with good enough accuracy to fall into the Sun?


The problem is not the accuracy but the speed. The Earth orbits the sun at 30km/s that is very fast. If we just nudge something away from earth it will just be orbiting with us and actually come back and hit us. If we could shoot it backwards at 30km/s it would actually be standing still relative to the sun and then the suns gravity would pull it in, but that is not easy to achieve.

It turns out actually the easiest way to the sun is around Jupiter. Orbital mechanics can be somewhat counter intuitive.

Edit:

screen317 wrote:
Sizik wrote:Because

gmalivuk wrote:If you want to decelerate them enough to fall into the sun, you'd have to do so by about 30km/s. If you decelerate them by less than this, they'll just end up continuing to orbit the sun, albeit in a more elliptical path than Earth's.
This is what I don't understand. If cargo is headed directly in the direction of the center of the Sun, why is deceleration necessary? Is the inaccuracy of launched crafts really that high?


It does not need to deccelerate from the fall towards the sun, it needs to deccelerate from the sideways motion it has when riding with us on Earth. We are moving fast, the sun is zooming by us. In order to hit it we need to throw backwards fast. Of course the suns gravity bends our trajectory so even though we are continually zooming past the sun we are actually not leaving it, just orbiting, but the conclusion about how to hit the sun still stands.
Last edited by Tass on Fri Mar 01, 2013 12:00 am UTC, edited 1 time in total.

User avatar
Yakk
Poster with most posts but no title.
Posts: 11129
Joined: Sat Jan 27, 2007 7:27 pm UTC
Location: E pur si muove

Re: Sun as final storage for radwaste?

Postby Yakk » Thu Feb 28, 2013 11:59 pm UTC

Suppose you are standing beside a road.

50 meters away there is a car, going by at 100 kph, perpendicular to your relative positions.

Throwing a rock to hit that car is hard. You have to throw it really really fast to have a hope, and the easiest ways to throw it involve "leading" the car (because it will move by the time your rock arrives).

Similarly, someone in that car (at that moment) has an equally hard time hitting you.

The earth/sun situation is similar, except the earth is always zooming along at 1 AU/365 days, or almost 5 km per second, or 18 thousand km/h. This makes it even harder to throw a rock and hit the sun.

And while the earth's trajectory does bend around the sun, at each point the earth is always moving perpendicular to the sun's position at 18 thousand km/h.

Now, the earth is a mere 150 000 000 km away from the sun, which is unlike the 50 meters above. In fact, it is further away. Further away makes it harder, as does smaller -- but in this case, the sun is much more far away than it is larger than the car, so the analogy holds pretty well.
One of the painful things about our time is that those who feel certainty are stupid, and those with any imagination and understanding are filled with doubt and indecision - BR

Last edited by JHVH on Fri Oct 23, 4004 BCE 6:17 pm, edited 6 times in total.

User avatar
Tass
Posts: 1909
Joined: Tue Nov 11, 2008 2:21 pm UTC
Location: Niels Bohr Institute, Copenhagen.

Re: Sun as final storage for radwaste?

Postby Tass » Fri Mar 01, 2013 12:04 am UTC

Yakk wrote: except the earth is always zooming along at 1 AU/365 days, or almost 5 km per second, or 18 thousand km/h.


Thirty kilometres per second not five. We do 2*pi*AU every year. 5 km/s would actually be doable (though still not economical (okay we *could* do 30km/s with electric propulsion, but it is very much not economical)).

Also in case it was missed I edited my post above to answer to the post the ninjaed me.

User avatar
dudiobugtron
Posts: 1098
Joined: Mon Jul 30, 2012 9:14 am UTC
Location: The Outlier

Re: Sun as final storage for radwaste?

Postby dudiobugtron » Fri Mar 01, 2013 12:06 am UTC

screen317 wrote:What I'm unclear about is why this effect is specific to the Sun. Can we really not throw a small target at the Sun with good enough accuracy to fall into the Sun?

You don't have to use a target, you could use any object. ;)

It seems really counter-intuitive though that it's easier to hit Mars than it is to hit the sun. Is it because there are times when Mars' relative velocity is slower?

--------------------------
Also, I misinterpreted this post by Tass initially, but in light of subsequent posts I now understand it to mean:
Tass wrote:The sun is actually one of the hardest places in the solar system to get to from the Earth.
Image

User avatar
Tass
Posts: 1909
Joined: Tue Nov 11, 2008 2:21 pm UTC
Location: Niels Bohr Institute, Copenhagen.

Re: Sun as final storage for radwaste?

Postby Tass » Fri Mar 01, 2013 12:13 am UTC

dudiobugtron wrote:
screen317 wrote:What I'm unclear about is why this effect is specific to the Sun. Can we really not throw a small target at the Sun with good enough accuracy to fall into the Sun?

You don't have to use a target, you could use any object. ;)

It seems really counter-intuitive though that it's easier to hit Mars than it is to hit the sun. Is it because there are times when Mars' relative velocity is slower?


You could say that. We are orbiting in the same direction after all. But it is not all about relative velocities either, orbital mechanics is complicated. It is about what trajectory exists which which gets you where you want to go through complicated gravitational interactions with minimal input from your side.

Even more counter-intuitive is the fact that the easiest (though not quickest) way to Mercury or the sun is to swing by freaking Jupiter.

User avatar
tomandlu
Posts: 1111
Joined: Fri Sep 21, 2007 10:22 am UTC
Location: London, UK
Contact:

Re: Sun as final storage for radwaste?

Postby tomandlu » Fri Mar 01, 2013 6:45 am UTC

I'm confused - wouldn't our current orbital velocity be too slow to maintain orbit once you got any nearer the sun? Not disputing what anyone's saying, but why wouldn't you spiral in towards the sun, eventually hitting it?
How can I think my way out of the problem when the problem is the way I think?

speising
Posts: 2364
Joined: Mon Sep 03, 2012 4:54 pm UTC
Location: wien

Re: Sun as final storage for radwaste?

Postby speising » Fri Mar 01, 2013 7:22 am UTC

different velocitys mean different orbits.
to get a spiralling path, you have to decelerate constantly.

User avatar
yurell
Posts: 2924
Joined: Sat Nov 13, 2010 2:19 am UTC
Location: Australia!

Re: Sun as final storage for radwaste?

Postby yurell » Fri Mar 01, 2013 8:35 am UTC

tomandlu wrote:I'm confused - wouldn't our current orbital velocity be too slow to maintain orbit once you got any nearer the sun? Not disputing what anyone's saying, but why wouldn't you spiral in towards the sun, eventually hitting it?


As you get closer to the sun, your gravitational potential energy is converted to kinetic energy (i.e. you speed up).
cemper93 wrote:Dude, I just presented an elaborate multiple fraction in Comic Sans. Who are you to question me?


Pronouns: Feminine pronouns please!

User avatar
tomandlu
Posts: 1111
Joined: Fri Sep 21, 2007 10:22 am UTC
Location: London, UK
Contact:

Re: Sun as final storage for radwaste?

Postby tomandlu » Fri Mar 01, 2013 8:48 am UTC

yurell wrote:
tomandlu wrote:I'm confused - wouldn't our current orbital velocity be too slow to maintain orbit once you got any nearer the sun? Not disputing what anyone's saying, but why wouldn't you spiral in towards the sun, eventually hitting it?


As you get closer to the sun, your gravitational potential energy is converted to kinetic energy (i.e. you speed up).


Ah - I sort-of assumed it must be that (mainly from my memories of playing on playground roundabouts when young).
How can I think my way out of the problem when the problem is the way I think?

HungryHobo
Posts: 1708
Joined: Wed Oct 20, 2010 9:01 am UTC

Re: Sun as final storage for radwaste?

Postby HungryHobo » Fri Mar 01, 2013 9:58 am UTC

seems a bit over the top for nuclear waste.

melt it into thick glass, seal it inside thick layers of ceramics, steel and glass, pop that in some nice dry artificial caves in a desert above the water table 100 miles from anywhere and stop worrying. The normal lead from the non radioactive plant down the road will probably be the bigger danger to you and your decendents.

plus, if you just left it in a pile on the moon with no shielding it wouldn't be any poblem for the earth. Space is already awash with radiation.
Give a man a fish, he owes you one fish. Teach a man to fish, you give up your monopoly on fisheries.

User avatar
EdgarJPublius
Official Propagandi.... Nifty Poster Guy
Posts: 3726
Joined: Tue Oct 09, 2007 4:56 am UTC
Location: where the wind takes me

Re: Sun as final storage for radwaste?

Postby EdgarJPublius » Fri Mar 01, 2013 10:04 am UTC

We'd have to deal with getting the stuff off Earth before we start thinking about throwing it into the Sun. As little as I like to admit it, getting stuff into space is kind of an expensive way to take out the trash. We'd have to invest a lot into launch capacity, and once we have that capacity, there'll still be a lot of better things to do with it.

Actually, I imagine that once we get it off the planet, getting it into the Sun wouldn't be all that difficult, just strap on an ion drive and off it goes, as long as you've done the math right it'll get there eventually.

On the gripping hand, why the Sun specifically? Why anywhere specifically? Space is really big, even just the area described by Earth's orbit around the Sun is slightly giganormous. As long as you set it off on a trajectory that won't come back around anytime soon, it shouldn't matter where it's going, or if it's even going anywhere. It's not like we're gonna run out of space to put stuff.
Heck, maybe we'll think of something useful to do with it someday, and it would suck to have to blow up our only sun to get it back.
Roosevelt wrote:
I wrote:Does Space Teddy Roosevelt wrestle Space Bears and fight the Space Spanish-American War with his band of Space-volunteers the Space Rough Riders?

Yes.

-still unaware of the origin and meaning of his own user-title

User avatar
Tass
Posts: 1909
Joined: Tue Nov 11, 2008 2:21 pm UTC
Location: Niels Bohr Institute, Copenhagen.

Re: Sun as final storage for radwaste?

Postby Tass » Fri Mar 01, 2013 10:19 am UTC

EdgarJPublius wrote:We'd have to deal with getting the stuff off Earth before we start thinking about throwing it into the Sun. As little as I like to admit it, getting stuff into space is kind of an expensive way to take out the trash. We'd have to invest a lot into launch capacity, and once we have that capacity, there'll still be a lot of better things to do with it.


Certainly. And the waste have used too and shouldn't be wasted.

EdgarJPublius wrote:Actually, I imagine that once we get it off the planet, getting it into the Sun wouldn't be all that difficult, just strap on an ion drive and off it goes, as long as you've done the math right it'll get there eventually.


Nope. Ion propulsion being low thrust means you can't just bleed off the 30km/s and then once it is done drop to the sun. You will gradually spiral towards the sun picking up speed as you go which means that the delta-v the ion drive has to deliver will be measured in hundreds of km/s. Lifetime of the drive might be a problem.

Of course one might argue that an orbit halfway to Venus is plenty good enough.

EdgarJPublius wrote:On the gripping hand, why the Sun specifically? Why anywhere specifically? Space is really big, even just the area described by Earth's orbit around the Sun is slightly giganormous. As long as you set it off on a trajectory that won't come back around anytime soon, it shouldn't matter where it's going, or if it's even going anywhere. It's not like we're gonna run out of space to put stuff.
Heck, maybe we'll think of something useful to do with it someday, and it would suck to have to blow up our only sun to get it back.


Oh well, that will teach me to read the entire post before starting to respond. Well said.

User avatar
yurell
Posts: 2924
Joined: Sat Nov 13, 2010 2:19 am UTC
Location: Australia!

Re: Sun as final storage for radwaste?

Postby yurell » Fri Mar 01, 2013 10:21 am UTC

I'm more looking forward to one of the rockets blowing up just after launch, spraying radioactive waste across the continent.
cemper93 wrote:Dude, I just presented an elaborate multiple fraction in Comic Sans. Who are you to question me?


Pronouns: Feminine pronouns please!

User avatar
tomandlu
Posts: 1111
Joined: Fri Sep 21, 2007 10:22 am UTC
Location: London, UK
Contact:

Re: Sun as final storage for radwaste?

Postby tomandlu » Fri Mar 01, 2013 10:26 am UTC

HungryHobo wrote:seems a bit over the top for nuclear waste.

melt it into thick glass, seal it inside thick layers of ceramics, steel and glass, pop that in some nice dry artificial caves in a desert above the water table 100 miles from anywhere and stop worrying. The normal lead from the non radioactive plant down the road will probably be the bigger danger to you and your decendents.

plus, if you just left it in a pile on the moon with no shielding it wouldn't be any poblem for the earth. Space is already awash with radiation.


I seem to vaguely recall something about them trying to devise a sufficiently clear warning symbol that would last thousands of years in such a scenario...
How can I think my way out of the problem when the problem is the way I think?

HungryHobo
Posts: 1708
Joined: Wed Oct 20, 2010 9:01 am UTC

Re: Sun as final storage for radwaste?

Postby HungryHobo » Fri Mar 01, 2013 11:01 am UTC

tomandlu wrote:I seem to vaguely recall something about them trying to devise a sufficiently clear warning symbol that would last thousands of years in such a scenario...


a thousand rosetta stones with hundreds of languages with clear explanations and explanations of basic physics and the the effects of radiation. from there assume that our decendents aren't morons.
Give a man a fish, he owes you one fish. Teach a man to fish, you give up your monopoly on fisheries.

User avatar
EdgarJPublius
Official Propagandi.... Nifty Poster Guy
Posts: 3726
Joined: Tue Oct 09, 2007 4:56 am UTC
Location: where the wind takes me

Re: Sun as final storage for radwaste?

Postby EdgarJPublius » Fri Mar 01, 2013 11:26 am UTC

HungryHobo wrote:
tomandlu wrote:I seem to vaguely recall something about them trying to devise a sufficiently clear warning symbol that would last thousands of years in such a scenario...


a thousand rosetta stones with hundreds of languages with clear explanations and explanations of basic physics and the the effects of radiation. from there assume that our decendents aren't morons.



I feel like the whole situation is helped by most waste sites being in places nobody reasonable would want to stick around anyway, and the waste itself is buried pretty deep. As long as you collapse the access tunnels when the dump is full, the problem should be largely self-solving. Any future civilization advanced enough to excavate a nuclear waste dump would probably be advanced enough to understand that doing so is not a great idea.
Roosevelt wrote:
I wrote:Does Space Teddy Roosevelt wrestle Space Bears and fight the Space Spanish-American War with his band of Space-volunteers the Space Rough Riders?

Yes.

-still unaware of the origin and meaning of his own user-title

User avatar
tomandlu
Posts: 1111
Joined: Fri Sep 21, 2007 10:22 am UTC
Location: London, UK
Contact:

Re: Sun as final storage for radwaste?

Postby tomandlu » Fri Mar 01, 2013 11:53 am UTC

HungryHobo wrote:
tomandlu wrote:I seem to vaguely recall something about them trying to devise a sufficiently clear warning symbol that would last thousands of years in such a scenario...


a thousand rosetta stones with hundreds of languages with clear explanations and explanations of basic physics and the the effects of radiation. from there assume that our decendents aren't morons.


Ah, found a bit about it:

http://en.wikipedia.org/wiki/Waste_Isolation_Pilot_Plant#Message_for_the_future

more detail:

http://www.damninteresting.com/this-place-is-not-a-place-of-honor/
How can I think my way out of the problem when the problem is the way I think?

User avatar
yurell
Posts: 2924
Joined: Sat Nov 13, 2010 2:19 am UTC
Location: Australia!

Re: Sun as final storage for radwaste?

Postby yurell » Fri Mar 01, 2013 11:59 am UTC

It'd be really hard to find symbols that universally affect people negatively, since so much is open to cultural bias (and let's face it, archaeologists have found cool stuff in the past by simply ignoring warnings too).
cemper93 wrote:Dude, I just presented an elaborate multiple fraction in Comic Sans. Who are you to question me?


Pronouns: Feminine pronouns please!

User avatar
Tass
Posts: 1909
Joined: Tue Nov 11, 2008 2:21 pm UTC
Location: Niels Bohr Institute, Copenhagen.

Re: Sun as final storage for radwaste?

Postby Tass » Fri Mar 01, 2013 12:01 pm UTC

yurell wrote:I'm more looking forward to one of the rockets blowing up just after launch, spraying radioactive waste across the continent.


That would be a matter of properly encapsulating it in a way that could survive reentry and be recovered. Not that hard relatively speaking. Though the politics of it would be terrible.

HungryHobo
Posts: 1708
Joined: Wed Oct 20, 2010 9:01 am UTC

Re: Sun as final storage for radwaste?

Postby HungryHobo » Fri Mar 01, 2013 12:09 pm UTC

yurell wrote:It'd be really hard to find symbols that universally affect people negatively, since so much is open to cultural bias (and let's face it, archaeologists have found cool stuff in the past by simply ignoring warnings too).

Forget symbols. get a team of people experienced in decoding ancient languages, ask them "what would have made your job really easy? rosetta stones? my first dictionary?" etc then make sure there are a lot of caches of basic intro material incribed in various ways around the site, into glass tablets, into stone, into metal or high end materials and lots of texts explaining exactly what is there in different ways.

If you want to make your point leave some caches of less dangerous but more obviously dangerous material sealed in a similar manner in the more accessible layers. if the first cask you crack open is full of cyanide and nothing else then you'll be more wary about the others.

symbols are for when you're trying to communicate with idiots in a hurry.

again, beyond a certain point you just have to assume the people of the future will have half a brain between them.
Give a man a fish, he owes you one fish. Teach a man to fish, you give up your monopoly on fisheries.

User avatar
tomandlu
Posts: 1111
Joined: Fri Sep 21, 2007 10:22 am UTC
Location: London, UK
Contact:

Re: Sun as final storage for radwaste?

Postby tomandlu » Fri Mar 01, 2013 12:15 pm UTC

yurell wrote:It'd be really hard to find symbols that universally affect people negatively, since so much is open to cultural bias (and let's face it, archaeologists have found cool stuff in the past by simply ignoring warnings too).


Indeed - and a lot of the discussion in the links and other sources I looked at emphasised that point.

http://en.wikipedia.org/wiki/Human_Interference_Task_Force

Thomas Sebeok

The linguist Thomas Sebeok was member of the Bechtel working group. Building on earlier suggestions made by Alvin Weinberg and Arsen Darnay he proposed the creation of an atomic priesthood, a panel of experts where members would be replaced through nominations by a council. Similar to the Catholic church - which has preserved and authorized its message for over 2000 years — the atomic priesthood would have to preserve the knowledge about locations and dangers of radioactive waste by creating rituals and myths. The priesthood would indicate off-limits areas and the consequences of disobedience.

This approach has a number of critical problems:

1. An atomic priesthood would gain political influence based on the contingencies that it would oversee.
2. This system of information favors the creation of hierarchies.
3. The message could be split into independent parts.
4. Information about waste sites would grant power to a privileged class. People from outside this group might attempt to seize this information by force.
How can I think my way out of the problem when the problem is the way I think?

User avatar
thoughtfully
Posts: 2253
Joined: Thu Nov 01, 2007 12:25 am UTC
Location: Minneapolis, MN
Contact:

Re: Sun as final storage for radwaste?

Postby thoughtfully » Fri Mar 01, 2013 1:21 pm UTC

Like Tass said, stop wasting it. Build some fast spectrum reactors, transition to Thorium and then fusion, and keep the breeders around as long as it takes to process the backlog.

I have this spooky image in my mind of a dystopian future where waste sites are mined, with the dangerous labor done by those who have been marginalized by society. Maybe it's not realistic; breeder reactors+reprocessing+Uranium from sea water=enough energy for many thousands of years, not even counting fusion. I've heard billions, but our power demands will surely increase. It'd be nice to exclude the possibility anyway.

Even just reprocessing Uranium and using the existing stockpiles would keep the lights on for some hundreds of years. This once-through business is scandalous.
Image
Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.
-- Antoine de Saint-Exupery

User avatar
scarecrovv
It's pronounced 'double u'
Posts: 674
Joined: Wed Jul 30, 2008 4:09 pm UTC
Location: California

Re: Sun as final storage for radwaste?

Postby scarecrovv » Fri Mar 01, 2013 2:23 pm UTC

HungryHobo wrote:
tomandlu wrote:I seem to vaguely recall something about them trying to devise a sufficiently clear warning symbol that would last thousands of years in such a scenario...


a thousand rosetta stones with hundreds of languages with clear explanations and explanations of basic physics and the the effects of radiation. from there assume that our decendents aren't morons.


Before you can assert that our descendants won't be morons, you have to determine if we are morons. Take the Love Canal disaster as an example. Hooker chemical dumped a zillion tons of highly toxic industrial waste in a hole, and then sealed it up, hopefully for all eternity. Years later, the local school board needed some land to build a new school, and there was this nice piece of land with nothing obviously on it, so they asked Hooker if they could buy it. Hooker refused to sell it, for obvious reasons, but the school board didn't give up, and threatened to take the land by Expropriation/Eminent Domain. Hooker finally sold it to them for $1, and included a disclaimer in the agreement telling the school board about the toxic wastes. A school and a residential neighborhood were subsequently built on the site, construction pierced the clay cap on the dump, toxic waste caused all sorts of horrible birth defects, and the site was evacuated a few decades later.

The moral of the story is that a site containing all manner of horrible things is not, in itself, enough to stop people from raising their children there.

User avatar
idobox
Posts: 1591
Joined: Wed Apr 02, 2008 8:54 pm UTC
Location: Marseille, France

Re: Sun as final storage for radwaste?

Postby idobox » Fri Mar 01, 2013 4:42 pm UTC

tomandlu wrote:I seem to vaguely recall something about them trying to devise a sufficiently clear warning symbol that would last thousands of years in such a scenario...

Even if you find the perfect symbol, but civilisation has collapsed or somehow forgotten about radioactivity, people will go and dig to see what is so dangerous, or what you're trying to protect maledictions, the way we did with Pharaohs' tombs.

Tass wrote:Nope. Ion propulsion being low thrust means you can't just bleed off the 30km/s and then once it is done drop to the sun. You will gradually spiral towards the sun picking up speed as you go which means that the delta-v the ion drive has to deliver will be measured in hundreds of km/s. Lifetime of the drive might be a problem.

Nuclear waste is a nice and compact source of high power radiation. Just strap a mirror to one side and let the thermal radiation push that baby where you want. Low thrust, but very low technology, minimal added mass, and you've got a lot of time.
The biggest risk would be for the trajectory to be affected by other bodies far in the future, like Venus or Mercury, and sending it back to us.
If there is no answer, there is no question. If there is no solution, there is no problem.

Waffles to space = 100% pure WIN.

HungryHobo
Posts: 1708
Joined: Wed Oct 20, 2010 9:01 am UTC

Re: Sun as final storage for radwaste?

Postby HungryHobo » Fri Mar 01, 2013 5:30 pm UTC

scarecrovv wrote:Take the Love Canal disaster as an example.


I find it hard to blame the company in this example. they could have found a better site for a dump but wow thats a lot of stupidity on the behalf of everyone else involved.

You can only warn people so much, if you communicate clearly to people that there is a danger and they ignore you and shoot themselves in the foot there's not much you can do. if you give an adult a lead weight and they proceed to eat it despite warnings does that indicate a problem with your lead storage?
Give a man a fish, he owes you one fish. Teach a man to fish, you give up your monopoly on fisheries.

douglasm
Posts: 630
Joined: Mon Apr 21, 2008 4:53 am UTC

Re: Sun as final storage for radwaste?

Postby douglasm » Fri Mar 01, 2013 6:23 pm UTC

screen317 wrote:
Sizik wrote:Because

gmalivuk wrote:If you want to decelerate them enough to fall into the sun, you'd have to do so by about 30km/s. If you decelerate them by less than this, they'll just end up continuing to orbit the sun, albeit in a more elliptical path than Earth's.
This is what I don't understand. If cargo is headed directly in the direction of the center of the Sun, why is deceleration necessary? Is the inaccuracy of launched crafts really that high?

If cargo is headed directly in the direction of the center of the Sun, then exactly as you would expect no deceleration is necessary. The problem is that anything on Earth is nowhere near "headed directly in the direction of the center of the Sun". Everything (even the planet itself) is going 30 km/s sideways. That 30 km/s of deceleration is needed to get something going directly towards the Sun in the first place. Anything less, and your projectile will not, in fact, be aimed at the Sun, but rather at some point a large distance to the side of the Sun.

User avatar
tomandlu
Posts: 1111
Joined: Fri Sep 21, 2007 10:22 am UTC
Location: London, UK
Contact:

Re: Sun as final storage for radwaste?

Postby tomandlu » Fri Mar 01, 2013 6:34 pm UTC

douglasm wrote:
screen317 wrote:
Sizik wrote:Because

gmalivuk wrote:If you want to decelerate them enough to fall into the sun, you'd have to do so by about 30km/s. If you decelerate them by less than this, they'll just end up continuing to orbit the sun, albeit in a more elliptical path than Earth's.
This is what I don't understand. If cargo is headed directly in the direction of the center of the Sun, why is deceleration necessary? Is the inaccuracy of launched crafts really that high?

If cargo is headed directly in the direction of the center of the Sun, then exactly as you would expect no deceleration is necessary. The problem is that anything on Earth is nowhere near "headed directly in the direction of the center of the Sun". Everything (even the planet itself) is going 30 km/s sideways. That 30 km/s of deceleration is needed to get something going directly towards the Sun in the first place. Anything less, and your projectile will not, in fact, be aimed at the Sun, but rather at some point a large distance to the side of the Sun.


So... you need to launch behind the earth at escape velocity + (30 km/s - escape velocity)?
How can I think my way out of the problem when the problem is the way I think?

screen317
Posts: 252
Joined: Mon May 16, 2011 7:46 pm UTC

Re: Sun as final storage for radwaste?

Postby screen317 » Fri Mar 01, 2013 7:01 pm UTC

Thanks for the answers everyone.

My question is now this:

If you launch a craft toward the direction of the center of the sun, yes the craft is still traveling with 30km/s "horizontally," but why is it doomed to only orbit the Sun? If it's traveling escape velocity toward the Sun, relative to the Earth, the path will be ellipsoid but wont it spiral toward the Sun and eventually fall into it?

User avatar
Yakk
Poster with most posts but no title.
Posts: 11129
Joined: Sat Jan 27, 2007 7:27 pm UTC
Location: E pur si muove

Re: Sun as final storage for radwaste?

Postby Yakk » Fri Mar 01, 2013 7:11 pm UTC

Half an orbit later, that same velocity vector you gained by launching yourself out of Earth orbit "towards the sun" is now pointing directly away from the sun. And if nothing gets in your way (like the Earth), you'll end up heading away from the sun at the same speed as you where heading "towards the sun" half an orbit ago.

The point where you will reach closest to the sun will be 1/4 of an orbit in your future, and 3/4 of an orbit in your future you'll be further from the sun than you started before you thrust towards the sun.
One of the painful things about our time is that those who feel certainty are stupid, and those with any imagination and understanding are filled with doubt and indecision - BR

Last edited by JHVH on Fri Oct 23, 4004 BCE 6:17 pm, edited 6 times in total.

screen317
Posts: 252
Joined: Mon May 16, 2011 7:46 pm UTC

Re: Sun as final storage for radwaste?

Postby screen317 » Fri Mar 01, 2013 7:13 pm UTC

Yakk wrote:Half an orbit later, that same velocity vector you gained by launching yourself out of Earth orbit "towards the sun" is now pointing directly away from the sun. And if nothing gets in your way (like the Earth), you'll end up heading away from the sun at the same speed as you where heading "towards the sun" half an orbit ago.

The point where you will reach closest to the sun will be 1/4 of an orbit in your future, and 3/4 of an orbit in your future you'll be further from the sun than you started before you thrust towards the sun.
I'm trying to understand how this makes sense if you constantly align yourself with the Sun.

User avatar
Yakk
Poster with most posts but no title.
Posts: 11129
Joined: Sat Jan 27, 2007 7:27 pm UTC
Location: E pur si muove

Re: Sun as final storage for radwaste?

Postby Yakk » Fri Mar 01, 2013 7:19 pm UTC

The direction you are pointing has nothing to do with the direction you are moving. "Aligning with the sun", as in facing the sun, doesn't do anything to where you are.

If you want to change the direction you are moving, you need to thrust.

If you thrust this way, you'll have to generate enough thrust that it would (if done "in the same direction") would generate a velocity that matches or exceeds the orbital velocity of the Earth.
Last edited by Yakk on Fri Mar 01, 2013 7:20 pm UTC, edited 1 time in total.
One of the painful things about our time is that those who feel certainty are stupid, and those with any imagination and understanding are filled with doubt and indecision - BR

Last edited by JHVH on Fri Oct 23, 4004 BCE 6:17 pm, edited 6 times in total.


Return to “Science”

Who is online

Users browsing this forum: No registered users and 11 guests