Nuclear waste. We’ve got a lot of it, it'll
stay dangerous for tens of thousands of years, and we don't really know what to do with it.
So why don't we just send it into space and crash it into the sun? Well, first, it's really dangerous to put
nuclear waste on a rocket, since rockets have a tendency to occasionally explode while launching,
making any nuclear-waste-filled exploding rocket into a really big dirty bomb. But the bigger reason is that it's actually
really really hard to *get* to the sun. It might seem like it should be easy, since the
sun's gravity is always pulling us towards it. But we're also orbiting really fast sideways
around the sun, so that as we fall towards it, we miss it. In order to crash _into_ the sun, you have
to slow down so that you're _not_ going sideways really fast. The earth - and everything on
it - is moving around the sun at around 30 kilometers per second, so you'd have to accelerate
to a speed of 30kilometers per second backwards away from the earth in order to stop moving
around the sun and do a sun dive. And you have to slow down all the way – with even
a little bit of sideways speed, you'll miss the sun and whip around, not crashing. Ok, so a speed of 30 kilometers per second
is really fast, but just how fast? Well, from earths’s orbit, you only need to be going
_11_ kilometers per second faster than the earth in order to escape from the entire solar
system. Which means that it's much, much harder to crash into the sun than to escape it altogether.
Let me say that again: it takes less acceleration to get to _other_ stars than it does to get
to our own sun. Crazy. But it gets weirder: because the gravity from
an object is stronger the closer you are to it, the smaller your orbit is, the faster
your orbital speed. For example, Mercury goes around the sun at a speed one and a half times
faster than earth, while Pluto goes only a sixth as fast. And that means it's actually
way harder to crash into the sun from Mercury than from the earth, even though you're closer,
because you'd have to accelerate to a speed of 48 kilometers per second backwards instead
of 30. And it's way _easier_ to crash into the sun from Pluto, since you only have to
accelerate to a speed of five kilometers per second backwards. In fact, if you're trying to crash into the
sun just using rockets, it's far more efficient to first go to the outer solar system where
your speed is much lower, then do a second burn to counteract that slow orbital speed
and allow you to fall directly into the sun. And that's precisely why early mission trajectories
for NASA's spacecraft to study the sun proposed going out to Jupiter first – to make it
easier to slow down and get to the sun. Ultimately they decided instead to use repeated flyby's
of Venus to slow down the probe and save on rocket fuel getting to the sun. But how gravity assists work is a topic for
another day. Speaking of which – how long would a day be on the sun?
If you've played kerbal you know just how hard it is to reach the sun
I'm going to ask the obvious here. Why do we even have to hit the sun at all? Why not just fire it off at a trajectory that would simply lead it into deep space and out of the system?
I would just crash it into Venus. That planet is fucked already.
If they launch the rocket at night, they will have a better chance because the gravity and sunlight won't affect the orbit as much. And, if they would do their calculations in american math instead of that crazy killometer stuff, they would see that you only need 16 miles per hour instead of 30 k/ps.
But this doesn't answer the question, "Can we crash into the sun?" Sure, it's hard, but can we?
surely you wouldn't need to totally decelerate the planet... you could just make the orbit overlap the sun so you'd crash in at an angle.
You don't need to fall at a right angle to the centre.
Orbital mechanics aside, we may want that waste some day. Tossing irretrievably into the sun may be a bad idea. What we need to do is put it somewhere where we could access it if needs be but where it will be safely stored until it is no longer deadly to be around. I thinks 50 - 100K years IIRC.
Pack it up and bury it in the subduction zones between the continental plates. It will be forced into the crust and taken away from the surface where it could cause harm
I need a physicist....
ELI5 a bit please?
Ok, I still don't get it.
If I pointed my rocket towards the sun I understand that I would be still following the Earth's orbit going sideways but wouldn't my forward velocity still propel me closer to the sun until I was eventually dragged in?
I'm picturing a leaf circling a drain.