6 ms·
> The whole approach is very sensitive to the detonation height, asteroid composition and color, rotational characteristics, etc. So Burkey’s group has really m
by lr1970 3y ago
> The whole approach is very sensitive to the detonation height, asteroid composition and color, rotational characteristics, etc. So Burkey’s group has really made a simulation framework for modeling the right thing to do for a given asteroid.
And don't forget that most asteroids are spinning over its own center-of-mass. The thrust generated by evaporating rocks on one of its sides will be changing direction as the asteroid spins around. Think of a rocket with thrust but no stabilization. Cool idea but very hard to make practical.
- jojobas 3y agoUnless it's spinning at 100rpm the rotation would have very little impact, the whole x-ray-heatup-boiloff cycle is under a second.
- sigmoid10 3y agoThe paper only simulated it up to 10 microseconds. But they also only used a simplified 2D toy model. They acknowledge that a realistic simulation will need to factor in a ton of other things, including rotation of the asteroid.
- hnuser123456 3y agoThe impacted side might outgas for years.
- picadores 3y agoEvery tumble has a "slow" pole, where the outgasing would form a vector, nearly almost away from earth. Also at least we cant have a ice-ball earth due to impact-winter.https://en.wikipedia.org/wiki/Snowball_Earth https://en.wikipedia.org/wiki/Snowball_Earth
- darkerside 3y agoSo if the universe threw a perfect spiral at us, we'd be fucked
- s3rv3rsi7e 3y agoNo because the vector can also change in magnitude. Even if the spiral was perfectly aligned to impact the perfect center of the Earth we could change the magnitude of the object by nuking either pole to either slow it down or speed it up. Enough energy on any pole could make it miss regardless of the orientation.
- jamesmontalvo3 3y agoPerfectly chaotic rotation might be worse. If it was a spiral then you could hit it at a pole. I think most things rotate about a semi-fixed axis (not totally fixed, often propagating over time)
- shagie 3y agoIf you can make the asteroid cross Earth's orbit 430 seconds sooner or later that's an Earth diameter. Two approaches to getting that number... https://www.wolframalpha.com/input?i=diameter+of+earth+%2F+%28length+of+orbit+of+earth+%2F+%28number+of+seconds+in+a+year%29%29 https://www.wolframalpha.com/input?i=diameter+of+earth+%2F+%... https://www.wolframalpha.com/input?i=%28430+seconds+*+earth+orbital+velocity%29+%2F+earth+diameter https://www.wolframalpha.com/input?i=%28430+seconds+*+earth+... Granted, you'd probably like more than a diameter... but we're talking about it getting there a few minutes faster and it would be a miss.
- cnlevy 3y agoIn that case, detonate the bomb above its axis of rotation. Unless the rotation axis is precessing as well...
- sandworm101 3y agoGiven the dimensions involved, the billions of miles, any deflection would create a miss. If we are certain that an asteroid is actually going to hit earth many years/decades out, then even a microscopic nudge in any direction would shift the closest approach by an earth-width. So precise aim might not be as important as getting the bomb out there asap. The earlier it is done, the less push is necessary to generate a miss. Of course, this is premised on us having near-perfect knowledge of the initial trajectory.
- mrangle 3y agoHeaven forbid their calculations aren't confident given that large distance, and the theoretical nudge instead generates a hit.
- j4yav 3y agoWhy would we be nudging ones that are going to miss?
- pdabbadabba 3y agoIf we mistakenly think it will hit because "their calculations aren't confident given that large distance."
- Arrath 3y agoPresumably the same distance that gives the calculations uncertainty allows time to adopt a wait and see approach, refine the data and calculations and then make a decision based off of stronger inputs and still avert disaster if necessary?
- Vecr 3y agoProbably better to hit it twice, the first time right after detection and a second time if the probability of impact is still too high.
- MetaWhirledPeas 3y ago> Think of a rocket with thrust but no stabilization. Cool idea but very hard to make practical. Given that the asteroid was heading directly at Earth prior to disruption, wouldn't any change in trajectory be welcome, even if it's chaotic?