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Asteroid Impact on Earth 2032 with Probability 1% and 8Mt Energy

cneos.jpl.nasa.gov

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Re: Asteroid Impact on Earth 2032 with Probability 1% and 8Mt Energy

#301

Post by crazygringo »

elif wrote: post #291

Completely out of my domain and seat of pants rationing here, but although the impact probability is 1%, aren't we far far more certain about the /time/ at which it would strike earth? Could humanity collectively just migrate to the side of the world that will be shielded for a day?

The bad news is no, we have nothing even remotely close to the infrastructure necessary to move half the world's population. We don't have the transport, being limited to planes and boats mostly.

The good news is that, worst-case scenario, this is going to wipe out a city. And cities and their surrounding areas can absolutely be evacuated. We definitely have the cars and buses necessary for that.

Re: Asteroid Impact on Earth 2032 with Probability 1% and 8Mt Energy

#303

Post by quesera »

timewizard wrote: post #214
quesera wrote: post #168

Earlier quoted context omitted.

Unanimous consensus is an impossible goal. Overwhelming agreement among experts is as gold as standards get. But FWIW, I don't think anyone believes that climate change is a quick duration species-existential event. Massive slow-roll geopolitical destabilization leading to societal collapse? That's definitely on the table.

> Unanimous consensus is an impossible goal. I know this. I was responding to the OPs appeal to authority. > Overwhelming agreement among experts is as gold as standards get. What is this agreement? That it will eventually happen? That's not much of an agreement. > I don't think anyone believes that climate change is a quick duration species-existential event. Among those who "agree" is there a common timeframe that…

I don't believe you would have any trouble answering these questions for yourself, and I do not have any confidence that you are engaging earnestly.

Re: Asteroid Impact on Earth 2032 with Probability 1% and 8Mt Energy

#304

Post by giantg2 »

fghorow wrote: post #155
Gare wrote: post #98

Earlier quoted context omitted.

I'd assume quakes transform much more energy into tsunami waves than meteorite hit does.

That is not correct. Earthquakes' energy doesn't all go to displacing water and hence generating tsunamis. An ocean impact is significantly more efficient at transferring energy into tsunamis. https://www.sciencedirect.com/science/article/abs/pii/B97804...

Interesting, I would assume surface wave dissipation to counteract that compared to seabed origin.

Re: Asteroid Impact on Earth 2032 with Probability 1% and 8Mt Energy

#306

Post by perihelions »

DennisP wrote: post #217
perihelions wrote: post #77

Earlier quoted context omitted.

Ah, I understand now. For one thing, you could weaponize asteroids as a second-strike response, if there's an imbalance where one superpower has asteroid deflection and one does not. Even if it's delayed by months, the certainty that the asteroid will eventually hit establishes a deterrent against attacking the asteroid-controlling country. If there's defenses against ballistic missiles, this circumvents those. For a…

I don't think a second strike from asteroids would work. You can't just arbitrarily redirect an asteroid towards Earth whenever you want. You need one that's already going to pass nearby. You might have to wait decades for it to hit, and during that time your enemy can send their own nuke and nudge it away. But if you could do second strikes with asteroids, that would be a good thing. Second strike capability helps p…

- "Second strike capability helps prevent nuclear war. Effective first strikes are what's destabilizing."

I don't disagree!

- "You need one that's already going to pass nearby."

There's a very large number of these already, within a small delta-v of Earth. We don't know where they are yet (it was a show-stopping issue with NASA's Constellation (?) program, when they wanted to demonstrate capturing an asteroid, but couldn't find one), but that's going to rapidly change.

- "and during that time your enemy can send their own nuke and nudge it away"

That's pretty useful: that brings it to a point where the defender has to invest an amount of resources comparable to the attacker. That's a win for the economically stronger country. If the difference grows large enough, they can simply overwhelm them with numbers.

That's even before opening the technological possibilities of stealth asteroids.

Re: Asteroid Impact on Earth 2032 with Probability 1% and 8Mt Energy

#307

Post by perihelions »

quesera wrote: post #166
perihelions wrote: post #133

Earlier quoted context omitted.

Right; but if the enemy thinks that's likely to happen, it'd only take them 15 minutes to nuke that one airbase that stores all the B-2's. Strategic bomber aircraft aren't very useful weapons for superpowers fighting each other (or else we'd have a lot more B-2's). Space-based weapons (which are banned by treaty) are more like submarine-basing, in that the enemy isn't necessarily sure where they are; but, in addition…

Forgive my naivete, but do we really have the precision measurements and kT payload calibration needed to alter an asteroid's trajectory and speed to the point that we can target specific (even very large) country landmasses as the Earth's rotation exposes them to the oncoming projectile?

No, nothing about asteroid deflection is precise; the physics are messy and we know little about them.

Re: Asteroid Impact on Earth 2032 with Probability 1% and 8Mt Energy

#308

Post by freen »

timewizard wrote: post #214
quesera wrote: post #168

Earlier quoted context omitted.

Unanimous consensus is an impossible goal. Overwhelming agreement among experts is as gold as standards get. But FWIW, I don't think anyone believes that climate change is a quick duration species-existential event. Massive slow-roll geopolitical destabilization leading to societal collapse? That's definitely on the table.

> Unanimous consensus is an impossible goal. I know this. I was responding to the OPs appeal to authority. > Overwhelming agreement among experts is as gold as standards get. What is this agreement? That it will eventually happen? That's not much of an agreement. > I don't think anyone believes that climate change is a quick duration species-existential event. Among those who "agree" is there a common timeframe that…

Hmmm… what level of agreement would constitute sufficient cause for massive change?

Eventually happen? What percentage of the Great Barrier Reef is gone?

How about this every single climate change skeptic I have offered this wager to has declined to take me up: if in the next calendar year, the average global temperature for a given month is below the average global temperature of that month in the year you were born I will pay you 10 times the amount you are willing to wager. If the opposite is true, that the month this year is warmer than the same month in the year you were born you must pay me the amount you are willing to wager.

Care to take that bet? Didn’t think so.

Re: Asteroid Impact on Earth 2032 with Probability 1% and 8Mt Energy

#309

Post by chrsw »

echoangle wrote: post #271
chrsw wrote: post #78

Earlier quoted context omitted.

Only if you managed to leave the trajectory the same if it was already on a collision course or change the direction to a collision course. Do you think you can control that with a nuclear explosion? You probably don't know enough about to the system to make a high confidence prediction of the new outcome.

Not really, blowing it up is going to create a lot of fragments with slightly different orbits, and some are going to have practically the same as the whole Asteroid had before. So the chance of anything at all hitting earth will increase, but the parts will be smaller. It would be like a bullet turning into buckshot during flight.

If we were talking about a projectile fired at relatively close range on the surface of the Earth I would agree with you. But we are talking about a very small object very far away with already only a 1% chance of impact. Buckshotting the object with a random explosion is unlikely to change the dynamics of system to point where you say with high confidence the chance of impact is much higher. Some fragments might hit but it's very difficult to predict.

Re: Asteroid Impact on Earth 2032 with Probability 1% and 8Mt Energy

#310

Post by grues-dinner »

thenthenthen wrote: post #265
dzdt wrote: post #148

Earlier quoted context omitted.

I wonder if we have a chance to catch it still on radar this pass. I know Arecibo used to do that and is now sadly gone, but Goldstone also has capability. Anyone know more?

FAST [0] in China maybe? [0] https://fast.bao.ac.cn/

FAST also doesn't have transmitters, unlike Arecibo. So you cannot do radar observations of radio-reflective but not emitting objects with it in the same way.
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