Asteroid and Comet Impacts of 1994 and 2009

What would the world look like today had an asteroid or actual comet fragment from Shoemaker-Levy measuring 1.6 km in diameter and another in 2009 measuring 0.5 km came our way as well? Do you think we would be able to rally sufficient resources in time by 2009 to deflect the latter or fight amongst ourselves for whatever was leftover? Impact site(s) and resulting effects are up to individual posters.
 
What would the world look like today had an asteroid or actual comet fragment from Shoemaker-Levy measuring 1.6 km in diameter and another in 2009 measuring 0.5 km came our way as well? Do you think we would be able to rally sufficient resources in time by 2009 to deflect the latter or fight amongst ourselves for whatever was leftover? Impact site(s) and resulting effects are up to individual posters.

So a Shoemaker-Levy impact in sometime in 1994 and then something else hits us 15 years later in 2009? Assuming that we don't see the S-L fragment coming, well, its 1.6 kilometres in diameter, right? That's probably an extinction event.
 

Saphroneth

Banned
1994 - that much comet would f*ck us over as a civilization but not a species. It's basically "Tsunami anything around the ocean it hits with tens of metres of water".

2009 - we'd not be able to build up.
 
What would the world look like today had an asteroid or actual comet fragment from Shoemaker-Levy measuring 1.6 km in diameter and another in 2009 measuring 0.5 km came our way as well? Do you think we would be able to rally sufficient resources in time by 2009 to deflect the latter or fight amongst ourselves for whatever was leftover? Impact site(s) and resulting effects are up to individual posters.

Assuming nobody sees it coming? Thats pretty much the end of much of civilized life on earth. If they do? It depends on what they have for warning, at the very least they might try salvoing some nuclear warheads off at it.
 

Yuelang

Banned
If the 1994 comet was seen and predicted from at least a year before, expect US, Russia, and EU will do a gigantic project to launch the biggest arrays of nuclear warheads sent to space in desperate attempt to knock the comet off way. With two variations prepared, the first is non explosive to latch and try to steer the comet away from its trajectory by applying tangential force, while the second failsafe is multiple gigaton nuclear warheads sent on most powerful rocket ever built to ram and destroy the comet.
 

Saphroneth

Banned
If the 1994 comet was seen and predicted from at least a year before, expect US, Russia, and EU will do a gigantic project to launch the biggest arrays of nuclear warheads sent to space in desperate attempt to knock the comet off way. With two variations prepared, the first is non explosive to latch and try to steer the comet away from its trajectory by applying tangential force, while the second failsafe is multiple gigaton nuclear warheads sent on most powerful rocket ever built to ram and destroy the comet.
What the heck do you mean "multiple gigaton"? Most ICBMs have low-mid megaton range weapons at most.

This is the early-mid nineties we're talking about, and frankly we'd be lucky to reach it early enough with a non-payload rocket - we don't even know how to make a Saturn V booster any more.


And DESTROY? What the f*ck?
We're talking about a lump of ice and some rock a mile across. Even if it was blown into thousands of pieces by multiple massive nuclear detonations that just means a spray of smaller bits raining down across a whole planetary hemisphere.



The reality is that we have no real capacity to deflect a bolide unless we put many years of planning and effort into it, and it is harder the larger the bolide is. This is a thing that many, many astronomers and scientists have been advocating we work out how to do, but we currently do not have the required tools to stop or deflect anything more than a very small rock with decades of lead time.
 
Even if it was blown into thousands of pieces by multiple massive nuclear detonations that just means a spray of smaller bits raining down across a whole planetary hemisphere.

Which would be preferable to one giant hit, right? The force of the impact would be much smaller and a lot more of the total mass would burn up in the atmosphere if it came in tiny (for a given definition of the word) little pieces rather than one large one.

If the warning is early enough, I would expect most world economies would be geared up towards building as many missiles with the most efficient warheads possible (e.g. B41) as fast as possible, damn the cost.
 
1 years notice?

Delta IV with a nuclear warhead stuck on some probe. get within a mile, and boom. Only need to give it a slight nudge to get it out the way. The nearer it gets, the bigger the nudge needs to be.
 
Which would be preferable to one giant hit, right? The force of the impact would be much smaller and a lot more of the total mass would burn up in the atmosphere if it came in tiny (for a given definition of the word) little pieces rather than one large one.

If the warning is early enough, I would expect most world economies would be geared up towards building as many missiles with the most efficient warheads possible (e.g. B41) as fast as possible, damn the cost.

It's described as the difference between being shot by a rifle or by a shotgun.

Tunguska showed that a fragment above 50 m diameter or so devastates the impact zone, despite "burning up" in the atmosphere. So a 500 m diameter comet could fracture into one thousand of them. Of course, there won't be a uniform distribution of fragments, but evening assuming that a quarter of the mass gets vaporised by the nuke and incident sunlight following disruption (probably deeply optimistic) and that another quarter occurs as small stuff that the atmosphere does shield us from, well, that's still many hundreds of 25 Mt blasts occurring in a few hours.

Also, you might only get one shot at nuking it. The first might kick up so much debris that the others get trashed on the way in...
 

Saphroneth

Banned
Which would be preferable to one giant hit, right?
No, not really - the atmosphere would be heated a lot by the thermal pulse and it'd be a scattergun of large scale nuclear blasts.

And comets move at 50+ km per second. Consider how long it took to launch the first impactor probes to the moon - well, the earth-moon distance could be covered by a comet in two hours.

Apollo 11 was travelling at 40,000 km per hour - that's about 11 km per second.

So if you get the rockets in space and through the boost phase by the time you have a year left - which would require two-three years warning, not one - then you reach the comet with two months left to go.
At that point you need to deliver it an impulse sufficient to make it miss the planet - call it a sideways perturbation of 5,000 km over 2 months. That's about one metre per second... which doesn't sound like much until you realize that the required impulse is one metre per second for two cubic kilometres of ice, which is to say two thousand million tonnes of ice.
That would require delivering a Saturn V rocket to the asteroid, and firing it for half the complete three-stage burn process facing directly up.

And we can't make those any more.




The people who actually know about this kind of thing (geologists and planetary scientists with a focus on bolides) are all pretty angry that there aren't measures in place already. It is not something we can just ad hoc from the ground up in a single year.
 
For a comet, you send the maximum megatonnage possible on every available launch system that can get something out there. You pick one side of the comet (are you slowing it down, or speeding it up) and set the nukes off at a short stand off distance.

You don't want the comet to break up, for the reasons stated (and which is one of the NUMEROUS reasons why 'Armageddon' is a stupid movie). What you do is hope the radiant energy of the nuke vaporizes enough cometary ice to use the COMET's own material as rocket exhaust to push the comet out of the way.

if the nukes arrive separately in about a dozen waves (as each launcher is prepped and launched out), then you can fine tune the fusing of the subsequent bombs. Maybe concentrate on the most dangerous fragments if early blasts split it.

Asteroids? Not nearly so nice. Not much nice high volatility water and methane ice to shove it off to the side.

Mind you, a comet that size probably would give us a fair bit of warning.
 

Saphroneth

Banned
For a comet, you send the maximum megatonnage possible on every available launch system that can get something out there. You pick one side of the comet (are you slowing it down, or speeding it up) and set the nukes off at a short stand off distance.

You don't want the comet to break up, for the reasons stated (and which is one of the NUMEROUS reasons why 'Armageddon' is a stupid movie). What you do is hope the radiant energy of the nuke vaporizes enough cometary ice to use the COMET's own material as rocket exhaust to push the comet out of the way.

if the nukes arrive separately in about a dozen waves (as each launcher is prepped and launched out), then you can fine tune the fusing of the subsequent bombs. Maybe concentrate on the most dangerous fragments if early blasts split it.

Asteroids? Not nearly so nice. Not much nice high volatility water and methane ice to shove it off to the side.

Mind you, a comet that size probably would give us a fair bit of warning.
Comets are tricky because we didn't really understand keyhole orbital mechanics in 1994 (AFAIK). Assuming it gets projected at us from the Jovian slingshot that broke it up, we'd have two years total.
If it's slingshotted at us more directly, we'd have much less time.
 
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It's described as the difference between being shot by a rifle or by a shotgun.

And a shotgun fired from sufficiently far away would have such a large spread that you'd only get some of the impact. If you shatter a comet fragment or asteroid sufficiently far from Earth, a lot of its mass will miss. Given that comets are not particularly dense, the gravitational binding energy of a comet of such sizes as the OP describes is not really that great, and a bunker-busting penetrator should be able to burrow many meters into the surface to maximize the explosive's effect.

The development of the spacecraft will take sufficiently long, I think, that not much can be done about the 1994 fragment, but in the aftermath of that impact, international outcry will demand that a constant anti-comet capability be maintained. That and a decade to rebuild Tsar Bomba and stick it in an armored shell should mean that the 2009 projectile is easily knocked out.

That said, the exact nature of the capability depends on where the 1994 impactor hits. If it strikes the North Atlantic, Kennedy Space Center is gone, so it's all up to Russia.

The 1.6 km impactor will be unpleasant, but not civilization-ending. Assuming it's mostly ice (comet fragment) and moving at 60 km/s and strikes the earth dead-on at 90 degrees, it'll kick up a tsunami many meters (or tens of meters) tall at a distance of 1000 km. The Pacific is the biggest ocean, so that's the most likely impact site--we can probably say goodbye to Japan, Hawaii, and most of the Pacific Coasts of the Americas, Australia, and China.
 
Another thing to consider is that despite the Fallout series, one of the sad things pointed out by the Biosphere-2 experiments, is that even under the best controlled conditions, we are terrible at creating a self -sustaining contIned environmental system. Remember the scientists nearly starved, the environment became filled with dangerous levels of carbon dioxide, the over-fished their stock, et. Al.,...

To make things worse, according to astronauts on the ISS, astronauts can suffer major bouts of depression starting 6 months into the journey. While this may seem like a minor problem, consider you have an already depressing situation get worse when people become suicidal and easily agitated...
 
And a shotgun fired from sufficiently far away would have such a large spread that you'd only get some of the impact. If you shatter a comet fragment or asteroid sufficiently far from Earth, a lot of its mass will miss. Given that comets are not particularly dense, the gravitational binding energy of a comet of such sizes as the OP describes is not really that great, and a bunker-busting penetrator should be able to burrow many meters into the surface to maximize the explosive's effect.
1) If you have enough energy in the bomb (singular) to blow up the comet such that all (or at least the vast majority) of fragments are blown far enough off course to miss the earth, then you probably have enough energy to shove the whole, intact comet off course the same distance in one direction and have all of it miss, not just most.

2) You want to try building a penetrator that will survive cometary impact speeds? Seriously?

3) a bomb that size probably doesn't exist, and would have to be engineered. A much better solution is to modify existing bombs and send them.

The development of the spacecraft will take sufficiently long, I think, that not much can be done about the 1994 fragment,
Today's spacecraft are carefully crafted for minimum mass, maximum reliability, and to limit cost.

In a 'save the earth' scenario, they'd kludge together a rube-goldberg-esque bus, cannabalizing anything handy, and could have SOMETHING together in a week or two. Sure, it would be twice the mass necessary, but it would get the job done.
 
In a 'save the earth' scenario, they'd kludge together a rube-goldberg-esque bus, cannabalizing anything handy, and could have SOMETHING together in a week or two. Sure, it would be twice the mass necessary, but it would get the job done.

Ummmm....no it probably wouldn't. Sputink 2 was almost literally designed on the back of a cocktail napkin and failed within four hours of launch.
 
1) If you have enough energy in the bomb (singular) to blow up the comet such that all (or at least the vast majority) of fragments are blown far enough off course to miss the earth, then you probably have enough energy to shove the whole, intact comet off course the same distance in one direction and have all of it miss, not just most.

2) You want to try building a penetrator that will survive cometary impact speeds? Seriously?

3) a bomb that size probably doesn't exist, and would have to be engineered. A much better solution is to modify existing bombs and send them.


Today's spacecraft are carefully crafted for minimum mass, maximum reliability, and to limit cost.

In a 'save the earth' scenario, they'd kludge together a rube-goldberg-esque bus, cannabalizing anything handy, and could have SOMETHING together in a week or two. Sure, it would be twice the mass necessary, but it would get the job done.

More than one probably, remove all safety considerations with total commitment of all resources you have from the world. Even without total commitment from all nations, the major ones will be throwing resources on a a scale beyond anything we have ever seen.
 

Yuelang

Banned
What the heck do you mean "multiple gigaton"? Most ICBMs have low-mid megaton range weapons at most.

This is the early-mid nineties we're talking about, and frankly we'd be lucky to reach it early enough with a non-payload rocket - we don't even know how to make a Saturn V booster any more.


And DESTROY? What the f*ck?
We're talking about a lump of ice and some rock a mile across. Even if it was blown into thousands of pieces by multiple massive nuclear detonations that just means a spray of smaller bits raining down across a whole planetary hemisphere.



The reality is that we have no real capacity to deflect a bolide unless we put many years of planning and effort into it, and it is harder the larger the bolide is. This is a thing that many, many astronomers and scientists have been advocating we work out how to do, but we currently do not have the required tools to stop or deflect anything more than a very small rock with decades of lead time.

It's described as the difference between being shot by a rifle or by a shotgun.

Tunguska showed that a fragment above 50 m diameter or so devastates the impact zone, despite "burning up" in the atmosphere. So a 500 m diameter comet could fracture into one thousand of them. Of course, there won't be a uniform distribution of fragments, but evening assuming that a quarter of the mass gets vaporised by the nuke and incident sunlight following disruption (probably deeply optimistic) and that another quarter occurs as small stuff that the atmosphere does shield us from, well, that's still many hundreds of 25 Mt blasts occurring in a few hours.

Also, you might only get one shot at nuking it. The first might kick up so much debris that the others get trashed on the way in...

And a shotgun fired from sufficiently far away would have such a large spread that you'd only get some of the impact. If you shatter a comet fragment or asteroid sufficiently far from Earth, a lot of its mass will miss. Given that comets are not particularly dense, the gravitational binding energy of a comet of such sizes as the OP describes is not really that great, and a bunker-busting penetrator should be able to burrow many meters into the surface to maximize the explosive's effect.

The development of the spacecraft will take sufficiently long, I think, that not much can be done about the 1994 fragment, but in the aftermath of that impact, international outcry will demand that a constant anti-comet capability be maintained. That and a decade to rebuild Tsar Bomba and stick it in an armored shell should mean that the 2009 projectile is easily knocked out.

That said, the exact nature of the capability depends on where the 1994 impactor hits. If it strikes the North Atlantic, Kennedy Space Center is gone, so it's all up to Russia.

The 1.6 km impactor will be unpleasant, but not civilization-ending. Assuming it's mostly ice (comet fragment) and moving at 60 km/s and strikes the earth dead-on at 90 degrees, it'll kick up a tsunami many meters (or tens of meters) tall at a distance of 1000 km. The Pacific is the biggest ocean, so that's the most likely impact site--we can probably say goodbye to Japan, Hawaii, and most of the Pacific Coasts of the Americas, Australia, and China.

Basically this, remember that the first thing in my proposal is considerably nudging it by applying tangential force with a lander, if it works, the second, more desperate measure of whacking it with the biggest nuclear hammer we had is not needed.

Plus this, it would sent many fragments hurtling, but instead of being shot with one big caliber rifle, we will get shot by shotgun if the worst come to worst, and in best scenario, the sheer energy of the explosion vaporated most of the ice and materials, and blown it veering completely missing earth.

And yeah, gigaton range nuclear explosion, stick twenty Tsar Bombas here, or launch twentry rockets with twenty tsar bombas,
 
Could we not land a spacecraft or two have some drilling equipment and nukes on them and bam ? :D

What if one of the two were to hit dead on Antarctica ?
 
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