Why can't we blow up an NEO on collision course
Discussion
I was watching a programme about near Earth objects. I was told that there was no point in blowing up an NEO the size of Everest as the bits would still hit Earth with all the energy of the original object.
OK, I get that. It’s obvious. No kinetic energy disappears.
However, surely the damage would be likely to be less. The smaller lumps would burn up in the atmosphere; still dangerous but unlikely to cause much damage. If, say, three lumps were big enough to hit the Earth, or perhaps explode near the ground, the detritus would not go as high in the atmosphere as a single object and so no ‘nuclear’ winter nor extinction event.
Also comets, if they are just ice and dirt held together by nothing more than friendship, would react well to being blown apart.
Before I write to LINEAR, am I wrong (yep, OK, I know I probably am) but why.
OK, I get that. It’s obvious. No kinetic energy disappears.
However, surely the damage would be likely to be less. The smaller lumps would burn up in the atmosphere; still dangerous but unlikely to cause much damage. If, say, three lumps were big enough to hit the Earth, or perhaps explode near the ground, the detritus would not go as high in the atmosphere as a single object and so no ‘nuclear’ winter nor extinction event.
Also comets, if they are just ice and dirt held together by nothing more than friendship, would react well to being blown apart.
Before I write to LINEAR, am I wrong (yep, OK, I know I probably am) but why.
That's interesting because as I understood it the dinosaur killer asteroid was probably several times to size of Everest. So blasting an Everest sized meteorite into smaller chunks does sound like it could make the impact survivable. On the other hand any piece bigger than a football is likely to make to the surface.
Thought the perceived wisdom at the moment is deflection, considering the requirements and extra risks with explosion. If there was a bomb big enough.
Edit.
https://www.nasa.gov/feature/nasa-s-first-asteroid...
Looks like they are testing something.
Edit.
https://www.nasa.gov/feature/nasa-s-first-asteroid...
Looks like they are testing something.
Edited by jmorgan on Sunday 4th February 10:13
Compare surface area between original large sized object and 'blown up' fragments and it results in the the fragments presenting a vastly larger surface area on impact to the atmosphere, this allows much more of the kinetic energy to be converted to heat and less kinetic energy would reach the surface...... so I'm also a little confused as to why blowing up an NEO is not an option pursued?
Atomic12C said:
so I'm also a little confused as to why blowing up an NEO is not an option pursued?
Perhaps for a given energy of X you can more reliably deflect it than shatter it?But as we've not had a life-changing asteroid hit since the dinosaurs, I can't think it's a probability worth spending much time/money on. Unless of course the spin-off is a man on Mars.
I feel a letter to NASA coming on. I'll let you know any reply.
I was watching Tomorrow's World some years ago with my elder lad, then around 8, when they said that two vehicles travelling at 50mph colliding head on would cause the same damage to each car as one colliding with a concrete bridge support at 100mph. I told my lad they were wrong but, with the 'teacher said' expression on his face, I realised he thought his dad had lost the plot. I wrote to TW explaining the damage they had caused to our father/son relationship was greater than a car colliding with a concrete structure at 100mph.
I received a lovely letter back, with an apology, and an included letter to my lad saying, virtually, question everything, even when someone on TV said it, and this years before it became a popular phrase, although years after Einstein said it.
My son was over the moon with the letter. I always wondered if he saw it as something to guide him through life or dad just pleased he'd got one over someone on the telly.
I was watching Tomorrow's World some years ago with my elder lad, then around 8, when they said that two vehicles travelling at 50mph colliding head on would cause the same damage to each car as one colliding with a concrete bridge support at 100mph. I told my lad they were wrong but, with the 'teacher said' expression on his face, I realised he thought his dad had lost the plot. I wrote to TW explaining the damage they had caused to our father/son relationship was greater than a car colliding with a concrete structure at 100mph.
I received a lovely letter back, with an apology, and an included letter to my lad saying, virtually, question everything, even when someone on TV said it, and this years before it became a popular phrase, although years after Einstein said it.
My son was over the moon with the letter. I always wondered if he saw it as something to guide him through life or dad just pleased he'd got one over someone on the telly.
Just a thought: Imagine an alien race trying to find out if other planets had intelligent life and are therefore a threat. Hurl asteroids into the solar system and see how the locals react. All life tries to preserve itself so if you see an asteroid disappear, change direction, etc. its likely there is intelligent life in there somewhere. Cheap, simple and easy to detect a bazillion miles away.
Mwahahahaha.
While NASA clinks their champagne glasses to celebrate a successful mission, killer tomatoes from planet X arrive on the back of space tortoises.
I, for one, welcome will our alien overlords.
Mwahahahaha.
While NASA clinks their champagne glasses to celebrate a successful mission, killer tomatoes from planet X arrive on the back of space tortoises.
I, for one, welcome will our alien overlords.
Dr Jekyll said:
That's interesting because as I understood it the dinosaur killer asteroid was probably several times to size of Everest. So blasting an Everest sized meteorite into smaller chunks does sound like it could make the impact survivable. On the other hand any piece bigger than a football is likely to make to the surface.
That scales up nicely, I suspect if you hit everest with the largest bomb we've ever made it'd be mostly still there once the dust has settled.Hitting an Everest moving at several thousand miles an hour in space with the same weapon would be difficult but also less likely to do any damage let alone blow the thing to bits.
Hitting something moving at tens of kilometres per second is not going to be easy.
And if it's big we probably cannot deflect it much even with nukes.
Or we could turn a near miss into a hit.
And this all assumes we've put a load of nukes into orbit without them blowing up on take off and causing our extinction.
And if it's big we probably cannot deflect it much even with nukes.
Or we could turn a near miss into a hit.
And this all assumes we've put a load of nukes into orbit without them blowing up on take off and causing our extinction.
Simpo Two said:
Perhaps for a given energy of X you can more reliably deflect it than shatter it?
But as we've not had a life-changing asteroid hit since the dinosaurs, I can't think it's a probability worth spending much time/money on. Unless of course the spin-off is a man on Mars.
Apparently* the probability of an end-of-the-world asteroid hitting in the next few decades is higher than that of any given individual being struck by lightning in the same period. So not to be completely disregarded, depending on how much trouble you go to in order to avoid lightning strikes.But as we've not had a life-changing asteroid hit since the dinosaurs, I can't think it's a probability worth spending much time/money on. Unless of course the spin-off is a man on Mars.
(* 'Apparently' in the sense of 'it was said on QI')
Simpo Two said:
Atomic12C said:
so I'm also a little confused as to why blowing up an NEO is not an option pursued?
Perhaps for a given energy of X you can more reliably deflect it than shatter it?But as we've not had a life-changing asteroid hit since the dinosaurs, I can't think it's a probability worth spending much time/money on. Unless of course the spin-off is a man on Mars.
If you know the rough mass of an asteroid, theoretically you could put a spacecraft nearby and use it's gravitational attraction to slowly deflect the asteroid. Because this is not dependent on what the asteroid is made of, it's structural integrity or size, the result is more predictable than firing some explosive device with unknown consequences.
This is also better than trying to land a rocket on it as you cannot be sure you'll land in the right place or attach at all (see Philae lander)
The Netflix series Salvation used the idea of a gravity tractor to push a NEO off track, by about 0.02 degrees or something, but thats enough at millions of miles. This was propelled by an EM drive. Im not sure either actually exist, and when the show has real time telemetry from a satellite orbiting Jupiter, Im not really convinced they have accurate science 
Dr Jekyll said:
Apparently* the probability of an end-of-the-world asteroid hitting in the next few decades is higher than that of any given individual being struck by lightning in the same period. So not to be completely disregarded, depending on how much trouble you go to in order to avoid lightning strikes.
(* 'Apparently' in the sense of 'it was said on QI')
No doubt, but the logic fail is that there are many more people than there are Earths, thereby skewing the stats several billion-fold.(* 'Apparently' in the sense of 'it was said on QI')
Fry 0, Simpo 1
From the wiki on underground nuclear explosions:
wiki said:
In contrast, if the device is buried at insufficient depth ("underburied"), then rock may be expelled by the explosion, forming a crater surrounded by ejecta, and releasing high-pressure gases to the atmosphere (the resulting crater is usually conical in profile, circular, and may range between tens to hundreds of metres in diameter and depth
So even a buried nuke will only make a hole hundreds of meters wide, a surface nuke would just scald the surface. Without strong gravity an Armageddon scenario might split it (maybe?) but the firecracker on the hand thing seems a good analogy.Simpo Two said:
Dr Jekyll said:
Apparently* the probability of an end-of-the-world asteroid hitting in the next few decades is higher than that of any given individual being struck by lightning in the same period. So not to be completely disregarded, depending on how much trouble you go to in order to avoid lightning strikes.
(* 'Apparently' in the sense of 'it was said on QI')
No doubt, but the logic fail is that there are many more people than there are Earths, thereby skewing the stats several billion-fold.(* 'Apparently' in the sense of 'it was said on QI')
Fry 0, Simpo 1
Dr Jekyll said:
Only a logic fail if you interpret it as 'a meteorite strike is more likely than someone somewhere getting struck by lightning'. If you interpret it as 'a meteorite strike is more likely than me personally getting struck by lightning' that's logical. The figures may be wrong, but the logic is fine.
I might not have got the maths spot on but the way I see it:About 500 people are hit by lightening in the USA per annum. A significant proportion of these are golfers. Therefore, if we want to lower the risks of getting hit by an asteroid we should ban golf.
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