X-Rays From a Nuclear Explosion Could Redirect an Asteroid (space.com) 29
Scientists have proposed a method to deflect dangerous asteroids using nuclear explosions, not by directly blowing them up, but by detonating a bomb above the surface to create an X-ray burst that vaporizes part of the asteroid and changes its course. Experiments using the Z machine at Sandia National Laboratories simulated this process, showing that it could potentially redirect even large asteroids to prevent catastrophic impacts on Earth. Space.com reports: In a new study, the researchers employed the Z machine at Sandia National Laboratory, the most powerful laboratory source of radiation in the world. It generates powerful electric pulses, magnetic fields and X-rays to find out how materials react under high pressures and temperatures. "At present, there is only one way to generate an intense enough X-ray burst to do an experiment like this, and that's using the Z Machine," said [Nathan Moore, a physicist at Sandia National Laboratories in Albuquerque, N.M.]. The scientists used electrical pulses from the Z machine to generate powerful magnetic fields. These in turn compressed argon gas to generate plasma, the same form of matter that makes up lightning and stars. This argon plasma produced the X-ray burst the researchers needed to simulate a similar one from a nuclear explosion.
"You have to concentrate a lot of power, about 80 trillion watts, into a very small space, the size of a pencil lead, and very quickly, about 100 billionths of second, to generate a hot enough argon plasma, several millions of degrees, to make a powerful enough X-ray burst to heat the asteroid material surface to tens of thousands of degrees to give it enough push," Moore said. The scientists hung up a pair of targets in a vacuum, each 0.47 inches (12 millimeters) wide -- one made of quartz, the other of fused silica. These materials are similar in composition to known asteroids. Previous attempts to study various asteroid deflection strategies all held targets fixed in place, "which wasn't very realistic," Moore said. "After all, asteroids in outer space aren't attached to anything. Besides, how would a mock asteroid accelerate realistically if it was anchored down?"
To overcome this problem, the researchers devised what they called "X-ray scissors." They hung the targets up using thin metal foil just 13 microns thick, or about one-eighth the thickness of an average human hair. This foil vaporized when the X-rays hit it, freeing the targets to accelerate naturally in space. The X-ray pulses generated vapor plumes from each target and accelerated each one to about 155 mph (250 km/h), matching computational predictions. "The ability to deflect miniature asteroids in a laboratory using the Z Machine is unlike anything else you can do anywhere else on Earth," Moore said. Scaling these findings up to a 2.5-mile-wide (4 kilometer) asteroid, with a 1 megaton nuclear bomb exploding about 1.25 miles (2 km) from its surface, the researchers suggested the resulting push could help deflect dangerous asteroids away from Earth.
"For reference, a 4-km [2.5-mile] asteroid is predicted to be large enough to cause global devastation and possible disruption of civilization, according to the NASA Planetary Defense Strategy and Action Plan," Moore said. Moore noted that asteroids come in a variety of compositions. "This new technique can be used to investigate the deflection response of different asteroid materials," he said. "Understanding how different asteroid materials vaporize and deflect will be critical for preparing for a planetary defense mission, should the need arise." The study has been published in the journal Nature Physics.
"You have to concentrate a lot of power, about 80 trillion watts, into a very small space, the size of a pencil lead, and very quickly, about 100 billionths of second, to generate a hot enough argon plasma, several millions of degrees, to make a powerful enough X-ray burst to heat the asteroid material surface to tens of thousands of degrees to give it enough push," Moore said. The scientists hung up a pair of targets in a vacuum, each 0.47 inches (12 millimeters) wide -- one made of quartz, the other of fused silica. These materials are similar in composition to known asteroids. Previous attempts to study various asteroid deflection strategies all held targets fixed in place, "which wasn't very realistic," Moore said. "After all, asteroids in outer space aren't attached to anything. Besides, how would a mock asteroid accelerate realistically if it was anchored down?"
To overcome this problem, the researchers devised what they called "X-ray scissors." They hung the targets up using thin metal foil just 13 microns thick, or about one-eighth the thickness of an average human hair. This foil vaporized when the X-rays hit it, freeing the targets to accelerate naturally in space. The X-ray pulses generated vapor plumes from each target and accelerated each one to about 155 mph (250 km/h), matching computational predictions. "The ability to deflect miniature asteroids in a laboratory using the Z Machine is unlike anything else you can do anywhere else on Earth," Moore said. Scaling these findings up to a 2.5-mile-wide (4 kilometer) asteroid, with a 1 megaton nuclear bomb exploding about 1.25 miles (2 km) from its surface, the researchers suggested the resulting push could help deflect dangerous asteroids away from Earth.
"For reference, a 4-km [2.5-mile] asteroid is predicted to be large enough to cause global devastation and possible disruption of civilization, according to the NASA Planetary Defense Strategy and Action Plan," Moore said. Moore noted that asteroids come in a variety of compositions. "This new technique can be used to investigate the deflection response of different asteroid materials," he said. "Understanding how different asteroid materials vaporize and deflect will be critical for preparing for a planetary defense mission, should the need arise." The study has been published in the journal Nature Physics.
Re: (Score:2)
Uh, no. Unless you're volunteering?
Re: (Score:1)
>> hating himself for being human and wanting to destroy everything
Who wants to destroy everything ?
Re: (Score:2)
Nope. Learn to read.
Re: (Score:2, Offtopic)
Found the dem woke hating himself for being human
Congratulaions. You said the magic word [imgur.com].
Re: (Score:2)
Re: (Score:2)
U 1st. ;)
Re: (Score:2)
Thickness 13 m = kitchen aluminium (Score:3)
using thin metal foil just 13 microns thick, or about one-eighth the thickness of an average human hair.
What they mean is they are using kitchen aluminium foil (11 m cheapest from supermarket, 33 m science grade).
Re:Thickness 13 um = kitchen aluminium foil (Score:3)
Apparently the micrometer symbol isn't working here (despite being part of good old Code Page 437 from from original IBM PC).
Re: (Score:2)
I can't write two letters from my alphabet here. It's annoying.
Re: Thickness 13 um = kitchen aluminium foil (Score:2)
#181;um what?
Bruce Willis will be glad to hear that (Score:2)
No need to go there.
Re: (Score:2)
There was never a need to send humans.
Armageddon [wikipedia.org] and Deep Impact [wikipedia.org] both had crewed missions only because it made the plot more relatable to audiences.
as long as it's solid (Score:2)
I'm all for starting work on the wave-motion gun for Space Battleship Yamato but doesn't this presuppose the asteroid in question is solid?
As I understand, most asteroids are more like rubble piles that a good shove will just break apart anyway, leaving you the same mass headed for earth, but now dozens of chunks instead of one.
Re: (Score:2)
leaving you the same mass headed for earth, but now dozens of chunks instead of one.
If a nuke blows apart a rubble pile [wikipedia.org] weeks or months before impact, the debris will scatter across a cross-section far larger than the Earth. Most will miss.
Even for the debris that hits the atmosphere, it is much better to arrive in smaller chunks.
Chicxulub had a mass of a trillion tonnes. The ejecta from the crater was a hundred times that amount. If it had arrived broken up, so each fragment burned up before reaching the surface, the dust would've been 1% as much, and there would've been no tsunami.
Re: (Score:3)
Rubble piles have been extensively simulated as well.
(A) Nukes still work great against them, including no-breakup scenarios (nukes can be used to either impart a small kick or impart enough kick that the rubble pile breaks up);
(B) Contrary to popular myth, many small impactors are usually a much better scenario than a single giant one, and indeed, the vast majority of typical rubble pile particle sizes are too small to even make it through Earth's atmosphere at all; and
(C) except with very late diversion e
Re: (Score:2)
And honestly, a destroyed rubble pile entering Earth would be the most spectacular night sky you've ever seen ;) The orbit of individual particles that do reenter would be spread out into a long ellipse. Along that ellipse it would be like every shooting star that's happened during your lifetime times a hundred all happening at once across a streak of the sky. Parts of the rubble pile that aren't fully diverted and do enter as the size of boulders (at least 5 meters across) may still reach the ground, but
Re:as long as it's solid (Score:5, Informative)
Forgot to include Earth Impact Effects calculations for Bennu hitting Earth whole (assumed 1500kg/m3, 45 degrees, 17km/s):
Incident frequency: Once every 10k years.
Starts breaking up at: 72,5km
Reaches the surface at: 16,1 km/s
9 times as much energy hits the ground as is lost to the atmosphere. Atmosphere experiences a 34 MT blast, while the ground experiences a 305 MT blast. Basically a good-sized fusion bomb.
Impact spread out across 1,4km x 1km
If hitting sedimentary rock:
Transient crater ~5km wide by 1,7km deep
Final crater ~6km wide by ~500m deep
For comparison, Meteor Crater is ~1,2km wide by ~0,18km deep.
From the thermal flash: Wood ignites at 40km distance. The body gets 3rd degrees at 50km distance. Grass and paper ignite at 60km distance. The body gets 2nd degree burns at 70km distance. Etc.
An earthquake of scale 6,9 is caused
Ejecta: at 25km, about 30cm with mean size 1,44m. At 40km, 7,3cm with mean size 41,5cm. At 70km, 1,4cm with mean size 9,4cm.
Air blast: at 25km, 303 m/s (678 mph), 107dB, 218 kPa (31 psi), all but the most hardened concrete structures destroyed.. At 40km, 149 m/s (334 mph), 98dB, 83kPa, most multistory buildings still collapse. At 70km, 61 m/s (136 mph), 89 dB, 29 kPa, wood frame buildings and about 30% of trees blown down. At 100km, 34 m/s (77 mph), 84 dB, 15,6 kPa, glass shatters.
If impacting the ocean (depth 1000m):
Tsunami: At 25km, an 80-160m wave. At 40km, a 50-100m wave. At 70km, a 30-60m wave. At 150km, a 13,5-27m wave. At 300km, a 7-13,5m wave.
By contrast, one of Bennu's larger boulders, say 10m solid dense rock on the same trajectory:
* Probably airbursts at around 30km into small fragments. Fragments moving at 13km/s, so significant burnup of them. No meaningful flash. Air "blast" right underneath it is 1,23 m/s (2,75mph) and 54db. No crater and no tsunami.
Let's go big and say there's a 25m boulder in there.
* Airbursts into fragments at 17,7km. Fragments moving at 9,6km/s, so still some burnup. No meaningful flash. Airburst is 8,9m/s (20mph), 72db, and just barely powerful enough to shatter glass if you're right under it. No crater and no tsunami, though the breakup fragments may physically damage what they hit.
Now which would you rather have hit Earth, the large fusion bomb, or a random shower of loose rocks? And again, this scenario assumes that the explosion doesn't divert the lion's share of the mass away from Earth.
Re: (Score:2)
Since the chance of the large fusion bomb being targeted at a ground target, or satellite target, is far higher than the chance of an asteroid strike, it's a moot point. Or haven't you noticed the current criminal, sexually abusive, and treasonous Republican candidate for the White House whose followers tried to extort the election count from his own vice president?
Re: (Score:2)
Can you people please stop trying to turn every single topic, no matter how esoteric, into one of US politics?
Don't do it (Score:2)
I'm pretty sure we need a large meteorite impact or two now