Blowing up earth threatening asteroid?
So, a couple of things... you acknowledge we haven't the technology to accomplish this, but... let's say we do. First off, we need to know what kind of asteroid it is - iron, rock, mixture, what is it? The one that hit in Arizona 60,000 years ago and forming Barringer crater was an iron chunk 100 - 150 feet across; let's imagine this one is iron, only 6 *miles* in diameter. Say we *could* get down to the core, and stuff it with a few megaton H-bombs... Iron is viscous, so when the actual explosion happens, it won't *shatter*, it'll break. Take one of your plates, and drop it on the floor - there will be 3 or 4 big pieces, and lots of little ones. Those big pieces continue on (nearly) the same trajectory as the whole was earlier - only, now instead of one localized event - you'll have 3 or 4. Even if you blow it up in deep space - the force of the explosion won't be *enough* to push those pieces away - their own gravity will eventually have them 'fall together' again - so if you blow it up *too far* in advance of it's impact on Earth, you won't have accomplished very much. A rocky asteroid *might* shatter, but you still have the problems above - it's own gravity will eventually re-form the rock as it barrels in to Earth. Now, let's look at *many* pieces hitting the Earth as opposed to *one*.... One will cause a lot of localized damage, and - with the size we're talking about - the damage doesn't stay local. With *many* pieces, now you have impacts all over... remember the Russian meteor in February? That was the size of an SUV - and it had 20 times the power of the bomb we dropped on Hiroshima. Imagine *millions* of those in our atmosphere, all at once... how many SUVs fit into a 6-mile wide rock? Really - either way - it would be very bad news for us. I think the single impact is *more* survival than the millions of impacts, as the damage to our surface is localized, rather than spread everywhere. But the heat and energy entering our atmosphere is increased (I would think it'd be doubled or tripled) by breaking up a massive rock into thousands of pieces, and increasing the area of friction over the single big rock that is coming in.... Just speculation... hopefully, we'll never need to find out.
Are asteroids or comets a bigger threat to humanity?
My *assumption* is that we are more likely to be hit by an asteroid than a comet because there is an asteroid belt nearby. They orbit around the sun and many of them cross earth's orbit every time, so they get lots of chances to hit us. Comets, I think, tend to come in from out in the Kuiper belt or Oort cloud and have much longer orbit periods. So they don't come by so often and therefore have fewer chances to hit us. But if they do, they will have a higher relative velocity and would do more damage for the same mass. But perhaps there are many more comets out there than asteroids in the asteroid belt, and maybe they make up in numbers what they lack in chances to collide each time they come around. I just don't know. I don't have data to back up any of this. I'm just speculating.
Between asteroids and comets, which pose the greater threat to Earth? Explain why in detail.
That is a toss-up.There are, by some accounts, between 1.1 and 1.9 million asteroids, larger than 1 km in diameter, most of these are in the asteroid belt between Mars and Jupiter.Comets are a different celestial body, and either come from the Kuiper Belt (from beyond Neptune) or from the Oort cloud (at the edge of the solar system). There are only 5,253 known comets, but comets in the Oort cloud / Kuiper belt that have never traversed the inner solar system, are “without number” and could be upwards of a trillion.Comets differ from asteroids by having some kind of volatile mix, a gravitationally unbound atmosphere that surrounds the central nucleus. Comets can lose all their volatiles by multiple trips around the sun, and can then mimic asteroids, which normally have no such atmosphere. Comets are thought to be in the range of 10 km in diameter.Graphic courtesy of WikipediaOn the odds alone, there is a greater chance that an asteroid will impact the earth with between 1.1 and 1.9 million active asteroids in the solar system, and most of those in the asteroid belt or closer (Near Earth Asteroids).Comets have hit the Earth in the past, and with their size and chemical composition, could inflict serious damage (the average size of 10 km is about the size of the impactor that caused (or hastened) the extinction of the dinosaurs).Given an impactor of size in the range of 10 km (size of the impactor from 65 million years ago) to 32 km (size of the impactor from 3.x billion years ago), were anything that large to hit us again, the Earth would suffer greatly.
What is causing now a days more asteroids threatening Earth?
After comet Shoemaker-Levy 9 impacted Jupiter, more attention has been turned towards the other objects that cross Earth’s orbit. And surprise, surprise - there’s quite a few of them.Comet Shoemaker-Levy Homepage (JPL)NEO Earth Close Approaches
Between a comet and an asteroid impact, which is the most imminent threat to humanity?
Between a comet and an asteroid impact, which is the most imminent threat to humanity?Imminent - about to happen, occur, or take place very soon, especially of something which won't last long.Neither. The chances of a comet or an asteroid threatening humanity this century are near zero, in the next thousand years less than 0.0001%, in the next million years less than 1 %.The chances of one or the other inconveniencing humanity are a bit higher, perhaps as high as 10% in the next million years.
If an asteroid ever threatened Earth, how would we stop it?
The best method for destroying a huge asteroid that is headed towards Earth that I’ve come across is to explode a thermonuclear warhead a few miles above the surface. If done properly, the bomb would not break up the asteroid, but it would vaporize anything volatile on the surface (such as ice or methane). As these blew off they would provide a gentle and fairly uniform push to deflect the asteroid. It’s easier for a comet than for an asteroid.When I saw the movie Armageddon, I watched the scientists trying to figure out what to do. Then they decide to explode a bomb on the surface of the asteroid, blowing it to smithereens. NO! NO! I shouted (in my head). You’ll just turn a bullet into shotgun shrapnel, doing more damage than the single impact would have done! It turned out, of course, that I was right. The scientists should have first checked the theory, not simply made up a new idea just because it sounded good and used it without peer review.The warhead could be one (or several) from our existing fleet of intercontinental ballistic missiles. We would just have to reprogram their flight paths, and their detonation program. These weapons typically explode before they reach the surface, in order to inflict maximum damage in a war, so the modifications should not be difficult. The multiple warheads don’t need to be detonated simultaneously, since the deflections can be quite small.The problem, of course, is that we really should test such an approach before we try it. Right now that is impossible, since international treaties prohibit nuclear weapons in space. However, if an asteroid were predicted to hit the Earth, then there might be time to agree to an exception to the treaty, both to make a test (on a distant non-threatening asteroid) and to do the actual deflection. There is great value in doing the deflection early, when even 1 degree change in orbit would cause the asteroid to go miles away.
What protects Earth from asteroids and comets?
Jupiter has protected us from a lot of asteroids and comets due to its large gravity pulling things away. But sometimes it can do the opposite and sling shot things at us. It is hypothesized that its gravity was what caused the rogue mars sized planet to crash into Earth, creating our moon we see today. There is a low chance of this happening since we are a very very small target and many of the larger bodies have already been cleared from the asteroid belt. But, it is estimated in 2036 the Apophis asteroid MAY hit Earth, but it will not become clear till 2030–31. By then, hopefully humanity can come together to deal with that threat. There are talks of building satelites to deflect asteroids and large heavenly bodies from bringing about the Apocalypse.
How big would an asteroid or comet have to be to end life on Earth?
Here is an excellent diagram by astronomer Alan Harris that provides a lot of information on the relationship between asteroid size, damage, and frequency of impact:(magnify for a better view)The K-T impact event that caused the extinction of about 3/4 of the Earth's animal and plant species was likely caused by an impact from a body with a diameter of about 10 km. The good news is that there's an inverse relationship between the size of the impactor and the number of years between events of similar magnitude (in this case about a 100 million years for a mass-extinction event). The bad news is that we're likely due for another event fairly soon (The K-T event was 66 million years ago.)To end all life on Earth, an impactor with a diameter between 10-100 km would likely do the job.Some notes on the plot:NEO=Near Earth ObjectThe Absolute Magnitude (H) on the bottom axes is a measure of a body's brightness and is correlated with size. The larger an asteroid is, the brighter it will appear, assuming that all asteroids have the same surface composition (which they don't, but the assumption is likely good enough to give a rough estimate of the body's size).
The resulting scar from Asteroid or Comet strikes is called?
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