I was wondering, what really are the chances earth will be mostly destroyed by a killer asteroid some day? Is it all but inevitable? And would science be able to do anything to protect us, in such an event?
And, generally speaking, how would it effect life on earth? Human life specifically? Would it wipe all of us out? Or just some of us? And would the survivors be able to rekindle the human race?
:):)
As long as we have Bruce Willis or Sean Connery, there should be no problems:)
On a more serious note, it depends on how long there is before there is a collision and how large the asteroid is
Given enough time and assuming the asteroid is not Texas sized, there is probably a good chance of diverting it with various space missions. it would not take much of a course deviation of the asteroid to keep it from hitting the earth.
Despite the movies and TV shows, I doubt if it would be a nuclear bomb that would be used.
Pretty well most of the larger asteroids have been charted (but not all of them) that would be planet killers for the foreseeable future.
A bigger problem would be a smaller asteroid that would sneak in undetected (say 30 - 50 m across ) similar to the 1905 Siberia asteroid that could cause major damage if it hit in the right location but it would not be a planet killer
Of course I could be totally off base on this but that is my amateur opinion
I thought there would be a dope question on this but I don’t see one yet with a quick search through the archives
I forgot to answer the other question about survivability
Again depending on the size of the strike I would say that it would be probable.
Going by Pop Culture as a guide, the movie Deep Impact has humanity (or some of them under 50) hiding it out in caves
Whether this would work for more than the 2 years anticipated in the movie, I don’t know but it would be a good chance. Remember that canned foods can last for a long time and even the fruits and vegetables can be canned and will survive for some time.
Of course, under ground there would be wells and lots of water available. Every cave I have been in has been rather wet inside.
Of course the social implications of living in the caves cramped up would be another issue. Think of too many Rats in a cage and the panic that would come from this may be another big issue.
Also having the lottery of who goes in and who stays out would be a nightmare
For the survivors rekindling the human race, read some of the thread on the manned mission to mars. That gives an idea of how many people would be needed to rekindle the human race.
As Dr Strangerlove says we need 10 women (all attractive of course) to each man to quote another pop culture reference.
As you said, it depends on how big the asteroid is.
When people think of mass extinctions caused by asteroids, they’re usually thinking of the K–T extinction, which happened about sixty-five million years ago. That was the one that wiped out the dinosaurs. The asteroid that caused this was estimated to be about ten kilometers across and it landed in the Gulf of Mexico.
But there was a much bigger mass extinction two hundred and fifty million years ago: the P-Tr extinction, also known as the Great Dying. This wiped out almost all of the life on Earth. It took about five million years for a normal environmental balance to be restored.
So based on previous history, there are 2 potentially deadly strikes in the past 250 millions years.
The one that killed the Dinos 65 million years ago might be survival able for humanity with some advanced preparation
The other big one 250 millions years ago would be a lot harder to survive even in the caves especially since it took 5 millions years to get back to normal and I don’t think a bottle or even a million of them of air freshener is going to fix that.
There’ve been a number of extinction events over the history of the Earth, some of which are attibuted to impacts. There’s a list on that page with their probably causes. But note that these causes are mostly just guesswork. It’s really difficult to say what caused specific extinctions based just on the fossil record.
Keep in mind that we still don’t have reliable detection or any countermeasures for most large meteors. It was just in February 15, 2013 when everyone was watching for a close call with 367943 Duende when Russia got blasted with a completely unrelated meteor seemingly coming out of nowhere with 20 - 30x the power of the Hiroshima bomb. Luckily, it hit in a rather unpopulated area and, because of that, it didn’t cause any deaths but it did cause lots of structural damage to buildings because of the shockwave. It was brighter than the sun when it exploded in the atmosphere and it still wasn’t very big all things considered. Space objects even bigger than that could conceivably hit Tokyo, Manhattan or London if luck was running scarce tomorrow and it is likely that no one would even see it coming.
It is really hard to say because we know now that the dinosaurs never truly died and still walk and fly among us in the form of birds (yes, they are truly real dinosaurs in every way). It is probably more accurate to specify which species of dinosaurs died out because of an ancient impact and why. Small mammals didn’t do that badly either after the last strike. Some of them went on to produce much larger mammals like us that are now among the dominant species.
Interesting in that the Duende meteor was actually discovered a year before it had the closest approach. and even that close approach it was still 4.3 radii away (which is close but still some distance off)
Assuming that the Duende meteor was going to hit the earth when it was first discovered, and with the year’s notice, I think we would struggle to get a response to it in time considering the current lack of a heavy launch vehicle for the US to put up anything large in size to divert it.
Whether the smaller rockets could get something up in time (solar sail, rockets to nudge its orbit, or Bruce Willis), I don’t know but it would be a challenge to say the least even with an unlimited budget
To give an idea of how bad the P-Tr extinction was, one of the ways scientists spotted it was the so-called coal gap. Checking fossil records they found there was a period of about ten million years when no coal was produced. And it was caused by the fact that pretty much all the plants had died.
You’re refering to a single event (the K-T extinction) while I was refering to all of them. As it is, the K-T extinction is probably the best studied of them and we’re fairly certain the Chixulub meteor was the cause. The fact that some dinos survived does not change that in the least. It was still a major extinction and many of the existing dinosaurs, including some of the feathered flying ones, died out because of it. Also, many other species, including some mammals, went extinct due to it.
The Earth will not be destroyed by an asteroid or comet impact. There just aren’t any asteroids or comets around any more that are big enough to do that. The really big rogue bodies, like the Mars-sized object that collided with the Earth to form the Moon, either collided with something or were ejected from the solar system early in the history of the solar system.
The objects we’re worried about for extinction events are probably in the 1-50 km diameter size range. There are a fair number of those still around. Some famous examples are Comets Halley (about 10 km in diameter) and Hale-Bopp (40-80 km in diameter). There are also Earth-crossing asteroids in that size range. We think you’d need an asteroid or comet at least 1 km in diameter to have global effects. Something smaller than that could have devastating local effects, but we don’t think it would affect the global climate too badly. Of course, we have no historical data on any such impacts, so this is not certain.
Whether we could do anything about an incoming asteroid or comet depends on how much warning we get. It’s possible that we could discover one that was headed straight for us a couple of years before it impacted, in which case there’s pretty much nothing anybody could do. We discovered Comet Hale-Bopp about two years before it got to perihelion (its closest approach to the Sun). Fortunately, it wasn’t on a collision course with Earth. You have more options of how to deal with a potential impactor the more time you have between when it is found to be on a collision course with Earth and when you think the impact will be. It’s generally preferable to deflect an incoming asteroid or comet so that it doesn’t hit Earth, rather than trying to blow it up. If you blow it up, and all or most of the pieces hit Earth, you are still getting the same kinetic energy from the impact, so you haven’t really improved the situation, despite what you see in some movies. Of course, it’s going to be easier to deflect a smaller object than a bigger one.
I’m an astronomer, so I don’t really know what the chances are that humans would survive something like the K-T impact. I’ll speculate that most humans would be killed. Your best bet for surviving is probably to be underground when the impact happens. It would probably cause an impact winter, which would mean growing any crops for food would be difficult for a while. The global firestorms that the impact would likely cause would wipe out all crops that were growing at the time of the impact, as well.
I’ve seen various estimates of how likely you are to die from an asteroid impact. They generally range from about one in a million to 1 in 75 million.
We don’t know what caused the Great Dying. An asteroid impact may or may not have been involved. Same goes for a lot of other mass extinctions. Part of the problem is that, if there are impact craters from asteroid impacts, they aren’t always in places where we can find them. They could be on the ocean floor, and be very difficult to find. The ocean floor gets recycled- some oceanic crust gets subducted into the Earth’s mantle, and new ocean floor gets created at mid-ocean ridges. If a crater was later subducted, there is of course no way we could ever find it. Even if it were still there, finding it might not be easy. The disappearance of Malaysia Airlines Flight 370 showed how difficult it is to search for something on the ocean floor when you have no idea where it is. The impact crater would be bigger than the wreckage, but it could also be anywhere in the oceans, so it wouldn’t necessarily be easy to find. It’s not even always easy to find really big impact craters on land. There is one that was hiding more or less in plain sight in Germany for many years.
Anne, I might have asked this of you before, and if so, I apologize, but do we have any data on the frequency of extrasolar bodies and close approaches to Earth? By extrasolar, I mean bodies with high enough relative velocity that they couldn’t possibly have originated within the Solar System. Have we ever observed any? Larger than cosmic ray particle size?
There’s a theory that some or all long-period comets may be originally from other solar systems. But they’re now gravitationally bound to the Sun. Some may be gravitationally unbound, but not enough so that it’s obvious that they aren’t just Oort cloud comets that have just been scattered into an unbound orbit by interactions with something else in the solar system.
We’ve seen rogue planets, planets that have been ejected from orbit around their parent stars. It’s kind of tricky to observe these, and also tricky to determine that they are in fact planets and not very low-mass stars. Estimates of the number of rogue planets in the Milky Way range from two rogue planets for each star in the Milky Way to 100,000 rogue planets for each star.
We haven’t seen any object in the solar system that we can point to and say “this object definitely did not originate as part of the solar system”.
I can tell you that, if there were a Texas-sized asteroid on a course to collide with Earth in a few years, there is nothing Bruce Willis or anybody else could do about it.
Fortunately for us, there are no asteroids the size of Texas. I’ll assume that, by a “Texas sized asteroid”, the scientists in Armageddon meant an asteroid with about the same diameter as Texas. The longest straight-line distance in Texas is from Brownsville to the northwest corner of the Texas Panhandle, and is 1289 km. If you’d rather use an east-west distance, the greatest width is 1226 km. The largest asteroid (now considered a dwarf planet) in the solar system is Ceres, which has a diameter of 950 km. Ceres is not on an Earth-crossing orbit. Anything that could put it on an Earth-crossing orbit might also be able to destabilize the orbits of other planets, which means an incoming asteroid, even an almost 1000 km one, is one of the least of our problems.
Any asteroid on course to collide with Earth in a few years and big enough to do global damage would be difficult to do anything about. A more likely deflection scenario would have scientists finding an asteroid a few kilometers in diameter that is going to hit the Earth in 100 years. Of course, that’s not going to make as exciting a plot for a movie. There’s probably a sweet spot somewhere, where the threat is immediate enough to motivate people to put resources into doing something about it, but there’s still enough time that a rocket, solar sail, or what have you could do the job.
One asteroid that generated a fair bit of discussion about the possibility of it impacting Earth is Apophis. It was discovered in 2004, and thought to possibly be on a course to collide with Earth in 2029 or 2036. It was thought at the time to be about 450 m in diameter (estimates later revised to 350 m). We now have better orbital data that shows that it won’t hit the Earth in either 2029 or 2036.
The Bruce Willis and Armageddon was of course illustrating something way out of the realm of possibilities but it is a reference that many people can understand.
However suppose that Apophis was found to be striking the earth in 2029 or 2036?
Could we do something about that in time?
I think that this is one case that would be close to the point where maybe we could do something about it or maybe not
I am only an amateur pundit so that is why I am asking this
Thanks
With Apophis, maybe. We didn’t have that much time (as these things go), but it is a sub-kilometer size asteroid.
That’s one way on interpreting the line from the movie. But suppose you interpret the size of Texas to mean that the surface area of the asteroid is the same as the surface area of Texas. I did the math and, if I didn’t screw up my figures, that would give you an asteroid with a diameter around 450 km.
People who talk about asteroids that might impact Earth usually talk in terms of diameter, not surface area, though. Small asteroids aren’t spherical, so determining their surface area would be tricky.
Also, a 450 km asteroid is still bigger than all but three of the asteroids. None of the asteroids that size are on Earth-crossing orbits, and it wouldn’t be easy to perturb the orbit of something that size.
If any of those very large asteroids were headed for Earth, there’s still nothing we could do about it, especially if they were due to hit soon.