Why havent we encountered any life threatening asteroids yet?

Answer 1

One of the answerers provided a link to an article about 2002 MN, an object which came within around 120,000 km in June 2002 and mentioned that 6 objects had passed between us and the Moon. In fact as the link below at the Minor Planet Center shows, there have been nearly 50 objects known to pass between the Earth and the Moon. Admittedly most of these observations are more recent than 2002, reflecting the increasing tempo of our asteroid survey projects. 2002 MN remains the largest object known to have passed within the Moon's orbit, though 2004 XP14, which is around 300 m in diameter did pass just outside the Moon's orbit (1.1 LD) in July 2006. The host of close passes noted in recent years have been in the size range of a few meters to a few tens of meters. These could create a bit of a bang and something the size of 2002 MN could devastate a city. (99942) Apophis will beat 2002 MN for largeness and closeness when it passes at about 38,000 km in 2029. Maybe by then we will have been hit by something that makes a sizeable bang but the current estimates based on our asteroid surveys to date put the probability of a Tunguska-sized impact at around 1 every 1000 years. The basic fact is that the bigger ones we can observe hit so infrequently while the smaller ones are difficult to see except when they are close.

Answer 2

Because human history only goes back a few million years,a relative"blink of an eye"in Earth's history.65 mya,a large asteroid wiped out the dinosaurs.50,000 years ago,Meteor crater inArizona was caused by an impact.In 1908,a meteor or comet exploded over Tunguska ,Siberia,luckily one of the most remote places on Earth.had it come a few hours sooner or later,the earth's rotation may have been such that it would have impacted a city with an explosion equal to 1000's of atomic bombs.In the 60's,a lady was actually hit when a small meteorite crashed into her.In the 80's,the US went to defcom 4 for a while because one exploded over the Atlantic,this was duringa period called "the cold war"and we didn't know if we had been attacked.

Also,we DO NOT KNOW where all the asteroids are.Asteroid hunting only got serious attention after comet Shumaker-levy broke into pieces and impacted Jupiter,one impact causing a fireball larger than planet earth.There is now an effort to find and track all NEO's.Most scientists feel we still haven't located 100,000 of them yet.The ones we have located and tracked appear to pose no imminent threat.One could be on the way right now that we simply haven't detected yet.

Lastly,if one were detected,put yourself in ANY governments place.Of what possible good would it do to let that info out?It would bring an immediate breakdown of society worldwide,anarchy.I expect if the govt knew of any extinction level event,it would by worldwide governmental agreement be classified above super top secret.that knowledge getting out would destroy life before the meteor had a chance to

Answer 3

We are just lucky. Space is a huge place. A collsion between heavenly bodies are not a very common thing. Earth do get hit occasionally by asteroids. The last one wiped out the dinosaures and there were others before that. Looking at fossil record, it happens about every 65 million years or so. Guess what, it has been about 65 million years since the dinosaures were wiped out. So we are due for a hit any day now, plus minus a million years of so.

Answer 4

In the early history of the solar system, asteroid collisions with the Earth were very common. Now most of these rocks have been mopped up and big ones only occur every 100 million years.

Answer 5

We have some close calls like the one that hit Russia in early 1900's. caused a whole forest to flatten. There was a story on a asteriod come in our direction in around the year 2011-2012. They say it will come between the earth and the moon which is very close. i don't know what the details on that is now, this story was a couple of years ago.

Answer 6

we havn,t encountered any life threatening asteroids yet because their is no such asteroid which is going to become threat to earth as told by scientists in the near future.

Answer 7

The Earth has.. that's what took out the dinosaurs (well technically it was a comet, but it's happened before)

We must remember that humans have only existed for a tiny amount of time, compared to the age of the planet. The frequency of such major events isn't that high.

Answer 8

Well, I'm not really sure. The best I can say is LUCK. And just how the Earth spins. Not much of our asteroid layer are that close to hitting us.

Answer 9

We, as in individuals, or as the species Homo sapiens? Either way it is because we have not been around long enough, just be patient. The planet certainly has encountered some pretty large impacts.

Answer 10

Think about it.The powers that be aren't going to tell the general community that life as we know it nearly came to an end due to a near miss.That fact in itself could have serious consequences.It must happen from time to time because they even have a name for a near miss.Its called a bullet burn.
If we do get a direct hit the only questions we will be asking will be at Gods House.