What are the chances of a asteroid destroying earth?

Answer 1

Thousands of asteroid have been mapped, but none are soon to be hitting the earth. The closest to a near hit will be Apohphis in 2036.

Based upon the observed brightness, 99942 Apophis's length was originally estimated at 415 m (1350 ft); a more refined estimate based on spectroscopic observations at NASA's Infrared Telescope Facility in Hawaii by Binzel, Rivkin, Bus, and Tokunaga (2005) is 320 metres (1050 feet). Its mass is estimated to be 4.6×10^10 kilograms.

Apophis belongs to a group called the "Aten asteroids", asteroids with an orbital semi-major axis less than one astronomical unit. This particular one has an orbital period about the Sun of 323 days, and its path brings it across Earth's orbit twice on each passage around the Sun.

From your question it is clear that you are concerned about the possibility of an impact and how devastating that might be.

The chance of Apophis hitting us is very low, a near miss in 2029 will show how close the estimated hit in 2036 will be. The initial reports resulted in widespread discussion on many Internet forums, including armchair speculation about exactly where Apophis (then known only as 2004 MN4) would hit and what would happen when it did.

NASA initially estimated the energy that Apophis would have released if it impacted Earth as the equivalent of 1480 megatons of TNT. A more refined later NASA estimate was 880 megatons. The impacts which created the Barringer Crater or caused the Tunguska event are estimated to be in the 10-20 megaton range. The 1883 eruption of Krakatoa was the equivalent of roughly 200 megatons.

The exact effects of any impact would have varied based on the asteroid's composition, and the location and angle of impact. Any impact would have been extremely detrimental to an area of thousands of square kilometres, but would have been unlikely to have long-lasting global effects, such as the initiation of an impact winter.

The bigger threat is in 2880 and is from asteroid 29075 1950 DA. It is 4 times the diameter and thus ~64 times the volume of Apophis. Potentially more damaging consequences, therefore. If there were to be an impact.

Radar observations at the Goldstone and Arecibo Observatory from March 3 to 7, 2001 during the asteroid's 7.8 million km approach to the Earth give a mean diameter of 1.1 – 1.4 km. Optical lightcurves by Petr Pravec show that the asteroid rotates every 2.1216 hours.

Due to its short rotation period, 1950 DA is thought to be fairly dense (more than 3.0 g/cm³).

If 1950 DA continues on its present orbit, it will approach near to the Earth on March 16, 2880. One trajectory estimate misses the Earth by tens of millions of kilometers, while the other has an impact probability of 1⁄300. The radar observations are currently being reanalyzed, in combination with the optical lightcurves.

The energy released by a collision with an object the size of 1950 DA would cause major effects on the climate and biosphere which would be devastating to human civilization.

At a range of 50 km, almost all buildings are knocked down and your clothes are set on fire. Magnitude 6.8 earthquake, which will be minimum compared to the shockwave in the air.

At 100 km, the fireball is 5 times brighter than the sun but does not set your clothes on fire. The blast will be as lound as heavy traffic, and will shatter glass windows. 6.8 on the richter scale, which scares everyone but does not damage buildings that are up to building code.

So it destroys an area larger than Rhode Island, but smaller than Conneticuit. The Earth is not significantly perturbed by this blast, although the country that gets hit will be.

Impacts like this happen once every 38000 years on average.

These numbers are based on a pessimistic interpretation of NASA's most recent figures from their website. Actual impact may be less destructive.

The scary ones are the ones NOT mapped, especially the ones who's orbits come from behind the sun, at which time we'll only have about 2 years advance notice, little time to launch interdiction rockets or satellites. BTW nukes have been ruled out in eliminating the planet killers, since they'd create worse devastation on the earth, anyway, sleep tight.

Answer 2

At any given time, the chances of a large asteroid hitting the Earth are extremely small. Based on estimates of the numbers of various sizes of asteroids, an asteroid capable of destroying the entire ecosystem hits the Earth every 100 million years or so. So, the chances of an extinction-causing asteroid of hitting the Earth in the average human lifetime are about one in a million. Smaller asteroids may hit the Earth more often. An asteroid capable of destroying a city may hit the Earth as often as once per century. But there is no need for panic - the fraction of the Earth's surface inhabited by humans is very small. Any asteroid is much more likely to hit the ocean than land, and so we may not even notice if one of these small asteroids were to hit the Earth.
On June 30, 1908, an explosion rocked the Siberian forests near Tunguska. Trees were flattened over 2100 square kilometers (approximately a nine mile radius). Reports of a fireball streaking across the sky prior to the explosion were also recorded. The nature of this event has been debated for a long time, but the vast majority of reputable scientists now agree that the Tunguska event was caused by the explosion of a stony asteroid or a comet in the air above the blast zone. The explosion had about the same energy as a 40-megaton nuclear bomb. Scientists continue to study both the explosion and its aftermath in order to understand what happens when an asteroid impacts the Earth.

Over time, large asteroids will hit the Earth, but it may be millions of years before the next one occurs. Therefore, we as humans need to be concerned about the possibility of an impact, but we do not need to worry or panic about this. Most likely, we have thousands of years to think about impacts and develop a plan of attack should an asteroid or comet threaten the Earth.

Answer 3

G'day Leoness,

Thank you for your question.

It would be a possiibility for a large object to hit earth causing it to split apart. There are a number of earth-crosser asteroids that could collide. More likely are significant impacts which would cause massive tidal waves and/or lead to large amounts of dust cooling temperatures significantly. There have been a number of significant impacts leading probably to the formation of the moon and the extinction of the non-avian dinosaurs. There is a one in 43,000 chance of an impact with 99942 Atrophis in 2036 and a greater chance in 2880 (one scenario has one in 300).

I have attached sources for your reference.

Seasons regards

Answer 4

Since you haven't put a time limit on it I'd say the
chances are about 100%. Now "destroy" has many meanings.
Some would think of destruction as a total obliteration of
the physical planet. That's unlikely. Others might think of it as
the end of all life. That's also unlikely since rats will easily
inherit the earth. And lastly, some will think of the end of the
earth as the death of all mankind. That's quite easy to see.
I just hope that there's one small primitive tribe of Amazonian
Indians or an obscure band of Australian Aborigines or
a couple of Eskimo families left to start us all over again.
And with that statement I enter the world of Yahoo Answers
as a Level 5 participant. I have 4999 points and this puts me over the top.

Answer 5

Hi. Destroying Earth? 0%. Destroying life on Earth? 100%. Of course you may have to be patient.

Answer 6

i will furnish Earth a 50/50 possibility. on the day after, I guess 0.5 the planet documents for financial ruin. i think of that if Earth is at peace(i advise ,no wars are happening on the time), we would have a seventy 5/25 possibility in our prefer. yet while Micheal Jackson succeeds in Las Vegas, then all desire is lost for us.

Answer 7

crikey, the chances of that happening are slim but anything is possible... its categorized as an ELE, Extinction Level Event. i think a rock a mile in diameter is equivalent to a 100,000 megaton bomb, so it'd definitely be a disaster... not the end of earth but definitely the end of many species, humans included.

Answer 8

depends on size, velocity, density, and the way it hits ?

i found this
http://neo.jpl.nasa.gov/risk/

i think if you dig in there you get all you want to know

my personal opinion:
no need to worry
-space is called space cause its basically empty space.
-the majority of objects already hit us
-i've not yet figured where to find the real love in life and i would call it unfair if such a piece of dirt would end my affords in such an unsatisfying way

Answer 9

Apparently the likelihood is less than one occurrence in 4.5 billion years.

Answer 10

I don't know about the chances of it happening, but if you wanna see what goes down when it does happen, try this:


http://www.lpl.arizona.edu/impacteffects/