Impacts by Comets and Asteroids
Close approaches predicted for the next 2 months - plus list of recent - NASA - Near Earth Object Program
Table of the known closest approaches during the next year.- NASA - Near Earth Object Program
The 60+ fragments of Comet 73P/Schwassmann-Wachmann 3
Simulation results of asteroid / comet impacts for an average million years
| ASTEROID
DIAMETER
(m or km) |
No. OF EVENTS | No. OF FATAL EVENTS | % FATAL | TOTAL
FATALITIES |
AVERAGE FATALS PER YEAR * | AVERAGE FATALS PER FATAL EVENT | ANNUAL
RISK OF FATAL EVENT
1 in ... |
AVERAGE YIELD PER FATAL EVENT (Mt of TNT) |
| 0-99m |
8563
|
2619
|
31%
|
240
million
|
240
|
92,000
|
382
|
30
|
| 100-199m |
1065
|
736
|
69%
|
230
million
|
230
|
310,000
|
1359
|
300
|
| 200-499m |
311
|
295
|
95%
|
530
million
|
530
|
1.8
million
|
3390
|
3,900
|
| 500-999m |
45
|
44
|
98%
|
620
million
|
616
|
14
million
|
22727
|
29,000
|
| 1-1.9km |
14
|
14
|
100%
|
2.5
billion
|
2500
|
180
million
|
71429
|
220,000
|
| 2km+ |
2
|
2
|
100%
|
3.5
billion
|
3460
|
1.7
billion
|
500000
|
2,000,000
|
|
All
|
10000
|
3710
|
37%
|
7.6
billion
|
7576
|
2
million
|
270
|
2,600
|
Earth Impact Effects Program - Impact effects - put in your own figures and they calculate the effects.
final_eltanin.pdf - Impact tsunami calculations for the Eltanin impact 2.5 million years ago.
During the last few years it has become widely recognized that from time to time the Earth is hit by large objects from space. These are now known to be responsible for what are called 'extinction events' when most of the then existing life forms went extinct suddenly.
The Earth is traveling through space at quite high speed, orbiting around the Sun - and the Sun is orbiting the centre of the galaxy. Luckily, the Earth's atmosphere protects us from the small bits of debris that are being swept up by the Earth all the time.
The danger depends on the collision speed and the weight of the object. Any object falling on the Earth from space will end up doing 25,000 miles an hour before it hits the ground. This is seven miles per second. This is due to the Earth's gravity.
So that is the minimum speed of objects colliding with the Earth - a more likely collision would be one where the Earth gets in the way of an object falling into the Sun; which has much more powerful gravity, so the impact speed will be several times higher perhaps 20 or 40 miles per second. The worst case would be an object that has just done a 'slingshot' style near miss of the Sun. Such an object would be very hard to spot coming, since it would be close to the Sun in the sky, and it would be traveling at very high speed and would therefore arrive very quickly., and therefore unlikely to be seen.
The other main factor, the weight of the object, is fairly unlimited. Asteroids are objects big enough to be observed orbiting the Sun but too small to be called a planet. There is a belt of debris between the orbits of Mars and Jupiter. This stuff is possibly the remains of a destroyed planet. Most of it is between Mars and Jupiter in fairly stable orbits but not all of it. Some asteroids are in crazy orbits and some have been captured as moons by other planets. Mars has two in orbit and has no doubt been hit by many others. The largest is 500 miles across but most are much smaller. Small objects fall to Earth quite often, we call then shooting stars or meteorites, and they are just tiny asteroids. Some are made of rock and others are lumps of iron.
The object that killed off the dinosaurs may have been a lump of iron the size of a mountain traveling at about 30 miles per second. With an impact at that speed the energy of the collision is enormous and cannot be carried away by shock waves because shockwaves travel much slower than the impact speed. Enormous quantities of heat are generated which vaporize most of the impacting object and a similar amount of the Earth. The effect of this is similar to a nuclear explosion, but much larger, with a hole punched right through the crust and a crater a 100 miles across. The fireball will burn everything for huge distances, blastwaves in the atmosphere and ground waves through the earth will go round the Earth several times. If you survive the first ones you will hear and feel the impact several times as it reverberates around the planet.
The secondary effects will be tidal waves, freak winds, the sky darkened by dust, and heavy rain (if some of the sea was vaporized). The atmosphere may become close to unbreathable in some cases due to dust and volcanic gases - and the weather may be very cold for many years. Another big killer, that I have only recently become aware of, is the sky becoming red hot due to millions of tons of material ejected by the impact explosion falling back to earth from space. The diagram below is from New Scientist magazine 19th April 2003 - the whole article.
Comets come from deep space and are frozen lumps of rock and ice - the main difference between asteroids and comets is only that if it has a "tail" (a trail of dust and gas coming off it) it is called a comet. They can be just as massive as asteroids and may be traveling even faster. It is no help to be hit by a massive lump of ice. The heat of the impact is just the same as for the same weight of iron and therefore the explosion is the same size too. The only difference would be a lot more rain afterwards rather than a hail of molten iron and rock.
The most massive object known to have hit the Earth was the size of the planet Mars. We know it happened because after the impact some material splashed out to form a blob orbiting the Earth - and we now call it the Moon. This happened soon after the Earth first formed and must have completely liquefied the Earth and made it somewhat larger. No one would survive an impact like that; but there are reasons to think that most of these very serious impacts happened soon after the planets first formed. The orbits of all the very large objects orbiting the Sun seem to have been stable now for 100s of millions of years and we can hope they will stay that way.
An asteroid, named 2002-NT7, 1.5 miles (2km) in diameter travelling at 17 miles/second (28 km/sec) it was predicted it could hit the Earth on 1st Feb 2019. [See the links page for the updates]
The Kuiper Belt and The Oort Cloud
New Telescope to Revolutionize Asteroid Warning System
Possible
impact events described in the book of Revelation
8:7 "hail and fire mixed with blood hurled down upon the earth.
A third of the earth burned up" - this could be impact ejecta
from an impact large enough to blast debris right out of the atmosphere,
which then rains back down again. (See "turning and burning"
on this page )
8:8 "something like a huge mountain, all ablaze, was thrown
into the sea" - an asteroid, several miles across, impacts
into an ocean.
8:10 "a great star, blazing like a torch, fell from the sky"
- an asteroid or comet discovered by the Wormwood project perhaps
- (http://www.ips.gov.au/IPSHosted/neo/index.html
) ( http://www.exodus2006.com/learmonth.htm
)
8:12 "a third of the day was without light" - an impact
winter, the sky is dark with dust and smoke, or it could be volcanic.
9:1 "a star that had fallen from the sky to the earth"
- another asteroid impact, this one goes deep, perhaps made of iron.
16:21 "a hail of stones each weighing 100 pounds" -
a broken-up comet perhaps.
