Archive:Earth-impact events: Difference between revisions
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'''Near-Earth objects''' ('''NEO''') are asteroids, comets and large meteoroids whose orbits bring them close to [[w:Earth|Earth]]'s orbit, and which may therefore pose a collision danger. | '''Near-Earth objects''' ('''NEO''') are asteroids, comets and large meteoroids whose orbits bring them close to [[w:Earth|Earth]]'s orbit, and which may therefore pose a collision danger. | ||
On October 7, 2008 a meteoroid called [[w:2008_TC3|2008 TC<sub>3</sub>]] which was 2 - 5 meters (7 - 16 ft) in diameter entered Earth's atmosphere and burned up before it reached the ground. The object had just been discovered about a day before the impact. It exploded tens of kilometers above the ground with the energy of around 1 - 2 [[w:TNT equivalent|kiloton of TNT]], causing a large fireball in the early morning sky over northern [[w:Sudan|Sudan]]. An impact like this happens 2 - 4 times per year, but this is the first time that such an object has been observed and tracked before entering the atmosphere. | * On October 7, 2008 a meteoroid called [[w:2008_TC3|2008 TC<sub>3</sub>]] which was 2 - 5 meters (7 - 16 ft) in diameter entered Earth's atmosphere and burned up before it reached the ground. The object had just been discovered about a day before the impact. It exploded tens of kilometers above the ground with the energy of around 1 - 2 [[w:TNT equivalent|kiloton of TNT]], causing a large fireball in the early morning sky over northern [[w:Sudan|Sudan]]. An impact like this happens 2 - 4 times per year, but this is the first time that such an object has been observed and tracked before entering the atmosphere. | ||
=== Potentially Hazardous Asteroids === | === Potentially Hazardous Asteroids === | ||
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[[Image:Toutatis.jpg|thumb|right|Radar image of 4179 Toutatis]] | [[Image:Toutatis.jpg|thumb|right|Radar image of 4179 Toutatis]] | ||
On September 29, 2004 the asteroid [[w:4179 Toutatis|4179 Toutatis]] made a particularly close approach (within 4 LD, or [[w:lunar distance (astronomy)|lunar distance]]s) from Earth. The next close approach is November 9, 2008, but it will be five times more distant. It is about 4.6 km by 2.4 km in size. | * On September 29, 2004 the asteroid [[w:4179 Toutatis|4179 Toutatis]] made a particularly close approach (within 4 LD, or [[w:lunar distance (astronomy)|lunar distance]]s) from Earth. The next close approach is November 9, 2008, but it will be five times more distant. It is about 4.6 km by 2.4 km in size. | ||
The asteroid 2007 CN26 passed within 0.6 LD of the Earth on September 2, 1985. The size of this object is in the range of 170 - 380 meters in diameter. It was not discovered until February 2007, more than 20 years after the close approach to the Earth. | * The asteroid 2007 CN26 passed within 0.6 LD of the Earth on September 2, 1985. The size of this object is in the range of 170 - 380 meters in diameter. It was not discovered until February 2007, more than 20 years after the close approach to the Earth. | ||
There is some concern that the asteroid [[w:99942 Apophis|99942 Apophis]] could impact earth on April 13, 2036. The probability of a collision is currently esitmated to be 1 in 45,000. These calculations are uncertain due to another close encounter in 2029 which could modify the orbit of the asteroid, making a collision either more or less likely. It is about 210 - 330 meters in size. | * There is some concern that the asteroid [[w:99942 Apophis|99942 Apophis]] could impact earth on April 13, 2036. The probability of a collision is currently esitmated to be 1 in 45,000. These calculations are uncertain due to another close encounter in 2029 which could modify the orbit of the asteroid, making a collision either more or less likely. It is about 210 - 330 meters in size. | ||
The asteroid [[w:2007 VK184|2007 VK184]] is currently estimated to have a probability of 1 in 3,030 of impacting Earth on June 3, 2048. This 130 meter object has the potential of releasing 150 megatons of energy if it were to collide. | * The asteroid [[w:2007 VK184|2007 VK184]] is currently estimated to have a probability of 1 in 3,030 of impacting Earth on June 3, 2048. This 130 meter object has the potential of releasing 150 megatons of energy if it were to collide. | ||
=== Close-Approaches === | === Close-Approaches === | ||
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* [[w:Impact_events#Fictional_impact_events|Fictional impact events]] | * [[w:Impact_events#Fictional_impact_events|Fictional impact events]] | ||
* [[w:Asteroids_in_fiction#Collisions_with_Earth|Fictional asteroid collisions with Earth]] | * [[w:Asteroids_in_fiction#Collisions_with_Earth|Fictional asteroid collisions with Earth]] | ||
* [[w:Off on a comet|Off on a comet]] | * [[w:Off on a comet|Off on a comet]] ([[w:Jules Verne|Jules Verne]] novel) | ||
* [[w:Meteor (film)|''Meteor'']] (1979 film) | * [[w:Meteor (film)|''Meteor'']] (1979 film) | ||
* [[w:Armageddon (1998 film)|''Armageddon'']] (1998 film) | * [[w:Armageddon (1998 film)|''Armageddon'']] (1998 film) | ||
Revision as of 12:30, 19 October 2008
What objects exist in space near the Earth? How often do they collide with our planet? What are the risks of such an impact? Is this something that we should be worried about? Have scientists and journalists done a good job of informing the public? Please read the infomation on this page and visit the links, and then join the /Discussion.
The science of Near-Earth objects
The Solar System consists of the Sun, the planets and their moons, and many smaller objects. These smaller objects include asteroids, comets and large meteoroids. Most of these objects are distant from the Earth and never pass close to our planet. For example, the vast majority of asteroids orbit within the main asteroid belt. But there are objects that are known to approach the Earth very closely, and many have collided with our planet thoughout its history. These Near-Earth objects include some that are potentially hazardous.
Near-Earth objects
Near-Earth objects (NEO) are asteroids, comets and large meteoroids whose orbits bring them close to Earth's orbit, and which may therefore pose a collision danger.
- On October 7, 2008 a meteoroid called 2008 TC3 which was 2 - 5 meters (7 - 16 ft) in diameter entered Earth's atmosphere and burned up before it reached the ground. The object had just been discovered about a day before the impact. It exploded tens of kilometers above the ground with the energy of around 1 - 2 kiloton of TNT, causing a large fireball in the early morning sky over northern Sudan. An impact like this happens 2 - 4 times per year, but this is the first time that such an object has been observed and tracked before entering the atmosphere.
Potentially Hazardous Asteroids
Potentially Hazardous Asteroids (PHA) are Near-Earth asteroids that are big enough to cause unprecedented regional devastation if they were to hit the Earth.
- On September 29, 2004 the asteroid 4179 Toutatis made a particularly close approach (within 4 LD, or lunar distances) from Earth. The next close approach is November 9, 2008, but it will be five times more distant. It is about 4.6 km by 2.4 km in size.
- The asteroid 2007 CN26 passed within 0.6 LD of the Earth on September 2, 1985. The size of this object is in the range of 170 - 380 meters in diameter. It was not discovered until February 2007, more than 20 years after the close approach to the Earth.
- There is some concern that the asteroid 99942 Apophis could impact earth on April 13, 2036. The probability of a collision is currently esitmated to be 1 in 45,000. These calculations are uncertain due to another close encounter in 2029 which could modify the orbit of the asteroid, making a collision either more or less likely. It is about 210 - 330 meters in size.
- The asteroid 2007 VK184 is currently estimated to have a probability of 1 in 3,030 of impacting Earth on June 3, 2048. This 130 meter object has the potential of releasing 150 megatons of energy if it were to collide.
Close-Approaches
| Date | Object Name | Object size | Miss distance |
|---|---|---|---|
| 2008-Oct-03 | 2008 TN9 | 9 - 19 m | 0.6 LD |
| 2008-Oct-07 | 2008 TC3 | 2 - 5 m | impact |
| 2008-Oct-09 | 2008 TS26 | about 1 m | 0.03 LD |
| 2008-Oct-23 | 2008 TT26 | 49 m - 110 m | 3.6 LD |
| 2008-Oct-29 | 2005 VN | 72 m - 160 m | 4.1 LD |
| Date | Object Name | Object size | Miss distance |
|---|---|---|---|
| 2009-Feb-18 | 1999 AQ10 | 240 m - 540 m | 4.4 LD |
See the NASA/JPL Near Earth Object Program for up-to-date information.
In fiction
- Fictional impact events
- Fictional asteroid collisions with Earth
- Off on a comet (Jules Verne novel)
- Meteor (1979 film)
- Armageddon (1998 film)
- Deep Impact (1998 film)
In the news
Current
- Small Asteroid Predicted to Cause Brilliant Fireball over Northern Sudan - October 6, 2008
- Boulder-Size Asteroid to Be Fireball Over Earth Monday - October 6, 2008
- Impact of Asteroid 2008 TC3 Confirmed - October 7, 2008
- Incoming Asteroid Burned Up in Earth's Atmosphere Right on Time - October 8, 2008
- Little Asteroid Makes a Big Splash - October 9, 2008
- For first time, scientists predict arrival of asteroid - October 11, 2008
- Who's watching our skies? - October 12, 2008
Older news
- Near-Earth Asteroid 2007 TU24 to Pass Close to Earth on Jan. 29 - Should be Observable with Modest Sized Telescopes - January 22, 2008
- Asteroid to narrowly miss Earth - January 24, 2008
Commentary
- Asteroids ahead - don't panic - June 6, 1998
- Asteroid False Alarm Shows Limits of Alert Systems - March 8, 2004
- Impact! - March 7, 2007
- The Sky Is Falling. Really. - March 16, 2007
- The Sky Is Falling - June 2008
- What 'Deep Impact' might an asteroid make on Earth, astronauts ask - September 25, 2008
- Will an asteroid destroy Earth? Time for U.N. to keep tabs, say experts - September 25, 2008
- Death by meteorite - October 13, 2008