PDA

View Full Version : Today, March 23rd, is "Near Miss Day"



Humanist
2010-03-23, 11:40
On March 22nd, 1989, asteroid 4581 Asclepius (http://newton.dm.unipi.it/neodys/index.php?pc=1.1.0&n=4581), came within spitting distance of the earth. When it passed, it was only 700,000km off the necessary trajectory, or 2x the distance between the earth and the moon.

There have since been other extremely close calls (http://www.youtube.com/watch?v=8zQH4__EIo0). Considering that an impact of a sufficiently sized object would be the end of civilization as we know it, what sort of asteroid deflection/intercept strategies would you propose the governments of the world develop? Of course, any deflection/intercept strategy would also require consideration of the existing and potential NEO/NEA (Near Earth Object/Asteroid) detection technologies.

Apophis is set to give us another scare, in a couple of decades: Apophis 99942: The Killer Asteroid of 2036 (http://www.youtube.com/watch?v=zazuzkO9nNk&feature=related).
(99942) Apophis (http://newton.dm.unipi.it/neodys/index.php?pc=1.1.0&n=99942)

rogers
2010-03-23, 12:37
On March 22nd, 1989, asteroid 4581 Asclepius (http://newton.dm.unipi.it/neodys/index.php?pc=1.1.0&n=4581), came within spitting distance of the earth. When it passed, it was only 700,000km off the necessary trajectory, or 2x the distance between the earth and the moon.

There have since been other extremely close calls (http://www.youtube.com/watch?v=8zQH4__EIo0). Considering that an impact of a sufficiently sized object would be the end of civilization as we know it, what sort of asteroid deflection/intercept strategies would you propose the governments of the world develop? Of course, any deflection/intercept strategy would also require consideration of the existing and potential NEO/NEA (Near Earth Object/Asteroid) detection technologies.

Apophis is set to give us another scare, in a couple of decades: Apophis 99942: The Killer Asteroid of 2036 (http://www.youtube.com/watch?v=zazuzkO9nNk&feature=related).
(99942) Apophis (http://newton.dm.unipi.it/neodys/index.php?pc=1.1.0&n=99942)


Do you know how big it is?

Froll
2010-03-23, 13:45
Apophis is set to give us another scare, in a couple of decades: Apophis 99942: The Killer Asteroid of 2036 (http://www.youtube.com/watch?v=zazuzkO9nNk&feature=related).
(99942) Apophis (http://newton.dm.unipi.it/neodys/index.php?pc=1.1.0&n=99942)

If only.

JaM
2015-10-24, 01:04
Another near miss on Halloween, https://en.wikipedia.org/wiki/2015_TB145
It was discovered very late, just 10 October! According to some sources, it will be visible even through a relatively small telescope! The size estimate varies quite a bit, but it's relatively big, estimated to be 280-620 m wide, according to Wikipedia. Nasa says ~400m, and that it could be more like a comet than an Asteroid.

It moves in a different plane than Earth, and if it had happened to hit the Earth, it would have been at a very high speed, due to the orbit. It's good that it doesn't, because it would have been much more destructive than the aforementioned Apophis asteroid.

Normally it would take a 1 km Asteroid to disrupt life on earth world wide, but this one moves faster than usual, which makes it more destructive than its size would suggest - so it could have had global effects to some degree. The encounter speed is almost 3 x faster than the estimated impact speed of Apophis! If it is the size of the largest size estimate, and if it has the same density, then it would be ~50 x the energy compared with Apophis.

It just shows that we don't know all the sizeable earth crossers at this moment, and that we may get a very short notice before it hit, even if it has enough energy to cause global effects.

JaM
2015-10-24, 14:03
Apparently it is not the only one, another one will pass on 29 Oct. That one is much farther away, and it has been known for years, though.
https://en.wikipedia.org/wiki/(410777)_2009_FD
It cannot be seen from earth, as it's too far away. It is supposedly of a similar size as the asteroid 2015 TB145 mentioned above.