Two asteroids passed close to Earth Wednesday

Apr 07, 2011 By Nancy Atkinson
These are not the two asteroids that passed by Earth on Wednesday -- but is an illustration of a binary asteroid. Credit: ESO/L. Calcada

Earth got a double dose of close asteroid flybys on Wednesday, April 6, 2011. Two newly discovered small asteroids both passed within the distance of the Moon.

2011 GW9 (10 meters wide) came within half the distance to the , about 192,000 km 12:53 a.m. EDT and 2011 GP28 (6 meters wide) came within 77,000 km (.2 LD) at 3:36 p.m. EDT.

Spaceweather.com said the size of these asteroids are two to three times smaller than the Tunguska impactor of 1908, and assured there was no danger of a collision with Earth.

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Quantum_Conundrum
3.4 / 5 (5) Apr 07, 2011
the size of these asteroids are two to three times smaller than the Tunguska impactor of 1908, and assured there was no danger of a collision with Earth.


Things to take note of:

1) An airburst 1/2 or 1/3 the size of Tunguska whould still kill many millions if it happened over a large city.

2) The objects were discovered on the 4th of April of this year, two days before their closest approach, so they were not detected until it would have been far too late to respond had they been on a collision course.

3) Again, even a 10 meter asteroid has the potential to kill several million people in the worst case scenario. This was a very close call by comparison to the potential losses, and nobody even mentioned it, and nobody "really" has any plan to deal with this issue.

Impact velocity would have been perhaps 15km/s had it been on a collision course.

If the rock has a density of 3g/cm, then it would be a 42kiloton explosion, or ~4 x atomic bombs: A city killer.
apex01
1 / 5 (1) Apr 07, 2011
QC, i think the possibility of an asteroid hitting a city is same as trying to hit a 3' x 3' window with a rock a mile away.
gumpdy
5 / 5 (2) Apr 07, 2011
I think a good asteroid impact during our current times will take a great deal of people out of their bubble modern society and make them realize how fragile we and our earth really are. Maybe then it would mean less politics in the environmental debates.
SteWe
3 / 5 (1) Apr 07, 2011
What a crap!
Worst case of a 10m asteroid:
72km/h impact, 8000kg/cbm, 90° impact
Effect:
"The projectile begins to breakup at an altitude of 37300 meters = 122000 ft
The projectile bursts into a cloud of fragments at an altitude of 15900 meters = 52000 ft.
The residual velocity of the projectile fragments after the burst is 47.4 km/s = 29.4 miles/s.
The energy of the airburst is 6.16 x 10^15 Joules = 1.47 x 10^0 MegaTons.
Large fragments strike the surface and may create a crater strewn field."
Means 1500t TNT at 16km heigt - no effect on the ground!
www.purdue.edu/impactearth
TheGhostofOtto1923
3.7 / 5 (3) Apr 07, 2011
What a crap!
Worst case of a 10m asteroid:
72km/h impact, 8000kg/cbm, 90 impact
Effect:
"The projectile begins to breakup at an altitude of 37300 meters = 122000 ft
The projectile bursts into a cloud of fragments at an altitude of 15900 meters = 52000 ft.
The residual velocity of the projectile fragments after the burst is 47.4 km/s = 29.4 miles/s.
The energy of the airburst is 6.16 x 10^15 Joules = 1.47 x 10^0 MegaTons.
Large fragments strike the surface and may create a crater strewn field."
Means 1500t TNT at 16km heigt - no effect on the ground!
http://www.purdue...actearth
Depends on composition, speed, angle, etc. What made barringer crater was only 2x your example when it hit, 4x when it entered the atmosphere:
http://www.space....ved.html
paulthebassguy
not rated yet Apr 07, 2011
There was also another meteor that came closer and exploded over New Zealand on the 30th of March too!

http://www.stuff....h-Island
dan42day
3 / 5 (2) Apr 07, 2011
QC, i think the possibility of an asteroid hitting a city is same as trying to hit a 3' x 3' window with a rock a mile away.


If 50cal ball ammo can be considered a rock, I could do that easily.
CarolinaScotsman
5 / 5 (3) Apr 08, 2011
Two asteroids...hmmmmm. Reminds me of the three statisticians who took up bow hunting. They saw a deer. First one's arrow was ten feet to the left. Second one's arrow was ten feet to the right. Third one started jumping up and down and yelling, "We got it!"------- First asteroid was 200,000 miles to the left...
6_6
1 / 5 (1) Apr 09, 2011
More chances of calamities due to our own negligence with regard to the planet's welfare than "deep-impact" worries.