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Tuesday, February 5, 2013

Asteroid to Almost Hit Earth In 10 Days

Posted by on Tue, Feb 5, 2013 at 7:57 AM

Time:

What’s got a lot of cosmic worriers glancing skyward this month was the announcement that on Feb. 15, a 148-ft. (45 m) long asteroid known as 2012 DA 14 will pass just 17,200 mi. (27,7000 km) above the Earth. And if 17,200 miles sounds like a lot, consider that it’s only one-thirteenth of the distance to the moon and actually below the 22,000 mi. (35,800 km) altitude at which some of our satellites orbit. That leaves awfully little margin for error in NASA’s cosmic calculations. So there’s plenty of reason to worry, yes? Well, no, actually. But making that call for any one object—knowing which space bullets are likely to hit us and which ones we’re likely to dodge—can be a complicated business.
In this case, a miss is not as good as mile. A miss is much more unsettling than a mile. And if you want to be unsettled even more, visit NASA‘s Near-Earth Object Program website. It lists all of the known objects that, in the near future, will come near to our one and only world.

 

Comments (17) RSS

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Matt from Denver 1
I'm still more concerned about what humans are doing yo Earth. All this project has shown is that asteroids pass us closely all the time.
Posted by Matt from Denver on February 5, 2013 at 8:19 AM · Report this
Joe Szilagyi 2
Maybe if an asteroid takes out a US city they'll reallocate Homeland Security cash into a new War on Outer Space. I would apply in a heartbeat to work for the Department of Homeworld Security.
Posted by Joe Szilagyi http://twitter.com/joeszi on February 5, 2013 at 8:41 AM · Report this
Urgutha Forka 3
How much damage would a 45 meter asteroid do if it hit the planet?
Posted by Urgutha Forka on February 5, 2013 at 8:41 AM · Report this
rob! 4
@3, you'd notice it in your neighborhood. Just as a quick comparison, the Arizona meteor crater, 0.75 mile across, is thought to have been produced by a 50-meter object (which lost about half its mass during re-entry). Composition as well as speed and angle of impact are some obvious variables.
Posted by rob! http://www.youtube.com/watch?v=QZBdUceCL5U on February 5, 2013 at 9:00 AM · Report this
5
And if you actually go to that website you'll see the odds of any of those NEO's hitting earth are pretty steep. Man continues to be the number one threat against man in the short, medium, and long term.
Posted by johnjjeeves on February 5, 2013 at 9:01 AM · Report this
Joe Szilagyi 6
@3 let's say this asteroid hits 1 mile from you.

http://impact.ese.ic.ac.uk/ImpactEffects…

Using standard values from them:

Your Inputs:

Distance from Impact: 1000.00 meters ( = 3280.00 feet )
Projectile diameter: 45.00 meters ( = 148.00 feet )
Projectile Density: 1500 kg/m3
Impact Velocity: 17.00 km per second ( = 10.60 miles per second )
Impact Angle: 45 degrees
Target Density: 2500 kg/m3
Target Type: Sedimentary Rock
Energy:

Energy before atmospheric entry: 1.03 x 1016 Joules = 2.47 MegaTons TNT
The average interval between impacts of this size somewhere on Earth is 342.4 years
Major Global Changes:

The Earth is not strongly disturbed by the impact and loses negligible mass.
The impact does not make a noticeable change in the tilt of Earth's axis (< 5 hundreths of a degree).
The impact does not shift the Earth's orbit noticeably.
Atmospheric Entry:

The projectile begins to breakup at an altitude of 72500 meters = 238000 ft
The projectile bursts into a cloud of fragments at an altitude of 15100 meters = 49700 ft
The residual velocity of the projectile fragments after the burst is 6.71 km/s = 4.17 miles/s
The energy of the airburst is 8.73 x 1015 Joules = 2.09 x 100 MegaTons.
No crater is formed, although large fragments may strike the surface.
Air Blast:

What does this mean?

The air blast will arrive approximately 46 seconds after impact.
Peak Overpressure: 3160 Pa = 0.0316 bars = 0.449 psi
Max wind velocity: 7.35 m/s = 16.4 mph
Sound Intensity: 70 dB (Loud as heavy traffic)
More...
Posted by Joe Szilagyi http://twitter.com/joeszi on February 5, 2013 at 9:09 AM · Report this
7
@3: http://impact.ese.ic.ac.uk/ImpactEffects… lets you play with parameters. We know this one's a silicate asteroid, so the density's low. Assuming normal asteroidal speed and an average 45 degree impact, this one would have really minimal impact. Here's the results I got for being just 100 km away: http://impact.ese.ic.ac.uk/cgi-bin/crate…
Posted by Sean on February 5, 2013 at 9:12 AM · Report this
8
Ninja'd by @6!
Posted by Sean on February 5, 2013 at 9:13 AM · Report this
Joe Szilagyi 9
60 meter asteroid; glass windows shatter at 1 mile from impact.

http://impact.ese.ic.ac.uk/cgi-bin/crate…

100 meter asteroid:

http://impact.ese.ic.ac.uk/cgi-bin/crate…

Multistory wall-bearing buildings will collapse.
Wood frame buildings will almost completely collapse.
Multistory steel-framed office-type buildings will suffer extreme frame distortion, incipient collapse.
Highway truss bridges will collapse.
Highway girder bridges will collapse.
Glass windows will shatter.
Cars and trucks will be largely displaced and grossly distorted and will require rebuilding before use.
Up to 90 percent of trees blown down; remainder stripped of branches and leaves.

Posted by Joe Szilagyi http://twitter.com/joeszi on February 5, 2013 at 9:16 AM · Report this
Joe Szilagyi 10
If you up the values to 100,000 meters wide (a 56 mile wide asteroid) and have it hit Chicago, this is what happens to Seattle, in order.

Time for maximum radiation: 57 seconds after impact

Visible fireball radius: 657 km ( = 408 miles )
The fireball appears 74.6 times larger than the sun
Thermal Exposure: 8.09 x 109 Joules/m2
Duration of Irradiation: 3.5 hours
Radiant flux (relative to the sun): 643

Effects of Thermal Radiation:

Clothing ignites
Much of the body suffers third degree burns
Newspaper ignites
Plywood flames
Deciduous trees ignite
Grass ignites

The major seismic shaking will arrive approximately 6.67 minutes after impact.
Richter Scale Magnitude: 11.6 (This is greater than any earthquake in recorded history)
Mercalli Scale Intensity at a distance of 2000 km:

VI. Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight.

VII. Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken.

The ejecta will arrive approximately 12.7 minutes after the impact.
At your position there is a fine dusting of ejecta with occasional larger fragments
Average Ejecta Thickness: 9.64 meters ( = 31.6 feet )
Mean Fragment Diameter: 1.65 mm ( = 0.648 tenths of an inch )

The air blast will arrive approximately 1.68 hours after impact.
Peak Overpressure: 1.74e+06 Pa = 17.4 bars = 247 psi
Max wind velocity: 1030 m/s = 2300 mph
Sound Intensity: 125 dB (Dangerously Loud)
Damage Description:

Multistory wall-bearing buildings will collapse.
Wood frame buildings will almost completely collapse.
Multistory steel-framed office-type buildings will suffer extreme frame distortion, incipient collapse.
Highway truss bridges will collapse.
Highway girder bridges will collapse.
Glass windows will shatter.
Cars and trucks will be largely displaced and grossly distorted and will require rebuilding before use.
Up to 90 percent of trees blown down; remainder stripped of branches and leaves.

But if you live through all that? You WIN.
More...
Posted by Joe Szilagyi http://twitter.com/joeszi on February 5, 2013 at 9:19 AM · Report this
Joe Szilagyi 11
I love how they included this:

VI. Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight.


In the midst of being engulfed by a hell on Earth living rolling fireball of nuclear level doom that is wider than the horizon, having burning 30 foot chunks of Chicagoland soil raining down on our heads, and getting razed by an air blast moving at Mach 3, all the while dealing with a 2012-film level 11.6 earthquake that probably just activated the entire Ring of Fire and caused every volcano from Vancouver to California to probably Yellowstone to erupt.

My poor living room's feng shui.
Posted by Joe Szilagyi http://twitter.com/joeszi on February 5, 2013 at 9:24 AM · Report this
Max Solomon 12
we're going to get hit by one sooner or later. you should pray they're only this big, and that it hits somewhere useless like kamchatka or eastern australia.

the last big one to hit the PNW gave us the basalt flows of central wa, the snake river plan, and it still giving us yellowstone.
Posted by Max Solomon on February 5, 2013 at 9:31 AM · Report this
Matt from Denver 13
@ 12, it will be a lot more likely to land in the ocean and cause a tsunami.
Posted by Matt from Denver on February 5, 2013 at 10:29 AM · Report this
Urgutha Forka 14
Cool!

I hope it heads directly for the Westboro Baptist Church.
Posted by Urgutha Forka on February 5, 2013 at 10:46 AM · Report this
Will in Seattle 15
Hey, I got an idea!

Let's sequester the NASA budget so that we don't know we're all going to die, and spend it on stupid wars on the other side of the world that make no sense!
Posted by Will in Seattle http://www.facebook.com/WillSeattle on February 5, 2013 at 11:28 AM · Report this
doloresdaphne 16
I secretly wish for one to hit earth

(what's wrong with me)?
Posted by doloresdaphne on February 5, 2013 at 12:18 PM · Report this
lark 17
Charles,
I've telescope and my hope is to see it pass. Although, I'm dubious I will. Still, I think it a cool event.
Posted by lark on February 5, 2013 at 5:51 PM · Report this

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