An Empirical Study
Ali Rahimi, Ben Recht, Jason Taylor, Noah Vawter
17 Feb 2005
Posted on 12/09/2005 9:07:47 AM PST by emiller
LONDON — Scientists are monitoring the progress of a 390m-wide asteroid discovered last year that is potentially on a collision course with the planet, and are imploring governments to decide on a strategy for dealing with it.
The National Aeronautics and Space Administration has estimated that an impact from Apophis, which has an outside chance of hitting the Earth in 2036, would release more than 100,000 times the energy released in the nuclear blast over Hiroshima.
Thousands of square kilometres would be directly affected by the blast but the whole of the Earth would see the effects of the dust released into the atmosphere. In Egyptian myth, Apophis was the ancient spirit of evil and destruction, a demon that was determined to plunge the world into eternal darkness.
The experts fear that there is very little time left to decide.
(Excerpt) Read more at todayonline.com ...
It's 240,000 miles to the moon. So that would be about one-tenth the distance to the moon. I'm sure the calculation will be more firmed up as time goes by.
There is also a new mission to the Kuiper belt in the works. The activity centered on asteroids and comets is not exactly for scientific purposes, but more like prospecting to see what materials might be out there, and to see what the physical structure of these bodies might be so techniques can be designed to mine and produce useful materials for space development. At the same time, those techniques might be useful for moving comets and asteroids that might be in danger of approaching earth and other future space facilities.
Beat me to it.
But for those who wonder what this asteroid could do.
Impact Effects
Robert Marcus, H. Jay Melosh, and Gareth Collins
Please note: the results below are estimates based on current (limited) understanding of the impact process and come with large uncertainties; they should be used with caution, particularly in the case of peculiar input parameters. All values are given to three significant figures but this does not reflect the precision of the estimate. For more information about the uncertainty associated with our calculations and a full discussion of this program, please refer to this article
Your Inputs:
Distance from Impact: 5.00 km = 3.10 miles
Projectile Diameter: 390.00 m = 1279.20 ft = 0.24 miles
Projectile Density: 8000 kg/m3
Impact Velocity: 17.00 km/s = 10.56 miles/s
Impact Angle: 45 degrees
Target Density: 2500 kg/m3
Target Type: Sedimentary Rock
Energy:
Energy before atmospheric entry: 3.59 x 1019 Joules = 8.58 x 103 MegaTons TNT
The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 1.2 x 105years
Atmospheric Entry:
The projectile begins to breakup at an altitude of 14200 meters = 46500 ft
The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 16.9 km/s = 10.5 miles/s
The impact energy is 3.55 x 1019 Joules = 8.48 x 103MegaTons.
The broken projectile fragments strike the ground in an ellipse of dimension 0.627 km by 0.443 km
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 Earth's rotation period or the tilt of its axis.
The impact does not shift the Earth's orbit noticeably.
Crater Dimensions:
What does this mean?
Crater shape is normal in spite of atmospheric crushing; fragments are not significantly dispersed.
Transient Crater Diameter: 7.02 km = 4.36 miles
Transient Crater Depth: 2.48 km = 1.54 miles
Final Crater Diameter: 9.1 km = 5.65 miles
Final Crater Depth: 0.575 km = 0.357 miles
The crater formed is a complex crater.
The volume of the target melted or vaporized is 0.223 km3 = 0.0536 miles3
Roughly half the melt remains in the crater , where its average thickness is 5.77 meters = 18.9 feet
Thermal Radiation:
What does this mean?
Time for maximum radiation: 0.389 seconds after impact
Your position is inside the fireball.
The fireball appears 299 times larger than the sun
Thermal Exposure: 6.77 x 108 Joules/m2
Duration of Irradiation: 85.4 seconds
Radiant flux (relative to the sun): 7930
Effects of Thermal Radiation:
Clothing ignites
Much of the body suffers third degree burns
Newspaper ignites
Plywood flames
Deciduous trees ignite
Grass ignites
Seismic Effects:
What does this mean?
The major seismic shaking will arrive at approximately 1 seconds.
Richter Scale Magnitude: 7.2
Mercalli Scale Intensity at a distance of 5 km:
IX. General panic. Damage considerable in specially designed structures; well-designed frame structures thrown out of plumb. Damage great in substantial buildings, with partial collapse. Buildings shifted off foundations. Serious damage to reservoirs. Underground pipes broken. Conspicuous cracks in ground. In alluviated areas sand and mud ejected, earthquake fountains, sand craters.
X. Most masonry and frame structures destroyed with their foundations. Some well-built wooden structures and bridges destroyed. Serious damage to dams, dikes, embankments. Large landslides. Water thrown on banks of canals, rivers, lakes, etc. Sand and mud shifted horizontally on beaches and flat land. Rails bent slightly.
Ejecta:
What does this mean?
The ejecta will arrive approximately 32 seconds after the impact.
Your position is beneath the continuous ejecta deposit.
Average Ejecta Thickness: 174 m = 569 ft
Air Blast:
What does this mean?
The air blast will arrive at approximately 15.2 seconds.
Peak Overpressure: 1.67e+07 Pa = 167 bars = 2380 psi
Max wind velocity: 3280 m/s = 7340 mph
Sound Intensity: 144 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.
Tell me more...
Click here for a pdf document that details the observations, assumptions, and equations upon which this program is based. It describes our approach to quantifying the important impact processes that might affect the people, buildings, and landscape in the vicinity of an impact event and discusses the uncertainty in our predictions. The processes included are: atmospheric entry, impact crater formation, fireball expansion and thermal radiation, ejecta deposition, seismic shaking, and the propagation of the atmospheric blast wave.
God has sent this giant Kill Rock to show us his love!
The story did not mention the probability. "Percentages" is a common way of referring to probability in the real world.
Maybe it'll just nip us?
oops!
Here is the link.
http://www.lpl.arizona.edu/impacteffects/
I thought we were going to be obliterated by a huge cloud of anti-matter in 2014???? I swear, I read it somewhere on FR a couple months ago. Man it's tough to plan for the end of the world when nobody can even tell us when it is.
Some asteroids have not been detected until they have passed earth. Just last year one missed us, and came very close. It was not detected until it had actually passed us.
I always get a kick out of people laughing this off, thinking it's all nonsense.
But look no further than the lunar surface and the surface of other planets and moons in our solar system. Thousands of those lunar and planetary impacts are massive. Even with our atmosphere, many large objects can easily penetrate and cause a cataclysmic event.
It's only a matter of time, until earth sustains a massive strike. It will be interesting to see how so called "modern" man reacts prior to impact, and after.
Yeah, Nuclear missles in space would pollute the Sun, right?:)
An Empirical Study
Ali Rahimi, Ben Recht, Jason Taylor, Noah Vawter
17 Feb 2005
The orbits of asteroids and comets that cross the orbits of planets are diverted by the planets. The amount of diversion is very sensitive to how close the body passes to the planet. It is not possible to calculate exactly where an earth orbit crossing asteroid will be several orbits later since the net diversion will multiply. A probability of passing through an area of space can be calculated, but not the exact position.
So nuke the thing. On the other remarks, I just went to town and bought all the tinfoil in Kroger.
Aluminum foil? Look towards the moon tonight. Some of the impacts are so large, they can be seen from here on earth, with the unaided eye, at a distance of 240,000 miles away.
The only thing tin foil here are those that think earth being struck by a large astroid, is some kink of wacko idea. It's not. It's already happened, and will happen again.
As opposed to the BILLIONS of rocks that have hit the Earth during the past 4.5 billion years of its existence?
Why are you surprised that we find something when we start looking for it when we have ample evidence on Earth and the Moon that we have been hit by things throughout our entire history? There's very good evidence of several significant impact events in the last 400 years, and tons of direct evidence of impacts resulting in air burst explosions up to the multi-kiloton range in the last 30 years (those were recorded by our early warning satellites and, originally, we thought they were nuke tests).
I would have been VERY surprised if we didn't find anything. In fact, the fact that we hadn't found anything significant made me question the methodology and even the competence of the folks running the search.
This is real. It's not the only one. Get over it and deal. Is it happening tomorrow? Not likely. Is it going to happen? 100% guarantee.
If you truly were a pessimist you would take exactly the opposite position on this issue. I think you should change your forum name to "cockeyed optimist."
It would have a 70% chance of hitting water. I'll have to think about whether I'd prefer to drown or suffocate.
Well heck! if it's going to do a "fly by" before the actual impact, just blow it up as it whizzes past the planet earth. How hard can that be? We've got more than 20 years to plan for Pete's sake.
Whew! I thought there was actually something to worry about...
Anubis tried that a few years ago, but we're on to them now...
What do you mean "what is Bush doing about this"? Karl Rove's Weather Machine is responsible!
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