German schoolboy, 13, corrects NASA's asteroid figures: paper

physorg ^ | 4/15/08

[SunkenCiv]

Note: topic is from April.

The schoolboy took into consideration the risk of Apophis running into one or more of the 40,000 satellites orbiting Earth during its path close to the planet on April 13 2029... If the asteroid strikes a satellite in 2029, that will change its trajectory making it hit earth on its next orbit in 2036. Both NASA and Marquardt agree that if the asteroid does collide with earth, it will create a ball of iron and iridium 320 metres (1049 feet) wide and weighing 200 billion tonnes, which will crash into the Atlantic Ocean.

If this article is all there is to go on, the schoolkid is nuts. A 200 billion ton asteroid wouldn't even notice the impact on its surface of one of our puny little satellites. If the European experts actually agreed, and (again) if this article is contains all there is to it, those experts are just bungholes.

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[SunkenCiv]

99942 Apophis (2004 MN4)
Earth Impact Risk Summary
[still 1:45000]
http://neo.jpl.nasa.gov/risk/a99942.html

[JSteff]

Actually here are the calculations. There is a place to do that anc set the variables: http://www.lpl.arizona.edu/impacteffects/

Distance from Impact: 1610.00 km = 999.81 miles
Projectile Diameter: 609.60 m = 1999.49 ft = 0.38 miles
Projectile Density: 3000 kg/m3
Impact Velocity: 32200.00 km/s = 19996.20 miles/s (Your chosen velocity is higher than the maximum for an object orbiting the sun)
Impact Angle: 45 degrees
Target Density: 1000 kg/m3
Target Type: Liquid Water of depth 609.60 meters, over typical rock.
Energy:
Energy before atmospheric entry: 1.84 x 1026 Joules = 4.41 x 1010 MegaTons TNT
The average interval between impacts of this size is longer than the Earth's age.
Such impacts could only occur during the accumulation of the Earth, between 4.5 and 4 billion years ago.
Atmospheric Entry:
The projectile begins to breakup at an altitude of 175000 meters = 573000 ft
The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 31800 km/s = 19700 miles/s
The impact energy is 1.80 x 1026 Joules = 4.29 x 1010MegaTons.
The broken projectile fragments strike the ground in an ellipse of dimension 1.19 km by 0.844 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?

The crater opened in the water has a diameter of 315 km = 196 miles
For the crater formed in the seafloor:
Crater shape is normal in spite of atmospheric crushing; fragments are not significantly dispersed.

Transient Crater Diameter: 147 km = 91.2 miles
Transient Crater Depth: 51.9 km = 32.2 miles

Final Crater Diameter: 282 km = 175 miles
Final Crater Depth: 1.62 km = 1 miles
The crater formed is a complex crater.
The volume of the target melted or vaporized is 327000 km3 = 78400 miles3
Roughly half the melt remains in the crater , where its average thickness is 19.3 km = 12 miles
Thermal Radiation:
What does this mean?
Time for maximum radiation: 0.0355 seconds after impact
Visible fireball radius: 926 km = 575 miles
The fireball appears 131 times larger than the sun
Thermal Exposure: 2.56 x 1010 Joules/m2
Duration of Irradiation: 14700 seconds
Radiant flux (relative to the sun): 1740
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:
The major seismic shaking will arrive at approximately 322 seconds.
Richter Scale Magnitude: 11.4 (This is greater than any earthquake in recorded history)
Mercalli Scale Intensity at a distance of 1610 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.

Ejecta:
The ejecta will arrive approximately 662 seconds after the impact.
Average Ejecta Thickness: 99.3 cm = 39.1 inches
Mean Fragment Diameter: 1.25 mm = 0.0492 inches

Air Blast:
The air blast will arrive at approximately 4880 seconds.
Peak Overpressure: 4e+06 Pa = 40 bars = 569 psi
Max wind velocity: 1590 m/s = 3550 mph
Sound Intensity: 132 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.

[SunkenCiv]

NASA sets record straight
NASA refutes a widely reported story
about a 13-year-old’s calculations of an asteroid hitting Earth
by Molly McCall
2 hours ago Wed, 16 Apr 2008 16:45:10 PDT
http://buzz.yahoo.com/buzzlog/91346/wednesdays-buzz-you-missed

[RJL]

If the asteroid strikes a satellite in 2029, that will change its trajectory making it hit earth on its next orbit in 2036.

Both NASA and Marquardt agree that if the asteroid does collide with earth, it will create a ball of iron and iridium 320 metres (1049 feet) wide and weighing 200 billion tonnes, which will crash into the Atlantic Ocean.

Am I missing something here, a 200 billion ton iron asteroid is going to be diverted by a tiny man made(?) satellite?

Isn't that about the equivalent of a mosquito diverting an 18 wheeler, or even less?