Geoscience Reference
In-Depth Information
Fig. 9.4
Computer simulation
of the splash from an asteroid
striking the ocean off the coast of
Long Island. The asteroid is
1.4 km in diameter and is
traveling northwards at a speed of
20 km s
-1
. Note the vapor heated
over 5,000 C. Dark material is
water vapor; white material is
water. The simulations were
performed at Sandia National
Laboratories using an Intel
Teraflops super computer. They
took 18 h to complete. Images
are used courtesy Dr. David
Crawford. More images and
movies are located at
http://www.
Asteroid
trajectory
Asteroid
Impact
Long
Island
New York
Just before impact
Material
at 5000° C
2.9 seconds after impact
Material
at 5000° C
8.4 seconds after impact
D
¼
SpW
0
:
3
where
ð
9
:
2
Þ
W
= kinetic energy of impact (kilotons of TNT)
where
= impact velocity of asteroid (m s
-1
)
v
a
D
=
diameter of an impact crater (m)
m
¼
1
:
33 pq
a
r
a
ð
9
:
5
Þ
Sp
¼
90 q
0
:
3
e
ð
9
:
3
Þ
where
where
m
= mass of asteroid (kg)
Sp
= density correction
r
a
= radius of asteroid (m)
q
e
= density of material ejected from an impact crater
(g cm
-3
)
q
a
= density of asteroid (g cm
-3
)
Using Eq. (
9.4
), the kinetic energy of an iron meteorite
40 m in diameter with a density of 7.8 g cm
-3
, traveling at
a velocity of 20 km s
-1
—such as that which created the
W
¼
0
:
12
10
12
mv
a
ð
9
:
4
Þ
