Impact Effects

Gareth Collins, Robert Marcus, and H. Jay Melosh

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

Click each effect button (e.g. "Crater") to see the extent of each impact effect!

Your Inputs:

Projectile diameter: 40.00 meters ( = 131.00 feet )

Projectile Density: 3000 kg/m³

Impact Velocity: 17.00 km per second ( = 10.60 miles per second )

Impact Angle: 25 degrees

Target Density: 2750 kg/m³

Target Type: Crystalline Rock

Energy:

Energy before atmospheric entry: 1.45 x 10¹⁶ Joules = 3.47 MegaTons TNT

The average interval between impacts of this size somewhere on Earth is 469.0 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 54000 meters = 177000 ft

The projectile bursts into a cloud of fragments at an altitude of 18400 meters = 60200 ft

The residual velocity of the projectile fragments after the burst is 9.77 km/s = 6.07 miles/s

The energy of the airburst is 9.73 x 10¹⁵ Joules = 2.32 x 10⁰ MegaTons.

No crater is formed, although large fragments may strike the surface.

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.

Recent improvements in the airblast calculation are described here.