Chelyabinsk Main Mass gets its Weight Checked

[David Entwistle]

There's an article from Chelyabinsk Museum describing the Chelyabinsk Meteorite main mass being checked out with a gravity meter.

I guess they are trying to measure mass, or bulk density. Anyone any idea how that would work? The device is a Scintrex CG-5 Autograv gravity meter.

Gravity Meter?

ChelGravity.jpg (50.14 KiB) Viewed 5165 times

The meteorite is looking quite well.

[David Entwistle]

For the curious, Richard Lachapelle, B.Sc, Eng. Applications Geophysicist at Scintrex Limited has provided the following expanation:

The attached document, taken from a geophysics course at the University of Alberta, gives an approximate method to determine the excess mass of a spherical object (an approximation of the Chelyabinsk meteorite).

The formula is M=g * z2/G,

where: M is the excess mass, in Kg

g is the gravity anomaly in m/s2, as measured by the
CG-5 Autograv Gravity Meter illustrated in the pictures in the link below

Z is the distance from the gravity sensor to the centre of the meteorite
(in meters)

G is the Universal Gravitational Constant

Here's an image of the first page of the method's description.

Gravity Anomalies

If anyone wants a copy of the original pdf document, then drop me a private message.

Many thanks to Richard, and the team at Scintrex, for the excellent explanation.

Next question is obviously what was the result. Any offers? I's say at least ten Lake House meteorites mass....

[David Entwistle]

The result is in and it's 473 kg +/- 20 kg.