Chelyabinsk main mass weighs 473 kilograms (+/- 20 kg)
According to the recently performed gravimetrical measurements the current weight of the Chelyabinsk main mass is 473 kilograms (+/- 20 kilograms).
This new measurement is not really surprising, because after the main mass was lifted from Lake Chebarkul on 16 October 2013 it weight approx. 580 kg. Before it was put on public display in the Chelyabinsk Museum around 40 kilogram were removed during preparation and cleaning of the meteorite’s surface. The recent gravimetrical measurements did not take into account the two larger fragments with a combined weight of 72,5 kilograms that broke off under water during the lifting from the lake bottom. They were originally weighed together with the main mass at the beach of Lake Chebarkul but were not put on display in the Chelyabinsk museum.
Thus it was already known that the main mass must weigh around 467.5 kilograms.
The newly measured weight of 473 kilograms (+/- 20 kilograms) is not much more precise than the old estimation of 467.5 kilograms.
The headlines in today’s Russian media that the meteorite has apparently lost around 100 kg are thus misleading and based on lack of information.
The main mass’s average density is 3.085 g/cm³ based on the 3D-scans* of the main mass that were made in May 2014.
Apparently the current structural integrity of the main mass does not allow it to be lifted and weighed in any other way.