However, July conditions greatly reduced sea
ice drift speed in the Beaufort Sea and produced a counterclockwise drift pattern in the Laptev Sea (Figure 5a, bottom).
In a series of images taken over three days in January 2016, Hubble showed 25 fragments consisting of a mixture of
ice and dust that are
drifting away from the comet at a pace equivalent to the walking
speed of an adult, said UCLA astrophysicist David Jewitt, who led the research team.
Measuring the distance apart and
speed of 2 satellites in space orbiting the earth to the width of a human hair with no margin for error [damn those
drift recalculations], and taking into account unknown factors with respect to the true values for water depth, water weight at different salt concentrations,
ice depth magma flows, volcanic activity etc [ie making a lot of guesses], plus taking human motivation on board [like CO2 increase must melt
ice surely] can give you an accurate measurement of the volume
ice in Antarctica.