Our world is shrinking: Earth is roughly 5 millimetres smaller than the last measurement made 5 years ago

The world is smaller than we think, say scientists who say their new measurements could force other researchers to rejig their calculations.

Results of on international project show the Earth is roughly 5 millimetres smaller than the last measurement made five years ago.

But Dr Axel Nothnagel, a German researcher from the University of Bonn, says there is no evidence that the Earth itself is shrinking.

It's just that more accurate measurements, more data and better geophysical
models have led the researchers to come up with Earth's new size, a diameter of about 12,756.274 kilometres.

The researchers did not measure the diameter directly, however.

Nothnagel says that's impossible as the Earth has an irregular shape that indents and sticks out at certain regions by a hundred or so metres.

Their research, published in the Journal of Geodesy, used the technique of very long baseline interferometry or VLBI.

This uses radio telescopes in pairs or groups, as far away as several thousand kilometres, to receive radio waves from distant quasars.

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