It turns out that the saying “cry me a river” suggests a task that couldn’t be accomplished even if everyone on the planet worked together to accomplish it.

If all the people on Earth cried, it would be impossible for them to match the volume of water in even a very small river, student scientists at the University of Leicester have calculated.

However, an Olympic-sized swimming pool could be filled with tears — as long as each human shed about 55 of them, they estimated.

The students chose a river in Montana, the Roe River, because it was both very short and had a known daily flow rate.

But after crunching the numbers, they realised that all the tears in the world still couldn’t match its daily flow.

They had more success with another problem: Could all of humanity cry enough to fill an Olympic-sized swimming pool?

The average tear has a volume of about 6 microlitres (a microlitre is a millionth of a litre) and since an Olympic-sized swimming pool holds 2.5 million litres of water, the scientists report that if everybody cried 55 tears, they could fill a pool.

“This is therefore clearly not an effective means of filling a body of water,” the scientists dryly report in their paper, which was published in the student-run Journal of Interdisciplinary Science Topics.

Sad news, indeed.