How Long Would It Take To Fall From One Side Of Earth To The Other?

The question is often posed to physics students who have always given answers under the assumption that Earth has uniform mass. But now, Alex Klotz, a McGill University grad student, has come up with a new calculation that challenges this concept.

His findings were published in the American Journal of Physics - a publication of the American Association of Physics Teachers.

Professor David Jackson of Dickinson College is the editor of the journal. He tells Here & Now's Jeremy Hobson why Klotz's answer - the answer now accepted as right - is 38 minutes and 11 seconds, four minutes less than originally thought.