Scientists detected the gravitational waves after a pair of unusual black holes collided.
Over 100 Palestinians and at least three Israelis have died since Wednesday, when Israel launched its offensive aimed at stopping rocket fire from Gaza into Israel.
Israel says it is prepared to expand its operation, but both Israeli officials and representatives of Hamas, which governs Gaza, have been speaking behind the scenes with Egyptian diplomats about conditions for a ceasefire.
Robin Young and Jeremy Hobson are hitting the road. Our Tumblr brings you behind the scenes of our election coverage.