My advice to any heartbroken young girl is to pay close attention to the study of theoretical physics. Because one day there may well be proof of multiple universes. It would not be beyond the realms of possibility that somewhere outside of our own universe lies another different universe. And in that universe, Zayn is still in One Direction.

Today will still yearn to know why we are here and where we came from. Humanity's deepest desire for knowledge is justification enough for our continuing quest. And our goal is nothing less than a complete description of the universe we live in.

Our only chance of long-term survival is not to remain inward-looking on planet Earth, but to spread out into space.

Our only chance of long-term survival is not to remain lurking on planet Earth, but to spread out into space.

Because imaginary time behaves like another direction in space, histories in imaginary time can be closed surfaces, like the surface of the Earth, with no [existential] beginning or end.

It is impossible to imagine a four-dimensional space. I personally find it hard enough to visualize a three-dimensional space!