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

A million million million million (1 with twenty-four zeros after it) miles, the size of the observable universe.

You may see a cup of tea fall off a table and break into pieces on the floor... But you will never see the cup gather itself back together and jump back on the table. The increase of disorder, or entropy, is what distinguishes the past from the future, giving a direction to time.

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

Love the neighbor. But don't get caught.

While there's life, there is hope.

No one undertakes research in physics with the intention of winning a prize. It is the joy of discovering something no one knew before.