The Physics Behind Hangtime

If an object falls at the same rate it rises, how can basketball players hang in the air? In fact, it is an illusion. Gravity is always pulling a body towards the earth, but gravity works in an "up-down" (Y) direction. When a basketball player jumps towards the basket, he is moving in both the Y plane, and the forward-backward (X) plane. While gravity is pulling him down in the Y plane, it is not affecting his motion in the X plane - allowing for the illusion of the player hanging in the air. If you watch a dunk in slow motion, you will notice that the player is actually falling when he dunks the ball.

The trick to hangtime, then, is to maximize both X and Y vectors - by jumping off the tip of your toe at a 45° angle.

Watch Clyde Drexler's unbelievable hangtime.

What is Dark Matter and Dark Energy?

In 1933, Fritz Zwicky averaged the mass of certain galaxies and obtained a value far greater than expected - he determined there was an unseen "dark matter" that allowed for the discrepancy. Dark Matter was determined to be a directly undetectable state of matter with powerful gravitational effects.

But in 1998 an even more shocking discovery revealed that despite this 'dark' matter pulling galaxies together, the universe itself was expanding ... and at an increasing speed. While dark matter was keeping everything together, a stronger force was pushing everything apart! Moreover, galaxies were not being stretched ... instead, more space was being created. The same amount of acceleration of this expansion was observed irrespective of position.

This means that "dark energy" is uniform and also much stronger than dark matter.

It doesn't stop there ... the visible matter, as immense as it is, comprises only 4% of all the matter in the universe - dark matter is believed to take up 21% of the pie, with dark energy taking up an unbelievable 75% of distribution in the universe!

Here's an easy to understand documentary explaining the phenomenon.