Read this brilliant article in Wired:

1687: Isaac Newton

The universe has one absolute clock:
• Time and space are independant of the observer.
• Time’s arrow points forward; events move ahead from the now.

1905: Albert Einstein

every observer has his or her own (accurate) clock:
• The universe exists in a space-time manifold.
• Everyone’s “now” is different.
• Acceleration affects time.

2003: Peter Lynds

There is no clock; “time” is an illusion
• Time has no indivisible unit.
• There is no “now,” only sequences of events.

Everything is Maya!