Tag Archives | time

Does The Past Exist Yet?

past-present-futureThe future has yet to be determined, but what about the past? This recent Huffington Post piece discusses the possibility that what you do in the present shapes both future and past — “historical events such as who killed JFK, might depend on events that haven’t occurred yet.”

Recent discoveries require us to rethink our understanding of history. “The histories of the universe,” said renowned physicist Stephen Hawking “depend on what is being measured, contrary to the usual idea that the universe has an objective observer-independent history.”

Is it possible we live and die in a world of illusions? Physics tells us that objects exist in a suspended state until observed, when they collapse in to just one outcome. Paradoxically, whether events happened in the past may not be determined until sometime in your future — and may even depend on actions that you haven’t taken yet.

In 2002, scientists carried out an amazing experiment, which showed that particles of light “photons” knew — in advance −- what their distant twins would do in the future.

Read the rest
Continue Reading

Rethinking Relativity: Is Time Out of Joint?

Rachel Courtland asks a deep question in New Scientist:

Ever since Arthur Eddington travelled to the island of Príncipe off Africa to measure starlight bending around the sun during a 1919 eclipse, evidence for Einstein’s theory of general relativity has only become stronger. Could it now be that starlight from distant galaxies is illuminating cracks in the theory’s foundation?

Everything from the concept of the black hole to GPS timing owes a debt to the theory of general relativity, which describes how gravity arises from the geometry of space and time. The sun’s gravitational field, for instance, bends starlight passing nearby because its mass is warping the surrounding space-time. This theory has held up to precision tests in the solar system and beyond, and has explained everything from the odd orbit of Mercury to the way pairs of neutron stars perform their pas de deux.

Yet it is still not clear how well general relativity holds up over cosmic scales, at distances much larger than the span of single galaxies.

Read the rest
Continue Reading