can energy be created or destroyed ….

“You may be hesitant to believe that the total energy in the universe is constant because there appears to be so much of it, or because science seems to indicate that the universe is expanding. There are stars, planets, galaxies, globular clusters – everywhere, matter and energy seem to exist, and it’s constantly rushing off in all directions. But for starters, the expansion of the universe doesn’t have to take more energy – as the universe expands, the distances between stars or galaxies increases, and thus the gravitational energy between them decreases to compensate. And more importantly, thermodynamics doesn’t state what value the total energy should have. It could be a huge, but constant, number (this is what’s known as an “open” universe, where the amount of matter/energy in the universe exceeds a certain “cut-off” density: see http://hyperphysics.phy-astr.gsu.edu/hbase/astro/denpar.html). It could be, as most physicists now believe, zero (this is called a “flat” universe, where the matter density in the universe is equal to the cut-off density). It could be negative, even (a “closed” universe, where the amount of matter is less than the cut-off density). It could be anything, but whatever value it is now, it was at the very beginning! According to physics, all of the matter and energy in the universe now existed in some form at the Big Bang.”

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s