Energy where does it come from?!

Whovian

And they're reputable sources because? Most of those shows turn out to be rubbish.

In physics, the only things we take to be self-evident are that we exist and the Universe exists. We can then experiment on the Universe to try to figure out how it works.

Please explain this in a little more detail.

Correct, but what does this have to do with anything?

Then demonstrate so.

Anyway, your post seems to be philosophy, not physics. Please post in the appropriate forum.

Perchie

t = 0 is the divider between dimensionality and non-dimensionality - between the concrete and potentiality.

Our definition of 'existence' is currently confined to the realm of dimensionality.

Evidently, the universe existed without dimensionality - as an energy potentiality.

To deny this is to demonstrate the limitations on our current concept of existence.

If we can conceive that the existence of 'the potentiality' is possible without space-time, then the 'everything from nothing' conundrum is swept away.

Drakkith

Perchie, do you have a reputable source for saying the universe existed without dimensionality? To my knowledge we simply don't know. Thanks.

bcrowell

We have a FAQ about this: http://www.physicsforums.com/showthread.php?t=506985

Perchie

Sorry, no - it's purely my personal opinion.
And I cannot imagine that it could ever be knowable.
It's about as conjectural as it gets - but that won't stop me thinking about it.

Drakkith

Please stick to current mainstream science when posting here as per PF rules. Otherwise threads get bogged down with people who just post their opinions and no discussions of real science take place. If you don't know the current view on a subject you can ask about it, go look it up, etc.

Perchie

OK.
Is there a subforum for more conjectural discussion ?

Drakkith

There is not. PF is strictly for currently accepted mainstream theories only.

RUTA

Spacetime exists and does not change. However, in the context of spacetime, one can talk about the "temporal change" of a particular spatial hypersurface in a particular foliation. Analogously, one can talk about the "southern change" of lines of constant latitude on the surface of Earth. "Causes" for this "change" then lie north of any given point. There is nothing north of the North Pole, so it exists "uncaused." This does not present any conceptual problems as long as you realize the fundamental object is the Earth as a whole, not the slices and "change" associated with your particular map of it.

Rational T

Energy can be both positive and negative. The positive energy of matter and motion exactly offsets the negative energy of gravitational attraction. We do not know this for sure, but there are impressive calculations which show this, and negative energy has been experimentally verified using Casmir plates. This is basically the zero-energy universe hypothesis. If the universe has a net energy of zero, then you do not need any energy at all to get everything you see. Hopefully this helps a bit :)

bcrowell

You're confounding two things here: (a) "negative energy" in "the negative energy of gravitational attraction," and (b) "negative energy" in the sense of violating an energy condition ( http://en.wikipedia.org/wiki/Energy_condition ). These are not the same. If they were the same, then energy conditions would be trivially violated in all cases where gravity operates, and would therefore be of no interest.

Your stuff about the total energy of the unverse being zero is also not right; see our FAQ: http://physicsforums.com/showthread.php?t=506985

Rational T

Yes, certain things need to be changed to accommodate a zero-energy universe. This doesn't mean it's false.

Rational T

I've done much research on this subject. Stephen Hawking, Laurence Krauss, Neil DeGrasse Tyson, Edward Tryon and countless other esteemed physicists believe a zero-energy universe is plausible.

bcrowell

The idea may be right or wrong, but your explanation of it is definitely wrong.

Rational T

Well, that's how it's commonly explained.

"Astrophysicists Alexei Filippenko at the University of California, Berkeley and Jay Pasachoff at Williams College explain gravity's negative energy by way of example in their essay, "A Universe From Nothing": "If you drop a ball from rest (defined to be a state of zero energy), it gains energy of motion (kinetic energy) as it falls. But this gain is exactly balanced by a larger negative gravitational energy as it comes closer to Earth’s center, so the sum of the two energies remains zero."" - http://www.lifeslittlemysteries.com/...erse-zero.html

bcrowell

You've read some popularizations and then tried to apply them incorrectly. The Wikipedia article and FAQ entry linked to from #164 are both extensively referenced to professional-level sources such as graduate-level textbooks and peer-reviewed papers.

cristo

Thread closed, as this is drifting into the realm of speculation.