13 Jan '05 23:22>
is hell endo or exothermic?
i'd like a reasoned logical explanation for your answer.
i'd like a reasoned logical explanation for your answer.
Originally posted by PBE6Is there a theoretical answer to this? I mean, if I put an oven in a
I wonder, where does all the heat in the universe go? Heat is energy transfer as a result of a temperature difference, so all the objects in the universe above absolute zero are radiating heat to whatever cooler objects/spaces are around. But where does heat at the "edge" of the universe go (if such an boundary can and does actually exist)? Does it just he ...[text shortened]... If the heat doesn't go beyond some sort of boundary, why not?
That will mess with your head.
Originally posted by PBE6In the 'Big Bang' model, everything (matter and energy) is spreading out in all directions, so the 'edge', such as one exists, is moving away from us at the speed of light.
I wonder, where does all the heat in the universe go? Heat is energy transfer as a result of a temperature difference, so all the objects in the universe above absolute zero are radiating heat to whatever cooler objects/spaces are around. But where does heat at the "edge" of the universe go (if such an boundary can and does actually exist)? Does it just he ...[text shortened]... If the heat doesn't go beyond some sort of boundary, why not?
That will mess with your head.
Originally posted by AcolyteDoesn't current thinking suggest that space is curved? Thus if anything ever reaches the edge of the universe, it will actually be back where it started.
In the 'Big Bang' model, everything (matter and energy) is spreading out in all directions, so the 'edge', such as one exists, is moving away from us at the speed of light.
Originally posted by NemesioI assume by "perfect vacuum" you mean putting an oven in a universe with nothing else in it. I have no idea what would happen in that case. I guess energy would be radiating from the oven, but where would it go? And would it be due to a temperature difference between the oven and the surroundings (if not, it's not heat)?
Is there a theoretical answer to this? I mean, if I put an oven in a
perfect vacuum, are you saying that it doesn't radiate any heat because
there is nothing to attract the energy?
Nemesio
Originally posted by PBE6Temperature doesn't really measure this - for example, a puddle of water at room temperature has much more internal kinetic energy than a lump of copper of the same mass and temperature. Temperature measures the propensity of something to transfer its internal kinetic energy to its surroundings. So once the space around the oven has photons in it (from the oven), its temperature is above absolute zero.
What would the temperature of the surroundings be, anyway? That's not as dumb a question as it sounds - temperature is a measure of the average kinetic energy of the atoms, molecules and other components that make up some object. If there's no stuff, what do we mean by "temperature"?
Originally posted by AcolyteWe should clarify. There are many definitions of temperature, one of them being "the average kinetic energy of the components of an object", another being "the propensity of an object to give up kinetic energy to another object". There are others, too. No definition is useful or applicable in all cases.
Temperature doesn't really measure this - for example, a puddle of water at room temperature has much more internal kinetic energy than a lump of copper of the same mass and temperature. Temperature measures the propensity of something to transfer its internal kinetic energy to its surroundings. So once the space around the oven has photons in it (from the oven), its temperature is above absolute zero.
Originally posted by AThousandYoungThe usual way of explaining it is to imagine a being that lives in two dimensions, on a perfectly smooth planet. From his perspective, the planet is flat, because he has no conception of a third dimension for it to be round in. So, if he travels all he way around his world, he's going to be confused to find himself back where he started.
Is that what they mean when they say space is curved? I never understood that statement.
Now add a dimension. We are now in the position of the 2d creature. Space is curved in a fourth dimension of which we have no comprehension.Is that how it works? I had heard the universe was infinite in area but bounded, like a sphere. Since its surface bears an infinite number of points, ergo infinite area, but points beyond that surface can also be defined, the area is infinite but bounded. That still doesn't answer the question of what exists beyond the edge of the universe, though. It has to have some tangible reality, if it can be understood in terms of not-universe.
Originally posted by greendragonIf it has infinite volume, it can't be bounded, and spheres are always finite. But there is a space which you might see as having infinite area, which is in some sense sphere-like:
Is that how it works? I had heard the universe was infinite in area but bounded, like a sphere. Since its surface bears an infinite number of points, ergo infinite area, but points beyond that surface can also be defined, the area is in ...[text shortened]... ngible reality, if it can be understood in terms of not-universe.