Infinite quantity, infinite space, finite options?

[Dangus] "So, if the universe is infinite, both in space and in scale, then is it not inevitable that our there are exact copies of us?"

At first this seems to be the logical conclusion. But after some time pondering this fantastic possibility you come to the realization that their existence can never actually be identical to ours. Very similar at specific comparison points, but never IDENTICAL.

There is the inverse relationship between size and time, for example. If they are up scale from us their femtosecond would be a long time compared to our gigayear. So even figuring out a way to isolate a point in their world for comparison to a point in our world would be hard.

And the simple fact that they are up scale from us and we are down scale from them is a difference that can never be changed.

If they exist at the same scale we do, but in a part of the universe we can not presently observe, it is still not possible for us to be identical. Eventually they will detect us. Or we will detect them. Either way that will make us and them different, even if the time difference between detection events is close to zero.

Since time is infinitely divisible, the time difference between detection events can never be zero. And even if it were other details about their detection of us would be different from the details of our detection of them. For example, we are over here in the universe, they are over there.

Fun to think about, though.

LB

Thank you for the response. What about the possibility that the universe is "circular" in a sense. The idea being that if you travelled so far that you eventually found a repeat of the same pattern, you would actually be where you started?

Also, the concept of time as presented in physics has always struck me as pretty vague. I've never heard a good answer as yet to what time *IS* exactly. Have you?

"Regret can only change the future" -Me

Dangus, you're missing one crucial bit of mathematical understanding. There are different degrees of infinity. It has been proven that you cannot define a method of listing all of the real numbers (1st, 2nd, 3rd, etc.); therefore there are more real numbers than counting numbers; so the set of real numbers is not countable. The rational numbers, are countable, even though there are an infinite number of them. So there are infinity times as many real numbers as there are counting numbers.

Mathematicians refer to the cardinality of infinite sets. If the cardinality of infinite possibilities to choose from is greater than the cardinality of infinite coices available, then the probability of making the same exact choice twice is zero.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Since time is infinitely divisible, the time difference between detection events can never be zero.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Larry, we don't actually know whether space and time are infinitely divisible; we only know that we have not yet discovered a limit to how finely they may be divided. Isn't that all we ever can know about the subject?

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Also, the concept of time as presented in physics has always struck me as pretty vague. I've never heard a good answer as yet to what time *IS* exactly. Have you?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Heres my answer to what time is (for what it's worth).



In our universe there are only ones, one at a time, where time is the nothing ones are composed of.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">I've never heard a good answer as yet to what time *IS* exactly. Have you?
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Let me take a stab at it; as I understand it:

Time IS the orderly succession of events in our universe. (Philosophically speaking, time is only our perception of an orderly succession of events; we should be open to the possibility of some superior being or beings to whom all events in our tiny universe occur simultaneously or in random order.)

Our measure of time is a count of successive periodic events. Events are peridic if they repeat in such a way that the count of two periodic events in different places reliably maintains a constant ratio when relative velocity is zero.

Relative velocity may alter the ratio of periodic events. Special relativity is a mathematical relationship between relative velocity and the ratio of periodic events where relative velocity is constant. General relativity (in the generic sense) is a mathematical relationship between relative velocity and the ratio of periodic events where relative velocity is variable.

"GR" refers to Einstein's particular form of general relativity, based on the assumption that light has no medium and all inertial frames are equivalent. "LR" refers to Lorentz's particular form of general relativity, based on the assumption that light requires a medium (the aether) and there is a preferred frame of reference which is stationary relative to the aether. In most respects, SR and LR yield identical predictions of observations during relativistic space journeys---though the interpretation of those observations may differ drastically.

I am not yet convinced that the differences between GR and LR are of any consequence. I think they will continue to yield identical results unless and until we discover that the aether not only exists, but that it is not homogeneous thruought the universe, or that it does not behave like a perfect gas. Differences in quality (density, motion, temperature, composition, etc.) of the aether at different locations may affect the periodicity of similar events, thus throwing a monkey wrench into our measure of time.

[PhilJ] "'LR' refers to Lorentz's particular form of general relativity ... "

LR (1904) is an alternative to SR (1905) rather than an alternative to GR (1916). GR can use either SR or LR as a starting point.

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LR and GR are not directly comparable since they address different questions. The differences between LR and SR are profound, but they are also subtile. SR has a proof that it is physically impossible for matter or energy to travel faster than light in forward time. LR embraces ftl propagation of mater and energy in forward time. Both are supported by all experiments we have done to date.

When GR starts with SR, it inherits SR's speed limit and all of the paradoxes that come with it.

When GR starts with LR, it inherits LR's lack of a speed limit and all of the paradoxes go bye-bye.

Regards,
LB