Recent content by PeterDonis

The OP question has been answered. Thread closed.

Moderator's note: Thread level changed to "I".

@SWIRF your space.com reference is a pop science article. Those are not good sources for learning actual science. @Vanadium 50 gave you the correct answer to your question: you can't use entanglement to send information faster than light.

And in such cases there is no "identity" at all. So the OP question isn't even applicable.

And at this point that question has been sufficiently answered, and enough time has been spent on it. Thread closed.

Have nothing to do with the actual measurements you referenced in post #23.

Because the hydrogen atoms being measured are in gas clouds in our own galaxy, whose velocities relative to Earth are not going to be very fast when compared with the speed of light.

The "Signal" in degrees K in this graph appears to actually represent received power. The "previous post" says "The y axis shows the equivalent temperature of the signal in degrees °K." This temperature itself cannot correspond to a frequency, since frequency is shown on the X axis, as given in...

But until post #23, you did not tell us what "hydrogen atoms" you were even talking about. Not until post #23 did you actually give us a reference that showed specific measurements of particular hydrogen gas clouds--and then they turn out to be hydrogen gas clouds in our own galaxy, whose...

Says who? It looks like your "temperature to frequency calculator" is on a different web page that you have not provided a link to. Please provide a link.

Where on the physicsopenlab page does it say anything about temperature?

Is this the reason you actually started this thread? Because if so, you could have (and should have) given this particular reference and asked the question you just asked in your OP of the thread. Which would have saved us more than a day of trying to figure out what your actual question is.

For the OP question it should not matter; uniqueness of the identity should be provable for any group (or at least any group that doesn't have some other weirdness like zero divisors). @FactChecker seems to me to have come up with the simplest derivation.

You need to rephrase your question, because the loss of kinetic energy you describe, for example in cosmic rays, as the universe expands is not a "loss of energy". No stress-energy is destroyed; stress-energy is locally conserved. If your question is, is there any way to avoid the effect you...

Um, ionized hydrogen is free protons and electrons. (Or, rarely, free deuterons and electrons.) The 21-cm line has nothing to do with ionized hydrogen any more than it has to do with free protons and electrons. It is an emission line associated with the electron in a hydrogen atom making a...