Mille Grazie, Tullio

I enjoyed your post about these gentlemen at the Univ of Padua. This makes the Einstein biography richer for me.

Relativistic velocity: When 1 + 1 = 1
https://www.youtube.com/watch?v=IiKBbMtbGkw

Chris, you cannot simply add velocities in special relativity. On the other hand, I don't know of any galaxy moving away at speed greater than light. The speed of galaxies is given by the Hubble law, V=HR where H is the Hubble constant and R the distance.
Tullio

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Again that Einstein once said that "Everything is relative", except for also a better paragraph in the previous as well.

Perhaps just still fine for making it such a thing, because I could get to it that rather the energy needed, in order to bring an object to the speed of light,
has to close in on, or be infinite, and not its mass only.

Could we next make it that Logic, or perhaps a lack of it, could also be telling about "insanity", for a thing being almost ridiculous, when it comes to that of a meaning?

Is not the Universe based on sets of Laws, because of also rules, if not any Equations, because there are still boundaries, or limits, for also constraints,
in which these Laws should be valid, or perhaps matter?

So why just only possibilities here, except for not any Logic, or Probability, when perhaps only about numbers, and next such things as counting, for that of enumeration?

Except that we perhaps found ourselves within a framework here of almost classical science, except for not any mechanics either, when the silly, or stupid idiot,
could still be the "Man in the street", for a couple of things, except for not any "stupendous", or even better, for that of a scientific thought, or perhaps mind, either?

Presumably still only Proof, for a bit of Logic as well, but does it always tell a better story, for also that of the worse, if not any boring either?

Or that of the other thing as well, namely fear, mentioned before, which perhaps is not any elementary particles either, but rather could be telling about Creation,
for also that of a wider aspect, if not any given complexity either.

If such a thing as symbiosis, for also that of a symbiotic relationship, or interaction, could be possible, also that of the same, for that of possible life between the stars,
but also that a Probabilistic equation perhaps could not make any sense, or difference, for that of an outcome, when making it either 0, zero, or nil, for also that of many.

Creation could next be only that thing being possible, for that of also nature being at hand, or present, for such a thing, and also we could be knowing a couple of things,
for the same reason, because of only making it the Bible, when next perhaps that of God.

If still rather "absolutely" so, for next also a fact, that you will have to enforce that of Belief, in order to make it perhaps science, you next could be transforming,
if not any converting either, that of a Religious, or perhaps Theological belief, into science, in order to just make it such a thing, namely that of a Method.

Or maybe still only part versus whole, where it also could be the little 1+1=2, for also E=mc2, and they could be only part of a given scheme,
for perhaps that of infinity at the other end, except for not the Laws or Equations which we perhaps could be taking for granted.

I guess that there could still be a lack of Belief, for next that of science, but that does not mean that we should not believe in "Little Green Men" either.

We know that nature could be having the upper hand, for that of a couple of things, except for perhaps not meaning God either, but only that one thing
could still matter, for perhaps not the other, regardless of it being perhaps only numbers, for also that of Logic, and Probability.

Relativity, both special and general, has survived so far all experimental tests. Since it is based on the idea that c is an upper limit for all speeds, unless we find an example of something (carrying both mass and impulse) going faster than c we must accept it.
Tullio

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The conventional wisdom says that indeed galaxies are moving away from us at faster than the speed of light. The answer to this is always given that the space between them is what is expanding and they are not accelerating of their own accord.

If I were traveling right behind a one kilogram mass both of us moving at, say, 80% of the speed of light relative to let's say an observer on Earth. I believe that since the mass is at rest relative to me I would have little trouble accelerating it from my perspective. What's that you say? --it is traveling at a speed where this would not be so easy--well then I say "How do it know"?

A real mixup of Space/Time. The observer on earth would not see what i see since light takes a finite time to reach the Earth for the observer to make his measurement (observation).

Das Right !

I always like to comment on my own posts and thereby pool my ignorance with that of other mavens of cosmology.

Explain again how we know that far galaxies are accelerating in their expansion. Yes, having taught physics in college, I fully understand the doppler effect--but I think that we are seeing what happened at those galaxies about 13 billion years ago.

Also: if there is no absolute, inertial point of reference of a cosmic center to the universe then why can't we observe this faster than light expansion by looking at nearby galaxies. The fact that the Andromeda Galaxy is approaching us at 110 kilometers per second (over 4100 miles per hour) shows that gravity can overcome the putative expansion forces.

If we were at the center of the universe, and it were expanding topologically like a big balloon than the outermost galaxies would be separating faster than those close to us and their motion could be laid off partially to expanding space as well as outright acceleration. So what do we conclude--are we still expanding or were we expanding 13 billion years ago and we have no clue as to what is happening at the present moment beyond our time horizon ?

I will pray for enlightenment.

It looks like we have wandered off topic but maybe we can have a good discussion anyhow !

Chris, you cannot simply add velocities in special relativity. On the other hand, I don't know of any galaxy moving away at speed greater than light. The speed of galaxies is given by the Hubble law, V=HR where H is the Hubble constant and R the distance.
Tullio

According to Hubble's law all galaxies beyond the observable universe are receding FTL.
https://en.wikipedia.org/wiki/Hubble%27s_law#Hubble_volume
A sphere with the radius Hubble length is called a Hubble sphere and thus encloses a Hubble volume. What is outside of the Hubble sphere are receding from its center at an apparent velocity that exceeds the light speed.
When using relativity calculating the speeds however the observed speed (if we could observe them of course) are not exceeding the speed of light.
However what's inside receed at speeds below the light speed.

1 km/sec is about .625 miles per sec . ERGO 110(.625)(3600)=247,500

You are right my number was per minute. Thank you for the correction

No probs William, happy to help :-))
Andromeda

It looks like we have wandered off topic but maybe we can have a good discussion anyhow !

Agreed.

Agreed as well:)

Oh, Chris.

So, if an object has mass, how can it seem to move at FTL speeds? Consider two galaxies each moving away from each other at 75% light speed. One galaxy observing the other would see the speed of the other at 1.5 times light speed would it not?

I did the calculation using Lorentz math and it turn out to be that they are receeding to each other with 96% of the light speed.
Does it make sense to anyone?
Not to me anyway but there it is.

"relative" to each other yes 1.5 times apart but that mean nothing and it is not important! their real speed is still 3/4 ! thats the only thing that matter.
do they at least know at which speed, us, we are flying ? and which direction ?

Speed is very relative.
Without a reference frame you cannot tell if you are moving or not.

Speed is very relative.
Without a reference frame you cannot tell if you are moving or not.

That is the point several posters are missing.

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Speed is very relative.
Without a reference frame you cannot tell if you are moving or not.

That is the point several posters are missing.

Directions is however interesting.
The General Relativity theory suggest that everything in space are moving in a constant speed in our Space-Time universe. The Speed of Light.
Which means you can travel in space in both directions of Space and Time.
But the total sum of the speed travelling in the Universe is the travelling speed in Time and the travelling speed in Space.

But this thread has drifted from the title rather a lot now.

Agreed.
So I will make a new thread in "Science (non-SETI)" called "Science that doesn't make sense"

I have SETI and Einstein running also on my ulefone smart phone,which has 8 processors and also a GPU which is not used at the moment. SETI is also running on the Windows PC with its GTX 1050 Ti GPU board,where GPUGRIDS GPU tasks all fail. I was advised to reduce the GPU clock but,frankly, I don't know how to do it since I am not a Windows expert. The same GPU tasks run perfectly on my main Linux box with its GTX 750 Ti, set at default values.
Tullio

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SETI@home is only a minor player in SETI, but it is the only one that is a mass phenomenon. Maybe a sociological inquiry on SETI@home could find a reason. Something similar was done for Einstein@home users, although no one of them found any gravitational wave. But they found many pulsars, both radio and gamma-ray, the latter in data coming from the Fermi space telescope.
Tullio

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LHC has discovered the Higgs boson, not gravitational waves. They were discovered by the LIGO/VIRGO interferometers in USA and Italy.
Tullio

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Many years ago I edited the Italian version of a book, "The riddle of gravitation", by Peter G.Bergmann, a coworker of Einstein, which explains gravitational waves without recurring to mathematics. If you understand mathematics, my reference book on General Relativity is the biography of Einstein ("Subtle is the Lord") by Abraham Pais. Both books were written before the actual detection of GW. In 1970 I published on the Mondadori Yearbook of Science and Technology an article by Bergmann on whose front page I put a photo of Joseph Weber and his aluminium detectors, and was severely scolded by Antonino Zichichi because I had written in the caption that Weber had detected GW. He was right, of course.
Tullio

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Physicists have many different opinions on this and other subjects. It is only when an experimental evidence is available than on can say "physicists think".
Tullio

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