NowThatWeKnow

You don't need a single photograph to know that every location will share a point in time with any other location. Einstein Online just shows that events at any two locations can be simultaneous and they call that "now".

Gly is billion light years (see legend on calculator site). "Angular size distance D" is the distance the galaxy was away from us when the light was emitted. z at the top right is red shift and z + 1 is the expansion factor. "comoving radial distance" is the galaxies current location.

If the light took 13 billion light years to get here, then you are seeing light that came from a galaxy when it was only 3.3465 Gly away. That galaxy is now 29.701 Gly away from us. Space had an expansion rate of 8.875 times while the light traveled. http://www.astro.ucla.edu/~wright/DlttCalc.html If you put 13 in the left box that says "light travel time in Gyr" and click flat, You will see where the #'s came from. The expansion of space is z + 1.

An infinite number of cameras would show any location would share a point in time with any other location. Maybe my thoughts are not coming out clear but I do not disagree with what you are saying or have been saying. Actually, I am not sure how or why I got back into this thread.

Einstein considered it more then once and your friend Frank Wilczek will probably define it soon. From a layman's point of view it would solve many problems. For me it is hard to grasp the uniformity of the expansion of the universe without an ether. Or, you can only break the speed of light with the help of space (metric of nothing) expanding.

What you are saying is two people on different floors of a building can not share the same "now". Einstein Online defines "now" and I interpret it to say two events in two different frames can be simultaneous. Isn't that what you understand from the quote below? As posted earlier in this thread. The definition of "now" http://www.einstein-online.info/en/spotlights/Now/index.htmll "two events are simultaneous if and only if they can be seen on the same photograph, taken with a double camera placed exactly in the middle between their locations."

I see "now" as a single point in time if I could be everywhere in the universe at once. The clocks on Earth and the clocks on the GPS satellites may run at different speeds but they do share a simultaneous point in time. With enough information you could compare your "now" to any locations "now" in the universe. Therefore a universal absolute "now" is possible. What is the flaw in my logic?

It almost sounds like Martin is a closet ether person, waiting for the right definition of ether.

At this point, who has the authority to permit or stop another country from developing? We will just sit here and watch the coal go into the furnace.

No you didn't but your reply to me was in defense of a more optimistic view and did not offer any additional measures that might be considered for a healthy planet. I do not consider myself an environmental alarmist but do see a potential for future problems when it comes to population, pollution and consuming natural resources. I also believe a balance is good but if we do error one way or the other, not giving enough credit to the alarmist could be capable of more damage then following their advise.

So you are saying it is business as usual and no change is needed. Jump in the SUV and head to the boat on the lake. This planet can take any thing we can throw at it. The forest getting smaller and the deserts getting larger are no big deal. The scientist saying we are using up our planet faster then it can replenish itself are not only working with a bad time table, they are flat wrong. Hmmm, I am not so sure "optimistic" is the right word.

While there may be some argument left on how quickly man is destroying the environment, the fact that he does have a negative impact is obvious to most. Between pollution and consuming natural resources at exponential rates, we will be in trouble at some point. The pictures of air quality at the olympics in China suggest it may be sooner then later. If it is a matter of when and not if, what should we be doing now to correct the problem? While technology is moving quickly, I do not see it staying up with with the population explosion. The population of the world goes up by over 200,000 per day. That is like adding the population of my entire state (Oklahoma) plus another 1 million people to the world every month. How long can that go on? The waste alone from the 90,000 chickens a minute we consume is a problem by itself. http://www.peterrussell.com/Odds/WorldClock.php

http://en.wikipedia.org/wiki/Hubble's_law "Hubble's law is the statement in physical cosmology that the redshift in light coming from distant galaxies is proportional to their distance." It is often explained using a balloon with dots on it representing the galaxies. As the balloon expands, the distance between the dots increases no matter where you are on the surface of the balloon. The further away you are from a dot, the faster it is moving away from you. This expansion is from space expanding and not from the galaxies moving. Local gravitational forces keep galaxies and galaxy clusters from expanding.

It does not seem that is going to be the case around here.

A magnetic field strong enough to protect you would probably cause all sorts of problems. Digital media and instruments for one plus anything attracted by magnets would be stuck to the wall.

With the first law of thermodynamics in mind, what is the photon converted into and out of when being absorbed?

I did read your post above. The average speed and instantaneous speed being different is what may be confusing to some. Then you have the observed speed from different frames to complicate it more.

I am not disputing what is being said here but the speed of light, relative to different observers, is not observed as constant. Warped space or water, the time to travel a given distance is variable. Hence, the speed of light being constant may confuse many.

Does stopped or moving sound like a constant speed? If the photon can only maintain its speed the distance between molecules, then would it be harmonious with "Distance traveled divided by the time of travel"? It would be relative to a particular distance and your point of view.

It does make you want to slap at it. As far as light speed being constant. I can see why many would be confused. The explanations given and the physics definition of speed are not harmonious.

Most probably consider this thread over but could someone please explain how absorption and re-emission of photons is not slowing them down? I visualize a drop of water falling into a sponge and eventually making it out the other side, effectively being slowed down. I also do not see how refraction of something moving 186,000 miles per second can make it look like it is standing still. You can't shine a light into two opposing mirrors and expect it to continue when the source is turned off. It would seem the time between two points determines the speed.

Very interesting. Is this saying that to the naked eye, something would disappear as it falls into a BH since the photon frequency would be outside the visible light range?

Like a big magnet collecting matter? Could you elaborate on that? Or a link.

Good point. Right words for the wrong situation. I knew better if I would have thought about it. I see why they let you stay around. Merged post follows: Consecutive posts merged Hubble's law says that galaxies are moving away from us at a speed proportional to their distance but this does not always apply to nearby galaxies effected by local gravity. I see no reason why the expansion would not apply to spacetime outside of our visible universe. http://www.physlink.com/Education/askExperts/ae384.cfm "There are about 100 known galaxies with blueshifts out of the billions of galaxies in the observable universe. Most of these galaxies are in our own local group, and are all in orbit about each other. Most are dwarf galaxies among them include the Andromeda Galaxy,"

Welcome! The observer in between sees them seperate a 1.5c but to each other the galaxies are seperating at .96c. A few calculators to help with the math. http://www.cthreepo.com/cp_html/math1.htm http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/einvel2.html Merged post follows: Consecutive posts merged At this point the rate of expansion is actually increasing.