In another post there is an example of a vessel moving close enough to the speed of light that the journey to the galaxy Andromeda 2.5M light years takes only 4 hrs on the vessel's clock. In its own frame of reference the vessel is moving just above 600K LY/hr. Yet a photon that left at the...
Exactly where is the throat of the wormhole actually located, and when you transit it where are you? What is the energy source and where is it located? In the theory of these wormholes, can one manufacture them at will or are they already present and you simply adapt them to your needs? It seems...
Yes, it seems the "throat" should be stretched out through both space and time--btw what I meant in the question was the portals moved in lock-step with the movement of the inertial frames in which they were opened, not with the initial coordinates of those frames.
To help understand the...
What about "cosmic inflation" or an "expanding universe." These may be difficult concepts for astrophysicists to embrace or demonstrate. For economists and governments they are axiomatic. As for any difficulty in describing the "Big Bang" as creation ex nihilo from a scientific standpoint...
Hi- I am a bit new to PF and have also been struggling with some of the more basic aspects of Special Relativity--see "is the behavior of light all that remarkable" for a few juicy missteps. I was referred by George Jones for an understanding of how velocities add in special relativity. In...
Then for a vessel receding from a stationary observer at relative velocity .9c, light emitted by the stationary observer, and measured by him as moving through the vacuum of space at light velocity c, is also measured by the moving observer at light velocity c relative to his moving ship...
In post 1068268 you mention 4 methods of dealing with paradoxes. If I am reading the post correctly there are really only 2, since the last 2 methods deal with paradox problems by forbidding time travel altogether. This leaves the first 2 methods. The first is a bit ambitious--rewrite...
Well said, but without getting into "seeing sound sound waves" as per HallsofIvy--as opposed to IvyCoveredHalls?- if I turn off the jets and let the plane glide, open the windows and a stationary, let's call him listener, listens for the captain to make his landing announcement, what does he...
There is--actually was--a thread entitled something like "Feynman's double slit experiment" where passions ran so high the thread was locked down. At least one poster categorically denied that the statement "interference patterns continue to appear even when there is only one photon at a time...
According to your analysis the speed of the sound of the engines of a commercial jet flying overhead at mach .75 will be mach 1.75 (v(sound) + v(jet)) and would not be heard by a stationary observer as the customary roar, but as a sonic boom. In this case your analysis is not correct.
Excellent, thank you. This is not intended as a new observation as I discuss below, just an attempt to find everyday analogies to help in the education of the "general public." Continuing the analysis, the stationary observer can deduce the velocity of the source by observing the doppler shift...
Relative to the stationary observer the speed of sound in air IS EXACTLY the speed of sound in air no matter how fast the moving source is going as long as it is below the speed of sound and for the people on the train, the speed of sound IN THE TRAIN is independent of the speed of the train...
What about the special case in which the sound is emitted inside one of the cars of the moving train? Both then measure the speed of sound the same in contrast to the case of a tennis ball thrown inside the train where the mover measures the velocity of the ball, but a stationary observer...