Speed of Light

[jimijohnson]

if a black hole is so strong that light can't escape its event horizon, is it powerful enough to slow down light that comes close to that point but doesn't pass it? or is it one or the other?

 

[jimijohnson]

but if gravity has an effect on light, why doesn't is slow it down. if so, does then only travel in to the centre of a black hole at the same speed?

 

[siarad]

I thought energy shifts came in quanta & not linearly as Doppler shift shows. Am I wrong?

 

[Maddad]

jimijohnson<br />Space contracts, gets smaller, in the direction of a massive object such as a black hole. The reason we say that light cannot escape the black hole's even horizon is that the space there is contracting faster than the speed of light. It contracts even more inside the event horizon, and less outside.<br /><br />Light passing close to the black hole but missing the event horizon will be bent in its direction because that bent path is now a straight line in space. It only looks bent to us observing from the outside.

 

[bobw]

<font color="yellow">I thought energy shifts came in quanta & not linearly as Doppler shift shows. Am I wrong?</font><br /><br />It seems like there are two ways to look at your question.<br /><br />If you are talking about the emission spectral lines from different atoms then yes, they have discrete quantized frequencies based on the excited electrons falling back into lower energy orbitals. Once the photons are emitted, though, the overall, quantized, characteristic spectral patterns can exist at any frequency determined by the doppler shift so the shifted frequency can be linear or continuous while the original frequencies were quantum.<br /><br />The other way to look at it would be if you are talking about the Planck units. I guess in those terms everything including time is quantized as opposed to linear or continuous. That isn't the kind of thing that this thread is about, though, I think.<br /><br />I don't know if I explained my thoughts very well but I understand what I was trying to write <img src="/images/icons/smile.gif" /><br /> <div class="Discussion_UserSignature"> </div>

 

[siarad]

Thanks, not quite my problem but it'll distort the topic for more

 

[Maddad]

steve<br />"<font color="yellow">space is so tightly curved that light cannot get out. It has NOTHING to do with contraction of space & EVERYTHING to do with the curvature of space.</font><br />If it has nothing to do with contraction, then what is the shape of the curve?<br /><br />"<font color="yellow">For someone who so recently insulted me about my purported mistaken physics</font><br />Because you only repeat what other smart mothers have said, you cannot understand the nature of the curvature of space. Contraction is simply another way of describing it, blackie. As for your mistaken physics, you deserved that one. You come off all high and mighty, telling someone that you're going to give them a lesson in basic physics. In the first place you got the ratio wrong; it's not 11 to 1. In the second place you didn't even know enough physics to understand that it wasn't as basic as what you should have learned in high school. It was advanced physics in which the ratio is pressure related. It just makes your arrogant "basic physics lesson" all the sweeter because it demonstrates that your head's stuck so far up there that you can't see what's going on. As usual.

 

[jimijohnson]

so if i understand correctly, light travels at a constant rate no matter what shape space takes. we may observe it as being bent or curved but in reality its just the space that is warped.

 

[Maddad]

Bingo! You nailed it exactly.

 

[wisefool]

Check out my web site which discusses what may go on INSIDE black holes: http://members.cox.net/clarkt7/InsideBlackHoles.html

 

[paintwoik]

I wouldn't give curved or contracting space a snowballs chance of being proofed. A photon near a black hole will change course through interaction with the extensions of whatever the BH contains. Sort of like traversing through tentacles.

 

[alokmohan]

Our observed universe is both a womb and observational tomb.Well described.But black hole can never have zero diameter .I have never heard or read anywhere.

 

[jmeyer]

Question for someone:<br /><br />Can light change its speed inside a black hole? How could one ever tell? If the laws of our earthly physics can break apart within a singularity, then how do we know if light is constant in our known universe. <br /><br />A singularity is part of our universe because it is in it, and if what we think we know as physicists can be void in such a place, then why couldn't photons, under the right circumstances, change their acceleration if the right circumstances were applied.<br /><br />I think travelling at multiples of c is very conceivable...we just haven't got that far yet. Someday we will harness this power. Some can disagree, but I'll guarantee 500 years ago, no one could conceive an atom, let alone splitting one to create vast amounts of energy.<br /><br />They would have said, well, "if you can squeeze a large stone into a smaller one, then let's see it." My point is, jst because we haven't the technology, doesn't mean something is constant....and wouldn't that have to include the speed of light?<br /><br />We just haven't the means to detect light's 2nd gear, yet.<br /><br />Constancy is only viable until change knocks.

 

[unseen]

Just wanted to ask a question. Could the speed of light be called the speed of time? I know light travels at c = 299'792'458 m/s (metres per second). . I know that it is said that we cannot go faster than light because then we will be infinite. If light travels through time then the speed limit is set by time not by light? Or could time have it's own speed limit and light has it own limit in time? Or if I am just dumb you can say that also..... <div class="Discussion_UserSignature"> </div>

 

[kmarinas86]

http://www.rpi.edu/dept/phys/Dept2/APPhys1/optics/optics/node4.html<br /><br />The speed of light in a medium is not proportional to the speed of time in a medium. The density of the medium is not proportional to the gravitational time dilation. Mediums of different densities can have the same rate of time.

 

[unseen]

Ok, read the site you posted, I get light changes speed. In a vacuum light moves at C. in a vacuum there are no particles but there is still time. So light traveling through time moves at C if there are no particles. So the speed of time = C ?? Or at least the maximun speed achieved in time is C. Is this correct?? <div class="Discussion_UserSignature"> </div>

 

[alokmohan]

Now solved.

 

[siarad]

Supposedly time stops at C so it appears related to C, well a formula so says.<br />Whether time 'moves' wrt light- I can't think how to measure it.

 

[daniko]

So what was the "<b>the speed of Time</b>" again ???<br /><br />This is the definition which I miss. Any ideas ???

 

[kmarinas86]

Rate of time is not constant.<br /><br />It varies depending where you are in the universe.

 

[unseen]

So if time stops at C. Then light does not travel through time as time would be stopped all over the Place? just a guess does anyone know? Also you need time to calculate how fast light travels. light could travel 270 million miles but how fast does it get there you need time to measure speed......Am I getting anywhere? <div class="Discussion_UserSignature"> </div>

 

[daniko]

I thik I might have the answer of this "Time <-> C" riddle.<br /><br />If you look at the history of physics - first it was believed that there is "absolute Position" and there is "absolute Time".<br /><br />Then Newton discovered that there is no "absolute Position" but remained with the understanding of the "absolute Time".<br /><br />Then Einstein discovered that there is no "absolute Time" but because there must be something absolute at which everything to be build on, he decided there is "absolute C" in vacuum.<br /><br />So the speed of light is not measured - it's just postulated to be!<br />From here - if speed of time ( or rate of time) changes by using the "absolute C" we just recalculate the Meter so that space shrinks/enlarges. That is when we speak that space is twisted.<br /><br />About the speed of light in mediun different from vacuum:<br />You must not mix this "speed" with C. That's because in no vacuum the light does not flow - it jumps like a flee from atom to atom. The speed of this jumps is C but the time light rests in an atom results in overall speed decrease.<br /><br />I hope being usefull <img src="/images/icons/smile.gif" />

 

[nexium]

Hi DanIKo: I can't find fault with how you said that, even though it is different from the usual way it is said. Perhaps there are no contridictions other than with usual wording. Neil

 

[MBA_UIU]

<font color="green"><blockquote><font class="small">In reply to:</font><hr /><p>"Rate of time is not constant."</p></blockquote></font>blockquote><font class="small">In reply to:</font><hr /><p><br />Ack...wrong answer. Please give this person a departing door prize. <br /><br />The speed of light and the measurement of time are relative to the observer within that frame. In other words if you and Tom were in the same frame you would both measure time as T and the speed of light as C.<br /><br />Now let’s say that I and super model Tammy were observing you from a hyper state of motion. We would have to use our perception of time T and speed of light C has a means to measure what we observe happening in your frame. <br /><br />So to Tammy and I would see you and Tom as moving at a fraction of T and the light in your frame as moving at a fraction of C. Yet because you and Tom our in this frame both T and C are measured in the whole. <br /><br />If Tammy and I could jump from our frame to yours then we would observe T and C from your reference and state that T and C have a relative difference of X when compared to the two frames, but this does not change the speed of either time or C in reference to either frame.<br /></p> <div class="Discussion_UserSignature"> <p><strong><font color="#0000ff"><br /><br /> <br /><img id="268587ce-7170-4b41-a87b-8cd443f9351a" src="http://sitelife.space.com/ver1.0/Content/images/store/6/8/268587ce-7170-4b41-a87b-8cd443f9351a.Large.jpg" alt="blog post photo" /><br /></font></strong></p> </div>

 

[MBA_UIU]

“I know that it is said that we cannot go faster than light because then we will be infinite”<br /><br />This is a common misconception. The fact is that your matter (the particles that you are made of) does not change in mass as you near the speed of light. What is changing is the mass like energy that your matter stores. This is easy to see if we compare the relationships of matter, mass and energy to a baseball.<br /><br />The matter (those atoms that make up its material) in a baseball is what makes it solid. We can measure its physical size by saying it is a sphere that is 9 inches in diameter. We can measure its mass by saying that it weighs one pound in earth’s gravity. We can measure its energy by saying that at rest it places one pound of force on a table top. So we see that at rest its mass and its potential energy (ability to do work) are equal. <br /><br />Now let us lift that ball 10 feet into the air. We can see that the matter in the ball, its physical properties, has not changed. We can see that the mass of the ball, when compared to its mass at rest, is still one pound. But what has changed is the balls potential (measured as stored energy) to do work. <br /><br />When we release the ball we change its potential energy to kinetic energy (the energy an object has in motion). Has the ball travels through the air its matter and mass do not change but it gains energy that is equal to an increase in mass. The effect of gaining energy while not changing in mass is called having a mass like energy. Now using E=mc^2 we can see that when the ball hits the table it will hit with a mass like energy of 4 pounds (this is just a guess I didn’t do the math). <br /><br />So we see that the ball’s matter, and its mass, did not change. What did change is the amount of kinetic energy (measured as mass) that the ball carried has it fell. These same principles hold true as we try to fly at the speed of light.<br /><br />Because light has no matter (no physical properties) and on <div class="Discussion_UserSignature"> <p><strong><font color="#0000ff"><br /><br /> <br /><img id="268587ce-7170-4b41-a87b-8cd443f9351a" src="http://sitelife.space.com/ver1.0/Content/images/store/6/8/268587ce-7170-4b41-a87b-8cd443f9351a.Large.jpg" alt="blog post photo" /><br /></font></strong></p> </div>