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#15022940
Agent Steel wrote:Maybe the speed of light is a constant throughout history, but I do think that @Hindsite has a point about uniformity in general. For example look at geology - why do scientists assume for example that because the rate at which the continents are moving right now (a fraction of an inch per year) that this must have be the same rate they've been moving for all of history? That is simply not reasonable.

This is actually an open question in geology, and is the source of much debate.

Or, take the expansion of the universe. If there was a giant explosion in space that pushed away all matter, why do scientists make assumptions about the entire cosmic history based on just the rate of galaxies' movement that we observe in the present? Again, it's very speculative and in many ways just defies common sense. Also, isn't the finding of an accelerating universe evidence AGAINST the big bang? If there was a big bang we would expect things to be slowing down. So what does science say about this? Nothing really; they're baffled.

Being baffled is the necessary precursor to interesting science being done.

I do agree that many of the mainstream scientific ideas are based on unprovable assumptions. To be honest, I've heard even non-religious scientists reject the big bang theory. It was invented by a catholic priest after all, and in a way it's a religious view, sort of masquerading as science.

It doesn't matter who came up with the Big Bang theory - it is a perfectly respectable scientific theory. This is the thing about science - the ideas stand or fall on their own merits. Nobody cares whether the guy who came up with it was Jewish, a Catholic priest, a non-conformist preacher, or a stamp-collecting pervert. Doesn't matter. Lol.

Now as for light, I honestly don't think we fully understand how it works. Honestly, can anyone here really say they understand the theory of relativity? Most people can't grasp it.

The special theory of relativity is relatively straight-forward to understand. After all, thousands of physics graduates study it and pass exams on it every year. General relativity, on the other hand, is mind-bendingly difficult.
By B0ycey
#15022962
Agent Steel wrote:Maybe the speed of light is a constant throughout history, but I do think that @Hindsite has a point about uniformity in general. For example look at geology - why do scientists assume for example that because the rate at which the continents are moving right now (a fraction of an inch per year) that this must have be the same rate they've been moving for all of history? That is simply not reasonable. Or, take the expansion of the universe. If there was a giant explosion in space that pushed away all matter, why do scientists make assumptions about the entire cosmic history based on just the rate of galaxies' movement that we observe in the present? Again, it's very speculative and in many ways just defies common sense. Also, isn't the finding of an accelerating universe evidence AGAINST the big bang? If there was a big bang we would expect things to be slowing down. So what does science say about this? Nothing really; they're baffled.

I do agree that many of the mainstream scientific ideas are based on unprovable assumptions. To be honest, I've heard even non-religious scientists reject the big bang theory. It was invented by a catholic priest after all, and in a way it's a religious view, sort of masquerading as science.

Now as for light, I honestly don't think we fully understand how it works. Honestly, can anyone here really say they understand the theory of relativity? Most people can't grasp it.


Well hindsite has brought religion into this so I think Godstud has a point if you are looking to a scientific response AS. I have no issue with religion in this thread but at least understand the motives when reading the context.

Nonetheless if the speed of light varies it can answer why there is missing gravity in the universe (dark matter). So it should be questioned more actually.

Personally (no evidence that is published) I think the speed of light is a constant. But it is 0. It is in time limbo and only appears to move as it expanse within the universe you are in. Expansion is different depending where you are in the universe (so light speed varies). And in our part of the universe we expand at what we consider to be the speed of light and as such we can only measure that speed. I wrote a thread on this a while ago if you're interested.

Nonetheless in terms of your question in the OP, whatever you believe, light has to reach the lens before an image can be created. Better lens cannot improve the time in which you see the light. And as such light can be measured by observation.
#15022972
I get what you guys are saying, but why can't they prove the theory with testing? Everything they're saying is merely theoretical until it gets tested.

What I want to see is actual evidence, video footage if preferable, of a light beam traveling through space so that we can actually see it while it moves. How come we don't see any examples of beams of light shooting in different directions throughout space? And how many directions does light actually travel? Is it just a beam that goes in one direction or in every direction?

Light is largely mystery, unlike sound. We understand a lot more about sound waves than light particles. I'm still not convinced of the claim that because we SEE a dot of light, that therefore the light has reached our position. I see some good arguments but I don't see EVIDENCE.

Furthermore, how the hell do we even know what is we are looking at, billions of light years away? How do know when, where, and what the source of that light even is? How do we know it hasn't always existed that way?
#15022991
Agent Steel wrote:I get what you guys are saying, but why can't they prove the theory with testing? Everything they're saying is merely theoretical until it gets tested.

What I want to see is actual evidence, video footage if preferable, of a light beam traveling through space so that we can actually see it while it moves.


https://gizmodo.com/how-the-speed-of-li ... 1138348467

Also, that is not how optics works.

How come we don't see any examples of beams of light shooting in different directions throughout space?


Actually, we do.

And how many directions does light actually travel? Is it just a beam that goes in one direction or in every direction?


It radiates.
#15023000
anasawad wrote:@Potemkin
Correct me if I'm wrong, But isn't general relativity not complete thus far?

It is complete, and it's been complete since 1916, when Einstein finally crossed the t's and dotted the i's of his theory. However, it is not consistent with the other main pillar of modern physics - quantum theory. General relativity explains gravitation (and therefore cosmology), but quantum theory explains almost everything else. Given the choice, most scientists would rather throw out general relativity than throw out quantum theory. But either general relativity is wrong, or quantum theory is wrong. Something has to give.
#15023020
Agent Steel wrote:What I want to see is actual evidence, video footage if preferable, of a light beam traveling through space so that we can actually see it while it moves.




Ask and you shall receive...
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By Saeko
#15023024
Agent Steel wrote:Furthermore, how the hell do we even know what is we are looking at, billions of light years away? How do know when, where, and what the source of that light even is? How do we know it hasn't always existed that way?


One way of determining distances to distant stars is to use trigonometry. The distant star is observed when the Earth is at two different points in its orbit around the Sun. The star will appear to shift its position in the sky a little bit. It's then a simple calculation to figure out how far away the star is.

For objects that are much further out, such as distant galaxies, they measure the distance of things by measuring their brightness. The further away a bright object is, the dimmer it gets, and this dimming is always proportional to the inverse square of the distance, making the calculation easy. The only schtickler with this method is that you somehow have to figure out the true brightness of stars in the distant galaxy. This is done by using what are called "cepheid variables" which are special stars whose brightness is related in a very simple way to their pulsation period.
#15023037
Agent Steel wrote:Ok, this might be a stupid question, but it came to me, and I don't know how to answer it, so I want someone else to answer for me.

I was watching a video about the size of the universe, and one of the claims they made is that if we can see light from distant stars and galaxies that are billions of light-years away, then the light must have been traveling for billions of years.

I'm not entirely sure why to be honest. Sure, common sense might tell us that if we can see a light, that it has therefore reached our position. My brain doesn't see how that follows logically. Why does light have to reach us in order for us to see it at some distant point billions of light-years away, so long as it's bright enough and we have good enough equipment to see that far?


If you can understand that the speed of light is also a measure of the distance that light has travelled in time, then it shouldn't be too difficult.

Light is a particle(photon) as in a quantum state, but it's also a 'wave', which is how we measure it's spectral frequency, much the same as we do in the radio spectrum etc.
If you can understand that light is actually radiation, that it is within the 'visble' spectrum of a much wider band of radiation from Gamma-Infra Red, then that indicates that visible light operates within a frequency band of it's own, just as X-Rays, Gamma Rays, Infra Red et'c have their own frequency bands.

Consider the above with Hubble's 'Constant', as well as the speed of light, which is a constant that has been scientifically verified before your time, which has it's own character 'C' as used in equations, you will note that some stars have different colours, ranging from red,orange, yellow, white or blue, those colours indicate the type of radiation being emmitted from them, that is to say, their thermal temperature & the frequency of the light.

As galaxies are moving away from each other in general, they are also accelerating at higher speeds, so that every doubling of distance from the observer, so too their speed, when they reach some 8 billion light years away, the effects of red -shift can be observed.
As distance also equates with time, in this case, 8 billion light years, the galaxy has aged by 8 billion years,so it should be emitting radiation cooler than that if it was moving towards us, which is why it is redder & the opposite would happen if it were moving towards the observer- in the direction away from red-blue.

When you see light from stars, it looks exactly the same for any observer looking at it from the same distance & time anywhere in the universe.

If you could switch off one of those distant stars or galaxies, say it was some 8 billion light years away,it would be 8 billion years before you could observe that the light had been switched off.

There's nothing 'complicated' about it, it's just physics, of which we are also a part of.
#15023077
Godstud wrote:The thing about science that @Hindsite can't comprehend, is that unless you can prove otherwise, you can't make stupid, and outlandish claims. His suggestion that the speed of light has somehow changed, borders on sub-moronic, not "near genius". :knife:

What I am suggesting is that the conditions we live in today may not have been the same throughout all time and space. Even mainstream scientist of today say the space in the universe has been expanding from the beginning of the so-called Big Bang.

According to the Holy Bible, God created light first and then the water and earth in the early space before much expansion. Our sun and the moon were created to help regulate the seasons as soon as the earth had been made ready for plants and living creatures, including man. It appears from what is written that God stretched out the fabric of space in the heavens to expand it as more stars were created to fill it.

We can study, test, and learn about physics and other sciences as they exists in our world today, but it is likely wrong to assume we can extrapolate backwards in history to the beginning of creation based only on what we know about the science of today.
#15023138
Agent Steel wrote:I get that, but why couldn't we see distant light with TELESCOPES? The light doesn't have to reach US, it only has to reach the point where the telescope can see!

The light still has to reach the telescope, which isn't much further away from your eye. All a telescope does is magnify/focus the light you are interested in.

Agent Steel wrote:Theoretically if a light is big enough and bright enough shouldn't we be able to see it even it's billions of light-years away?

Think of sound and an echo. There's a time delay with light, it's just not easily perceived by humans.

Godstud wrote:Troll off, @Hindsite. We don't you need your bullshit religion in a serious discussion about something that's quite clearly scientific. Your religious nonsense is just stupidity, and peddling it is childish.

To a significant degree, physics depends on math, and math is not physical. As much as atheists think they have escaped metaphysics, they have not. They just put on blinders and project arrogance in lieu of answers.

Agent Steel wrote:Why don't we go to the moon and shine a huge beam of light towards earth so we can see the time delay and then prove the theory?

There are reflectors on the moon. They beam lasers up and catch the reflection. So it has already been done.

Godstud wrote:The thing about science that @Hindsite can't comprehend, is that unless you can prove otherwise, you can't make stupid, and outlandish claims. His suggestion that the speed of light has somehow changed, borders on sub-moronic, not "near genius". :knife:

However, modern theory suggests space is expanding. So the distance between the source and destination itself is not constant, even though we assume the speed of light is constant. So we can't simply do 'distance x rate = time,' because distance is elastic, unless you assume that space is only expanding at the edge of the universe. However, modern theory suggests otherwise.

Godstud wrote:The tone is always lowered when someone brings in religion where science is concerned, and the "insults" as you so put it are valid given the incessant bragging about being a "near genius".

Most of the great scientists have been religious. Copernicus was certainly a greater scientist than you could ever hope to be and he was also a doctorate of canon law, had a sinecure and worked for his uncle, a bishop. Galileo wanted to be a priest, but his father talked him out of it. So he studied medicine instead. Kepler used religious arguments in his works as well. So did Newton. Science does not preclude religion. Heck, even Max Planck was a church warden. Science simply attempts to observe, identity and describe phenomena. To the extent that it attempts to predict phenomena, it relies on mathematics, which is not physical.

Potemkin wrote:There is also nothing to support the hypothesis that the laws of physics are constant throughout all of time and all of space.

There is evidence to suggest the opposite--for example, that the strong and weak nuclear forces were unified early in the Big Bang but became separate forces.

Agent Steel wrote:To be honest, I've heard even non-religious scientists reject the big bang theory.

Yeah. The Big Bang is suspiciously close to a biblical interpretation of creation.

B0ycey wrote:Nonetheless if the speed of light varies it can answer why there is missing gravity in the universe (dark matter). So it should be questioned more actually.

Well, Bose-Einstein condensate has demonstrated that it can slow down the speed of light.

B0ycey wrote:Personally (no evidence that is published) I think the speed of light is a constant.

So you deny observations on the behavior of light through Bose-Einstein condensate then?

Agent Steel wrote:What I want to see is actual evidence, video footage if preferable, of a light beam traveling through space so that we can actually see it while it moves.

Well, that's what's kind of cool about Bose-Einstein condensate. Through a Bose-Einstein condensate, light travels about 17 MPH. :-)





By B0ycey
#15023139
blackjack21 wrote:So you deny observations on the behavior of light through Bose-Einstein condensate then?


How did you reach that conclusion from my quote? :eh:

I don't deny observations or why scientists reached their conclusions. Although I do believe we rely on our senses too much and that conclusions made can ultimately be wrong despite the observations noted. Although it does need to be said that if light has no speed and reacts with the expansion of spacetime (as light is within all time) and matter, how do you know what you observe is light moving or space time expanding?
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By Rancid
#15023157
The universe is expanding, so why aren't we expanding with it?

My understanding is because the nuclear forces that keep atoms together is stronger than he force that is expanding the universe.
#15023164
Rancid wrote:The universe is expanding, so why aren't we expanding with it?

My understanding is because the nuclear forces that keep atoms together is stronger than he force that is expanding the universe.

Precisely right. The strong and weak nuclear forces dominate the gravitational force on the short length scales on which humans live.
#15023165
Potemkin wrote:Precisely right. The strong and weak nuclear forces dominate the gravitational force on the short length scales on which humans live.


Does that mean we got the short end of the gravitational scale and it is keeping us in this horror of a nightmare of short term political thinking Bellisimo?

We are stuck in the short end of the stick for all time? :) :lol:
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By Rancid
#15023166
@Potemkin

Two questions for you. Not sure if these make sense.

1. Does light experience time? Is that even a valid question?
2. My understanding is we're are traveling at a constant rate through space-time. If you travel in one dimension you basically slow down your travel in the other. If I move through space really fast, my time relative to others slows. If I don't move through space relative to light, my time speeds up relative to others.. Some shit like that. ANyway, my question is, what is the rate of space-time as whole? Is there such a constant value?

What got me thinking about question 2. is that I'm currently doing some energy-time measurements on some stuff for my job. It got me thinking about space-time.


I forget, you studied physic at university right?
#15023173
[quote]
Two questions for you. Not sure if these make sense.

1. Does light experience time? Is that even a valid question?[/quote]
It's not really a valid question. Anything travelling at the speed of light experiences no elapse of any duration of time, subjectively. From the viewpoint of an external observer, however, a light photon moves from place to place at a certain (fixed) speed.

[quote]
2. My understanding is we're are traveling at a constant rate through space-time. If you travel in one dimension you basically slow down your travel in the other. If I move through space really fast, my time relative to others slows. If I don't move through space relative to light, my time speeds up relative to others.. Some shit like that. ANyway, my question is, what is the rate of space-time as whole? Is there such a constant value?[/quote]
Everything with non-zero mass is travelling through time at the speed of light. If we move through space at a constant speed, we are subjectively remaining stationary, and we are [i]still[/i] moving through time at the speed of light. From the viewpoint of an external observer relative to whom we are moving with a constant velocity, some of our motion through time has been replaced by motion through space. In other words, any acceleration is actually [i]a rotation in the 4-dimensional space-time manifold[/i]. But it's not just a standard rotation - the time axis is unlike the three space axes in the sense that time is measured using imaginary numbers and space is measured using real numbers (or vice versa, it doesn't make any difference). Replace the variable 't' with 'ict', where i is the square root of minus 1 and c is the speed of light, and then do a rotation away from the time axis. You'll find that you can derive the Lorenz-Fitzgerald equations directly from the rotation matrix. Length contraction, time dilation, the lot. Just from a simple rotation matrix. You're an engineer; you do the math. :)

[quote]
What got me thinking about question 2. is that I'm currently doing some energy-time measurements on some stuff for my job. It got me thinking about space-time.
[/quote]
It is time well spent. :)

[quote]
I forget, you studied physic at university right?[/quote]
I have an MPhil in nuclear physics.
#15023234
Saeko wrote:One way of determining distances to distant stars is to use trigonometry. The distant star is observed when the Earth is at two different points in its orbit around the Sun. The star will appear to shift its position in the sky a little bit. It's then a simple calculation to figure out how far away the star is.


Of course I understand trig just fine, as I excelled quite far in math and am adept in calculus.

But how in the world could trig be considered a reliable method to measure distances that are BILLIONS of light years away? How do you know that distant star has not also moved??

Then of course there's the whole problem of the 4 dimensional bending of space-time, which trigonometry does not account for.

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