The dumb questions thread

[beero1000]

If there are two ants walking at opposite ends of a rubber band holding a steady pace and the rubber band is stretched, one might conclude that the perceived speeds have increased while the actual speeds have not. I got that. The problem is that the formula for calculating their relativistic speed isn't supposed to account for the difference.

It is a prediction of general relativity, not special relativity. Specifically, the  FLRW metric.

 

[humbleman]

Try looking up at night: every star you see is an image of how it looked in the past, because light travels at a finite speed.



The finite speed of light was first demonstrated in 1676, by Ole Rømer.

https://en.wikipedia.org/wiki/Rømer's_determination_of_the_speed_of_light

By timing the eclipses of the Jupiter moon Io, Rømer estimated that light would take about 22 minutes to travel a distance equal to the diameter of Earth's orbit around the Sun. This would give light a velocity of about 220,000 kilometres per second in SI units, about 26% lower than the true value of 299,792 km/s.

Your answer is telling me that Romer's calculation for speed of light was 220,000 kilometers per second, and today is calculated at 299,792 kilometers per second.

Have no idea what such difference of calculations has to do with observation of images of far away bodies as if they were in their past.

 

[humbleman]

Holy contradiction Batman!

X can't do Y, but X does Y, and here is why.

No, nothing is travelling faster than c--the space between galaxies is expanding.

Light travels through space at c. If space increases in size then light will take longer to traverse the space between two points. As a result, two points in space can get farther apart without moving with respect to their local reference frame.

You are telling us that space is dividing itself, not so that it's expanding.

New theory!

The Tectonic plates of space!!!!

(Remember humbleman discovered it)

Intuitively, we are used to space remaining constant: we assume the distance between two objects cannot increase unless one of them moves. This assumption works fine at human scales (where the metric expansion of space is negligible), but fails when dealing with intergalactic distances.

Wow. Then space is an environment that changes when is far away. Such changes can't happen around us, right?

I think you owe a clear explanation with the correspondent empirical corroboration that between galaxies their distance increases only because space expands. However, we have a galaxy traveling in our way and it follows the same principle of objects moving in order to change distance between themselves. By symmetry, for those far away distance galaxies we are the ones going away and doing it slowly. What about if they are the correct ones in this issue? How can you prove it?

I think you are confused. An explanation of such rare phenomena of the no need by galaxies to move in order to increase distance between themselves is badly needed. Space is not expanding unless you have a device capable to detect such expansion.

 

[James Brown]

[YOUTUBE]https://youtu.be/tXkBfkeJJ5c[/YOUTUBE]

 

[Jokodo]

I think you are confused.

I think you need to get a mirror if you want to see someone who's really confused.

 

[Jokodo]

Try looking up at night: every star you see is an image of how it looked in the past, because light travels at a finite speed.



The finite speed of light was first demonstrated in 1676, by Ole Rømer.

https://en.wikipedia.org/wiki/Rømer's_determination_of_the_speed_of_light

By timing the eclipses of the Jupiter moon Io, Rømer estimated that light would take about 22 minutes to travel a distance equal to the diameter of Earth's orbit around the Sun. This would give light a velocity of about 220,000 kilometres per second in SI units, about 26% lower than the true value of 299,792 km/s.

Your answer is telling me that Romer's calculation for speed of light was 220,000 kilometers per second, and today is calculated at 299,792 kilometers per second.

Have no idea what such difference of calculations has to do with observation of images of far away bodies as if they were in their past.

It's a demonstration that the speed of light is finite.

Another one would be laser distance meters, although here we're talking about nanoseconds rather than minutes. Fun fact: Astronomical and earth based measures agree to a high level of accuracy (in fact, the speed of light in air is slightly slower, but earth based measures in an artificial vacuum agree with space-based ones even better).

Given that we know light travels at a finite speed, and given that we know stars are far away, it follows that the light we see left there many years ago.

In fact, the most precise measurement for the distance of nearby stars is through parallax: We use the apparent shift of position caused by the movement of the earth around the sun to determine the stars distance through simple trigonometry. This gives us the stars distance in multiples of the earth-sun-distance. The earth-sun-distance, in turn, is measured by bouncing radio waves off Venus and measuring the time before you receive an echo (you can't bounce radio waves of the sun directly, the signal would be drowned). Then again some simple trigonometry based on the maximal angular distance of Venus and the sun tells you how much further the sun is than Venus.

One consequence of this is that, even if we couldn't measure the speed of light directly and had no idea how to express it in absolute terms as in meters per second, we'd still know that it takes the light from star y x many years to get here - because what we're measuring is its distance in multiples of the time it takes light to go to Venus and back!

 

[steve_bank]

Try looking up at night: every star you see is an image of how it looked in the past, because light travels at a finite speed.



The finite speed of light was first demonstrated in 1676, by Ole Rømer.

https://en.wikipedia.org/wiki/Rømer's_determination_of_the_speed_of_light

By timing the eclipses of the Jupiter moon Io, Rømer estimated that light would take about 22 minutes to travel a distance equal to the diameter of Earth's orbit around the Sun. This would give light a velocity of about 220,000 kilometres per second in SI units, about 26% lower than the true value of 299,792 km/s.

Your answer is telling me that Romer's calculation for speed of light was 220,000 kilometers per second, and today is calculated at 299,792 kilometers per second.

Have no idea what such difference of calculations has to do with observation of images of far away bodies as if they were in their past.

Better techniques and finer accuracy in clocks.

 

[humbleman]

[YOUTUBE]https://youtu.be/tXkBfkeJJ5c[/YOUTUBE]

What a wonderful idiocy.

No doubt that the video was made for entertainment purposes.

Here is a video that compare those distant galaxies with close galaxies to our location. This makes sense. As I said before, if something is going on far away from us, no doubt that we must experience the same.

Here is a more presentable video for teenagers and for adults. You really will learn a lot watching it.



And best, a video for seniors. (Bring your pillow)

 

[4321lynx]

If there are two ants walking at opposite ends of a rubber band holding a steady pace and the rubber band is stretched, one might conclude that the perceived speeds have increased while the actual speeds have not. I got that. The problem is that the formula for calculating their relativistic speed isn't supposed to account for the difference.

I agree. And what happens to all that Dark Matter and Dark Energy in the expanding Universe/Cosmos? Does it get "thinned out?"

 

[steve_bank]

Not thought experiments, real world mechanics. If you do not understand the ideas of inertial frames then you will not understand any of it. The problem of relative motion in Newtonian mechanics existed well before AE. What AE showed is that there is no absolute reverence frame in the universe, or at least we have no way of determining it.

The moving train is an inertial frame, imagine an XYZ set of axis in motion. Imagine an observer on the ground at the center of another set of axis. The observer on the ground is bnot stationary, the Earth rotates and moves around the solar system. An observer on Mars is a third frame.The choice of reference is arbitrary. The train example is a simple one. In practical work it gets much more complex with multiple frames. A complex machine with multiple moving parts and assemblies is a real world engineering example.

Obliviously you reject relativity. I assume then you reject the relativist principle that force equals mass times acceleration?

 

[steve_bank]

Also the speed of light is the limiting factor in the speed of your computer. It sets an upper limit how fast signals can travel in the processor and on the circuit board. A well established limitation.

Light refers to the visible portion of the electromagnetic spectrum, in practice the term infers all of the EM spectrum

 

[humbleman]

Your answer is telling me that Romer's calculation for speed of light was 220,000 kilometers per second, and today is calculated at 299,792 kilometers per second.

Have no idea what such difference of calculations has to do with observation of images of far away bodies as if they were in their past.

It's a demonstration that the speed of light is finite.

Another one would be laser distance meters, although here we're talking about nanoseconds rather than minutes. Fun fact: Astronomical and earth based measures agree to a high level of accuracy (in fact, the speed of light in air is slightly slower, but earth based measures in an artificial vacuum agree with space-based ones even better).

Given that we know light travels at a finite speed, and given that we know stars are far away, it follows that the light we see left there many years ago.

In fact, the most precise measurement for the distance of nearby stars is through parallax: We use the apparent shift of position caused by the movement of the earth around the sun to determine the stars distance through simple trigonometry. This gives us the stars distance in multiples of the earth-sun-distance. The earth-sun-distance, in turn, is measured by bouncing radio waves off Venus and measuring the time before you receive an echo (you can't bounce radio waves of the sun directly, the signal would be drowned). Then again some simple trigonometry based on the maximal angular distance of Venus and the sun tells you how much further the sun is than Venus.

One consequence of this is that, even if we couldn't measure the speed of light directly and had no idea how to express it in absolute terms as in meters per second, we'd still know that it takes the light from star y x many years to get here - because what we're measuring is its distance in multiples of the time it takes light to go to Venus and back!

OK. You were talking of sending radio signals bouncing in bodies and returning back.

However, look inside the entire internet that there is not a single connection between such a bouncing of signals with perception of images.

I will express better. Send a spark of light to the Moon which is closer and takes barely a moment for bouncing in the mirror and return. The spark of light will have a dark figure, with colored borders, lets say, a pig.

If you are correct, then you send the pig spark, the spark of light hitting the lunar mirror, returning back, and the lens of the receiver will sense and print the spark of light with the dark pig with colored borders.

The example given is a way you can prove that images travel with light.

Otherwise, the only thing you are saying is that light is finite, and I will tell you that images don't travel with light.

Your explanation explains finite light but not the observing of the universe as it was in its past, because such is not how the universe works. (I know how this part of the universe works but will be a lot of interchange of messages and in this thread only a few messages are allowed for a question)

Here right above, you guys must recognize, it was another question without the proper answer.

Dumb question.

A theory is not a law but just a hypothesis trying to explain something. In other words, science is not ruled by theories but theories must accomplish the rules established by science. One of the regulations of science is verification of evidence and verification of instruments used for measurement.

Actually, even when it has been taken as a great tool, the radiometric method of measurement has never ever been verified.

This means that the whole results obtained using this method are just conjectures. One can't lean on conjectures to affirm that a fossil is two million years old when the radiometric method still is unreliable.

Why do you think life on earth is of millions of years when in reality nothing corroborates it?

 

[Jokodo]

Your answer is telling me that Romer's calculation for speed of light was 220,000 kilometers per second, and today is calculated at 299,792 kilometers per second.

Have no idea what such difference of calculations has to do with observation of images of far away bodies as if they were in their past.

It's a demonstration that the speed of light is finite.

Another one would be laser distance meters, although here we're talking about nanoseconds rather than minutes. Fun fact: Astronomical and earth based measures agree to a high level of accuracy (in fact, the speed of light in air is slightly slower, but earth based measures in an artificial vacuum agree with space-based ones even better).

Given that we know light travels at a finite speed, and given that we know stars are far away, it follows that the light we see left there many years ago.

In fact, the most precise measurement for the distance of nearby stars is through parallax: We use the apparent shift of position caused by the movement of the earth around the sun to determine the stars distance through simple trigonometry. This gives us the stars distance in multiples of the earth-sun-distance. The earth-sun-distance, in turn, is measured by bouncing radio waves off Venus and measuring the time before you receive an echo (you can't bounce radio waves of the sun directly, the signal would be drowned). Then again some simple trigonometry based on the maximal angular distance of Venus and the sun tells you how much further the sun is than Venus.

One consequence of this is that, even if we couldn't measure the speed of light directly and had no idea how to express it in absolute terms as in meters per second, we'd still know that it takes the light from star y x many years to get here - because what we're measuring is its distance in multiples of the time it takes light to go to Venus and back!

OK. You were talking of sending radio signals bouncing in bodies and returning back.

However, look inside the entire internet that there is not a single connection between such a bouncing of signals with perception of images.

What, exactly, do you think an image is if not a collection of points with various light intensities? How do you think an image is recorded or received if not through light detectors?

Once we've established light travels at a finite speed, we've established that the images we see of distant objects are from the past -- be it in the nanoseconds range for things whose distance we measure with a laser distance meter, be it in the tens or hundreds of years for relatively nearby stars, and thousands and more for distant ones, millions for other galaxies.

 

[bigfield]

That is a weird opinion, because there is not an instrument capable to detect expansion of space.

Astronomers use an instrument called a telescope. It allows them to look at the electromagnetic radiation emitted by galaxies and measure the rate at which those galaxies are moving away from Earth by measuring redshift. Using telescopes, they have observed that the universe is expanding at an accelerating rate, something that cannot be explained by Newtonian mechanics but which is predicted by General Relativity.

 

[bigfield]

Your answer is telling me that Romer's calculation for speed of light was 220,000 kilometers per second, and today is calculated at 299,792 kilometers per second.

Have no idea what such difference of calculations has to do with observation of images of far away bodies as if they were in their past.

Since time has a finite speed, everything you see is seen as it was in its past. That is not difficult to grasp.

Intuitively, we are used to space remaining constant: we assume the distance between two objects cannot increase unless one of them moves. This assumption works fine at human scales (where the metric expansion of space is negligible), but fails when dealing with intergalactic distances.

Wow. Then space is an environment that changes when is far away. Such changes can't happen around us, right?

Yes, actually it is happening all around us (and inside us), but since we live in the gravity well of a a planet, the expansion is negligible.

I think you owe a clear explanation with the correspondent empirical corroboration that between galaxies their distance increases only because space expands. However, we have a galaxy traveling in our way and it follows the same principle of objects moving in order to change distance between themselves. By symmetry, for those far away distance galaxies we are the ones going away and doing it slowly. What about if they are the correct ones in this issue? How can you prove it?

From another (distant) galaxy's point of view, the light from the Milky Way is redshifted. No matter which galaxy you choose.

 

[bigfield]

Actually, even when it has been taken as a great tool, the radiometric method of measurement has never ever been verified.

This means that the whole results obtained using this method are just conjectures. One can't lean on conjectures to affirm that a fossil is two million years old when the radiometric method still is unreliable.

Why do you think life on earth is of millions of years when in reality nothing corroborates it?

We asked Satan to verify it. He said it totally checks out.

 

[steve_bank]

It is like trying to explain humans have been on the moon to an aboriginal tribe in the Amazon with hand gestures.

 

[Loren Pechtel]

OK. You were talking of sending radio signals bouncing in bodies and returning back.

However, look inside the entire internet that there is not a single connection between such a bouncing of signals with perception of images.

http://sci.esa.int/venus-express/50372-radar-map-of-venus-surface/

Observations made by NASA's Magellan spacecraft between 1990 and 1994 form the base of the image, with gaps in the data filled in by the Arecibo Observatory, which is based in Puerto Rico.

That's Earth -> Venus -> Earth.

https://en.wikipedia.org/wiki/Lunar_Laser_Ranging_experiment

Earth -> Luna -> Earth

This is used to get a very accurate measurement of the distance to the moon. That's by counting how long it takes.

Otherwise, the only thing you are saying is that light is finite, and I will tell you that images don't travel with light.

What do you think images are besides light???

And using Jupiter's moons as a clock is a case of images.

This means that the whole results obtained using this method are just conjectures. One can't lean on conjectures to affirm that a fossil is two million years old when the radiometric method still is unreliable.

Why do you think life on earth is of millions of years when in reality nothing corroborates it?

Radiometric dating is fine, despite what some creationists would have you think. So long as you are dealing with an uncontaminated sample it gives good results. C-14 dates are short enough ranged that they can be directly cross-checked against tree rings and ice cores, both of which generally give a year-accurate count.

 

[fast]

If there are two ants walking at opposite ends of a rubber band holding a steady pace and the rubber band is stretched, one might conclude that the perceived speeds have increased while the actual speeds have not. I got that. The problem is that the formula for calculating their relativistic speed isn't supposed to account for the difference.

It is a prediction of general relativity, not special relativity. Specifically, the  FLRW metric.

Maybe I'm not expressing what I'm wanting to express.
I'm not saying an object is exceeding the speed of light through space. I'm saying an object is exceeding the speed of light.

Let's go to the Wild West where two gunfighters stand back to back and begin walking away from each other and they each take off at 95% the speed of light. Neither one is exceeding the speed of light relative to the ground, but if the ground itself between them begin to stretch causing their respective distances from one another to substantially increase, then although it will still be the case that neither is traveling greater than the speed of light relative to the ground (that's still at .95c), if the ground stretching is substantial enough, then calculating their speeds relative to each other (not the ground) should yield a speed that yields an answer greater than c.

 

[fast]

If there are two ants walking at opposite ends of a rubber band holding a steady pace and the rubber band is stretched, one might conclude that the perceived speeds have increased while the actual speeds have not. I got that. The problem is that the formula for calculating their relativistic speed isn't supposed to account for the difference.

I agree. And what happens to all that Dark Matter and Dark Energy in the expanding Universe/Cosmos? Does it get "thinned out?"

Seems like a reasonable explanation.