"The speed of light can only be measured one way"...... Just asking.

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shykitten55

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Nov 8, 2021, 3:06:42 PM11/8/21
to Robots & Dinosaurs
Sorry folks, it isn't I want to annoy anyone but I think people here may be able to help with this question:

A fair while back I watched a video on youtube:  something about the speed of light can only be measured one way.

Sorry it is:  This link

The guy doesn't look like he posts just to say things and does his homework.

I'm posting here because it is a bit of a long post and "you" know me better than that person and may better understand what I am asking.

I get what is said and the reason/s why it holds true.

But the other day I was thinking:  what is the speed of "bumping matter"?

The problem with measuring the speed of light is any dilation will cause problems measuring the time taken to get from A to B.

Let's go with the example of Earth to Moon.

The distance is known between the two.
So you are on Earth and about to send a message to the moon and want to know how long it takes.
Then send it back and compare the two times.

As is, it can't be done because of the dilation problem as explained in the video.

To get around this problem why can't you:

Have a very long rod from where you are sending it to the receiver.
When the message is sent, you "bump" (push) the end of the rod.

At the other end the rod will move.....

Will there be any "delay" in this happening?

Electrons (and radio waves) are limited to the speed of light - which we are trying to measure, so we can't use this medium to measure things.

Would my thought of a solid rod from the sender to receiver get around the speed of light problem?

I know it isn't practical, but just to ask how this works in comparison to the speed of light?

Andrew Larkin

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Nov 8, 2021, 3:46:54 PM11/8/21
to sydney-h...@googlegroups.com
"Bumping matter" results in signals travelling at the speed of sound in matter. This is faster than speed of sound in air but nothing compared to speed of light.

Remember that solids aren't actually solid as they are mostly empty space and create the appearance of solidity via forces between particles. 

shykitten55

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Nov 8, 2021, 3:50:55 PM11/8/21
to Robots & Dinosaurs
Ah, ok.  Thanks.
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