question

Relative to what exactly? I mean, is there any point in knowing a number
when we have nothing to measure it against. No centre of the universe.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Max Demian" wrote in message
...
"Dave Farrance" wrote in message
...
Graham. wrote:

You want me to say ether and then give me Stephen Fry's klaxon for not
spelling it aether.

(Let's call the whole thing off).

Ya know, Einstein himself said that his own model of space could itself
be
thought of as an aether, as it brought back the idea that empty space has
its own physical properties. i.e. it's not "nothing".

But at what speed is the earth travelling through it?

--
Max Demian

I think he was just musing. Does there have to be something behind a
question?
Here is another one.
We have made materials that appear to slow light down significantly, ie
Refraction etc, but it seems if you measure it in such materials its still
the same speed. I suppose it all depends on where you view things from.

There is also this weird effect that a single photon can create an
interference pattern when fired through slits of course.
Where is Schrödinger's cat when you need it?
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Steve Thackery" wrote in message
...
Bill Wright wrote:

What is the medium through which radio waves travel?


Space. Which is to say, there is no medium. Nor is there any need for
one.

But you know that, so what's really behind the question?

--
SteveT

On Mon, 26 May 2014 00:19:43 +0100, "Brian Gaff"
wrote:

Mystic Meg?

Brian


They wheeled out Russell Grant on the box last week. I hadn't seen him
in years.



--

Graham.

%Profound_observation%

Steve Thackery wrote:
Bill Wright wrote:

What is the medium through which radio waves travel?


Space. Which is to say, there is no medium. Nor is there any need for
one.

How can a 'wave' (for want of a better word) exist without a medium?


But you know that, so what's really behind the question?

It's something I often wonder about. There are other things of course.

Bill

On Sun, 25 May 2014 22:23:08 +0100, Graham. wrote:

On Sun, 25 May 2014 21:12:21 +0100, Bill Wright
wrote:

Graham. wrote:
I'm sorry, I'll write that again.

You want me to say ether and then give me Stephen Fry's klaxon for not
spelling it æther.

(Let's call the whole thing off).

That's better.

Bill

I had to look for the diphthong glue.

The gluon?
--
Peter.
The gods will stay away
whilst religions hold sway

On Mon, 26 May 2014 00:31:01 +0100, Brian Gaff wrote:

Relative to what exactly? I mean, is there any point in knowing a number
when we have nothing to measure it against. No centre of the universe.
Brian

We could use the Earth as a reference - call me geocentric if you will.
--
Peter.
The gods will stay away
whilst religions hold sway

On Mon, 26 May 2014 02:02:19 +0100, Bill Wright
wrote:

How can a 'wave' (for want of a better word) exist without a medium?

Why should it need one?

How can a question exist without an answer?

Rod.

Bill Wright wrote:

How can a 'wave' (for want of a better word) exist without a medium?

I'll explain how I see it. Clearly, we all know that some waves *do*
exist in a medium - sound waves, ocean waves, etc. These are
"mechanical" in that they involve the medium itself moving back and
forth, up and down, etc. We know that the medium itself does NOT
travel along with the wave, but it DOES move to facilitate the wave
passing through it. In other words, sound waves cannot exist without a
medium to conduct them.

There is another type of mechanical wave which does not require a
medium. Longbowmen can synchronise their firing and send "waves" of
arrows through the air. The waves propagate at a particular speed, and
they have identifiable peaks and troughs. You can measure the
frequency, the wavelength, and the velocity with respect to the
longbowman. Yes, they behave differently from normal waves in some
ways, but I'm mentioning arrows to illustrate my main point, coming
next. Importantly, waves of arrows do not require a medium - they can
travel through air or space. In other words, when it comes to arrows
the medium is irrelevant and not required.

Now replace the arrows with a magnetic or electric field. You will
agree that a magnet works just the same in air or a vacuum? Take an
electromagnet. Switch on the current. A magnetic field is formed and
expands outwards at the speed of light. Switch the current on and off
quickly and "pulses" or waves of magnetism spread outwards. The waves
spread outwards from you at three hundred million metres per second.

The magnetic field doesn't need a medium, just as the arrows don't.
The magnetic field spreads through air, wood, or outer space just as
happily. The same, of course, applies to electric fields.

Sound waves have no independent existence in their own right - they are
nothing more than vibrations in a medium. Electromagnetic waves, on
the other hand, are a force field which you can create with an
electromagnet and which spreads outwards from you, similarly to the way
arrows spread outwards from a bowman. Both are "physical" in that they
exist in their own right, and don't need a medium to travel through.

Best I can do!

--
SteveT

On 25/05/2014 22:39, Indy Jess John wrote:
On 25/05/2014 18:47, the dog from that film you saw wrote:
On 25/05/2014 18:45, Bill Wright wrote:
What is the medium through which radio waves travel?

Bill


doris stokes?

You beat me to it!





should have seen it coming.

--
Gareth.
That fly.... Is your magic wand.

In article , Richard Tobin
wrote:
In article , Bill Wright
wrote:
What is the medium through which radio waves travel?

The Michaelson-Morley experiment demonstrated that there is none.

Not so! :-)

Interesting that there are still people who think that.

The MM experimental results are quite consistent with an 'aether', *and
*with their being no 'aether'.

Hint: Bear in mind that all physical materials involved in the experimental
arrangement were made from 'atoms' which space themselves apart by the
exchange of EM fields (virtual photons).

So *if* the experiment was moving though an 'aether' which altered the
speed of light in the direction of travel that would alter the lengths of
the measurement 'arms' by the same amount. Nulling the result.

If there is no 'aether' you get the same result.

The experiment doesn't give you a way to tell if the 'aether' exists or
not.

The curio is that people still say the MM experiment shows there is no
'aether'. When in fact its result shows that EM / photons / light behave
with consistency.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
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