Re: Questions (Space)

Tina Hall wrote:
David Friedman <ddfr@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

Tina_Hall@xxxxxxxxxxx (Tina Hall) wrote:


I'm going to have to think about this, Tina. Clearly you have a
real problem with /abstract/ -- that is, with things that don't
have a solid, concrete "thing" that they refer to. Most of this
stuff is like that. There isn't anything at the core that's solid,

If there isn't anything, there can't be anything that travels. Not
solid doesn't matter, as long as you explain what else it is. Right
now, I don't have an alternative to 'solid'.


What there is is a magnetic and electric field, at right angles to
each other


Do you want me to get a headache?

(I have no idea what you're trying to say, it looks just like those things that don't explain anything and just lead to frustration. If you want to talk about this, explain it in a way I understand.)


and to the direction the light is traveling.


The light that travels has to be something. There's something that first hits the cupboard, then my eye, for example. Or comes from a distant star.

Energy.

Light is energy, no matter involved. In a broad sense, "light" includes not only the light we can see with, but all other forms of electromagnetic energy including various bands of radio waves, microwaves, infrared (generally thought of as "heat" radiation), ultraviolet, x-rays, and gamma rays. If you want to know WHAT energy is, I'm afraid you'll go straight to the stuff that gives you a headache, because it's not only not solid, it doesn't even have a consistent manifestation. Physicists had to invent a new term to describe it -- the old-fashioned term was "wavicle" because sometimes light acted as though it was a wave (even though there was no medium for a wave to exist in) and sometimes light acted as though it was a big bunch of little tiny particles.

I feel much the same way you do, Tina, though I apparently have a somewhat better ability to handle the abstractions that have to be used. But I don't *UNDERSTAND* them in my gut the same way, for instance, I know that a thrown baseball on Earth will come down.

If you don't have any NEED to understand exactly how and why energy works that way, then you can stop at the "it's energy" bit and just know the important macroscopic ("large-scale") properties of electromagnetic energy: it almost always travels in a straight line (the cases where it doesn't get into the areas that will give you a headache), it all travels at the exact same speed (speed of light) in vacuum, and it can all be reflected, refracted, or absorbed (but, depending on the exact type of energy, by different materials; for instance, the metal germanium makes an excellent material for windows and lenses for infrared, but is completely opaque to visible light).

Some radio satellites were just big radio mirrors -- they reflected radio transmissions from them to other locations. Others are "repeaters" or relays. They receive the transmission, then amplify the signal, and send the same signal out in another direction, but much stronger than before.



Do you actually understand it, or do you just talk about the effect? Because the effect isn't the issue.

Unfortunately, Tina, when you get below a certain level, the effect IS the issue, the mathematics and field equations the ONLY effective description of "what's there". The interaction of fields IS the energy, at the level they're discussing.

Yes, most of the people throwing this stuff at you DO actually understand it. Far better than I do. Partly because it doesn't make any intuitive sense to me (or to you), but does to them.

Put bluntly, once you get past the levels that we normally work on, the world doesn't make any sense at all.


--
Sea Wasp
/^\
;;;
Live Journal: http://seawasp.livejournal.com

.

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