h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Re. 159, mental typo. The amount of mass is the amount of inertia built up during acceleration, which can approach infinity. I was trying not to go into this. A similar concept is found in B.H.P., (this time power not mass - for illustration), which is achieved by estimating (originally) how many horses it would take to stop the vehicle.

The original big bang is thought to have been the explosion of something, we know not what, of no dimensions and infinite mass. Black holes happen when the grotesquely powerful gravitational field of a body or bodies (could be fast sub-protons after collision) achieves almost infinite mass and falls in on itself.

Many philosophers and scientists feel that we need concepts like acceleration, inertia, power, infinity and mass as theoretical terms to help explain things, but we still don't really/fully understand what they mean.

Sorry for all this, but my original short version wasn't accurate.

Jab

"Paul - the trouble is that particles approaching almost the speed of light are approaching almost infinite mass. Speed x velocity. But it's all 'almost' this time." [Jabberwok]

That seems counterintuitive to me. Usually, the more mass an object has to lug around, the slower it would have to go. It isn't just the interference of the stuff it's travelling through (putting these particles in a vacuum would eliminate that...), it's the problem of attaining any momentum. Using tiny particles of almost mass would make it possible for them to travel at almost the speed of light.

But maybe we need a reality check. Light itself travels at the speed of light. Does light have infinite mass, or anything close? No.

Traveller in Time counting
"The mass of the particles would be finite, the mass and the induced energy are proportional.

Light photons have a finite mass, where the actual mass is related to the energy of the wavelength. "

Maybe light is called light because it isn't heavy.

is satellite dish, no! its bloody heavy

Cute pun!

Light has no mass. It defines the universe with its speed. When you talk about the speed of light (c) common sense flies out the window. Think of Einstein's example of the train reaching the speed of light relative to the observer and becoming infinite. And the fact that the speed of light is constant, relative to the observer, whether you are approaching it or retreating from it. I suggest a reading of Einstein's book on Relativity. Bertrand Russell's guide is good too. I am not a physicist. Einstein was.

As far as the lack of understanding of the basic terms we use, try 'How The Laws of Physics Lie' and 'Physics as Metaphor', which are on my bookshelves somewhere. This is a far more interesting topic to me.

Jab

Just add that light has no speed at the speed of light, as time expands and changes. Speed of course depends upon time. As I said, common sense does not operate here.

then it's right up my alley

Mine too.

found out the true reason why it's brokethey've been firing protons around and that make of car is just too bigfor the job
http://www.carpages.co.uk/info/usedproton.asp

(Take a deep breath mate, you are about to expose your stupidity)

I am an ignorant man in the fields of science so perhaps someone can explain why something that has no mass can be affected by gravity.
As far as I am concerned something that has no mass, yet exists, belongs in the spirit world. So all those boffins who figure to move space craft using light-sails will be drifting in the deep space doldrums. And what are solar winds anyway? And while I am at it, why do scientists figure that if you give something a name you have solved the problem. Electricity, magnetism, gravity, big bang. These are just words. They enable us to use their effects without being stuck on why or how. Is photon just a word too?

No Jab. Don't bother explaining. I am a man like Pooh Bear.

Very little brain.

Very good questions, Lew. Not stupid at all.

1. Something with no mass is affected by gravity because it has to travel through space or spaces. Einstein showed that gravity is a distortion of space and time caused by objects with mass (e.g. planets). So light, for instance, travels through gravity-distorted space and is thus affected by gravity.

2.Solar winds are large groups of particles given off by the sun.

3."why do scientists figure that if you give something a name you have solved the problem. Electricity, magnetism, gravity, big bang. These are just words. They enable us to use their effects without being stuck on why or how. Is photon just a word too?"

This is an excellent philosophical question. See posts 161 and 168 where I introduce the very same question. I agree with you. We'd be, in the jargon 'instrumentalists', who believe these terms are good instruments for explaining things, but even the best scientists don't really understand what they might really mean. Some other theorists are called Realists, believing that science really does describe reality.

The distinction can apply to science as a whole. I don't think we do really understand what these words mean, and I believe that science has only been shown to be, more than anything else, an instrument for some kind of understanding, not full understanding. It's a prediction instrument too. The leap to 'reality' is not logical, in my view.

This basic lack of understanding of the real is most clearly shown in Quantum Physics, where the actions of quanta and subatomic particles can be predicted, but what they are and their actions are not understood.

As I keep saying, I'm not a physicist. But I am a philosopher.

Jab

Electrons and photons wouldn't have *no* mass, just very very little. Gravitational fields from large celestial bodies could bend them as they passed through space, hence the effect where light from a body *behind* a large body can curve around the large body and still be seen.

Paul - photons are paradoxical in that they have no mass. That's how they can behave like waves as well as like particles. (Michelson-Morley Experiment that set Einstein off).

[The photon differs from many other elementary particles, such as the electron and the quark, in that it has zero 'rest' mass (=mass - J.); therefore, it travels (in a vacuum) at the speed of light. - Wikipedia]

Electrons of course do have mass.

Anything with any mass has a gravitational effect on everything else. Thus an elementary particle without much mass has a gravitational effect on everything else in the universe. Not necessarily a measurable effect, of course.

You're absolutely right about the bending of light, understood via Einstein as the bending of space itself through which it travels.

But common sense? Best not go there!

Jab

But even an elementary particle can have huge mass - just not much size! As thought to be something like the case of the big bang when something of no size had infinite mass (or so the story goes).

I was a solar collector once, but it didn't pay enough

I have a solar watch...
http://www.pmwf.com/Watches/Junghans/JunghansSolar1Front.htm
mine was bought through world wide fund with a panda on it...

how very appropriate. i believe all s are solar powered

at least as much as the rest of us