LovesTheStars

That's awesome. There are a lot of smart people here whom you'll find very helpful in your journey into physics. They're here to help so make full use of them. Best wishes.

There certainly are. Thank you, will do

Did you find those pages helpful?

Hi pmb

Thanks for those links. I had a good look at them and realised how much I didn't know that I didn't know!

But having said that it did start to cement some of what I had read on these forums. I think just seeing things written again and again helps make sense of it and it starts sinking in (that's the hope anyway!)

It's a great place to learn things and to get help from others who can help.

Cheers again!

You're most welcome. Here is a more detailed treatment on inertial mass

http://home.comcast....ertial_mass.htm

 

There is more here too

http://home.comcast....ariant_mass.htm

 

That page describes proper mass (sometimes called invariant mass) of macroscopic systems

This is brilliant thank you! - this will keep me busy for a while

Light is a wave, too. If light were not a particle, we could not explain photoelectric effect properly?

Wave/Particle duality is very interesting to me. I would like to learn so much more about it than I know at the moment. Thanks for your reply.

A complete treatment can be found in the physis FAQ at - http://math.ucr.edu/...hoton_mass.html

 

It really depends on what one means by the term "mass". Particle physicists and quantum physicists tend to use the term to mean "proper mass" aka "rest mass." Others use the term to mean inertial mass. When it comes to more general systems the inertial mass is more meaningful. proper mass can't be applied to open and extened systems such as a body which is radiating energy, thus having a variable mass. Inertial mass is defined as the p in p = mv. For a particle traveling at the speed of light this relationship still holds. We now have v = c so that p = mc. For photons E = pc which implies that m = E/c² = hf/c².

 

I see cosmologists and GRists use the term to mean inertial mass as well as active and gravitational mass.

Thank you for your reply pmb. I will follow your link and have a look at it.

http://en.wikipedia....ical_properties

Fantastic! Thank you Juanrga

I'm not sure I understand that but I appreciate you taking the time to answer. Cheers. I'll have a look and try and understand the threads. Thanks again for your answers

No, the photon does not have mass, by the common physics definition of mass. That's why it travels at c.

Thanks swansont. Something I've learned from your answer that I find interesting is that a particle of light (photon) doesn't have mass by the "common physics definition of mass", which suggests to me that there is another definition of mass. Is this correct? And does this have anything to do with Planck length? Or am I way off base?

Hi there

My question is: "If light can a particle, does it have mass. If so how can something that has mass travel at the speed of light?"

Please be gentle, I am no expert. Just pondering on something I thought of the other day. Also if any answers could be given in layman's terms I would be very grateful -

- thanks for taking the time to read

* can be a particle

Hi I'm LovesTheStars. I love the stars. Lol - sorry that's my attempt at trying to have as good a sense of humour as the rest of you. Failed miserably ;-P

I love astronomy, astrophysics, quantum. Looking at the posts I don't think I know nearly as much as most people on this site but still find the discussions around them interesting as hell.

Great idea having people introduce themselves. Thanks for the thread