[raf21]

I think i understand the inverse square law thing.  sorta like shooting a shot.... further away you are from said target,  the wider your shot pattern gets,  i.e. less pellets per square inch. .....your comments have made me think of another question pertaining to light and gravity.  does gravity"travel" at the same speed as light? I'm not referring to its effect on mass (9.7 meters per second per second or whatever that acceleration is), but the actual speed it operates at. there's not a physical rubber band connecting us to the sun,  it's some kind of force.  were the sun to be removed,  would it take 8 minutes for the effect of gravity (or lack of) to be observed? or longer? surly it cannot be shorter? like magnets,  gravity really trips me out,  where does all that energy come from to make such things operate apparently indefinitely? gee,  I haven't even finished my second cup of coffee.  well,  time to get to work,  I'll check in on break.

[Bill S]

Hitch-hiker level understanding.

does gravity "travel" at the same speed as light?

Slightly misleading wording, as it suggests that gravity travels.  Obviously you are aware of this, as you later refer to the effects of gravity travelling.

If the sun were removed, its light and gravitational attraction would vanish at the same time.

where does all that energy come from to make such things operate apparently indefinitely?

I struggled with this for a long time.  Reading Mark McCutcheon’s “The Final Theory” compounded the problem, but it’s an interesting read. 😊

I think I got there in the end, and would be happy to share some thoughts, but there are others who would probably do a better job.

[PmbPhy]

Hitch-hiker level understanding.

does gravity "travel" at the same speed as light?

Slightly misleading wording, as it suggests that gravity travels.  Obviously you are aware of this, as you later refer to the effects of gravity travelling.

If the sun were removed, its light and gravitational attraction would vanish at the same time.

where does all that energy come from to make such things operate apparently indefinitely?

I struggled with this for a long time.  Reading Mark McCutcheon’s “The Final Theory” compounded the problem, but it’s an interesting read. 😊

I think I got there in the end, and would be happy to share some thoughts, but there are others who would probably do a better job.

Changes in the gravitational field propagate at the speed of light, This was proved experientially recently at LIOGS. Among others. Kip Thorne won the Nobel Prize because of it.

[PmbPhy]

See:

Apparent weight of photons by Pound and Rebka, Physical Review Letters. 4 (7): 337–341.

You might be able to download if from here
http://booksc.org/book/21582115/7c47c0

The experiment is described here. It's a very famous one

https://en.wikipedia.org/wiki/Pound%E2%80%93Rebka_experiment

[raf21]

Pbm Phy, I'm obviously aware of very little.  I have zero education in physics,  and can only remember a little from algebra about speeds and acceleration formulas,  high school was a long time ago.  I'm just a hack observer that has finally found a place to ask questions that people don't laugh at. most of this stuff I ask is probably mundane extremis to everyone here.  I am curious of the difference in definition between propagate and travel,  I will look this up next break if I remember.

[PmbPhy]

Pbm Phy, I'm obviously aware of very little.  I have zero education in physics,  and can only remember a little from algebra about speeds and acceleration formulas,  high school was a long time ago.  I'm just a hack observer that has finally found a place to ask questions that people don't laugh at. most of this stuff I ask is probably mundane extremis to everyone here.  I am curious of the difference in definition between propagate and travel,  I will look this up next break if I remember.

When it comes to things like this my physics advisor/mentor made me look in a dictionary. Start there.

[raf21]

like a physics dictionary? I'm not sure I could afford something like that right now but I'll keep my eyes open at goodwill.... is there an online one possibly?  not that I think I could understand something like that,  I barely grasp half of what's said here and the large amount may as well be Greek to me. .....very cool that gravity operates at the same speed as light,  for some reason it seemed to me that they had to,  almost like gravity was some weird anti electromagnetic radiation. ...does a magnetic field have the same property?

[raf21]

sadly,  I cannot seem to download the "apparent weight of photons" and I can't figure out how to edit my last post or do the quote thing y'all do.

[raf21]

Changes in the gravitational field propagate at the speed of light, This was proved experientially recently at LIOGS. Among others. Kip Thorne won the Nobel Prize because of it.

hey,  think I got the quote thing

[raf21]

dictionary didn't help with propagate,  talked about seeds and ideas. ....
ok,  please correct me if I'm wrong and forgive me if I use simple language. ... light and gravity share a common quality. .... for lack of a better term,  they both "manifest" themselves in a similar fashion,  propagating at the same velocity. ....
gravity can affect light,  whether by curving space or just tugging on it. ....does light have a similar interaction with gravity? the whole "for every action there is an equal and opposite reaction" bit.  in a black hole,  light is supposedly affected, it gets "stuck".......oh I have a bunch of stuff going oin my head now

[Bogie_smiles]

I would submit to you that you didn't quite get the "quote thing" right yet. Try to eliminate the "/" in the first use of the word quote.

ok,  please correct me if I'm wrong and forgive me if I use simple language. ... light and gravity share a common quality. .... for lack of a better term,  they both "manifest" themselves in a similar fashion,  propagating at the same velocity. ....

That seems to be the case. I suppose that speculating about why that is the case would be on the boarder line for the type of content permitted in this particular sub-forum, but lets speculate about a possible explanation to why light and gravity could traverse space at the same velocity.


If the photon is a particle with mass, and if all particles with mass emit gravitational waves, then the out flowing gravitation wave energy from all particles and objects, including photons, would be called gravitational wave energy, and would traverse space at the same velocity, the speed of light. That would make the light of the electromagnetic spectrum the outflowing gravitational wave energy of the photon.

gravity can affect light,  whether by curving space or just tugging on it. ....does light have a similar interaction with gravity? the whole "for every action there is an equal and opposite reaction" bit.  in a black hole,  light is supposedly affected, it gets "stuck".......oh I have a bunch of stuff going oin my head now

Hmm, many things to ponder.

[raf21]

bogie smiles,
yes,  epic fail trying to quote.
I will not even pretend to understand what you just said,  perhaps I should change my name to "star struck Neanderthal with a phone".
is what your are saying implying that light has both mass and gravity? if either or both are true,  could I mention my 4.24 light year radius sphere,  and again ask what effect that volume of photons has on its surrounding space over billions of years? most see a star as a pin point of light,  but I think otherwise.  I might be wrong,  but I don't think you can see light from the side,  only the photons headed your way.  I speculate the photons headed at right angles to ones observation point are "unseen". but nonetheless,  very much there. but again,  I'm not well educated and might be missing something. ...
but if correct,  this its a huge volume of unobserved photons,  and if they have mass (does mass indicate that they would have gravity? ) then regardless of the inverse square law,  this is a tremendously large amount of "material" affecting its environment. However minutely, over millions of years surely this must amount to something,  either with the push imparted by a photons velocity,  or a pull from the photons mass.  multiplied by the amount of estimated stars,  makes for quite a wrestling match. .....unless they just canceled each other out. ........ugh. ......

[Bogie_smiles]

…
is what your are saying implying that light has both mass and gravity?

In case this discussion begins to get too “new theories-like”, it may not be appropriate for this sub-forum, where the consensus view of science is the first order, and discussions that are speculative can be subject to close scrutiny, so be aware of that.

What I said was presented as a speculation that could explain how both light and gravity travel at the speed of light. To answer your next question, “is what you are saying/implying is that light has both mass and gravity?”, then that would be a logical conclusion, if the given the circumstances were true, i.e., that if photons were particles with mass, and if particles and objects with mass all emitted gravitational waves, then light would be gravitational wave energy emitted by photons, and would have frequencies in the range of the electromagnetic spectrum.

A soft ball would have a higher frequency than a gamma ray. That is why they don’t let softballs travel at the speed of light; too dangerous. But yes, given the scenario I speculated about, light would have weight, just like a softball has weight, if we define “weight” as the mass of an object being accelerated in a gravitational field.

if either or both are true,  could I mention my 4.24 light year radius sphere,  and again ask what effect that volume of photons has on its surrounding space over billions of years? most see a star as a pin point of light,  but I think otherwise.  I might be wrong,  but I don't think you can see light from the side,  only the photons headed your way.  I speculate the photons headed at right angles to ones observation point are "unseen". but nonetheless,  very much there. but again,  I'm not well educated and might be missing something. ...
but if correct,  this its a huge volume of unobserved photons,  and if they have mass (does mass indicate that they would have gravity? ) then regardless of the inverse square law,  this is a tremendously large amount of "material" affecting its environment. However minutely, over millions of years surely this must amount to something,  either with the push imparted by a photons velocity,  or a pull from the photons mass.  multiplied by the amount of estimated stars,  makes for quite a wrestling match. .....unless they just canceled each other out. ........ugh. ......

I’m not going to try to get into all of that with you, but there are answers to that in the consensus theories, and someone more qualified than I am in those areas may jump in and help you.

[raf21]

please speculate away if that is within the guidelines of this forum,  as all I'm doing with my limited intelligence and education is speculating. ..... but if I'm inn contradiction to any rules regarding my primitive attempt at gaining knowledge,  then perhaps you could redirect me to amore appropriate place to speculate.  that would make me a bit sad,  I've thoroughly enjoyed this whole experience here,  and learned tremendous things,  like gravity propagating at light speed. .....my apologies if I've caused disruption.

[Bogie_smiles]

I think you are fine here. It is just that I am a frequent poster in the New Theories sub-forum, and it is out of respect for the moderators and administrators that I try to be clear about what is appropriate in this sub-forum, vs what is appropriate in the "lighter side" sub-forums.

[PmbPhy]

dictionary didn't help with propagate,  talked about seeds and ideas. ....

See https://en.oxforddictionaries.com/definition/propagate

[with adverbial of direction] (with reference to motion, light, sound, etc.) transmit or be transmitted in a particular direction or through a medium.
[with object] ‘electromagnetic effects can be propagated at a finite velocity only through material substances’

Try googling  "<word> definition oxford"

[Colin2B]

I am curious of the difference in definition between propagate and travel,  I will look this up next break if I remember.

Although I agree with @PmbPhy sometimes I find dictionaries can be less than clear.
Consider a car, you can say it travels, but clearly it does not propagate ie make a new copy, or object.
However, waves do propagate. When you see waves approaching the shore it looks as though the water is moving, this is an illusion. The water does not flow as in a current, but the height of the wave is passed on (propagated, created anew) from one point to another. This is also true of sound and light waves.

sadly,  I cannot seem to download the "apparent weight of photons" and I can't figure out how to edit my last post or do the quote thing y'all do.

The paper is rather technical, start with wiki.
I’ll send you a pm on editing

.....if all particles with mass emit gravitational waves

But, they don’t. Only accelerating masses emit gravitational waves and photons are not accelerating.
Also gravitational waves do not behave like em waves, very different properties, very different phenomena.

I might be wrong,  but I don't think you can see light from the side,  only the photons headed your way.  I speculate the photons headed at right angles to ones observation point are "unseen". but nonetheless,  very much there. but again,  I'm not well educated and might be missing something. ...

You are right, only light reaching your retina, or a sensor are detected. However, if you move around a star you can check that light is emitted in all directions.

but if correct,  this its a huge volume of unobserved photons,  and if they have mass (does mass indicate that they would have gravity? ) then regardless of the inverse square law,  this is a tremendously large amount of "material" affecting its environment. However minutely, over millions of years surely this must amount to something,  either with the push imparted by a photons velocity,  or a pull from the photons mass.  multiplied by the amount of estimated stars,  makes for quite a wrestling match. .....unless they just canceled each other out. ........ugh. ......

No they don’t cancel out, but the critical point is where you say “regardless of the inverse square law”. I’m sorry but you can’t disregard it, it is key to understanding why the force at a distance becomes negligible regardless of how much you start off with.

[PmbPhy]

like a physics dictionary?

Do such things exist. I use oxford. But in all cases I first look in a physics text. They don't always define things though such as these two terms since they're commonly used terms.

[raf21]

perhaps I worded that poorly. .... I didn't say disregard the inverse square law,  I said regardless,  and intended the use of regardless to acknolage the law exists,  and possible effects could co exist.....

.neg·li·gi·ble
ˈneɡləjəb(ə)l/Submit
adjective
so small or unimportant as to be not worth considering; insignificant.
taking this word as classically defined,  I'm surprised it's used in science. if the amount of stuff 4.24 light years away becomes so insignificant it should be regarded as nothing,  then we shouldn't be able to see other stars,  the photons would be negligible. ...no?

[Bogie_smiles]

.....if all particles with mass emit gravitational waves

But, they don’t. Only accelerating masses emit gravitational waves and photons are not accelerating.

Can we say that any two objects in relative motion are accelerating relative to each other?

Also gravitational waves do not behave like em waves, very different properties, very different phenomena.

Can we say that photons are emitted by electrons, and are traveling at the speed of light when emitted?

Agreed, that certainly puts them in a different class from other particles with very different properties, and evidences that they are very different phenomena. But can we say that there is gravitational wave energy traversing space to and from all directions at all points in space?