# Mass of electromagnetic energy in a galaxy?

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#### tjstardestr

##### Guest
Has anyone ever tried to calculate the equivalent mass of all the electromagnetic energy in a galaxy at a given time? Up to the rim? This calculation has to have been done before. I would like to see it.

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#### tjstardestr

##### Guest
In a flat cylinder or a sphere... any type of calculation like that.

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#### B_Cary

##### Guest
I hope somebody has an answer...This is cool. I wonder if the mass-equivalent would make a star?

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#### Saiph

##### Guest
Shouldn't be to hard to do...lets see, some quick googling gives a galactic luminosity ~10^11x that of our sun, which produces ~4x10^26 Joules/second...so we're looking at 4x10^37 joules/second

E=MC^2, so M = E/C^2.

4x10^37/3x10^16 = 1.3x10^21 kg/second

mass of the earth is ~6x10^24 kg...so we're looking at a mass equivelence of 1/1000 of earths mass....every second, over an entire galaxy.

Of course this is energy liberated, for the most part, by fusion, which transforms mass into energy... So this is also the rate of mass loss via conversion to energy.

If you looked at the galaxy as a closed system, all the energy/mass there doesn't change...it just moves around from stellar cores to spreading EM waves.

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Erased text.....

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#### tjstardestr

##### Guest
Your mass per second value is actually all someone really needs to expand on... Take that multiplied by the number of seconds you want (which equates to distance on the galactic scale) to get the mass the galaxy has turned into EM radiation.... Thanks, Sorry for being picky with my last post... I hate posters like that!

Thanks again bro!

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#### carmana

##### Guest
ET could well be a programed electromagnetic energy, on mass? :?:

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#### origin

##### Guest
carmana":22zz94iy said:
ET could well be a programed electromagnetic energy, on mass? :?:

Huh?

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#### Saiph

##### Guest
ah, I see I didn't quite finish answering the question. But now that I think about it, it's not quite as straightforward as one would think.

First, that light is emitted across the entire galaxy, some at the core, some at the edge. So some will leave long before the rest. Also that's only the energy created and disbursed from within the galaxy...it doesn't count all the EM radiation that has arrived from other galaxies and is transiting through ours.

I haven't the foggiest how to go about calculating that.

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#### tjstardestr

##### Guest
Fun to think about all of the reactions that add energy to space. Beige Foam!

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#### B_Cary

##### Guest
Well, let's see how long it would take to generate the equivalent of a star...

1/1000 Earth mass per second times 60 = 6/100 of Earth per minute, times 1440 minutes/day ~= 90 Earth masses per day.

Wikipedia gives the mass of the sun as ~333,000 times the mass of the Earth; @90 per day, that's 3700 days or 10 and a fraction years for the Galaxy to put out energy equal to the mass of the Sun! Wow.

But the Sun is not the smallest star . That, also per Wikipedia, requires 75-87 Jupiter masses.

Jupiter has about 300 Earth masses; so, 300 Earth masses/ 90 Earth masses per day ~=3 1/3 days for the Galaxy to produce energy equal to the mass of Jupiter. Using an intermediate figure of 81 Jupiter masses (because 1/3 of it is a whole number!) for a minimal star times 3 1/3 days per mass of Jupiter yields 270 days, or 9 months, for the Galaxy to radiate energy equal to the mass of a minimal star. Wow again.

Now I know--with many approximations, the energy equivalent of mass to create a minimal star is produced by the Galaxy in 9 months. Like many other worthwhile creations.

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#### acsinnz

##### Guest
I think that we live in an alternative 3D electric universe which means that our sun supplies energy mostly to its own planets, moons and other asteroids/space rocks that rotate it. At the solar system boundaries the amount of outgoing energy is balanced by the incoming energy from other stars. Our sun does not just blast off energy going nowhere!!
CliveS

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#### origin

##### Guest
acsinnz":5gnu981f said:
I think that we live in an alternative 3D electric universe which means that our sun supplies energy mostly to its own planets, moons and other asteroids/space rocks that rotate it. At the solar system boundaries the amount of outgoing energy is balanced by the incoming energy from other stars. Our sun does not just blast off energy going nowhere!!
CliveS

That is nice that you think that, but that is just idle conjecture because there is not one scrap of evidence to support your position.

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#### tjstardestr

##### Guest
There are so many other things to calculate... We all know how much energy is released during a supernova!
I know people do galactic simulations; That's how they found dark matter right! There seems to be a lot of books and papers on the subject. I guess I'm going to look for some intro books via torrent.

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#### EarthlingX

##### Guest
B_Cary":2pkic2wv said:
Well, let's see how long it would take to generate the equivalent of a star...

1/1000 Earth mass per second times 60 = 6/100 of Earth per minute, times 1440 minutes/day ~= 90 Earth masses per day.

Wikipedia gives the mass of the sun as ~333,000 times the mass of the Earth; @90 per day, that's 3700 days or 10 and a fraction years for the Galaxy to put out energy equal to the mass of the Sun! Wow.

But the Sun is not the smallest star . That, also per Wikipedia, requires 75-87 Jupiter masses.

Jupiter has about 300 Earth masses; so, 300 Earth masses/ 90 Earth masses per day ~=3 1/3 days for the Galaxy to produce energy equal to the mass of Jupiter. Using an intermediate figure of 81 Jupiter masses (because 1/3 of it is a whole number!) for a minimal star times 3 1/3 days per mass of Jupiter yields 270 days, or 9 months, for the Galaxy to radiate energy equal to the mass of a minimal star. Wow again.

Now I know--with many approximations, the energy equivalent of mass to create a minimal star is produced by the Galaxy in 9 months. Like many other worthwhile creations.
How much of that mass is in the bounds of our galaxy at the same time ?
How long does it stay inside, on average ? 30 000 years ? 40 000 ? (times a little star, over the thumb)

How much mass is then in a milion ly circle ?

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#### B_Cary

##### Guest
Those are interesting questions, but you've gone beyond my ability to answer! My figures ultimately come from Saiph's figure on January 27--that the Galaxy's light output per second has a mass equivalent of 1/1000 of Earth's mass.

Remember that that figure includes light that's headed toward the edge of the Galaxy as well as light that's headed for a star's neighbors. You'd have to take some kind of average...but again, I'm going to leave that to the more well-informed.

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#### EarthlingX

##### Guest
Here are some more (no more after that, i already need an aspirin) :
How much mass radiates our galaxy over 13.5 billion years ? What about all of hundreds billions of galaxies ?

Could this mass have some effect on the intergalactic space, like bending it ? Do we live in 13.5 billion years old pit, made by light ?

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#### robnissen

##### Guest
EarthlingX":3kxoyuq9 said:
Here are some more (no more after that, i already need an aspirin) :
How much mass radiates our galaxy over 13.5 billion years ? What about all of hundreds billions of galaxies ?

Could this mass have some effect on the intergalactic space, like bending it ? Do we live in 13.5 billion years old pit, made by light ?

1. Assuming that the MW is 13.5 g years and that energy production has been more or less constant over that time, then its simple math using the numbers from above (and doing this in my head): about 90 earth mass per day, about 30K earth mass/year, about 400 trillion earth mass over 13.5 g years. (That seems like a lot.)

2. No, this "mass" does not gravitational effects, because it is not MASS. Einstein explained that mass can be CONVERTED into energy, not that energy has MASS. Indeed, because this energy travels at c, it can't have mass. No mass, no gravitational effects. This is undoubtably what Roberto Duran was referring to when during his fight with Sugar Ray Leonard, he said "NO MAS."

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#### Saiph

##### Guest
Well, energy can bend spacetime too...but the energy is released from mass destroyed, so there is no increase in gravity by considering this amount of EM energy in the galaxy, as we had to destroy an equivalent amount of mass to get it. On the other hand, it is leaving, so the MW's gravity is slowly shrinking.

The 400 trillion earth masses over the galaxy's lifetime is about right. Seems like a lot, but put that in perspective, thats about 400 million solar masses...and the galaxy has over 200 billion stars. It's total mass (stars, nebulae, etc) is about....geez my memory is fuzzy here, but I shall not stoop to google!, 400 billion solar masses...? Giving us a...1/1000 total mass loss due to stellar fusion. Not bad for over 13 billion years of operation.

As for the final calculation about how much energy is in the galaxy...it could be done using calculus by integrating a function describing the stellar distribution in the galaxy that's coupled with luminosity output...or sheer computational brute force...

But that makes my head hurt, and I doubt it would be quite that straightforward.

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#### EarthlingX

##### Guest
Thanks
Mass–energy equivalence (Wikipedia)

Obviously, i should have been more careful when talking about mass, not only one kind.
Mass in special relativity (Wikipedia)

I will try to slowly digest this ... :roll:

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#### robnissen

##### Guest
Saiph":1cmed2k8 said:
Well, energy can bend spacetime too...but the energy is released from mass destroyed, so there is no increase in gravity by considering this amount of EM energy in the galaxy, as we had to destroy an equivalent amount of mass to get it. On the other hand, it is leaving, so the MW's gravity is slowly shrinking.

A question and a comment. To prove that mass bends space-time, it was necessary to use light traveling near the sun, because that much mass was needed to show the bend. I can't imagine how much energy would be needed to bend space-time, and I have no idea how it could be tested. Even if you were to use the energy released by a quasar, it seems to me that the mass of the quasar would so over-power any bending effects of the energy release by the quasare that it could not be measured. So, my question is whether there is ANY experimental proof that energy bends space-time?

My comment is that to the extent energy does bend space-time, the MW's gravity would be shrinking slower than the computation of E=Mc2 would show. Because while gravity would be lost as energy leaves the MW, gravity would also increase as energy from other galaxies enters the MW, although it seems likely that much more energy would exit than enter the MW.

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#### EarthlingX

##### Guest
Could the trick be hidden in the frame of reference ?

I would agree, that in the bubble of expanding light/em-radiation balances remain, but at short range, ... ?
If we, as is not so uncommon, neglect the influence of the distant galaxies, let say, out of the local cluster, what picture do we get ?

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#### EarthlingX

##### Guest
Is it possible to directly measure the mass of a star, without the sphere of EM-waves ?
Perhaps in some binary star system ?

There is another thing with the expanding EM-wave .. It expands with the same speed as gravitation, might be related ..

Another one:
What happens to a virtual particle if it gets hit by a photon ? Is it possible, does it happen ? Does it change the picture, i mean with all the background radiation ..
How much does background radiation bend time-space ?

Those couple of K don't sound much, but that is a lot more than 0 ..

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#### ramparts

##### Guest
EarthlingX":1uha868j said:
Is it possible to directly measure the mass of a star, without the sphere of EM-waves ?
Perhaps in some binary star system ?

I don't know exactly what you're referring to by "the sphere of EM-waves", but our most reliable measurements of mass always come from measuring the force that mass most affects - gravity! We can measure the mass of the Sun quite precisely by, say, placing a test mass in orbit.

There is another thing with the expanding EM-wave .. It expands with the same speed as gravitation, might be related ..

Indeed they are! But not in as direct a way as you might think, and certainly not one suggesting a very deep connection between the two; the reason is that both electromagnetism and gravity, when looked at in terms of particles, end up being mediated by massless particles, either the photon or the graviton. And some special relativity will tell you that anything which has no mass propagates at c - a speed which we call the speed of light mostly for historical reasons, but actually isn't a peculiar property to light at all.

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#### EarthlingX

##### Guest
ramparts":1u73uwed said:
EarthlingX":1u73uwed said:
Is it possible to directly measure the mass of a star, without the sphere of EM-waves ?
Perhaps in some binary star system ?

I don't know exactly what you're referring to by "the sphere of EM-waves", but our most reliable measurements of mass always come from measuring the force that mass most affects - gravity! We can measure the mass of the Sun quite precisely by, say, placing a test mass in orbit.
Exactly. And you get space-time bending measurement that includes everything. That's why i thought it could show in binary systems, where one might be able to compare (is it possible?), sum of measurement for each star, and a influence of a binary system as a whole.
Is there a difference in calculated/observed masses ?

By the sphere of EM-waves i mean not only light, but everything of a photon nature, in a sphere centered at the light source. What did i miss this time :? .. .. What is light ? .. khm ... no, no, please ... I must admit, i quit reading that thread, it was just too much .. got it .. :roll:

ramparts":1u73uwed said:
EarthlingX":1u73uwed said:
There is another thing with the expanding EM-wave .. It expands with the same speed as gravitation, might be related ..
Indeed they are! But not in as direct a way as you might think, and certainly not one suggesting a very deep connection between the two; the reason is that both electromagnetism and gravity, when looked at in terms of particles, end up being mediated by massless particles, either the photon or the graviton. And some special relativity will tell you that anything which has no mass propagates at c - a speed which we call the speed of light mostly for historical reasons, but actually isn't a peculiar property to light at all.
Thank you. Another headache coming up ..

It seams as i will have to learn some more math, to be able to understand this ..

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