Mass of Universe

[npk77]

i know the universe it expanding, but can anyone tell me if there is more mass, in it now, than there has been in the past, if the mass stays the same, grows or decreases as the universe expands? basically is there more stuff in it now?

 

[MeteorWayne]

To our best knowledge the amount of mass and energy is the same now as in the beginning (right after the big bang, there was only energy, it was to hot for atoms to form).

Since then it's been spreading out into the expanding space.

 

[bushwhacker]

Probably a naive question, but what if these supermassive "blackholes" in the center of galaxies are actually whiteholes?

We have all seen pictures of the jets emanating from them. Would that add to the mass of the universe?

 

[MeteorWayne]

There's no evidence at all that white holes exist, and the theoretical support is not firm.

The jets shooting from black holes are the material from the accretion disk being recycled and shot away, so there is no change in mass.

 

[npk77]

well balck holes aren't really holes at all, we just cant see whats there, all the matter it swallows is still there, i thought, see i've been thinkin that they are part of a process reclyling and dispersing matter, or changing it, there seems to be similar cylces everywher, to cellular activity, to the carbon cycle here on earth, then the stars on a larger scale, etc, black holes could just be another one of the cycles on a bigger scale, but i have things in my head that i think the universe will never end, that the big bang, hasnt finished, its always happening, but thats why i had to ask about the mass of the universe. couldn't black holes also be the big bang of another universe, coursed here but happening there, if you get me? lol

 

[ramparts]

The conservation of mass and energy is completely key to the Universe as we know it. Now, matter can be converted into energy, and vice versa (by E=mc^2), but the total amount of both those is unchanging.

 

[neilsox]

Since the many suns are converting mass to energy, the mass of the universe is likely decreasing very slowly. The reverse occurs quite rarely, we think, the past 12 billion years, so the mass may have decreased by 2%, by the time that most of the stars (including those not born yet) leave main sequence = 2 trillion years? By then, perhaps 20% of the mass will be in compact stars including black holes. Are cold brown dwarf stars considered compact stars? How about Class M out of fuel? Will super nova be half as frequent in 5 billion years? The photons in motion will be perhaps 10% more numerous because they will be less energetic on the average = infrared instead of visable light and more energetic, but the volume of the Universe will be up by 50%, due to accelerating expansion? The volume of the observable universe will have decreased by about 2%? I'm guessing, so please correct. 2 trilion is a million times two million. Neil

 

[MeteorWayne]

You missed the point of the first replies. In the beginneing, there was no mass at all, only energy.

It really makes no difference how much is in what form at any time. The total stays the same.

How can you say that "so the mass may have decreased by 2%,". That's pure making stuff up.

As for the observable Universe, that is unrelated to the original question.

 

[neilsox]

I understand the desire to ignore the part beyond the the observable universe, but the name universe suggests all of it, unless we specify observable universe. Worse, only a tiny portion of the universe was observable for the period following the early rapid expansion = inflation, if there had been an observer.
I understand the desire to avoid specific numbers, but the generalities suggest that there are real numbers, even if they are at present very speculative. I'm hoping (and perhaps the OP hoped for some real numbers, even if they need to be qualified with "we aren't sure how big the the universe was at the end of the inflation = rapid expansion." We aren't sure if the present accelerating expansion will persist long term = 2 trillion years, and a host of other qualifications. There may be experts out there who are willing to speculate. I confess I am not an expert, but merely trying to learn what mainstream opinions are by testing the waters, by suggesting numbers. My guess is the present calculated acceleration rate will make the present universe seem tiny, if the present acceleration persists for 2 trillion years. The OP did not mention energy, but I agree that the energy mass sum is a constant, and key to almost any discussion. Neil

 

[csmyth3025]

...In the beginneing, there was no mass at all, only energy.

...It really makes no difference how much is in what form at any time. The total stays the same...

One thing I'm curious about is, if the total amount of mass/energy in the universe remains constant and dark energy is responsible for the expansion of the universe, doesn't it get diluted as the universe gets bigger? I guess what I'm saying is, at some point shouldn't the expansion of the universe start to slow down - sort of like a compressed spring relaxing to its natural length?

Another thing I wonder about is the idea that all of the forces may have been unified at the very beginning (Planck epoch) and then, for some reason there was symmetry breaking. Is the resulting miniscule strength of gravity relative to the other forces possibly the trigger that caused exponential inflation?

Chris

 

[MeteorWayne]

...In the beginneing, there was no mass at all, only energy.

...It really makes no difference how much is in what form at any time. The total stays the same...

One thing I'm curious about is, if the total amount of mass/energy in the universe remains constant and dark energy is responsible for the expansion of the universe, doesn't it get diluted as the universe gets bigger? I guess what I'm saying is, at some point shouldn't the expansion of the universe start to slow down - sort of like a compressed spring relaxing to its natural length?

Actually, it's the opposite. Think of dark energy (WEII) as a background that permeates all spacetime at a constant level. Meanwhile, as the Universe expands, the MATTER is becomong more diluted, so the gravity betweien the pieces is decreasing (as the square of the distance), so the expansion is accelerating. (This is as I understand it as of now)

Another thing I wonder about is the idea that all of the forces may have been unified at the very beginning (Planck epoch) and then, for some reason there was symmetry breaking. Is the resulting miniscule strength of gravity relative to the other forces possibly the trigger that caused exponential inflation?

Chris

That is one a many possible ideas.

 

[ZenGalacticore]

There's no evidence at all that white holes exist, and the theoretical support is not firm.

The jets shooting from black holes are the material from the accretion disk being recycled and shot away, so there is no change in mass.

If nothing, not even light can escape the massive gravity of a black hole, how is that they emit jets of radiation? Shouldn't that radiation, before it can be ejected, be sucked right back down the hole?

(A question I've had in me head for a while. )

 

[MeteorWayne]

Again, the material that is jetted away is from outside of the event horizon, so is never "in" the black hole. It is orbiting the black hole, just as it would any other star or planet, and is jetted away before reaching the event horizon.

MW