The big freeze

[sunshaker]

1 second after big bang universe 1 billion kelvin, Now 2.75kelvin.

 

I have not yet read up on the big freeze theory, but I was looking at the gas to solid temperature of the elements

http://www.ptable.com/#Property/State

 

I was interested in hydrogen/heliums gas to solid temperatures.

 

Helium freezes at 1.15K / 457.6F(Under pressure) unsure without .

 

Hydrogen freezes at 434.45F,

 

As the universe temperature is roughly 454F, Already 20F below the freezing point of hydrogen, I was wondering how long the stars/sun can still function in these dropping temperatures,

 

The sun is 15 million celsius at core but only 5526 celsius surface/photosphere, 4320celsius at the chromosphere.

 

I was wondering if there must be a tipping point temperature where the cold of space first reduces the chromosphere then photosphere, turning stars/sun into a iceball?

 

We have gone from 1 billion kelvin to 2.75 in only 13.8billion years, if the universe is 454F And absolute zero is 459.6F The universe as only to drop another 5 degrees F to reach this temperature,

Which may be the tipping point?

 

Also if the universe is expanding it will be cooling quicker, how long to drop just 4degrees F ?

what effects would this have on new stars forming in colder temperatures?

would this result in larger stars forming as perhaps more hydrogen is needed to obtain enough mass to ignite a star?

Edited November 11, 2014 by sunshaker

[Mordred]

You got your universe temp wrong. It's -454.77 Fahrenheit. Well below freezing. The density of concentrated gas quickly raises the temperature. You can use the ideal gas laws to run the calcs.

 

The big freeze is in the order of close to a 100 billion years into the future. The main problem is that gases will no longer gather enough to form New stars. Stars that are already formed are unaffected except additional supply of new material runs out. So once they exhaust their fuel they will also die. With no new stars to take their place.

 

Now keep in mind galaxy clusters and gravitationally bound large scale clusters are unaffected by expansion.

 

The reason is the cosmological constant aka dark energy per cubic meter is significantly low. Roughly ,[latex]6.62*10^{-10}[/latex] joules per meter cubed.

 

This low energy density is easily overpowered by gravity. It's the volume between Large scale structures that are affected. As the volume increases so does the the total amount of dark energy. However the density itself is constant. The accelerating expansion is due to volume increase.

Edited November 11, 2014 by Mordred

[swansont]

1 second after big bang universe 1 billion kelvin, Now 2.75kelvin.

 

I have not yet read up on the big freeze theory, but I was looking at the gas to solid temperature of the elements

http://www.ptable.com/#Property/State

 

I was interested in hydrogen/heliums gas to solid temperatures.

 

Helium freezes at 1.15K / 457.6F(Under pressure) unsure without .

 

Hydrogen freezes at 434.45F,

 

As the universe temperature is roughly 454F, Already 20F below the freezing point of hydrogen, I was wondering how long the stars/sun can still function in these dropping temperatures,

 

The sun is 15 million celsius at core but only 5526 celsius surface/photosphere, 4320celsius at the chromosphere.

 

I was wondering if there must be a tipping point temperature where the cold of space first reduces the chromosphere then photosphere, turning stars/sun into a iceball?

 

Stars generate their own heat, well into the interior, so this is not an issue.

 

The "cold of space" has essentially no thermal mass to it, so there is no conduction heat loss. It's primarily radiative, so it follows the Stefan-Boltzmann equation. The difference in loss between a reservoir at 3K vs one at 0K is negligible.

[Mordred]

To add to Swansons reply. Bose-Einstein distribution for bosons. Fermi-Dirac distribution for the fermions. Both are derivitives of the Boltzmann equations

[sunshaker]

You got your universe temp wrong. It's -454.77 Fahrenheit. Well below freezing. The density of concentrated gas quickly raises the temperature. You can use the ideal gas laws to run the calcs.

For some reason my -negative as disappeared.

 

 

 

The main problem is that gases will no longer gather enough to form New stars

I was thinking more alone the lines that towards the end it would take these gases longer to gather and reach mass/heat to ignite into stars, So the stars when they do ignite would tend to be massive stars. Until as you say they reach a time when they are no longer able to form.

 

 

 

Now keep in mind galaxy clusters and gravitationally bound large scale clusters are unaffected by expansion.

 

The reason is the cosmological constant aka dark energy per cubic meter is significantly low. Roughly , joules per meter cubed.

 

This low energy density is easily overpowered by gravity. It's the volume between Large scale structures that are affected. As the volume increases so does the the total amount of dark energy. However the density itself is constant. The accelerating expansion is due to volume increase.

I understand the the density is constant, but temperature of the universe as not remained constant, it is always getting colder.

There was also something i was reading the other day where there is more light between galaxies than within, Believing there are many more stars between galaxies than within galaxies.

 

 

swansont:

Stars generate their own heat, well into the interior, so this is not an issue.

I realize stars work by nucleur fusion, but was still unsure how a temperature of space of near absolute zero would effect said stars,

 

 

swansont

The "cold of space" has essentially no thermal mass to it, so there is no conduction heat loss. It's primarily radiative, so it follows the Stefan-Boltzmann equation. The difference in loss between a reservoir at 3K vs one at 0K is negligible.

This concerns "black bodies"? is space defined as a black body? Also as universe cools stella winds would also cool, which I thought may cool the outer atmospheres of a star.

 

 

Mordred

To add to Swansons reply. Bose-Einstein distribution for bosons. Fermi-Dirac distribution for the fermions. Both are derivitives of the Boltzmann equations

I was thinking along the lines of space at these temperature acting like a Bose Einstein condensate,

 

At the moment we use sodium atoms which are cooled with lazers, then "blown on with radiation" to reach near zero kelvin.

What I believe the when helium is cooled to 2 kelvin it can act as a Bose Einstein condensate, And have read that in theory deuterium can also form a BEC,

As light can be brought to a stand still in a BEC state, I thought that maybe when our universe temperature drops another 4 degrees F, These states may be possible and effect stars already in existence(Which tend to be hydrogen/helium) by slowing cooling them down from the outside inwards,

If these states could be reached, you would have solar radiation/winds blowing upon stars adding to cooling effect.

[Mordred]

Yes as the overall density decreases the temp also decreases as per any ideal gas. Bose-Einstein distribution formula is different than a Bose-Einsein condensate.

With most Bosons this occurs around 0.000,000,001 k. 3k is well above this point. Even though it doesn't sound like it.