# How large would the sun be if it were frozen?

• B
• dennis_n
In summary, the sun has a complex density profile and is already denser than liquid hydrogen. If all its hydrogen and helium were to turn to liquid, the sun's volume would decrease, but it is not possible in reality due to the immense energy required to compress the core. The sun's average density is 1410 kg/m3, while liquid hydrogen has a density of 70 kg/m3. The sun's core would have to reach a state of electron degeneracy, similar to a White Dwarf, to compress to a smaller size. The sun's density varies greatly from core to surface, and it is a common misconception that stars are mainly composed of light gases and plasma. In reality, the sun is a dense, complex
dennis_n
How much smaller would the sun be if all it's hydrogen and helium turned to liquid?
I can't figure out how to calculate this. But I thought it would be fun to visualize how much smaller in size a frozen sun would be compared to it's gas/plasma state.
Anyone?

This should be pretty easy to compute. The Sun's mass composition can be readily found on the internet, as can the densities of liquid hydrogen and helium, which are the Sun's main components. Just take the masses of hydrogen and helium and compute the corresponding volume using the densities.

unusually_wrong, PeroK and russ_watters
Orodruin said:
This should be pretty easy to compute. The Sun's mass composition can be readily found on the internet, as can the densities of liquid hydrogen and helium, which are the Sun's main components. Just take the masses of hydrogen and helium and compute the corresponding volume using the densities.

No, it isn´t.
Hydrogen and helium will be self-compressed by gravity.

White dwarf mass-radius relationships won´t help, either, because white dwarfs are carbon or heavier.

Orodruin said:
This should be pretty easy to compute. The Sun's mass composition can be readily found on the internet, as can the densities of liquid hydrogen and helium, which are the Sun's main components. Just take the masses of hydrogen and helium and compute the corresponding volume using the densities.
I thought that too, but then the gases change density from surface to core, so I thought a simple computation might not solve this.

snorkack said:
No, it isn´t.
Hydrogen and helium will be self-compressed by gravity.

White dwarf mass-radius relationships won´t help, either, because white dwarfs are carbon or heavier.
But this was not the question as I read it. The question as I read it is just "if the hydrogen and helium were liquid of the typical densities, how much volume would it occupy". It is obviously not going to happen in reality.

dennis_n said:
I thought that too, but then the gases change density from surface to core, so I thought a simple computation might not solve this.
You do not need the volume of the gases. You just need the mass.

The average density of the Sun is 1410 kg/m3
Liquid hydrogen has a density of only 70 kg/m3
Thus the Sun is already denser than liquid hydrogen would be.
If you were to remove the energy source that keeps the Sun from collapsing, it would compress until its core reaches a state of electron degeneracy. At this point you have the equivalent of a White Dwarf, and an object with a radius comparable to the Earth's.

dennis_n and Imager
Janus said:
The average density of the Sun is 1410 kg/m3
Liquid hydrogen has a density of only 70 kg/m3
Thus the Sun is already denser than liquid hydrogen would be.
If you were to remove the energy source that keeps the Sun from collapsing, it would compress until its core reaches a state of electron degeneracy. At this point you have the equivalent of a White Dwarf, and an object with a radius comparable to the Earth's.

I never thought to search for average density. It was faulty logic to assume that an extremely compressed plasma core wouldn't increase the average density to more than that of a liquid or solid state. Might be the public misconception that stars are mainly bodies of "Gas" and "Plasma" and we conceive both of these as very light, only experiencing gas as the air around us and thinking of plasma as an even more expanded form of it. Thanks! I learned something new today.

Weird.
So a liquefied sun would be 2.7 times larger in diameter. (Using Janus's hydrogen density)

I tried to figure out how big droplet of liquid He can exist.

By my estimate, somewhat smaller than Pluto, unless extra heating is provided. On account of the extra heating from relic radiation, a Pluto sized drop of He can be liquid without other heating.

So, how is it that Jupiter has approximately the same density as the sun?

1300 kg/m^3 Jupiter
1410 kg/m^3 Sun​

dennis_n said:
Thanks! I learned something new today.

I learned, by going down your rabbit hole, that I know way too little about how things work, on not-even-a-cosmic scale.

nikkkom
The sun has a larger variation in density. It's quite dense at the core and much less dense near the surface,

OmCheeto
dennis_n said:
I never thought to search for average density. It was faulty logic to assume that an extremely compressed plasma core wouldn't increase the average density to more than that of a liquid or solid state. Might be the public misconception that stars are mainly bodies of "Gas" and "Plasma" and we conceive both of these as very light, only experiencing gas as the air around us and thinking of plasma as an even more expanded form of it. Thanks! I learned something new today.

Here is a good article from NASA with a nice density vs radius graphs:
https://solarscience.msfc.nasa.gov/interior.shtml

dennis_n and OmCheeto

## 1. How would the size of the frozen sun compare to its current size?

If the sun were to freeze, it would actually decrease in size. This is because the sun's volume is primarily made up of gas, which would condense and shrink as it freezes.

## 2. How would the frozen sun affect the Earth's orbit?

If the sun were to freeze, it would not have a significant impact on the Earth's orbit. This is because the sun's mass would remain the same, and therefore its gravitational pull on the Earth would not change.

## 3. Would the frozen sun still emit light and heat?

No, a frozen sun would not emit light or heat. It would essentially become a giant frozen ball of gas, with no nuclear fusion occurring to produce energy.

## 4. Could the sun realistically freeze?

The sun freezing is highly unlikely, as it is constantly producing heat and energy through nuclear fusion. It would require a massive decrease in temperature, which is not possible in the sun's current state.

## 5. How would the frozen sun impact other planets in our solar system?

The frozen sun would not have a significant impact on other planets in our solar system. Its gravitational pull and mass would remain the same, and it would continue to orbit the center of the solar system as normal.

• Astronomy and Astrophysics
Replies
5
Views
1K
• Astronomy and Astrophysics
Replies
49
Views
3K
• Astronomy and Astrophysics
Replies
2
Views
1K
• Astronomy and Astrophysics
Replies
17
Views
2K
• Astronomy and Astrophysics
Replies
21
Views
3K
• Astronomy and Astrophysics
Replies
7
Views
2K
• Astronomy and Astrophysics
Replies
7
Views
3K
• Astronomy and Astrophysics
Replies
6
Views
2K
• Astronomy and Astrophysics
Replies
12
Views
5K
• Science Fiction and Fantasy Media
Replies
14
Views
2K