Venus cooled off?

[Moontanman]

If Venus was swapped into the orbit of Mars and Mars was moved to the orbit of Venus would Venus cool down to the temps Mars has now or would Venus remain hot? Right now Venus's atmosphere is "at the surface" a supercritical fluid. If it cooled down to the Temp of Mars wouldn't the CO2 freeze out and make Venus a ball of dry ice? Or would the greenhouse effect keep Venus very hot? 

[swansont]

The final answer depends on whether Venus would keep its atmosphere, but it would definitely cool down. The temperature is a function of the insulation from the greenhouse effect and the incoming amount of solar power. The latter would be significantly smaller. You'd settle in to the final state when incoming and outgoing power equalizes. Since that's lower, the temperature would be, too. If it retained (much of) its atmosphere, it would still be warmer than Mars currently is.   

[Sensei]

1 minute ago, swansont said:

The latter would be significantly smaller.

Average power per area unit is ~4.45 times smaller. @Moontanman use inverse-square law with average distance from the Sun to the Venus, and to the Mars, to get amount of power they're receiving at such distances. You would also need to take into account that Venus is bigger than Mars. i.e. area pointing at the Sun of Venus is bigger.

Also internal heat capacity depends on size of object. i.e. bigger objects cool down slower than small objects (if they're made of the same material).

 

[swansont]

1 hour ago, Sensei said:

Average power per area unit is ~4.45 times smaller. @Moontanman use inverse-square law with average distance from the Sun to the Venus, and to the Mars, to get amount of power they're receiving at such distances. You would also need to take into account that Venus is bigger than Mars. i.e. area pointing at the Sun of Venus is bigger.

Also internal heat capacity depends on size of object. i.e. bigger objects cool down slower than small objects (if they're made of the same material).

 

 

The heat capacity will affect the rate of cooldown, but not the final average temperature, which is reached when incoming and outgoing power is the same.

[Moontanman]

On 5/23/2019 at 6:18 AM, Sensei said:

Average power per area unit is ~4.45 times smaller. @Moontanman use inverse-square law with average distance from the Sun to the Venus, and to the Mars, to get amount of power they're receiving at such distances. You would also need to take into account that Venus is bigger than Mars. i.e. area pointing at the Sun of Venus is bigger.

Also internal heat capacity depends on size of object. i.e. bigger objects cool down slower than small objects (if they're made of the same material).

 

 

On 5/23/2019 at 7:56 AM, swansont said:

 

The heat capacity will affect the rate of cooldown, but not the final average temperature, which is reached when incoming and outgoing power is the same.

 

On 5/23/2019 at 6:10 AM, swansont said:

The final answer depends on whether Venus would keep its atmosphere, but it would definitely cool down. The temperature is a function of the insulation from the greenhouse effect and the incoming amount of solar power. The latter would be significantly smaller. You'd settle in to the final state when incoming and outgoing power equalizes. Since that's lower, the temperature would be, too. If it retained (much of) its atmosphere, it would still be warmer than Mars currently is.   

I am assuming Venus will keep it's now liquid CO2 atmosphere, at some point that atmosphere is freeze out into dry ice depending on temps and pressure. Since at Mars current position CO2 freezes would Venus receive enough energy from the sun for much of the CO2 to freeze? Or would the greenhouse effect prevent that from happening? I'm not sure at what temperature CO2 would freeze at the pressure currently at the surface of Venus but the current pressure and Temperature allow the CO2 to be a supercritical fluid.   

https://en.wikipedia.org/wiki/Supercritical_carbon_dioxide

 

If I m reading this correctly it looks like the CO2 should freeze at about 220k. Currently the surface temp of venus is about 735k.

 

By Ben Finney Mark Jacobs - Commons, Image:Carbon dioxide pressure-temperature phase diagram.jpg, CC0, https://commons.wikimedia.org/w/index.php?curid=4315735

 

[swansont]

Once you liquify the CO2, you lose the greenhouse effect

[dimreepr]

1 hour ago, swansont said:

Once you liquify the CO2, you lose the greenhouse effect

TBH the greenhouse effect seems redundant at that point.

[swansont]

4 minutes ago, dimreepr said:

TBH the greenhouse effect seems redundant at that point.

Redundant? How so?

[dimreepr]

 

1 minute ago, swansont said:

Redundant? How so?

You're not going to grow much.

Edited May 28, 2019 by dimreepr

[Moontanman]

5 hours ago, swansont said:

Once you liquify the CO2, you lose the greenhouse effect

The CO2 is a critical fluid only at a certain depth and above that depth it is just CO2. In fact there is some speculation about colonizing Venus high in it's atmosphere since breathing gas is a lifting gas in a CO2 atmosphere. Huge floating cities is the idea but not what I am talking about. 

3 hours ago, dimreepr said:

TBH the greenhouse effect seems redundant at that point.

Since there would be plenty of gaseous CO2 I don't see how it would redundant...  

Edited May 28, 2019 by Moontanman

[swansont]

1 hour ago, Moontanman said:

The CO2 is a critical fluid only at a certain depth and above that depth it is just CO2. In fact there is some speculation about colonizing Venus high in it's atmosphere since breathing gas is a lifting gas in a CO2 atmosphere. Huge floating cities is the idea but not what I am talking about. 

Since there would be plenty of gaseous CO2 I don't see how it would redundant...  

You said “I am assuming Venus will keep it's now liquid CO2 atmosphere, at some point that atmosphere is freeze out into dry ice depending on temps and pressure” but this response is talking about plenty of gas being present.

Please stick with one scenario at a time.

 

[Moontanman]

5 hours ago, swansont said:

You said “I am assuming Venus will keep it's now liquid CO2 atmosphere, at some point that atmosphere is freeze out into dry ice depending on temps and pressure” but this response is talking about plenty of gas being present.

Please stick with one scenario at a time.

 

I am sticking with one scenario, moving Venus as it is to the orbit of Mars. Mars would have to be moved someplace else of course. What would happen to Venus? The atmospheric pressure would remain the same so at depth the supercritical CO2 would remain as well. As the temp dropped at some point the CO2 should begin to freeze out. This should begin at around 225K if I am reading the graph correctly. Would this result in thick layer of dry ice with a somewhat less pressure atmosphere of CO2. The less thick CO2 atmosphere should result in less of a greenhouse effect resulting in lower temps and more dry ice. I would think this would stop at some point but at what point? 

My question is simple, at that distance to the sun would venus be able to maintain a surface temp high enough to keep the supercritical CO2 from freezing or would a point be reached where much if not most of the CO2 would freeze out? 

[swansont]

22 minutes ago, Moontanman said:

I am sticking with one scenario, moving Venus as it is to the orbit of Mars. Mars would have to be moved someplace else of course. What would happen to Venus? The atmospheric pressure would remain the same

Pressure varies with temperature 

22 minutes ago, Moontanman said:

so at depth the supercritical CO2 would remain as well. As the temp dropped at some point the CO2 should begin to freeze out.

Pressure also varies with the number of atoms.

22 minutes ago, Moontanman said:

This should begin at around 225K if I am reading the graph correctly. Would this result in thick layer of dry ice with a somewhat less pressure atmosphere of CO2. The less thick CO2 atmosphere should result in less of a greenhouse effect resulting in lower temps and more dry ice. I would think this would stop at some point but at what point? 

My question is simple, at that distance to the sun would venus be able to maintain a surface temp high enough to keep the supercritical CO2 from freezing or would a point be reached where much if not most of the CO2 would freeze out? 

Simple questions do not necessarily have simple answers.

[Moontanman]

On 5/28/2019 at 8:13 PM, swansont said:

Pressure varies with temperature 

That is true but irrelevant to the question or obvious because as the CO2 freezes or condenses that would be obvious.  

On 5/28/2019 at 8:13 PM, swansont said:

Pressure also varies with the number of atoms.

The number of atoms would stay the same as per the OT. 

On 5/28/2019 at 8:13 PM, swansont said:

Simple questions do not necessarily have simple answers.

That is why I asked them here... 

[swansont]

2 hours ago, Moontanman said:

That is true but irrelevant to the question or obvious because as the CO2 freezes or condenses that would be obvious.  

The number of atoms would stay the same as per the OT. 

It doesn’t work that way. You can’t assert that pressure remains constant by fiat. It follows laws of physics.

If the temperature drops, the pressure will drop, all else being the same. If the number of gas atoms is reduced, pressure will drop, all else being the same.

2 hours ago, Moontanman said:

That is why I asked them here... 

Putting it in speculations does not turn complex situations into simple ones.

[Endy0816]

Just checked, people have already done this in Universe Sandbox.

https://www.youtube.com/watch?v=vDHAcmgQpRE

In the simulations it remained good and warm.

 

There is definitely too many variables to easily say anything for sure. Slow retrograde rotation. Possibility of the atmospheric composition changing. If it did freeze, there would be less atmosphere and less atmospheric pressure as a result. Weak magnetic field could lead to further reduction in atmosphere.

Probably would be stupidly hot for the longest time though.

 

Edited May 30, 2019 by Endy0816

[Moontanman]

8 hours ago, Endy0816 said:

Just checked, people have already done this in Universe Sandbox.

https://www.youtube.com/watch?v=vDHAcmgQpRE

In the simulations it remained good and warm.

 

There is definitely too many variables to easily say anything for sure. Slow retrograde rotation. Possibility of the atmospheric composition changing. If it did freeze, there would be less atmosphere and less atmospheric pressure as a result. Weak magnetic field could lead to further reduction in atmosphere.

Probably would be stupidly hot for the longest time though.

 

Weak magnetic field doesn't seem to be significant factor with Venus current position much closer to the sun I can't see it being worse in the orbit of Mars. whether or not it would freeze into a ball of dry ice but with deep atmosphere of lesser pressure but enough to keep all of the atmosphere from freezing out. 

8 hours ago, swansont said:

It doesn’t work that way. You can’t assert that pressure remains constant by fiat. It follows laws of physics.

If the temperature drops, the pressure will drop, all else being the same. If the number of gas atoms is reduced, pressure will drop, all else being the same.

Putting it in speculations does not turn complex situations into simple ones.

The question is would Venus become a covered in a deep layer of dry ice, over time, I should have specified the time factor, but the number of CO2 atoms would remain the same ice or gas, you should have noted that. I did not insinuate the pressure would remain the same. I just wanted to know how much cooler venus would become and would that result in the surface being covered by dry ice. Hell possibly even types of dry ice that are similar to water ice like ice 2 or ice 7. 

There are are some really interesting possibilities here, I am sorry I posted it in speculation, I'll ask a real physicist on another forum who is interested in the effects of moving planets around. Which is by the way possible... 

[Endy0816]

2 hours ago, Moontanman said:

Weak magnetic field doesn't seem to be significant factor with Venus current position much closer to the sun I can't see it being worse in the orbit of Mars. whether or not it would freeze into a ball of dry ice but with deep atmosphere of lesser pressure but enough to keep all of the atmosphere from freezing out. 

Mixture of gases might change though. Lighter gases could be stripped away.

 

Swansont wasn't saying there would be less CO2 molecules, but rather enough of them turning into a solid would cause the pressure to decrease.

 

There may actually be a cold layer on Venus already

https://www.esa.int/Our_Activities/Space_Science/Venus_Express/A_curious_cold_layer_in_the_atmosphere_of_Venus

ran across it while searching. Know a number of bodies have definitely managed to surprise us in the past.

 

I'm thinking the distance to Mars probably wouldn't be enough due to the winds/rotation/green house effect. If you are moving planets you could just as well move it further out too though. At some point temperatures would drop to reasonable levels. It is honestly not bad in the upper atmosphere today, but a balmy uniform temperature on the surface would be nice too.

 

Edited May 31, 2019 by Endy0816

[swansont]

6 hours ago, Moontanman said:

 The question is would Venus become a covered in a deep layer of dry ice, over time, I should have specified the time factor, but the number of CO2 atoms would remain the same ice or gas, you should have noted that. I did not insinuate the pressure would remain the same. I just wanted to know how much cooler venus would become and would that result in the surface being covered by dry ice. Hell possibly even types of dry ice that are similar to water ice like ice 2 or ice 7. 

You said "The atmospheric pressure would remain the same" and it would not.

PV = nRT for an ideal gas. n is the number of gas molecules. If some CO2 becomes solid, that decreases. One or all of P, V and T will change

 

[Moontanman]

On 5/31/2019 at 4:30 AM, swansont said:

You said "The atmospheric pressure would remain the same" and it would not.

PV = nRT for an ideal gas. n is the number of gas molecules. If some CO2 becomes solid, that decreases. One or all of P, V and T will change

 

Show me where I said the atmospheric pressure would remain the same?  "The atmospheric pressure would remain the same" no place did I say that, I asked if it would remain the same or would the atmosphere freeze out or, another possibility occurs to me, would more of it condense into a liquid while the rest maintained an atmosphere that was hot by out standards? 

Ok I found it, but you took it out of context, I was saying moving Venus as it is, with the atmospheric pressure the same. The was meant to mean at the time of movement. I then said said: 

Quote

 

I am sticking with one scenario, moving Venus as it is to the orbit of Mars. Mars would have to be moved someplace else of course. What would happen to Venus? The atmospheric pressure would remain the same so at depth the supercritical CO2 would remain as well. As the temp dropped at some point the CO2 should begin to freeze out. This should begin at around 225K if I am reading the graph correctly. Would this result in thick layer of dry ice with a somewhat less pressure atmosphere of CO2. The less thick CO2 atmosphere should result in less of a greenhouse effect resulting in lower temps and more dry ice. I would think this would stop at some point but at what point? 

My question is simple, at that distance to the sun would venus be able to maintain a surface temp high enough to keep the supercritical CO2 from freezing or would a point be reached where much if not most of the CO2 would freeze out? 

Now I am willing to assume you mistakenly did this but no where did i claim that videus would stay the same temp other than when it was moved. In in fact  I  stated many times that Venus would cool down once it was moved and asked what would happen. All of the atmosphere would not freeze out due to the greenhouse effect and as I suggested might result in a surface covered in liquid CO2 instead of dry ice. 

 

On 5/31/2019 at 12:34 AM, Endy0816 said:

Mixture of gases might change though. Lighter gases could be stripped away.

Lighter gases have already been stripped away.

Quote

There may actually be a cold layer on Venus already

https://www.esa.int/Our_Activities/Space_Science/Venus_Express/A_curious_cold_layer_in_the_atmosphere_of_Venus

ran across it while searching. Know a number of bodies have definitely managed to surprise us in the past.

Yes this is why Venus is being considered as the best planet to colonise. Our breathing gas being a lifting gas much the same way Helium is on earth.

Quote

 

I'm thinking the distance to Mars probably wouldn't be enough due to the winds/rotation/green house effect. If you are moving planets you could just as well move it further out too though. At some point temperatures would drop to reasonable levels. It is honestly not bad in the upper atmosphere today, but a balmy uniform temperature on the surface would be nice too.

 

A reasonable idea but the immense CO2 atmosphere almost 100 times as dense as Earth's atmosphere creates a problem...

Edited June 2, 2019 by Moontanman

[swansont]

I don’t know another way to parse would remain the same other than as a prediction of the future,

[Moontanman]

1 hour ago, swansont said:

I don’t know another way to parse would remain the same other than as a prediction of the future,

No the phrase would remain the same was in reference to the planet being moved as it currently is, change would begin immediately upon it's arrival in Mars orbit, the question is what the changes would be. 

Edited June 2, 2019 by Moontanman

[swansont]

1 hour ago, Moontanman said:

No the phrase would remain the same was in reference to the planet being moved as it currently is, change would begin immediately upon it's arrival in Mars orbit, the question is what the changes would be. 

That was not at all clear

[dimreepr]

19 hours ago, Moontanman said:

No the phrase would remain the same was in reference to the planet being moved as it currently is, change would begin immediately upon it's arrival in Mars orbit, the question is what the changes would be. 

Different, is the only possible answer.

Don't make me break out 'Frankie Boyle'.

[Moontanman]

11 hours ago, dimreepr said:

Different, is the only possible answer.

Don't make me break out 'Frankie Boyle'.

Go for it

On 5/30/2019 at 1:40 PM, Endy0816 said:

Just checked, people have already done this in Universe Sandbox.

https://www.youtube.com/watch?v=vDHAcmgQpRE

In the simulations it remained good and warm.

 

There is definitely too many variables to easily say anything for sure. Slow retrograde rotation. Possibility of the atmospheric composition changing. If it did freeze, there would be less atmosphere and less atmospheric pressure as a result. Weak magnetic field could lead to further reduction in atmosphere.

Probably would be stupidly hot for the longest time though.

 

This universoul sandbox game how fast amd no much memory is required for it for it run? Looks like something I could really get into.