An interesting observation about planetary temperatures

[Ozric]

So here's something that I found quite interesting.

A few years ago Frontier named a planet after my Nephew who passed away, it's in the middle of nowhere in a nice system and when 3.3 dropped I raced out there and back to make sure I was the first person to get First Mapped on it. So with the addition of First Footfall, I made sure I headed straight out there when Odyssey launched but I could not disembark from the ship/srv because the minimum temperature was 860K and the suits can only handle 800K. The range went up to about 1,600K

Well last week I was explaining to someone a few things about first discoveries and I used the system as an example. I clicked on the planet and it said the temperature range was around 600 - 900K... I said that someone must have changed it, unless it was something to do with orbits and temperature fluctuations, but I didn't see how that was possible to that extreme when it's in a close orbit around a Class B star...

Today I looked at the system again. 704-1,375K I noticed that the orbit is not quite centred on the star which means that actually I must have reached it at a point where it was close to the star, and now it's at the furthest point it's a lot cooler.

The slightly frustrating thing is I'm now over 30,000Ly from the system, but the two bits of good news are that I get the opportunity to get First Footfall again. And how amazing is the Stellar Forge I thought there might be subtle temperature fluctuations based on orbits, but this is at least a 200K shift in the minimum temperature.

 

[alexzk]

Yes, it accounts NS too. Yday landed on planet in NS system. Staying outside on day light was getting 300K - 600K swapping each 10s in period. Like passing through jet. or so.

 

[ORANGEORANGE]

Interesting discovery CMDR.

Orbits in ED are modelled as ellipses. The parameter that we care about is "orbital eccentricity" which is a value from 0 to 1, where 0 is a perfect circle and, at the limit, 1 is a parabolic escape trajectory (so 0.999 would be a VERY eccentric orbit but not escaping yet). Ellipses have 2 foci, and in astronomy, one of the foci will be the parent object that the body in question is orbiting (the other foci is a "ghost" and doesn't do anything).

Eccentricity is simply the ratio of the distance between the center of the ellipse to one of the foci and the semi major axis, which is one of the parameters of an ellipse. From this, we can estimate from the eccentricity of 0.2177 in the image what the swings in distance will be. It comes out that at its furthest point, the planet is 1.56x further away from the star than at its closest point.

With 1.56x further away we know that from the inverse square law for flux, the light that that planet receives will be 1.56^2 times less intense, or in other words, it will receive 0.41x the intensity of light at its further point than at its closest point.

From there, the temperature of the planet will vary, but this is much more complicated than the previous 2 conclusions. In real life there are many different factors that affect this, such as rotation rate, atmosphere heat retention, composition of the planet, etc. Even the color of the planet matters, as white reflects much more than black. I do not know what ED takes into account in determining this temperature. Perhaps that is a topic for someone else to figure out!

 

[Ozric]

Interesting discovery CMDR.

Orbits in ED are modelled as ellipses. The parameter that we care about is "orbital eccentricity" which is a value from 0 to 1, where 0 is a perfect circle and, at the limit, 1 is a parabolic escape trajectory (so 0.999 would be a VERY eccentric orbit but not escaping yet). Ellipses have 2 foci, and in astronomy, one of the foci will be the parent object that the body in question is orbiting (the other foci is a "ghost" and doesn't do anything).

Eccentricity is simply the ratio of the distance between the center of the ellipse to one of the foci and the semi major axis, which is one of the parameters of an ellipse. From this, we can estimate from the eccentricity of 0.2177 in the image what the swings in distance will be. It comes out that at its furthest point, the planet is 1.56x further away from the star than at its closest point.

With 1.56x further away we know that from the inverse square law for flux, the light that that planet receives will be 1.56^2 times less intense, or in other words, it will receive 0.41x the intensity of light at its further point than at its closest point.

From there, the temperature of the planet will vary, but this is much more complicated than the previous 2 conclusions. In real life there are many different factors that affect this, such as rotation rate, atmosphere heat retention, composition of the planet, etc. Even the color of the planet matters, as white reflects much more than black. I do not know what ED takes into account in determining this temperature. Perhaps that is a topic for someone else to figure out!

That's a really great explanation thanks!

I remember a few years ago when the planets were changed for the first time, so the colouration and distribution of materials on the planets were adjusted to reflect their composition more. I wouldn't be surprised if such things did affect the temperature in some way at least.

 

[iain666]

That's a really great explanation thanks!

I remember a few years ago when the planets were changed for the first time, so the colouration and distribution of materials on the planets were adjusted to reflect their composition more. I wouldn't be surprised if such things did affect the temperature in some way at least.

Colour effects temperature because the colour is essentially an indication of how much of the incoming star light is reflected. The less starlight is reflected the more the ground heats up and the slower the night side of the planet will cool as all that absorbed energy radiates back out from the dark side when the heating has stopped, the more that is reflected the hotter the day side will be - it gets you coming and going - and the less is absorbed to keep the night warm (the sea absorbs more heat than dry land on earth so the air gets hotter over land in the day and we get breezes blowing off shore, at night the land then cools quicker and we get onshore winds).

Throw atmosphere into the mix with greenhouse effects trapping reflected heat off the ground, the possibility of reflecting incoming sunlight at altitude due to atmospheric composition - including clouds and anything thrown out by local volcanism. Depending on the atmospheric pressure, local gravity and frequency of eruptions the effects of volcanic activity could be highly variable - a big one off eruption on earth can cause years of cooling, a sustained period of on-land volcanism could have impacts lasting hundreds of millenia, and the short term variability of weather is well known.

I'd hope ED has at least some of that modelled, however simplistically.

 

[BoNeMacHiNe]

On another chat a chap mentioned some tidally locked planets being to hot to land when they are to close to the star. Are these tidally locked planets cooler on the dark side in ED?

 

[varonica]

On another chat a chap mentioned some tidally locked planets being to hot to land when they are to close to the star. Are these tidally locked planets cooler on the dark side in ED?

Yes.

 

[Ozric]

On another chat a chap mentioned some tidally locked planets being to hot to land when they are to close to the star. Are these tidally locked planets cooler on the dark side in ED?

As Varonica said yes they are. They will have a temperature range listed in the details on the System Map. You can disembark on the dark side and then walk across onto the light side. The only trouble is because it's so hot you will start to cook yourself alive in your suit, you won't last too long

 

[ORANGEORANGE]

As Varonica said yes they are. They will have a temperature range listed in the details on the System Map. You can disembark on the dark side and then walk across onto the light side. The only trouble is because it's so hot you will start to cook yourself alive in your suit, you won't last too long

It would be cool if an engineer let you mod your suit to go higher than the 800K range. For example "Better Heat Resistance" can survive up to 1500K temperatures or something like that. Would let you get that footfall on stupid hot planets.

 

[varonica]

It would be cool if an engineer let you mod your suit to go higher than the 800K range. For example "Better Heat Resistance" can survive up to 1500K temperatures or something like that. Would let you get that footfall on stupid hot planets.

What, useful engineering, where will it end, lava paddles?

 

[Orvidius]

I would very much love to walk around on the lava worlds. Just not on the liquid parts.

 

[varonica]

I would very much love to walk around on the lava worlds. Just not on the liquid parts.

Oh same here, and planets with hundreds+ atmospheres, be fun looking for life on those, and those funny little yellow planets with apparantly 0.00 atmospheres that we still can't land on for no reason at all, well all of them really, I wonder what ones we will get next? I am sure that will be the next big update!

 

[BoNeMacHiNe]

I would like to see more detailed life on planets to. Not sure ED will go there for it focuses on space sim, the wish list can go forever. Animal life amd/or planets that evolved rudimentary AI life from leftovers of a defunct civilization.