Horizons Atmosphere and Gravity

[Leadfoot]

General question concerning atmosphere and gravity.

I was always under the impression that the heaver the gravity of a planet, the more likely it was to retain some type of atmosphere. I know that Mars has one but rather thin. This is why I was rather surprised to see listing of planets with 2 or more g's with no atmosphere. Now, if it's close to a star, I could see where the solar wind would blow the atmosphere away, but a lot of the planets I'm seeing in these videos are more than capable of holding atmosphere. So, why don't the landable planets of 1g or more have one?

Just curious...

 

[CMDR Heisenberg B. Damned]

You're right and I suspect the full answer is "it's a game". Impacts can also drastically affect if gases are retained but again they tend to affect the inner planets more as the higher gravity near the central star increases the velocity of orbiting bodies. Magnetic fields can also protect atmospheres, so maybe something there.

Really though a lot of this is clutching at straws because our only reliable model for a system is ours and everything else is pretty much speculation. I landed on an almost 10 G planet and it's hard to understand how something with such high levels of gravity couldn't hold onto gases, it should be capable of retaining any gas. Which is diametrically opposed to me after the sprout fest of Christmas (sorry - overshared!).

All we can do is acknowledge our own lack of knowledge in this area and suspend disbelief.

Happy New Year anyway

 

[nexxo]

Not all big rocks produce an atmosphere or accumulate one. It all depends on how they form, and when.

 

[Chris Simon]

You are completely right. I think it's widely believed that 80% of planets have some or another kind of atmosphere and only 20% don't. (completely omitting gas giant's, naturally, we're speaking of solid planets) Which is the exact opposite to what we see in Elite.
Generally, due to the age of the universe, almost every planet of Earth's age or older should have had enough time to get bombarded by comets and asteroids and gain the concentration of gasses to develop an atmosphere.

Planets that don't have atmosphere are either exceptions or too young.

 

[Leadfoot]

You are completely right. I think it's widely believed that 80% of planets have some or another kind of atmosphere and only 20% don't. (completely omitting gas giant's, naturally, we're speaking of solid planets) Which is the exact opposite to what we see in Elite.
Generally, due to the age of the universe, almost every planet of Earth's age or older should have had enough time to get bombarded by comets and asteroids and gain the concentration of gasses to develop an atmosphere.

Planets that don't have atmosphere are either exceptions or too young.

I suppose that's one way of looking at it. A planet full of rock and iron not making any volcanoes won't be belching gasses into the outer parts of the world and therefore, no gas to hold down. Then again, no volcanoes at all on anything bigger than Earth still sounds a bit odd, but you're all correct - it's just a game.

 

[Apos]

"Likely" is the keyword there.

The comparison would have to take into consideration that planets with an atmosphere at 1g+ are much more abundant like they should be. We just can't land on them yet, so they go unnoticed.

Also, some hand crafted ones like Achenar 3 should be excluded as results of the forge.

 

[CMDR Heisenberg B. Damned]

I suppose that's one way of looking at it. A planet full of rock and iron not making any volcanoes won't be belching gasses into the outer parts of the world and therefore, no gas to hold down. Then again, no volcanoes at all on anything bigger than Earth still sounds a bit odd, but you're all correct - it's just a game.

Well yes geological activity and even life can change the composition of an atmosphere (look up the great oxygenation event)* but solar systems are formed in gas clouds. With a large enough G planet it should be able to hold onto any gas it grabs whilst forming. Gas giants are solid in the core they just picked up lots of extra gas whilst the system was forming. Eventually (without close proximity solar activity to bast it away) that gas increases the gravity and is sucks up more and more gas.

Although yeah - just a game!

* Worryingly we're doing the exact opposite with our atmosphere right now.

 

[Chris Simon]

* Worryingly we're doing the exact opposite with our atmosphere right now.

We are not destroying the atmosphere. We are just changing it.
I'm not saying it's particularly good for US, but planet generally doesn't give a damn.
Live certainly have an impact on atmospere, but has nothing to do with creating it.

 

[CMDR Heisenberg B. Damned]

We are not destroying the atmosphere. We are just changing it.
I'm not saying it's particularly good for US, but planet generally doesn't give a damn.
Live certainly have an impact on atmospere, but has nothing to do with creating it.

Oh GOD you're one of them aren't you! You can breathe CO2!

Yeah the point is most large planets will have atmospheres just from dragging in gases whilst forming. Not from life or geological activity.

Now as for Earths atmospheric changes...

Just from a personal point of view I don't give a damn if the planet doesn't give a damn because I give a damn!

I just hope I've made myself clear

H.B.Damned

 

[Chris Simon]

Eggsactly!

 

[Ddraig]

As far as I know, it depends on many things; star proximity, gravity, geological formation, tectonic or volcanic activity, age, formation process, a big etcetera that I do not know well.

If the planet is too close, the atmosphere is blown away by solar winds. Too far and the cold makes the planet a ball of ice.
I see the planets in Elite and most are a graveyard of craters, probably in the formation process it simply lost its atmosphere due to massive and constants impacts.
Tectonic and volcanic activity is required to sustain an atmosphere over long time on relatively small rock worlds, regardless of impacts or other factors. And here is where the argument falls into place, many of the landable planets are volcanic active with sulfur emissions typically, these should be atmospheric if the mass is nearly or above Earth.

So yeah, but... It does not bothers me one bit. XD

 

[Chris Simon]

I think nobody is bothered by it.
If anything, I'm happy not that many planets have an atmosphere, because it means I can land on more things.

OP just raised an interesting point. If you look at our solar system, every planet either has the atmosphere or is a gas giant with the exception of Mercury, because it's too close to the star. Even many bigger moons have atmospheres of some degree.

From the game's perspective, as the owner of Horizons, I'd sure as hell hated this game if most systems were like this.

 

[lenna]

Atmospheres only form if the planet's composition contains materials appropriate to create an atmosphere or the planet is bombarded with suitable materials to establish one.
---
Whether a planet can retain an atmosphere depends on numerous factors including stellar conditions the nature of a planet's magnetic and gravitational fields, and solar system local magnetic/gravitational factors. Temporal or constant magnetic or gravitational influences of sufficient strength could in theory prevent a planet of nominally sufficient mass from keeping an atmosphere.
---
Whether a planet can support human-like life depends on a specific subset of these conditions, as well as specific levels of electromagnetic radiation of various kinds (infrared, ultraviolet, visible, and others - too much or too little of the wrong type and Earth would be lifeless, or at least not as hospitable, in theory).
---
The whole science behind it is almost certainly more complex than this and the above may even be inaccurate on the details - in truth though, we probably are only starting to understand what we think we know in terms of planetary science.

 

[Zorronov]

This is just one of a number of scientifically dodgy things in Elite, so I wouldn't let it bother me. I don't...and I'm a scientist (retired).

 

[El Dragoon!]

General question concerning atmosphere and gravity.

I was always under the impression that the heaver the gravity of a planet, the more likely it was to retain some type of atmosphere. I know that Mars has one but rather thin. This is why I was rather surprised to see listing of planets with 2 or more g's with no atmosphere. Now, if it's close to a star, I could see where the solar wind would blow the atmosphere away, but a lot of the planets I'm seeing in these videos are more than capable of holding atmosphere. So, why don't the landable planets of 1g or more have one?

Just curious...

if the planet dosent have a magnetic core, the atmosphere will dissipate, over time

mars's and Venus's atmosphere is slowly being ripped away by the sun, its kinda cool look it up

 

[Zorronov]

if the planet dosent have a magnetic core, the atmosphere will dissipate, over time

mars's and Venus's atmosphere is slowly being ripped away by the sun, its kinda cool look it up

Well...not exactly. Earth doesn't have a magnetic core but it does have a magnetic field due to the dynamo effect. All that's needed is a metallic core (which is quite common...especially for high-g worlds) and a short enough rotational period. The reason Venus doesn't have a magnetic field is that it rotates very slowly...but it will take a long time to rip away that​ atmosphere.

 

[El Dragoon!]

Well...not exactly. Earth doesn't have a magnetic core but it does have a magnetic field due to the dynamo effect. All that's needed is a metallic core (which is quite common...especially for high-g worlds) and a short enough rotational period. The reason Venus doesn't have a magnetic field is that it rotates very slowly...but it will take a long time to rip away that​ atmosphere.

lol there is so much wrong with what you just said its funny


IDK if you know this but mars lost its atmosphere because it lost its magnetic core & mars is lost most of its magnetic core when a Pluto sized planet crashed into it while the solar system was forming. the core and crust of mars match tempters and the result was a slightly polarized core , similar things could happen to similar planets out in the galaxy, not to mention venus is losing .5% of its atmosphere every hundred years, in astronomic years thats alot

the 1g+ planets you see in game are possible and probably more common than they are in game,

and the dynamo effect ISN'T common for high G worlds , maybe High metal content planets, lol not high g 1s lmao


next time read up before you try and confuse noobs about exogeology k

 

[Zorronov]

lol there is so much wrong with what you just said its funny


IDK if you know this but mars lost its atmosphere because it lost its magnetic core & mars is lost most of its magnetic core when a Pluto sized planet crashed into it while the solar system was forming. the core and crust of mars match tempters and the result was a slightly polarized core , similar things could happen to similar planets out in the galaxy, not to mention venus is losing .5% of its atmosphere every hundred years, in astronomic years thats alot

the 1g+ planets you see in game are possible and probably more common than they are in game,

and the dynamo effect ISN'T common for high G worlds , maybe High metal content planets, lol not high g 1s lmao


next time read up before you try and confuse noobs about exogeology k

Read up? You mean like on the Internet? LOL! I guess I 'll have to give my PhD in physics back then.

 

[SpitTheDog]

Oh GOD you're one of them aren't you! You can breathe CO2!

Yeah the point is most large planets will have atmospheres just from dragging in gases whilst forming. Not from life or geological activity.

Now as for Earths atmospheric changes...

Just from a personal point of view I don't give a damn if the planet doesn't give a damn because I give a damn!

I just hope I've made myself clear

H.B.Damned

I think the distinction being made was that the opposite of creating atmosphere is destroying/losing atmosphere. Changing is not the same as losing so even if our atmosphere become 80% Nitrogen, 19% CO2 and 1% Oxygen then it would still be an atmosphere.

Unless you meant "Oh GOD you're one of them aren't you!" to mean they were a pedant rather than a climate change non-believer.

 

[CMDR Heisenberg B. Damned]

I think the distinction being made was that the opposite of creating atmosphere is destroying/losing atmosphere. Changing is not the same as losing so even if our atmosphere become 80% Nitrogen, 19% CO2 and 1% Oxygen then it would still be an atmosphere.

Unless you meant "Oh GOD you're one of them aren't you!" to mean they were a pedant rather than a climate change non-believer.

Or it was a joke, doesn't always come across when typed hence the

I took it that both me and Chris Simon were putting forward similar points. If you look up the great oxygenation event (and sorry if you're already aware of it - not met many that are) it's about life changing the atmosphere to be oxygen rich and we appear to be doing our best to reverse that!

I only replied to clarify that.

I'm not entirely sure where it was suggested life destroys atmospheres though, certainly nothing in the GOE suggests that.