Let's create an alien biosphere!

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Biblaridion said that the planet has to be somewhat large in order to have a magnetic field. How does Ganymede work? Wikipedia says that it's probably created by convection. I wonder why Biblaridion said that then.

Ganymede has a metallic core. Also, if I recall correctly, if two bodies with metallic cores are orbiting each other, the interaction can induce or strengthen a magnetic field in at least one of the bodies. (I think that some scientists believe that this happened with Mars when it had a larger moon, but that moon eventually crashed into the planet, so Mars's magnetic field today is much weaker.)

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Ganymede has a metallic core. Also, if I recall correctly, if two bodies with metallic cores are orbiting each other, the interaction can induce or strengthen a magnetic field in at least one of the bodies. (I think that some scientists believe that this happened with Mars when it had a larger moon, but that moon eventually crashed into the planet, so Mars's magnetic field today is much weaker.)

So how far are we placing this moon assuming it also has a metallic core? Also, are we sure we're placing the planet in the other Lagrange point?

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So how far are we placing this moon assuming it also has a metallic core? Also, are we sure we're placing the planet in the other Lagrange point?

Maybe we should just forget having life on a moon and just settle for having life on both planets.

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Maybe we should just forget having life on a moon and just settle for having life on both planets.

If you really think so, then fine, we can give up on the moon. I would like to have the organisms, or at least the initial ones, to be considerably different on both planets.

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If you really think so, then fine, we can give up on the moon. I would like to have the organisms, or at least the initial ones, to be considerably different on both planets.

Yes, I agree. How different should we make them, though?

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Yes, I agree. How different should we make them, though?

I mean convergent evolution will happen even early on, but there will definitely be differences. Is the second planet a very massive super-Earth? I had made it that just for a strong magnetic field. Chemical differences will be the most important at first because in water gravity is less important.

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I mean convergent evolution will happen even early on, but there will definitely be differences. Is the second planet a very massive super-Earth? I had made it that just for a strong magnetic field. Chemical differences will be the most important at first because in water gravity is less important.

If the planet is larger, it will likely be more geologically active, which will cause it to inject more sulfur (and, to a lesser extent, other elements, such as fluorine and chlorine) into the environment, and life will likely take advantage of these elements.

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If the planet is larger, it will likely be more geologically active, which will cause it to inject more sulfur (and, to a lesser extent, other elements, such as fluorine and chlorine) into the environment, and life will likely take advantage of these elements.

Yes. It might even be enough to color the atmosphere a bit. Exactly how massive will the second planet be? Is a bit over 200% Earth gravity okay?

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Yes. It might even be enough to color the atmosphere a bit. Exactly how massive will the second planet be? Is a bit over 200% Earth gravity okay?

Volcanoes emit chlorine in the form of hydrogen chloride, not elemental chlorine gas. (They also emit some halocarbons, which could pose a threat to ozone since they are prone to having a halogen radical broken off.)

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Volcanoes emit chlorine in the form of hydrogen chloride, not elemental chlorine gas. (They also emit some halocarbons, which could pose a threat to ozone since they are prone to having a halogen radical broken off.)

Are halocarbons heavier than regular air? If so, they might stay closer to the surface and this planet will already have a higher atmosphere, protecting the ozone.

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Are halocarbons heavier than regular air? If so, they might stay closer to the surface and this planet will already have a higher atmosphere, protecting the ozone.

Things don't work that way on Earth. While this planet will have somewhat higher gravity, I don't think that that will effect matters much.
Keep in mind that Earth also has volcanoes, so things probably won't be much worse on the alien planet, but we should make sure. Also, we could just make the planet have different elements as long as it's realistic.

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Things don't work that way on Earth. While this planet will have somewhat higher gravity, I don't think that that will effect matters much.
Keep in mind that Earth also has volcanoes, so things probably won't be much worse on the alien planet, but we should make sure. Also, we could just make the planet have different elements as long as it's realistic.

There's a fictional planet called Niflheim where everything is just halogenized (is that even a real word?). Or there's Clorox, where there's a tiny amount of biological chlorine. We could do something like either of them.

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There's a fictional planet called Niflheim where everything is just halogenized (is that even a real word?). Or there's Clorox, where there's a tiny amount of biological chlorine. We could do something like either of them.

I still think that life should be able to use molecules with carbon backbones. The only other easy way to make chained molecules that I can think of is using oxyacids/oxyanions, but long chains of those would likely be vulnerable to hydrolysis.

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I still think that life should be able to use molecules with carbon backbones. The only other easy way to make chained molecules that I can think of is using oxyacids/oxyanions, but long chains of those would likely be vulnerable to hydrolysis.

Creatures on Clorox use halocarbons. There are PVC trees with trash bag-like black leaves and bones are made of plastic. We could do something like that. Maybe a lot of phosphorus or sulfur. By analogy to Clorox, maybe these creatures can very early on evolve cyanide as a means of attack/defense?

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Creatures on Clorox use halocarbons. There are PVC trees with trash bag-like black leaves and bones are made of plastic. We could do something like that. Maybe a lot of phosphorus or sulfur. By analogy to Clorox, maybe these creatures can very early on evolve cyanide as a means of attack/defense?

Are the oceans going to be made of halocarbon compounds or water? If the former, that might make it harder for life to form. If the latter, it will be unlikely for the creatures to evolve to not need water.

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Are the oceans going to be made of halocarbon compounds or water? If the former, that might make it harder for life to form. If the latter, it will be unlikely for the creatures to evolve to not need water.

Water. What do you think of my suggestions?

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Water. What do you think of my suggestions?

It's interesting, but it needs some adjustments. First of all, plants that make reduced hydrocarbons as fuel are definitely going to expel the elemental fluorine and chlorine into the atmosphere. Of course, they won't stay in the atmosphere for long; elemental fluorine will react with water if it doesn't react with something else first (which will produce dioxygen), and elemental chlorine will do the same, although not quite as readily. The highly oxidizing environment will make it difficult for organisms to use too many compounds vulnerable to oxidation, so their bones will either start out as halocarbons or be turned into halocarbons. Likewise, they won't be able to have polyvinyl chloride on the outside of their leaves, at least not if they want it to stay polyvinyl chloride.
The large amounts of halogens in the atmosphere will lead to enough halogen radicals to prevent the formation of an ozone layer. This means that ultraviolet light with a wavelength greater that two hundred nanometers would be free to reach the surface. This will likely be beneficial because oxidizing fluorine requires a considerable amount of energy, and the oxidizing environment will likely force organisms to use stabler compounds for their DNA anyway.
As mentioned before, the planet will exhibit increased geologic activity, which will mean more hydrothermal vents on the ocean floor. This will likely provide organisms there will a source of energy, as not only will the hydrothermal vents emit heat, but they will also pump out reducing agents, such as carbon monoxide, hydrogen sulfide, and sulfur dioxide. Therefore, it is likely that life will start there.

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It's interesting, but it needs some adjustments. First of all, plants that make reduced hydrocarbons as fuel are definitely going to expel the elemental fluorine and chlorine into the atmosphere. Of course, they won't stay in the atmosphere for long; elemental fluorine will react with water if it doesn't react with something else first (which will produce dioxygen), and elemental chlorine will do the same, although not quite as readily. The highly oxidizing environment will make it difficult for organisms to use too many compounds vulnerable to oxidation, so their bones will either start out as halocarbons or be turned into halocarbons. Likewise, they won't be able to have polyvinyl chloride on the outside of their leaves, at least not if they want it to stay polyvinyl chloride.

Should we have a biological explanation for the fluorine like on Clorox?

The large amounts of halogens in the atmosphere will lead to enough halogen radicals to prevent the formation of an ozone layer. This means that ultraviolet light with a wavelength greater that two hundred nanometers would be free to reach the surface. This will likely be beneficial because oxidizing fluorine requires a considerable amount of energy, and the oxidizing environment will likely force organisms to use stabler compounds for their DNA anyway.

Artifexian said in his video that chlorine would also block short-wavelength light.

As mentioned before, the planet will exhibit increased geologic activity, which will mean more hydrothermal vents on the ocean floor. This will likely provide organisms there will a source of energy, as not only will the hydrothermal vents emit heat, but they will also pump out reducing agents, such as carbon monoxide, hydrogen sulfide, and sulfur dioxide. Therefore, it is likely that life will start there.

Yes, let's start life there. The high energy gradient will help.

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Should we have a biological explanation for the fluorine like on Clorox?

Let's first decide whether we even want halogens.

Artifexian said in his video that chlorine would also block short-wavelength light.

And that includes ultraviolet light, so my idea unfortunately wouldn't work. This means that we're going to have to prevent the volcanoes from pumping at least one of fluorine and chlorine into the atmosphere. I would prefer getting rid of both, but we should remember that we're bound by realisticness.

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Let's first decide whether we even want halogens.

We could try something like iron maybe?

And that includes ultraviolet light, so my idea unfortunately wouldn't work. This means that we're going to have to prevent the volcanoes from pumping at least one of fluorine and chlorine into the atmosphere. I would prefer getting rid of both, but we should remember that we're bound by realisticness.

Why do we need to stop volcanoes? Sorry if I've missed anything.

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Why do we need to stop volcanoes? Sorry if I've missed anything.

On Earth, some of the gases that volcanoes emit into the atmosphere have fluorine or chlorine. I assume that on the alien planet, volcanoes would be similar.

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On Earth, some of the gases that volcanoes emit into the atmosphere have fluorine or chlorine. I assume that on the alien planet, volcanoes would be similar.

Well on Earth it's not much so on this planet would the increased geological activity be enough to cause a significant change? Can we use the square cube law here like atmospheric volume goes up by r^3 and geological activity goes up by r^2? Or would that be naïve?

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Well on Earth it's not much so on this planet would the increased geological activity be enough to cause a significant change? Can we use the square cube law here like atmospheric volume goes up by r^3 and geological activity goes up by r^2? Or would that be naïve?

I'm not sure of the exact power, but I'm confident that the geologic activity would increase. There would be more volume per surface area, so there would be more internal heat without proportionally more ways to get out, but the interior would be even hotter than that of Earth because of the increased gravity.

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I'm not sure of the exact power, but I'm confident that the geologic activity would increase. There would be more volume per surface area, so there would be more internal heat without proportionally more ways to get out, but the interior would be even hotter than that of Earth because of the increased gravity.

We could have increased amounts of everything that volcanoes create and life would certainly take advantage of that. We don't necessarily need to keep the chemicals too Earth-like.

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We could have increased amounts of everything that volcanoes create and life would certainly take advantage of that. We don't necessarily need to keep the chemicals too Earth-like.

That's a fair point. For example, we could have fluorine be rarer in that solar system without being too unrealistic.