Alternate Planets, Suns, Stars, and Solar Systems Thread

[Maxwell Edison II]

Let see, lets compare Si to C.

SiO2 is a solid and is also insoluble in everything that isn't ridiculously alkaline.

Analogues of hydrocarbons, polysilanes, are very unstable at room temperature (=they break down), and also they react with oxygen.

Silicones, formed by Si-O-Si-O chains with "R" (often alkyl groups) attached to the Si's, are very stable and are used in oven sealants and so on. The carbon analogue would be some kind of poly-aldehyde, which wouldn't be stable at all, and would very likely (like paraldehyde does) spontaneously react with oxygen.

Carbon is rather unique, as is oxygen. The amino acids are even worse, trying to imagine something else being as incredibly versatile as amino acids, peptides and proteins is very, very hard.

My bet is that higher alien life would all be carbon based, breathe oxygen and would be composed of amino acids and would most likely use some kind of carbohydrates for energy. These three have so many advantages it is highly unlikely that something else would spontaneously evolve.

Then the weirdness can start, but realistically, not before. All we "know" about sentient life in the universe is that it evolved from un-sentient life, so if an imaginary alien couldn't handle simple tools as well as crude weapons and fight/ run away from predators , the design is bad.

 

[Sub Lord Hawk]

CO2 also displaces air, if it is released in a certain way, the way animals release CO2 it doesn't accumulate near ground level in ventilated spaces. Consider that even heavier molecules like freon-12 make their way all the way to the ozone layer.

TWA (=safety exposure limit) is something like 2,5mg/m^3. TWA's are usually defined by a normal work-day, 8 hours, so it'd be lower if the exposure was constant.

If we imagine 0,25mg/m^3, then that is something like 0,25/1250 000 = 0,2 ppm. Which, since it is 6500x stronger than CO2 as a greenhouse gas means it is the equivalent of 1300ppm CO2. Right now on Earth CO2 is at ~385ppm.

EDIT: Scratch the above! Apparently the relationship between CO2 and delta radiative forcing is logarithmic, while for CFC's (and presumably "CF's" like CF4) it is linear. This means that if a certain level of CO2 raises the temp with x degrees, and (in another atmosphere) another level of CF4 would do the same, quadrupling the CO2 means the temp rises by x*ln(4) while for CF4 it rises by 4. This makes sense, it explains why the CFC's are even mentioned despite being such a small part of our atmosphere.

Hmm okay that's defiantly interesting then, but I'm a bit confused about what you mean with the difference it the temp rises for CO2 and CF4.

My bet is that higher alien life would all be carbon based, breathe oxygen and would be composed of amino acids and would most likely use some kind of carbohydrates for energy. These three have so many advantages it is highly unlikely that something else would spontaneously evolve.

Then the weirdness can start, but realistically, not before. All we "know" about sentient life in the universe is that it evolved from un-sentient life, so if an imaginary alien couldn't handle simple tools as well as crude weapons and fight/ run away from predators , the design is bad.

I don't see why there couldn't be methane breathers in an ammonia environment.

While ammonia's hydrogen bonds and surface tension are less than that of water, this should not be seen as a definite no.
On a cold world far from it's primary (or close with a cooler star), simple methane breathing bacteria may be able to take hold using ammonia as a solvent. Given enough time they may be able to greatly thicken the atmosphere to pressures where ammonia has a much higher boiling point, while also giving more energy for life processes as methane is a potent greenhouse gas.

Perhaps the life could also be Boron based, as such a reducing atmosphere would be conductive to it.

So a methane-nitrogen atmosphere of around 60atm (maybe a higher g world too hold that too?), with ammonia as the solvent, and life based on boron.

 

[Maxwell Edison II]

Like I said before, colder biospheres = slower bioprocesses, which means fewer generations to evolve. Consider that it took life three billion or so years to go from the first prokaryotes to multicellular organisms, while from there to here took no more than 6-700 million years, if life evolved a quarter slower during that last phase, we'd be mollusc's.

Life based upon reducing chemistry is an interesting thought. People have pointed out that saturating a unsaturated hydrocarbon would give chemical energy, the organisms would be breathing either hydrogen, methane or "absorb" ammonia.

Ammonia is unlikely to occur without water, and then it'll be a solution of ammonia in water. They form low-melting solutions though to occur as a "mantle" on Titan.

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Boron is neither very common nor very likely to form analogues of carbon compounds. It does form cluster-like molecules with interesting chemistry, but due to its low abundance, why would life evolve from them?

 

[Dorozhand]

Like I said before, colder biospheres = slower bioprocesses, which means fewer generations to evolve. Consider that it took life three billion or so years to go from the first prokaryotes to multicellular organisms, while from there to here took no more than 6-700 million years, if life evolved a quarter slower during that last phase, we'd be mollusc's.

That's kind of what I was talking about before. In a high UV environment, a planet might be able to rust itself through enough in the beginning to skip the cyanobacteria period and the Oxygen Catastrophe that wiped everything almost clean. That's a huge chunk of time right there. You could have multicellular life very early on with a little luck.

Then there's the factor of higher energy output of a larger star. The UV radiation put out by a white-blue star, rather than be detrimental to life, might foster faster evolutionary change over fewer generations and allow for high energy metabolisms in relatively lower temperatures (where the radiation being received is the same amount as in a yellow or lower star but the composition of the radiation is more towards the UV range)

 

[Sub Lord Hawk]

Like I said before, colder biospheres = slower bioprocesses, which means fewer generations to evolve. Consider that it took life three billion or so years to go from the first prokaryotes to multicellular organisms, while from there to here took no more than 6-700 million years, if life evolved a quarter slower during that last phase, we'd be mollusc's.

At 60atm ammonia boils at 98 Celsius so not exactly cold.

Life based upon reducing chemistry is an interesting thought. People have pointed out that saturating a unsaturated hydrocarbon would give chemical energy, the organisms would be breathing either hydrogen, methane or "absorb" ammonia.

Ammonia is unlikely to occur without water, and then it'll be a solution of ammonia in water. They form low-melting solutions though to occur as a "mantle" on Titan.

Why is ammonia unlikely to occur without water? Ammonia is NH3, it requires no oxygen. In a reducing environment the hydrogen would not be bonded with oxygen, and if the buffer is already nitrogen...

Boron is neither very common nor very likely to form analogues of carbon compounds. It does form cluster-like molecules with interesting chemistry, but due to its low abundance, why would life evolve from them?

No it's not very common, but carbon isn't a very common element of Earth on its own.
Boron does form polyhedral clusters and three-center two-electron bonds, which carbon also often forms (hyperconjugation).

Just because something isn't of great abundance doesn't mean that it can't be used in life; the universe is a very big place after all. Would just mean it's rare.

 

[Maxwell Edison II]

That's kind of what I was talking about before. In a high UV environment, a planet might be able to rust itself through enough in the beginning to skip the cyanobacteria period and the Oxygen Catastrophe that wiped everything almost clean. That's a huge chunk of time right there. You could have multicellular life very early on with a little luck.

Then there's the factor of higher energy output of a larger star. The UV radiation put out by a white-blue star, rather than be detrimental to life, might foster faster evolutionary change over fewer generations and allow for high energy metabolisms in relatively lower temperatures (where the radiation being received is the same amount as in a yellow or lower star but the composition of the radiation is more towards the UV range)

UV-light isn't a magic fix that makes photosynthesis happen faster. Yes, you need a certain number of eV:s to perform a chemical reaction, but that is what the chloroplast does, it absorbs both red and blue light, and then stores that energy as a proton gradient inside the cell, splitting water in the process. Being continuously pumped in to the thylakoid lumen and then utilized by ATP synthase to form ATP, having more "punch" per photon is not going to do any good.

Going into xenobiology, the light from another sun would only be a problem if there is extremely little higher-frequency light, then it would have trouble producing electrons that can be used to split water (which forms the H+, =protons). This takes 1.229eV (=1009 nm, a.t.m.c near-IR ) but IIRC the chlorophyll and other auxiliary pigments are capable of both gearing the high frequency light "down" and to some degree gearing low frequency light "up". There are phenomena like that, called "frequency doubling" and also "frequency tripling". If we find life on a planet orbiting a red dwarf, expect them. They're kind of like inverted UV-to-visible light fluorescence.

Addendum: a star with a high surface temperature is likely a short lived star. Not good for evolution. UV-level at ground level is probably just as dependent on the composition and thickness of the atmosphere as it is on its sun's UV-output. Too many powerful photons and the plant will have to evolve protection so that unwanted reactions doesn't happen.

At 60atm ammonia boils at 98 Celsius so not exactly cold.

Why is ammonia unlikely to occur without water? Ammonia is NH3, it requires no oxygen. In a reducing environment the hydrogen would not be bonded with oxygen, and if the buffer is already nitrogen...


No it's not very common, but carbon isn't a very common element of Earth on its own.
Boron does form polyhedral clusters and three-center two-electron bonds, which carbon also often forms (hyperconjugation).

Just because something isn't of great abundance doesn't mean that it can't be used in life; the universe is a very big place after all. Would just mean it's rare.

First of all, in never devolatilized bodies (like Triton, Pluto.... you get the picture) nitrogen mostly appears as itself. Ammonia is less volatile and will be where N2 can be found once you go inwards in the system of the "nitrogen frost limit", but all along water, the most common volatile compound, is also present. Devolatilized bodies like Mercury, the Moon, Earth before the late-heavy bombardment, and to a degree Mars will have contained both water, nitrogen and ammonia, and then lost all of them, in order of volatility.

I cannot imagine a process that would selectively remove water, which is much more stable than ammonia, from the volatile-mix that make up primordial clouds, plutinos, cubewanos and what not. It is what the universe (outside of stars) is made up out of. Its kind of like trying to imagine a planet without silicon.

Concerning boron, I'm not saying it is impossible, just that it is very unlikely.

 

[Sub Lord Hawk]

First of all, in never devolatilized bodies (like Triton, Pluto.... you get the picture) nitrogen mostly appears as itself. Ammonia is less volatile and will be where N2 can be found once you go inwards in the system of the "nitrogen frost limit", but all along water, the most common volatile compound, is also present. Devolatilized bodies like Mercury, the Moon, Earth before the late-heavy bombardment, and to a degree Mars will have contained both water, nitrogen and ammonia, and then lost all of them, in order of volatility.

I cannot imagine a process that would selectively remove water, which is much more stable than ammonia, from the volatile-mix that make up primordial clouds, plutinos, cubewanos and what not. It is what the universe (outside of stars) is made up out of. Its kind of like trying to imagine a planet without silicon.

Concerning boron, I'm not saying it is impossible, just that it is very unlikely.

Fair enough, it's unlikely but possible I believe, much like the Boron.

 

[Chairwoman Roxelana]

Is anyone knowledgeable about how alt-climates would work? I am having trouble figuring out what to do with the planet I have been building in my free time:

 

[Emperor Julian]

Is anyone knowledgeable about how alt-climates would work? I am having trouble figuring out what to do with the planet I have been building in my free time:

Yes, assuming that it is mostly like earth.

Here is how they work on earth:

The belts of high pressure are the driest, the belts of low pressure the wettest. There are exceptions by large continental areas which can produce monsoons due to the dramatic temperature differences, and coastal westerly areas on certain sides of the high-pressure anticyclones can receive wet air from the South (see the South-east US and Southern China).

I can run a temperature estimation on your planet using the Clima-Sim program if you want me to. I'll guess where the deserts and forests are.

Someone posted this in another thread, looks useful: http://jc.tech-galaxy.com/bricka/climate_cookbook.html

 

[Chairwoman Roxelana]

Yes, assuming that it is mostly like earth.

It is mostly like earth.

I can run a temperature estimation on your planet using the Clima-Sim program if you want me to. I'll guess where the deserts and forests are.

That would be nice if you could.

Someone posted this in another thread, looks useful: http://jc.tech-galaxy.com/bricka/climate_cookbook.html

I have been using this, but I have been confused with how temperature and rainfall (I have a vague idea of some of the aspects of the rainfall from using "Climate Cookbook") would work on this planet, and how biomes would work on the northern and southern edges of the two main continents.

 

[Emperor Julian]

That would be nice if you could.

OK, I am mostly done with an approximation of the map (as best as my drawing skills and the simple map on the program can do). I have a couple questions though:

Do any of those islands at the north and the south that cross the light blue areas (which I assume are where the oceans freeze in the winter) have permanent glaciers on them like Greenland?

Is this world Pre-industrial or Post-industrial? For levels of CO2 in the air.

How do you want your results? I can show numbers and/or isotherms for any month of the year, or an annual average, which do you want? I can show the daily maximum, minimum, or average as well. Also, Fahrenheit or Celsius?

 

[Chairwoman Roxelana]

Do any of those islands at the north and the south that cross the light blue areas (which I assume are where the oceans freeze in the winter) have permanent glaciers on them like Greenland?

Yes. If the light blue areas do not seem correct to you, you are free to change them.

Is this world Pre-industrial or Post-industrial? For levels of CO2 in the air.

Pre-Industrial.

How do you want your results? I can show numbers and/or isotherms for any month of the year, or an annual average, which do you want? I can show the daily maximum, minimum, or average as well. Also, Fahrenheit or Celsius?

Numbers and Isotherms of every month in the year with the daily average. In Fahrenheit.

 

[Maxwell Edison II]

OK, I am mostly done with an approximation of the map (as best as my drawing skills and the simple map on the program can do). I have a couple questions though:

Do any of those islands at the north and the south that cross the light blue areas (which I assume are where the oceans freeze in the winter) have permanent glaciers on them like Greenland?

Is this world Pre-industrial or Post-industrial? For levels of CO2 in the air.

How do you want your results? I can show numbers and/or isotherms for any month of the year, or an annual average, which do you want? I can show the daily maximum, minimum, or average as well. Also, Fahrenheit or Celsius?

The climatic difference between "industrial" and "post industrial" atmosphere is is nothing compared to what variations in insolation, eccentricity, axial tilt, albedo and longer-term CO2-variation one could expect between different planets.

http://en.wikipedia.org/wiki/Geologic_period
Click around on those, look at CO2-levels.

 

[Emperor Julian]

The climatic difference between "industrial" and "post industrial" atmosphere is is nothing compared to what variations in insolation, eccentricity, axial tilt, albedo and longer-term CO2-variation one could expect between different planets.

http://en.wikipedia.org/wiki/Geologic_period
Click around on those, look at CO2-levels.

Yeah, but he didn't give me a specific level, and it is easier to just choose 1750 or 2011 for the levels of CO2.

Not wanting to fill the thread with images, I will just post January and July here, and then I'll PM the rest to TurkishCapybara.



Note that the sea ice at the lowest latitudes is not all melted, it just is too warm for any more to freeze. The simulation only runs a year; over the years the ice would accumulate more and more.

 

[Emperor Julian]

And here is July:



For the locations of the deserts and forests, I generally just stuck with the climate pressure belts, except on the western continent which had those two giant mountain chains which I figured would be able to create huge enough rain shadows to extend the desert and savannah further north than it should go.

The map was a bit difficult, as the program has a Mercator projection which makes all land masses really large near the poles. I'm afraid I've left the corners emptier than they should be.

 

[Chairwoman Roxelana]

For the locations of the deserts and forests, I generally just stuck with the climate pressure belts, except on the western continent which had those two giant mountain chains which I figured would be able to create huge enough rain shadows to extend the desert and savannah further north than it should go.

The map was a bit difficult, as the program has a Mercator projection which makes all land masses really large near the poles. I'm afraid I've left the corners emptier than they should be.

Thank you. I didn't expect the planet to be that warm.

I will make a biome map from the data and send it to you for review.

 

[Emperor Julian]

Thank you. I didn't expect the planet to be that warm.

I will make a biome map from the data and send it to you for review.

It's really not that much hotter than Earth, except for the desert with the two giant mountain ranges on either side on the western continent. Oh, and no Antarctica makes the far south a bit warmer.

 

[Chairwoman Roxelana]

It's really not that much hotter than Earth, except for the desert with the two giant mountain ranges on either side on the western continent. Oh, and no Antarctica makes the far south a bit warmer.

It looks like it, though, because only two large islands fall below freezing and most of the land doesn't fall below 50 F.

Are there any other tips that you have for the biomes?

 

[Emperor Julian]

It looks like it, though, because only two large islands fall below freezing and most of the land doesn't fall below 50 F.

Note that this is the daily average temperature.

 

[rickyrab]

Universe Sandbox It's a really fun program

Universe Sandbox is a good program, true.

Agreed