The dumb questions thread

[Loren Pechtel]

We can live anywhere with all the elements we need.

That may be true, but "can live" falls a LONG way short of "will choose to live".

Why would anyone choose to go to some "Earthlike" exoplanet where the living is harder than it would be in Antarctica? And if we have to force people to go - ie establish a penal colony - why would we bother to send them to another solar system, when there are plenty of miserable hell-holes in our own system?...

To escape from religious freedom -- same reason some English Puritans decided they didn't like the Netherlands and came to America? If a minority culture expects to be wiped out locally by a majority culture that's more attractive to its kids, it may try to get as far from the source of infection as possible.

I don't think religion would be the only reason for this sort of thing. When interstellar colonization becomes viable for outgroups it's going to happen unless prohibited.

 

[steve_bank]

For the Brits North America was a convenient place to send a growing number of healthy young males who had nothing to do.

In the world today there is no pace to go, not like it was. There is no pressure relief valve.

 

[Jokodo]

For the Brits North America was a convenient place to send a growing number of healthy young males who had nothing to do.

In the world today there is no pace to go, not like it was. There is no pressure relief valve.

Oh, the good old days when we could send off rowdy youngsters to go kill some brown people! These days, they are sticking around, some of them ending up harassing their poor old white neighbours!

I mean, quite apart from the fact that nonsense on empirical grounds - crime rates today anywhere in the west are a fraction what they were in Victorian England or earlier - don't you see the ethical ramifications of what you wrote?

 

[bilby]

For the Brits North America was a convenient place to send a growing number of healthy young males who had nothing to do.

In the world today there is no pace to go, not like it was. There is no pressure relief valve.

This is the dumb questions thread, not the dumb answers thread.

 

[steve_bank]

Somebody said he was taking applications for people who would want to take a one way trip to Mars and establish a colony. Don't remember what kind of a scam it was but there were people who signed up.

Our iconic myth of Puttams who were searching for relgious freedom set up a restrictive oppressive culture.

Maybe that is why nature put stars so far apart, isolation.

 

[Jokodo]

Dumb question about exoplanets: I'm seeing it said in a lot of places that the terminator zone of a tidally locked planet could potentially be habitable. Now I get that on a planet where one side is continuously bathed in light and becomes too hot for liquid water while the other side is a frozen wasteland, there is going to be a transition zone with temperatures in the right range for liquid water. My issue is that it seems to me that the water isn't going to stay there: Whenever water evaporates, some of it will be carried to the dark side, where it snows down never to be seen again (except if its molten by volcanic activity or pushed back front by plate tectonics, both processes that would seem to slow to cancel out the losses). Even CO2 may well freeze - even on Earth, there are places where its cold enough for CO2 to freeze, if only we had a bit more in our atmosphere. Once CO2 and water have left the atmosphere, not much of a greenhouse effect will remain and it may well get cold enough for nitrogen to snow as well (there are apparently places on the moon, which, being the same average distance from the Sun as the Earth, is by definition in the habitable zone, where it is cold enough for solid nitrogen).

In conclusion, wouldn't the most likely outcome be that all water, and indeed most of the volatiles, become locked in a thick iceshield on the dark side within a short few tens of million years?

Related question: what would be the effect of such iceshields on the tidal locking? would the planet gaining a lot of mass on one side in the form of a thick iceshield help it escape the tidal locking (so that some of the ice would be exposed to the sun again? Or would it even help stabilize the synchronicity of orbit and rotation, being that the ice is less dense than whatever makes up the bulk of the planet?

 

[Shadowy Man]

Dumb question about exoplanets: I'm seeing it said in a lot of places that the terminator zone of a tidally locked planet could potentially be habitable. Now I get that on a planet where one side is continuously bathed in light and becomes too hot for liquid water while the other side is a frozen wasteland, there is going to be a transition zone with temperatures in the right range for liquid water. My issue is that it seems to me that the water isn't going to stay there: Whenever water evaporates, some of it will be carried to the dark side, where it snows down never to be seen again (except if its molten by volcanic activity or pushed back front by plate tectonics, both processes that would seem to slow to cancel out the losses). Even CO2 may well freeze - even on Earth, there are places where its cold enough for CO2 to freeze, if only we had a bit more in our atmosphere. Once CO2 and water have left the atmosphere, not much of a greenhouse effect will remain and it may well get cold enough for nitrogen to snow as well (there are apparently places on the moon, which, being the same average distance from the Sun as the Earth, is by definition in the habitable zone, where it is cold enough for solid nitrogen).

In conclusion, wouldn't the most likely outcome be that all water, and indeed most of the volatiles, become locked in a thick iceshield on the dark side within a short few tens of million years?

Related question: what would be the effect of such iceshields on the tidal locking? would the planet gaining a lot of mass on one side in the form of a thick iceshield help it escape the tidal locking (so that some of the ice would be exposed to the sun again? Or would it even help stabilize the synchronicity of orbit and rotation, being that the ice is less dense than whatever makes up the bulk of the planet?

You are probably on to something here and I would be interested to see if any planetary scientists have run actual climate models for a scenario like this or if this statement is merely a “popular science” hypothesis.

What would the weather be on a planet like this? One would think that a hot side and a cold side would drive currents, as the warm air on the star facing side would likely try to creep to the backside.

I find it unlikely that there’s an equilibrium situation where there’s a perfectly habitable terminator zone, but I admit to not knowing or looked into whether anyone has seriously studied this.

 

[Jimmy Higgins]

Life can flourish just about anywhere... as long as provided with enough time to iron out the kinks of the environment and the rate of change is slow enough. As far as mass shifting, I've got to imagine the mass of the planet would be as such that the center of gravity's shift in a half ice ball scenario would still be near negligible. 5,000 mile radius planet... and if you add 50 miles of ice (much more than likely ever possible), it just doesn't add up to much at all. Also, the center of rotation is based on both the mass (center of mass) of the planet and the star(s). And the star isn't changing, so even if the center mass shifts a tad for the planet, the gravitation remains about the same.

The issue for liquid water comes down to a number of things. How much are the solar winds bashing on the planet, wicking away the atmopshere, what is the status of the atmosphere and climate patterns in general? Hunter Biden's laptop!

 

[Jokodo]

Life can flourish just about anywhere... as long as provided with enough time to iron out the kinks of the environment and the rate of change is slow enough. As far as mass shifting, I've got to imagine the mass of the planet would be as such that the center of gravity's shift in a half ice ball scenario would still be near negligible. 5,000 mile radius planet... and if you add 50 miles of ice (much more than likely ever possible), it just doesn't add up to much at all. Also, the center of rotation is based on both the mass (center of mass) of the planet and the star(s). And the star isn't changing, so even if the center mass shifts a tad for the planet, the gravitation remains about the same.

The gravitation remains *exactly* the same, unless another body interferes. The tidal forces change. I'm not sure it's negligible either - e.g. compare the very different nature of the moon's near and far sides. As far as I know, it's no coincidence she's showing us the side with the maria, large basaltic plains: this kind of rock is denser than what is found in the highlands. In a similar vein, if Earth were locked to the Sun, I assume we be showing some point in the Pacific, while Africa, Europe, most of Asia and the Eastern parts of the Americas would be permanently cold and dark. Unfortunately, that's ideal for the formation of thick ice sheets. A large ocean on the dark side would be more conducive to continued recycling of the ice, wouldn't it?

 

[Shadowy Man]

I started looking into this and there appears to be a reasonably healthy literature the subject on the climate of tidally locked planets around M stars.

One thing that appears to be important is heat transport through ocean currents. Water will flow from the bright side to the dark side and keep the dark side warm enough to not freeze over completely. But the papers I saw so far assume water planets and so point out that continents can disrupt that transport.

So, it’s really going to depend on the specifics of the geology of the planet.

Two papers I have looked at so far:

“Role of ocean hat transport in climates of tidally locked exoplanets around M dwarf stars” by Hu and Yang (2014)

“No snowball on habitable tidally locked planets with a dynamic ocean” by Checlair et al. (2019)

I’m sure there are many more to read.

 

[Loren Pechtel]

I started looking into this and there appears to be a reasonably healthy literature the subject on the climate of tidally locked planets around M stars.

One thing that appears to be important is heat transport through ocean currents. Water will flow from the bright side to the dark side and keep the dark side warm enough to not freeze over completely. But the papers I saw so far assume water planets and so point out that continents can disrupt that transport.

So, it’s really going to depend on the specifics of the geology of the planet.

Two papers I have looked at so far:

“Role of ocean hat transport in climates of tidally locked exoplanets around M dwarf stars” by Hu and Yang (2014)

“No snowball on habitable tidally locked planets with a dynamic ocean” by Checlair et al. (2019)

I’m sure there are many more to read.

Another factor: Wobble. Tidally locked worlds can still wobble (and must do so if their orbits aren't perfectly circular.) Non-solids will tend to migrate to the center of the dark side but this will only doom the planet if the equilibrium point between radiation to space and heat inflow from the warm side is too cold to maintain an atmosphere and hydrosphere. A decent wobble is a big help in this regard.

 

[bilby]

“Role of ocean hat transport in climates of tidally locked exoplanets around M dwarf stars” by Hu and Yang (2014)

I'm going out on a limb here, but if a planet has developed a civilisation sufficient that its resident milliners are employing transoceanic logistics, it is almost certainly in possession of considerable inhabitable areas.

Or should that be "heat transport"?

 

[Shadowy Man]

“Role of ocean hat transport in climates of tidally locked exoplanets around M dwarf stars” by Hu and Yang (2014)

I'm going out on a limb here, but if a planet has developed a civilisation sufficient that its resident milliners are employing transoceanic logistics, it is almost certainly in possession of considerable inhabitable areas.

Or should that be "heat transport"?

Can’t type Well on my phone. And don’t always catch all Typos on proofreading

 

[Jokodo]

I started looking into this and there appears to be a reasonably healthy literature the subject on the climate of tidally locked planets around M stars.

One thing that appears to be important is heat transport through ocean currents. Water will flow from the bright side to the dark side and keep the dark side warm enough to not freeze over completely. But the papers I saw so far assume water planets and so point out that continents can disrupt that transport.

So, it’s really going to depend on the specifics of the geology of the planet.

Two papers I have looked at so far:

“Role of ocean hat transport in climates of tidally locked exoplanets around M dwarf stars” by Hu and Yang (2014)

“No snowball on habitable tidally locked planets with a dynamic ocean” by Checlair et al. (2019)

I’m sure there are many more to read.

I guess I was thinking more of a planet with at least as much land area as the Earth, in a similar distribution. I can see how a few Greenlands and Antarcticas scattered across the dark side probably won't hurt. Geothermal heat may well provide a lubricant film at the ice rock interface that ensures glaciers can move with considerable speed (would they though? I imagine ice at -150° C to behave quite differently from ice at -50), and once it reaches the sea, the ice is slowly but surely transported to the warm side. I can imagine that this process is too efficient for the seas to ever dry up for good and break the cycle. Just don't go on the Titanic.

I just don't see this applying to a scenario where most of Africa-Eurasia and the Americas are under ice, let alone Pangaea.

 

[Bomb#20]

“Role of ocean hat transport in climates of tidally locked exoplanets around M dwarf stars” by Hu and Yang (2014)

I'm going out on a limb here, but if a planet has developed a civilisation sufficient that its resident milliners are employing transoceanic logistics, it is almost certainly in possession of considerable inhabitable areas.

Or should that be "heat transport"?

SM was clearly referring to variation in the ocean's unit vector.

 

[Shadowy Man]

I started looking into this and there appears to be a reasonably healthy literature the subject on the climate of tidally locked planets around M stars.

One thing that appears to be important is heat transport through ocean currents. Water will flow from the bright side to the dark side and keep the dark side warm enough to not freeze over completely. But the papers I saw so far assume water planets and so point out that continents can disrupt that transport.

So, it’s really going to depend on the specifics of the geology of the planet.

Two papers I have looked at so far:

“Role of ocean hat transport in climates of tidally locked exoplanets around M dwarf stars” by Hu and Yang (2014)

“No snowball on habitable tidally locked planets with a dynamic ocean” by Checlair et al. (2019)

I’m sure there are many more to read.

I guess I was thinking more of a planet with at least as much land area as the Earth, in a similar distribution. I can see how a few Greenlands and Antarcticas scattered across the dark side probably won't hurt. Geothermal heat may well provide a lubricant film at the ice rock interface that ensures glaciers can move with considerable speed (would they though? I imagine ice at -150° C to behave quite differently from ice at -50), and once it reaches the sea, the ice is slowly but surely transported to the warm side. I can imagine that this process is too efficient for the seas to ever dry up for good and break the cycle. Just don't go on the Titanic.

I just don't see this applying to a scenario where most of Africa-Eurasia and the Americas are under ice, let alone Pangaea.

Sure, but you are just hypothesizing, whereas the papers that I have cited have implemented models with realistic physics to simulate the effects. I have only looked at this a little bit and there does appear to be a lot out there, so perhaps there are other papers that have looked more into what happens when landmasses and geothermal energy is added to the mix. But surely a good place to start is to get at the basics before adding complexity.

 

[Elixir]

I'm going out on a limb here, but if a planet has developed a civilisation sufficient that its resident milliners are employing transoceanic logistics, it is almost certainly in possession of considerable inhabitable areas.

Or should that be "heat transport"?

SM was clearly referring to variation in the ocean's unit vector.

@bilby just wanted to use the word “milliner“.

 

[bilby]

I'm going out on a limb here, but if a planet has developed a civilisation sufficient that its resident milliners are employing transoceanic logistics, it is almost certainly in possession of considerable inhabitable areas.

Or should that be "heat transport"?

SM was clearly referring to variation in the ocean's unit vector.

@bilby just wanted to use the word “milliner“.

Keep it under your hat.

 

[Loren Pechtel]

“Role of ocean hat transport in climates of tidally locked exoplanets around M dwarf stars” by Hu and Yang (2014)

I'm going out on a limb here, but if a planet has developed a civilisation sufficient that its resident milliners are employing transoceanic logistics, it is almost certainly in possession of considerable inhabitable areas.

Or should that be "heat transport"?

No, it's talking about garments meant to be worn by those engaged in ocean transport.