Can life emerge around a white dwarf?(centauri-dreams.org)
centauri-dreams.org
Can life emerge around a white dwarf?
https://www.centauri-dreams.org/2024/12/06/can-life-emerge-around-a-white-dwarf/
103 comments
What I love about the idea of planetary systems around dwarf stars is that if the planets were close it would make interplanetary flight quite a bit faster and easier.
Now imagine multiple ones with life. Someone out there in the vastness of the cosmos might be LARPing Buck Rogers or Commando Cody.
Simple rockets could take you everywhere. It’d be like The Expanse but without the physicists nightmare fusion torches. Such things can maybe be built but it’s many orders of magnitude harder. These folks could be living the dream with 1950s level tech.
They probably look like crabs though.
Now imagine multiple ones with life. Someone out there in the vastness of the cosmos might be LARPing Buck Rogers or Commando Cody.
Simple rockets could take you everywhere. It’d be like The Expanse but without the physicists nightmare fusion torches. Such things can maybe be built but it’s many orders of magnitude harder. These folks could be living the dream with 1950s level tech.
They probably look like crabs though.
Although rockets could take you between closely spaced planets, the delta V to escape the system would be much greater than in our solar system, by an order of magnitude. The habitable planet would be much deeper in the star's gravity well than we are in our Sun's.
Travel times between inner planets would be very short, I admit.
Travel times between inner planets would be very short, I admit.
You should be able to sling shot multiple times to improve that though?
Some, although I think that would need either lots of slingshots or really heavy planets. If there are many closely spaced planets it could work, I think, and the encounter cadence would be high.
If there are lots of planets in closely spaced orbits I'd think orbital resonances could force planets into elliptical orbits, which would drive strong tidal heating, as on Io (but more so, due to the much stronger gravity of the primary.)
If there are lots of planets in closely spaced orbits I'd think orbital resonances could force planets into elliptical orbits, which would drive strong tidal heating, as on Io (but more so, due to the much stronger gravity of the primary.)
Also due to tidal lock “weather” they can simply kite their satellites (and rockets/missiles) to the orbit, for the most part. You open the hatch and let it fly. Don’t forget to close the hatch though, or your entire dream will fly too.
Whoa… I never thought of that. If complex life were possible on a tide locked planet that held onto its atmosphere you could ride the powerful currents this would create at least much of the way to orbit. You’d probably need a rocket to reach orbital velocity and escape but the atmosphere might be almost like your first rocket stage.
Such a civilization would also have endless free energy via solar harnessed from the sun side and continuous prevailing powerful winds. The latter would probably get tapped first. Huge wind turbines would just always spin.
This would be true from their dawning of industry, which would be interesting. No energy wars. I’m sure they’d find something else to fight about if they were aggressive and territorial like us.
Such a civilization would also have endless free energy via solar harnessed from the sun side and continuous prevailing powerful winds. The latter would probably get tapped first. Huge wind turbines would just always spin.
This would be true from their dawning of industry, which would be interesting. No energy wars. I’m sure they’d find something else to fight about if they were aggressive and territorial like us.
Wouldn’t the amount of habitable land mass on a tidal locked planet be rather small? Like the bulk of the planet is either hotter than hells freezer or colder than its hot tub. You’ve got only a fixed ring of land that would be usable.
Unless life can survive & thrive in the remainder. Which I’m sure it can and does.
Unless life can survive & thrive in the remainder. Which I’m sure it can and does.
It would be quite different from Earth in lots of ways.
The most habitable region would probably be the twilight zone but “life will find a way” as Jeff Goldblum famously said. Life would have been evolving for billions of years in that environment before intelligence arose.
The temperature gradient might not be as nuts as you’d think. A thick atmosphere would develop powerful prevailing currents that would move heat from the hot side to the cold one, basically a heat engine. It would keep the hot side from being insane and the cold side from being cryogenic. My guess is that the far poles would be extreme but anywhere from 1/3 to 2/3 of the non-twilight sides would be potentially habitable by something.
If there were large oceans you'd get prevailing currents there that would move heat too.
There’d also be a water cycle. Imagine regions of the hot side where it rains a lot. You might have this hot steamy jungle in eternal daylight, meaning 2X the energy available for photosynthesis.
There’d probably be critters that would migrate around. I can imagine stuff living on the night side by eating those, scavenging, etc.
I wonder if an environment with massive prevailing winds would drive the evolution of wind energy harvesting? Imagine a big tree like thing with big leaves or vanes shaped to flap in the wind and specialized cells that use that mechanical energy to make food and nutrients. Muscles go from sugars to motion. Seems plausible that something could go the other way, especially with billions of years of evolution and a massive amount of energy available that way.
If that kind of thing evolved you could have wind powered ecosystems on the night side and solar powered ones on the day side.
Lots of possibilities.
The most habitable region would probably be the twilight zone but “life will find a way” as Jeff Goldblum famously said. Life would have been evolving for billions of years in that environment before intelligence arose.
The temperature gradient might not be as nuts as you’d think. A thick atmosphere would develop powerful prevailing currents that would move heat from the hot side to the cold one, basically a heat engine. It would keep the hot side from being insane and the cold side from being cryogenic. My guess is that the far poles would be extreme but anywhere from 1/3 to 2/3 of the non-twilight sides would be potentially habitable by something.
If there were large oceans you'd get prevailing currents there that would move heat too.
There’d also be a water cycle. Imagine regions of the hot side where it rains a lot. You might have this hot steamy jungle in eternal daylight, meaning 2X the energy available for photosynthesis.
There’d probably be critters that would migrate around. I can imagine stuff living on the night side by eating those, scavenging, etc.
I wonder if an environment with massive prevailing winds would drive the evolution of wind energy harvesting? Imagine a big tree like thing with big leaves or vanes shaped to flap in the wind and specialized cells that use that mechanical energy to make food and nutrients. Muscles go from sugars to motion. Seems plausible that something could go the other way, especially with billions of years of evolution and a massive amount of energy available that way.
If that kind of thing evolved you could have wind powered ecosystems on the night side and solar powered ones on the day side.
Lots of possibilities.
Upvoted for "they probably look like crabs". I see what you did there and I am here for it.
>They probably look like crabs though.
It's crabs all the way down. https://en.wikipedia.org/wiki/Carcinisation
It's crabs all the way down. https://en.wikipedia.org/wiki/Carcinisation
If it's super easy to get to orbit, it's also super easy for your atmosphere to get to orbit.
True. I was thinking of time between planets though. It’s hard to get to Earth orbit but it also takes six to twelve months to get to Mars without some kind of crazy torch rocket. In a smaller system it might take a few weeks. Big difference.
At 1/100 distance, wouldn't a hypothetical planet be tidally locked to the white dwarf?
Could tidally locked planets be suitable for life?
Could tidally locked planets be suitable for life?
> At 1/100 distance, wouldn't a hypothetical planet be tidally locked to the white dwarf?
Probably. Well, usually. If something gave that planet a very hard knock, it could spin up for a while, especially if it's around the outer limits of the proposed habitable zone.
> Could tidally locked planets be suitable for life?
Definitely. Depends how well they're able to redistribute heat from the hot side to the dark side. So atmospheric composition and water content (also the presence and extent of surface water) would be the decisive factors. You'd get wild weather, though.
Probably. Well, usually. If something gave that planet a very hard knock, it could spin up for a while, especially if it's around the outer limits of the proposed habitable zone.
> Could tidally locked planets be suitable for life?
Definitely. Depends how well they're able to redistribute heat from the hot side to the dark side. So atmospheric composition and water content (also the presence and extent of surface water) would be the decisive factors. You'd get wild weather, though.
> Definitely. Depends how well...
I'm less optimistic. Between the fraction of the planet's surface that's suitable for life, the lack of tides, the (likely) lack of plate tectonics, and impairment of the various cycles ( https://en.wikipedia.org/wiki/Biogeochemical_cycle ) - tidal locking to the star will profoundly degrade the planet's suitability for life.
Tidal locking may also rule out having a planetary magnetic field. Though "protect the atmosphere" may not matter much, if said atmosphere (plus the water) has all condensed and frozen on the dark side of the planet.
I'm less optimistic. Between the fraction of the planet's surface that's suitable for life, the lack of tides, the (likely) lack of plate tectonics, and impairment of the various cycles ( https://en.wikipedia.org/wiki/Biogeochemical_cycle ) - tidal locking to the star will profoundly degrade the planet's suitability for life.
Tidal locking may also rule out having a planetary magnetic field. Though "protect the atmosphere" may not matter much, if said atmosphere (plus the water) has all condensed and frozen on the dark side of the planet.
Depending on the thickness and composition of the atmosphere, convection may be sufficient to prevent ice buildup.
The thing about a tidally locked planet, and about marginally habitable planets in general, is that whatever the average, there are a wide range of surface conditions and often the spectrum is large enough that some subset of them are habitable.
The thing about a tidally locked planet, and about marginally habitable planets in general, is that whatever the average, there are a wide range of surface conditions and often the spectrum is large enough that some subset of them are habitable.
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Does the atmosphere need protecting? White dwarfs don’t have solar wind.
it's a hard knock white dwarf dust
That's almost a joke. I don't know what to categorize that as. It isn't a pun. What is that?
It's technically a filk, just really short.
“It’s a hard knock white.. dwarf dust!” Is the joke
Yes. I understand. I was saying it's almost a joke.
But for real what is it called when the things you're saying don't necessarily rhyme with the original phrase but have a similar cadence?
But for real what is it called when the things you're saying don't necessarily rhyme with the original phrase but have a similar cadence?
This does (nearly) rhyme
Not quite that close but Mercury seems to have an interesting interaction with the sun
https://en.m.wikipedia.org/wiki/Mercury_(planet)#Spin-orbit_...
https://en.m.wikipedia.org/wiki/Mercury_(planet)#Spin-orbit_...
On a tidal locked planet, conditions should be very static. The point facing the sun is the hottest, and the opposite point is the coldest.
Which means there is a constant "spectrum" of climates in between, and you only need one of these thousands of microclimates to be beneficial for creating life.
So this may be the planets most suitable for life, if this theory I just made up has any validity!
Which means there is a constant "spectrum" of climates in between, and you only need one of these thousands of microclimates to be beneficial for creating life.
So this may be the planets most suitable for life, if this theory I just made up has any validity!
It does make some sense, even if life would be viable only in (for example) the twilight rim of the planet (such as around the poles)
A large moon should absolutely mess this tidal locking up fwiw since it will have far more influence than the star just as our moon has far more tidal influence than our sun.
Not that I think tidal locking is a blocker for life but it’s also not a big deal since large moons are extremely common and therefore the tidal locking is not guaranteed.
Not that I think tidal locking is a blocker for life but it’s also not a big deal since large moons are extremely common and therefore the tidal locking is not guaranteed.
I once read an article that speculated about this.
The conclusion was that perhaps there could be a ring around the planet, at the border of the side facing the sun from the side facing away from the sun. That ring could be a habitable zone.
The conclusion was that perhaps there could be a ring around the planet, at the border of the side facing the sun from the side facing away from the sun. That ring could be a habitable zone.
> All of this can happen via quantum processes at zero temperature. So they end as lumps of indefinitely stable cold iron.
Assuming no proton decay, of course.
Assuming no proton decay, of course.
Which has yet to be experimentally observed. At some point we'll be able to rule it out, I'm sure.
Sorry if this is a stupid question. If proton decay does not happen, but a proton is say in motion through a galaxy, where does the energy for its gravitational waves come from? Its momentum and therefore it slows down?
A lone proton coasting inertially through empty space at a constant velocity, even if it's moving quickly, does not generate any gravitational waves. It might generate gravitational waves if it's accelerated, but then those would come from the energy budget responsible for that acceleration.
Is it only accelerating objects that emit gravity waves/particles, or do decelerating objects do it too?
This must be a joke, right?
That's the same thing
Acceleration is a general term for both increases and decreases in velocity. It might also surprise you to know that "incline" functions the same way.
Reminds me of a joke we have in racing, noobs often carry too much speed into a corner, reluctant to brake too much thinking that is quicker when in reality braking harder, earlier, often enables better lap time.
To get over this mental hurdle we say ‘it’s not slowing down it’s reaching your minimum speed faster!’
To get over this mental hurdle we say ‘it’s not slowing down it’s reaching your minimum speed faster!’
That still breaks my head. Reaching your minimum speed slower means you have a higher speed for a longer time, covering more distance?
I know nothing about racing, is it maybe about reaching a higher minimum speed by doing so before the curve?
I know nothing about racing, is it maybe about reaching a higher minimum speed by doing so before the curve?
If you brake too late, you often end up going below the minimum speed to avoid going off the outside of the track when you find out your grip wasn't as much as you thought.
Obviously, you want to brake as late as possible while still reaching the minimum speed demanded by the radius of the turn and your tires/downforce, which keeps your average speed as high as possible before the turn. But it very easy to get in a habit of braking too late, overshooting the turn, and taking a sub-optimal trajectory, which would be passed by someone who braked sooner and used some additional physics concepts.
The absolute fastest way is to brake as late as possible without overshooting, start the turn while you are about to let off the brakes (when the weight of the car has shifted towards the front wheels while braking, so you get more grip on your tires which are doing the steering), and as you let off the brakes, the car has rotational inertia that carries through the turn without needing the tires as much. (but too much rotational inertia = spinout.) Once you have the rotational inertia, you can start giving it gas before you finish the turn, and if the car is RWD, use the engine/oversteer to both increase your speed again and give you extra force pushing you through the inside of the turn. (By getting slightly too much inertia at the start of the turn (but not enough to spin out), then at the end of the turn, when your car would go off the outside of the track, instead have it slightly over-rotate the turn, so that you can use the engine to angle your forces both forward and into the turn, to help you finish without going off.) This way you get to use the engine to make some of the turn instead of the brakes for all of it, which is obviously faster. Then straighten the wheel when you've exited.
Drifting is just over-playing into the above mechanics, getting too much inertia too soon and doing a sideways burnout while countersteering (to bleed off the excess rotation) through the turn to look cool. The fastest is halfway between drifting and "driving naive", aka braking early and coasting through like normal road driving.
I play racing sims and couldn't win consistently until I understood all the above.
Obviously, you want to brake as late as possible while still reaching the minimum speed demanded by the radius of the turn and your tires/downforce, which keeps your average speed as high as possible before the turn. But it very easy to get in a habit of braking too late, overshooting the turn, and taking a sub-optimal trajectory, which would be passed by someone who braked sooner and used some additional physics concepts.
The absolute fastest way is to brake as late as possible without overshooting, start the turn while you are about to let off the brakes (when the weight of the car has shifted towards the front wheels while braking, so you get more grip on your tires which are doing the steering), and as you let off the brakes, the car has rotational inertia that carries through the turn without needing the tires as much. (but too much rotational inertia = spinout.) Once you have the rotational inertia, you can start giving it gas before you finish the turn, and if the car is RWD, use the engine/oversteer to both increase your speed again and give you extra force pushing you through the inside of the turn. (By getting slightly too much inertia at the start of the turn (but not enough to spin out), then at the end of the turn, when your car would go off the outside of the track, instead have it slightly over-rotate the turn, so that you can use the engine to angle your forces both forward and into the turn, to help you finish without going off.) This way you get to use the engine to make some of the turn instead of the brakes for all of it, which is obviously faster. Then straighten the wheel when you've exited.
Drifting is just over-playing into the above mechanics, getting too much inertia too soon and doing a sideways burnout while countersteering (to bleed off the excess rotation) through the turn to look cool. The fastest is halfway between drifting and "driving naive", aka braking early and coasting through like normal road driving.
I play racing sims and couldn't win consistently until I understood all the above.
It also depends on what comes next. E.g. if you have a long straight coming up, you want to straighten out things as soon as you can, so you can accelerate early and take that speed into the straight. It often makes sense to sacrifice speed in the turn for better speed on the straight.
Quite the opposite. Consider
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Ah, thanks. Here I thought that the distance that you’re not driving at full speed would be equal in both cases, in which case you want to “minimize the minimum speed time”, but the situation you present, where the distance you drive at minimum speed is equal, makes much more sense of course.
How would we do that?
We will probably just keep downgrading its probability into more and more absurdly low values.
We will probably just keep downgrading its probability into more and more absurdly low values.
It is possible to rule out such things. Lets suppose that physicist invented a theory of everything, and all the predictions of the theory were confirmed experimentally except for proton decay. At that point physicists will declare that protons do not decay and leave physics because there is nothing more to do in physics.
> Intelligent life can hang around white dwarfs for a long time. Good candidate star type for Dyson spheres.
I would imagine that if intelligent life can build a Dyson sphere, it can probably travel to different stars as well.
I would imagine that if intelligent life can build a Dyson sphere, it can probably travel to different stars as well.
Wouldn't gravity tidal forces rip those planets eventually apart? Like we expect ie Phobos to end up, and Mars has much gentler gravity gradient than this would have.
Or would tidal locking somehow prevent it?
Or would tidal locking somehow prevent it?
I think even for a white dwarf the Roche limit is well inside the inner edge of the habitable range. So a planet that gets torn apart by gravity would already have been uninhabitably close.
A planet formed out of an accretion disk is generally a planet under continued bombardment from further accretion.
The only exception that we know of is our own Solar System. Where Jupiter acts like a vacuum cleaner to reduce material that might hit Earth. We knkw of no other system with both Earth-like planets and gas giants. Given how catastrophic the remaining asteroids have been for us (bye bye dinosaurs), this is unlikely to be a coincidence.
Unless we find a similar arrangement around a white dwarf, the time spent in the habitable zone isn't the only important factor for stability over evolutionary time frames.
The only exception that we know of is our own Solar System. Where Jupiter acts like a vacuum cleaner to reduce material that might hit Earth. We knkw of no other system with both Earth-like planets and gas giants. Given how catastrophic the remaining asteroids have been for us (bye bye dinosaurs), this is unlikely to be a coincidence.
Unless we find a similar arrangement around a white dwarf, the time spent in the habitable zone isn't the only important factor for stability over evolutionary time frames.
> The only exception that we know of is our own Solar System. Where Jupiter acts like a vacuum cleaner to reduce material that might hit Earth. We knkw of no other system with both Earth-like planets and gas giants.
Isn't this a current limitation of our exoplanetary detection capabilities rather than something we know about other star systems in general? IIRC exoplanets are most easily discovered by the effect they have on their parent star's brightness when transiting it and/or due to causing the parent star to "wobble". Both those methods would tend to favor finding close and massive planets without necessarily ruling out smaller/more distant ones.
Have exoplanet detection methods improved since I last read about them?
Isn't this a current limitation of our exoplanetary detection capabilities rather than something we know about other star systems in general? IIRC exoplanets are most easily discovered by the effect they have on their parent star's brightness when transiting it and/or due to causing the parent star to "wobble". Both those methods would tend to favor finding close and massive planets without necessarily ruling out smaller/more distant ones.
Have exoplanet detection methods improved since I last read about them?
> Both those methods would tend to favor finding close and massive planets without necessarily ruling out smaller/more distant ones.
They also favor ones whose orbit passes between us and their star, which dims the star and lets us see it. If the planet’s orbit doesn’t block the star, we’ll never know it was there using our current toolset.
I read somewhere that only like 2% of all planet’s have orbits that come between us and their star—which seems like a plausible figure to me, it’s a number you can probably derive from some simple math. This means until we find other ways to observe planets, we are only able to see a very small number of them out there.
Incidentally if other intelligent life is out there planet hunting using the same method of observing planets pass between the star and the observer, it means the odds of them finding earth are pretty small. They’d have to be positioned such that the earth comes between our sun and their line of sight.
They also favor ones whose orbit passes between us and their star, which dims the star and lets us see it. If the planet’s orbit doesn’t block the star, we’ll never know it was there using our current toolset.
I read somewhere that only like 2% of all planet’s have orbits that come between us and their star—which seems like a plausible figure to me, it’s a number you can probably derive from some simple math. This means until we find other ways to observe planets, we are only able to see a very small number of them out there.
Incidentally if other intelligent life is out there planet hunting using the same method of observing planets pass between the star and the observer, it means the odds of them finding earth are pretty small. They’d have to be positioned such that the earth comes between our sun and their line of sight.
A large enough telescope in space, with a coronagraph could, in teory, find such planets by direct imaging. Right now, I believe only JWST fits the bill, but using it for this purpose would interfere with other types of research, so the coronagraph us used only only to observe planets the wer already discovered by other methods.
I’m pretty sure that new telescope being constructed in Chile will be large enough to directly image planets but I could be wrong.
"Dragon's Egg" by Robert L. Forward, published in 1980, is a hard sci-fi novel about intelligent life forms living on a neutron star. It's superb.
One of my favorite hard sci-fi books! Well worth a read
One of my favorites too and immediately came to mind when I saw OP. I recommend the book highly if the subject matter of this thread interests you.
Does it still hold up, technology prediction wise?
It doesn’t really concern itself with human technology. Yes, there are humans, and a human spaceship, but their role is secondary at best.
it’s not really that kind of book. It’s more physics than tech.
Highly recommend to a certain type of person. Many of whom frequent this message board !
Highly recommend to a certain type of person. Many of whom frequent this message board !
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More recently, "Flux" by Stephen Baxter is about a engineered human analogues living on a neutron star.
That book is wonderful
Have there ever been any further developments and investigations along these lines?
I'd never seek to deprive anyone of entertaining alien-life theories, but in general people wildly underestimate the factors that play into making Earth habitable. The only evidence for a habitable planet-type is the very precise conditions that comprise this one. Worse, it's unclear as to how much those conditions rely on the complete configuration of the greater solar system.
The universe is a big place, and we don't really possess the ability to find or see an Earth-like candidate as of yet. Our exoplanet searches are fairly rudimentary. For the solar system, it's very possible that at least two planets have had life and that even some moons may currently have it. Given that, it seems pretty unlikely that there isn't life elsewhere.
Given the right conditions, such as Earth, life isn't hard. It showed up almost immediately.
Given the right conditions, such as Earth, life isn't hard. It showed up almost immediately.
Given that they've found living organisms in nuclear reactors and other extreme conditions it doesn't seem likely that "earth like conditions" are a requirement for life
There's a difference between life forms that can survive a particular environment, and all of the phases of incremental steps towards forming the first life in such an environment.
There's nothing to do but speculate until proven otherwise, since we don't actually know what those steps exactly are. My personal suspicion is that we are more likely to find life in earth like conditions than anywhere else, though.
There's nothing to do but speculate until proven otherwise, since we don't actually know what those steps exactly are. My personal suspicion is that we are more likely to find life in earth like conditions than anywhere else, though.
And yet nuclear reactors are on Earth. Again, people underestimate the factors involved. Have these organisms been shown to derive from an alien taxonomy?
While your argument is true, I would guess aliens will be quite a lot different than anything we know on this earth. Even different in so called life and death cycles, or even in the very definition of what we can call alive and dead. We should much broaden our search scope.
Forgetting that we just leapt over the fact that the conditions of this planet are the only-evidence for the genesis of Life, and went straight to evolution, and while you logic is sound in theory, I'd again point to the probable fact that the necessary conditions for Life are massively underestimated.
Perhaps mostly in terms of genesis, but also sustainability and even given theoretical evolutionary differences for hypothetical aliens.
But genesis is really the only discussion that matters. Which is also very true for those that believe that there is a good possibility for alien Life.
The math is beyond me to do, but I once got into a conversation with Claude that sought to find the probable distance of the nearest exoplanet that has possible Earth like conditions matching only a couple of additional factors that aren't commonly considered. Whereas I have dozens more. Claude's estimation was that the nearest such planet would be over two million light years away.
Another conversation sought to understand the probability of an exact replica of this solar system somewhere else in the Universe. That probability is zero.
Perhaps mostly in terms of genesis, but also sustainability and even given theoretical evolutionary differences for hypothetical aliens.
But genesis is really the only discussion that matters. Which is also very true for those that believe that there is a good possibility for alien Life.
The math is beyond me to do, but I once got into a conversation with Claude that sought to find the probable distance of the nearest exoplanet that has possible Earth like conditions matching only a couple of additional factors that aren't commonly considered. Whereas I have dozens more. Claude's estimation was that the nearest such planet would be over two million light years away.
Another conversation sought to understand the probability of an exact replica of this solar system somewhere else in the Universe. That probability is zero.
Water is practically a miracle in itself. Reasonable range between freezing and boiling, simple structure, polar solvent and non-flammable.
The hydrogen bonds allow lots of interesting processes, and it gets used in many many foundational biological functions as hydroxyl groups.
The chemistry of such a simple molecule is difficult if not impossible to replace, and if you have it, the processes that we are familiar with are already efficient enough that there wouldn't be an advantage to not using them.
Is it possibly there are configurations of life, such as not using either DNA or RNA? Sure. Is it likely that we wouldn't recognize that it is life? I doubt it very much. Aside from virii which likely devolved from living things rather than forming along side them, it's not hard to make a distinction at all.
The hydrogen bonds allow lots of interesting processes, and it gets used in many many foundational biological functions as hydroxyl groups.
The chemistry of such a simple molecule is difficult if not impossible to replace, and if you have it, the processes that we are familiar with are already efficient enough that there wouldn't be an advantage to not using them.
Is it possibly there are configurations of life, such as not using either DNA or RNA? Sure. Is it likely that we wouldn't recognize that it is life? I doubt it very much. Aside from virii which likely devolved from living things rather than forming along side them, it's not hard to make a distinction at all.
It’s also magnetic, making MRIs (and floating frogs) possible.
Right, this particular solar system happens to have a planet that peoples.
Yet the origins of life are elusive, and perhaps even multiple and relative, that the origins of life might just be a process the universe does countless times, independently. Or perhaps the seeds all started long ago, and life on this side of the universe is related to life on every side of it.
Yet the origins of life are elusive, and perhaps even multiple and relative, that the origins of life might just be a process the universe does countless times, independently. Or perhaps the seeds all started long ago, and life on this side of the universe is related to life on every side of it.
Meanwhile on the HN-equivalent on some planet around a white dwarf: “can life emerge around a yellow star?”
"No way! Those things shoot out flares, and any planet would have to be so far out from the star that it wouldn't be tidally locked; between the wild swings in temperature on a daily basis and the fact that the literal lithosphere is constantly swirling around under you, there's approximately zero chance that life could evolve there, and even if it did, even less chance for it to survive long enough to achieve anything interesting."
The orbital speed of such a planet would be extreme, something like 300 km/s.
This also means other planets (like Venus or Mars are to Earth) would be visible in the sky as perceptible disks.
This also means other planets (like Venus or Mars are to Earth) would be visible in the sky as perceptible disks.
It's the same scale as the orbits of the large moons of Jupiter (roughly 0.003 au–0.013 au). If you were standing on one of those, the others would appear as very large disks—some of them larger than the Earth moon.
(Jupiter itself would be much larger still).
(Jupiter itself would be much larger still).
suedo - science
and less fun than speculating about Gods preferenc in tooth care, paste or powder?
Everyone agrees, right!, that we need a several orders of magnitude greater power space based telescope, solely devoted to examining extra solar planets,and then just see what is there. No matter what, it will be very interesting,and generate data usefull in many lines of study. That, or there is an astronomicaly slim chance we will get lucky and someone out there is broadcasting on a frequency that we are look8ng at. Starship changes the equasion, and its time to get the job, done.Now. Think about it, the whole world will drop tools and watch, everytime a new planet comes into focus. Way better than what we are watching now, and will cost, a whole lot less. tick twitch mega goog tube, blarg!
and less fun than speculating about Gods preferenc in tooth care, paste or powder?
Everyone agrees, right!, that we need a several orders of magnitude greater power space based telescope, solely devoted to examining extra solar planets,and then just see what is there. No matter what, it will be very interesting,and generate data usefull in many lines of study. That, or there is an astronomicaly slim chance we will get lucky and someone out there is broadcasting on a frequency that we are look8ng at. Starship changes the equasion, and its time to get the job, done.Now. Think about it, the whole world will drop tools and watch, everytime a new planet comes into focus. Way better than what we are watching now, and will cost, a whole lot less. tick twitch mega goog tube, blarg!
Here's a (not completely flippant) answer: yes. At least in the case of Sirius B, and let's be hones, this is the case we care about, a planet that orbits it would be very close to Sirius A too. The distance between Sirius A and Sirius B is always between about 8 AU and 32 AU (1 AU = Sun-Earth distance). Since Sirius A is about 25 times more luminous than the Sun and Sirius B about 50 times dimmer, it is very likely that a planet orbiting Sirius B will receive most of its light/heat from Sirius A, and it would be somewhat comparable to what the Earth and Mars receive from the Sun.
compare Forward, Dragon's Egg (1980)
For reference, https://mdpub.github.io/cheela
while we're at it*, RLF82: "Flattening spacetime near the Earth": https://journals.aps.org/prd/abstract/10.1103/PhysRevD.26.73...
* (and I am admiring the specificity of that HN acct)
* (and I am admiring the specificity of that HN acct)
Or, more directly, Niven’s “The Smoke Ring” about humans living directly in an oxygenated accretion disk around a white dwarf.
I think you wrote compare forward as a long version of cf., but I believe cf. is actually short for the latin confer
Forward is the author :) https://en.wikipedia.org/wiki/Robert_L._Forward#Fiction
note wrt to comment elsewhere in this thread that Forward was also involved with physical aspects of the Integral Trees/Smoke Ring world build.
note wrt to comment elsewhere in this thread that Forward was also involved with physical aspects of the Integral Trees/Smoke Ring world build.
One unclear point: how would these planets form?
Stars go through the red giant phase before becoming white dwarves, so they will swallow all the planets close to the star. And blow away any remnants of the accretion disk.
Stars go through the red giant phase before becoming white dwarves, so they will swallow all the planets close to the star. And blow away any remnants of the accretion disk.
Maybe the white dwarf captures a rogue planet? The planet doesn't need to be from the star's original accretion disk.
You can't capture a body with only a two-body interaction. You need at least 3 bodies for that.
I guess a star with a Jupiter-class planet that survived the red giant phase might qualify. But then the conditions will have to be just right for the captured planet to end up near the star.
I guess a star with a Jupiter-class planet that survived the red giant phase might qualify. But then the conditions will have to be just right for the captured planet to end up near the star.
White dwarfs have a surface, with 50km of crust. And they cool. They have a hydrogen atmosphere.
Life doesn’t take very long to appear, perhaps just a few million years. We keep revising the number down on earth.
It’s possible, and perhaps even likely, that most white dwarfs host life at some point in their lifecycle, when they’re cool enough.
Life doesn’t take very long to appear, perhaps just a few million years. We keep revising the number down on earth.
It’s possible, and perhaps even likely, that most white dwarfs host life at some point in their lifecycle, when they’re cool enough.
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Nice read! FWIW, I built a system the other day, its name, "whitedwf" :)
The end stage of stellar evolution cannot have life around it. There’s not enough water beyond the frost line to renew any planet around a white dwarf.
Depends how big his cory is
White dwarfs are also indefinitely stable; they keep cooling over billions of years to become black dwarfs. Then, over >10^100 years, all elements heavier than iron will decay to 56Fe by various processes such as fission and alpha emission. All atoms lighter than iron combine by nuclear fusion reactions, building gradually up to 56Fe. All of this can happen via quantum processes at zero temperature. So they end as lumps of indefinitely stable cold iron.
Intelligent life can hang around white dwarfs for a long time. Good candidate star type for Dyson spheres.