7 ms·

It's not in the habitable zone 100% of the time because of its eccentric orbit.

by platz 2y ago

ceejayoz 2y ago
It's not in our habitable zone. Life on such a planet seems likely to hibernate just like some Earth life already does.
- doctoboggan 2y ago
  > It's not in our habitable zone. The habitable zone is defined as the area around a star where liquid water could be found, there is no "our" habitable zone and "their" habitable zone.
  - ceejayoz 2y ago
    Parts of our own Earth aren't in the habitable zone, by that definition. Even here we get big surprises - undersea vents were unexpected oases, microbes miles deep underground, microbes living in boiling water in Yellowstone... Not all life in the universe may require liquid water, nor require it 24/7. In our own solar system, some planetoids outside our supposed habitable zone likely have some liquid water - Europa and Enceladus, for example.
    - patmorgan23 2y ago
      Do any of those zones actually have life? The two examples you gave... Include liquid water. As far as I know there is no life native to the coldest parts of the earth that have no liquid water. It is entirely possible there is some other form of life that does not require liquid water, but we have yet to discover it.
      - ceejayoz 2y ago
        > The two examples you gave... Include liquid water. This specific planet spends half its orbit in said zone. Here on Earth, we have creatures like https://en.wikipedia.org/wiki/Mudskipper https://en.wikipedia.org/wiki/Mudskipper that can survive severe dry spells, and fish that can happily freeze sold in ice for months. Europa spends zero time in our solar system's "habitable zone", but because of its conditions, may still possess large amounts of liquid water. It's a perfect example of why the "zone" may be overly narrowly defined, even for Earth-like water-dependent life. > It is entirely possible there is some other form of life that does not require liquid water, but we have yet to discover it. And we certainly won't if we only look in Earth-defined "habitable" zones.
    - dylan604 2y ago
      You seem to be deliberately trying to pervert the definition of habitable zone. Just because there are regions on a planet in the habitable zone that contains ice does not mean it is not in the habitable zone. If it were further out beyond the habitable zone, there would be no liquid water at the surface. To quote my friend Andy Dufresne, "How can you be so obtuse?...Is it deliberate?"
      - ceejayoz 2y ago
        > You seem to be deliberately trying to pervert the definition of habitable zone. No, I'm saying an Earth-life centric metric is a bit of an odd choice when evaluating extrasolar planets. It's like an African elephant declaring Norway uninhabitable.
        pc86 2y ago
        Earth is the only environment in which we've found life, so it makes sense to first focus on other Earth-like planets. Your point is not without merit but taken to the extreme it would be like sending exploratory teams to the Mariana Trench to look for un-contacted human tribes. We have incontrovertible evidence that water + carbon + time sometimes equals life. We have no evidence of any other non-carbon or non-water chemistries resulting in life so why wouldn't we focus on locations potentially rich in water and carbon first?
        ceejayoz 2y ago
        The first exoplanet detection was in 1992; in my lifetime, "there are no planets outside our solar system" was roughly as supportable as "there is no life outside our solar system" is today. Here on Earth, we can barely decide if viruses are life or not, and discover new things within our own bodies pretty regularly, despite... a lot of direct access to them. (Example: https://www.science.org/content/article/it-s-insane-new-viruslike-entities-found-human-gut-microbes https://www.science.org/content/article/it-s-insane-new-viru...) We should be casting a pretty wide net.
        2y ago
    - throwup238 2y ago
      > Parts of our own Earth aren't in the habitable zone, by that definition. What parts would that be? Even the polar caps have huge liquid water oceans underneath. Unless you’re talking about the mantle or molten core, there are no uninhabitable areas on earth as per astrobiology (not even miles underground). > Not all life in the universe may require liquid water, nor require it 24/7. You might as well be talking about leprechauns and unicorns and Horta. Water is the universal solvent and has at least five unique properties that are as critical to life as carbon’s ability to form four chemical bonds. You’re correct that moons experiencing tidal heating can contain liquid water, but that’s irrelevant to a planet. The habitable zone is specifically talking about planets (rocky ones at that), not any arbitrary satellite. It’s a term of art in astronomy, not a colloquialism.
      - ceejayoz 2y ago
        > Unless you’re talking about the mantle or molten core, there are no uninhabitable areas on earth as per astrobiology (not even miles underground). We've found microbes that can survive at 120 Celsius, -25 Celsius, very high and very low pH, large amounts of ionizing radiation, intense pressures, etc. Habitability is a wide range encompasing scenarios not conducive to liquid water. > Water is the universal solvent and has at least five unique properties that are as critical to life as carbon’s ability to form four chemical bonds. None of that rules out life on other chemistries. It makes water+carbon-based life the most likely scenario on planets with liquid water, but hardly rules out other potential biologies. > You’re correct that moons experiencing tidal heating can contain liquid water, but that’s irrelevant to a planet. The habitable zone is specifically talking about planets (rocky ones at that), not any arbitrary satellite. But we should absolutely be looking at planet-sized moons with potentially habitable conditions, which we believe to be quite common. They are, after all, more common than the single "habitable zone" planet even within our own system.
        throwup238 2y ago
        Dude, just read the Wikipedia article: https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry#Non-water_solvents https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemi... It’s not impossible, but we’ve got a ton of evidence why it’s extremely unlikely. It’s a long list including stuff like possible quantum transition states enabling biochemistry, reactivity with oxygen (the third most abundant element), and spectroscopic transparency. It’s an active area of research that keeps coming up with dead ends. Ammonia and methane are the best candidates but those would only be possible at low temperatures that preclude lots of other reactions.
  - connorgutman 2y ago
    Regardless of the official definition, the word “habitable” is highly subjective. Extremophiles like tardigrades can survive being frozen and/or completely dehydrated. A planet with an eccentric orbit like this one could hypothetically support species capable of entering some form of extreme hibernation during part of their year.
    - hajola 2y ago
      While it's possible for conditions for life to emerge or sustain itself to be present beyond the habitable zone (e.g. there's likely a subsurface ocean orbiting the farthest plant from the Sun on Triton), afawk it is more probable that life forms in the habitable zone. That is the only one we have a data point for.
      - ceejayoz 2y ago
        A sample size of one tells us it it possible, but nothing about what’s most likely.
        hajola 2y ago
        Well, we also know where we haven't found signs of life. So from that perspective we have more data.
    - glenstein 2y ago
      >Regardless of the official definition, the word “habitable” is highly subjective Well, one constructive way to take it out of the realm of subjectivity is to put forward a specific definition.
    - ziddoap 2y ago
      >the word “habitable” is highly subjective. Sure, but not in the context of "habitable zone" which is a specific term of art in astrobiology.
      - ceejayoz 2y ago
  - steve_adams_86 2y ago
    Given the mass of the planet, if there's a lot of water it's entirely possible there could be oceans which stay warm due to a hot core.
- nirav72 2y ago
  Reminds me of the planet inhabited by Arachna spider species in Vinge's A Deepness in the sky.
- xelxebar 2y ago
  The terminology was probably chosen specifically to be somewhat clickbait, so it's probably not worth picking apart the words "habitable zone". The core idea really boils (heh) down to water, _i.e._ the "universal solvent". You can certainly argue that liquid water may not be necessary for life, but it's hard to argue that water's presence isn't a decent prior for potential life. But directly detecting liquid water in extrasolar planets is _hard_. So we do the next best thing and try to use whatever indirect signals we got. We know that liquid water can only exist within some range of temperatures and pressures. So let's just start with temperature. What things can affect the surface temperature of a planet? Amount of energy received from the parent star (i.e. stellar irradiance), geothermal heating, tidal forces between a moon and planet, and probably many others. Stellar energy stands out as being the biggest contributor of energy and, fortunately, the easiest one to measure. Of course, you could have localized sources of favorable conditions, like thermal vents or whatever, but those kinds of things are _way_ beyond our ability to detect with current tech. So, we've narrowed down our focus to _one big contributing factor for potential life_, the amount of energy received from a planet's host star. But how can we relate energy to temperature? This is effectively where all the physics and astronomy come in via thermodynamics, orbital mechanics, and stellar physics. Suffice it to say that all the effects combine to give a range of possible orbital radii and planet sizes where liquid water has a good chance of existing on the planteary surface. This range of radii and planet sizes is the concept that matters. The name for this idea is "habitable zone", which suggests why we might care, compared to the more precise "orbital and planetary mass parameters favorable to liquid water formation at average planetary surface".
K0balt 2y ago
This kind of resource variability seems likely to favor the development of intelligence, so there’s that. But I m sure we will find that the planet has issues that make complex life unlikely, just on a statistical basis. Simple life seems increasingly likely to propagate through panspermia, based on what we find deep inside the crust of our planet. Life forms that feed off of radioactive decay especially seem promising for panspermia. I wouldn’t be surprised at all if we discovered that for habitable zone, earth-like planets , the presence of simple life forms deep inside the crust turns out to be the rule rather than the exception, at least in our corner of the galaxy.
UltraSane 2y ago
in Vernor Vinge's novel A Deepness in the Sky the alien planet freezes for part of the year and the intelligent aliens have evolved to survive being frozen and thawed. One group develops technology to say unfrozen while their enemies are frozen and this gives them a huge advantage. Great book and I highly recommend it. Also has concepts of realistic mind control that is VERY creepy and the ultimate in distributed computing based on smart dust.
- dmix 2y ago
  How do they evolve when they are frozen part the year before evolution?
  - rmsaksida 2y ago
    Life in that planet evolved to essentially hibernate during their long winter. Presumably the processes that resulted in the very earliest life forms happened countless times until some surfaced that had that feature.
- UncleOxidant 2y ago
  So kind of like living in Minnesota?
  - mcswell 2y ago
    Ya' know, Oly was very happy to find his farm was in Iowa, rather than Minnesota. When his friend Sven asked him why, given that taxes were higher in Iowa, Oly replied "Vell, now I don't have to put up vith those lousy Minnesota vinters no more!"
- ZYbCRq22HbJ2y7 2y ago
  This general idea is explored in many other pieces of science fiction literature, but it has also recently been visualized in https://en.wikipedia.org/wiki/3_Body_Problem_(TV_series) https://en.wikipedia.org/wiki/3_Body_Problem_(TV_series)
pmontra 2y ago
> Its distance from its star changes significantly, causing the planet to move from the outer edge of the habitable zone to the inner edge throughout its year Too bad that the year is relatively short. If it were hundreds of Earth years that could be like Helliconia https://en.m.wikipedia.org/wiki/Helliconia https://en.m.wikipedia.org/wiki/Helliconia

It's not in the habitable zone 100% of the time because of its eccentric orbit.

by platz 2y ago

It's not in the habitable zone 100% of the time because of its eccentric orbit.

ceejayoz 2y ago

It's not in our habitable zone. Life on such a planet seems likely to hibernate just like some Earth life already does.

doctoboggan 2y ago
> It's not in our habitable zone. The habitable zone is defined as the area around a star where liquid water could be found, there is no "our" habitable zone and "their" habitable zone.
- ceejayoz 2y ago
  Parts of our own Earth aren't in the habitable zone, by that definition. Even here we get big surprises - undersea vents were unexpected oases, microbes miles deep underground, microbes living in boiling water in Yellowstone... Not all life in the universe may require liquid water, nor require it 24/7. In our own solar system, some planetoids outside our supposed habitable zone likely have some liquid water - Europa and Enceladus, for example.
  - patmorgan23 2y ago
    Do any of those zones actually have life? The two examples you gave... Include liquid water. As far as I know there is no life native to the coldest parts of the earth that have no liquid water. It is entirely possible there is some other form of life that does not require liquid water, but we have yet to discover it.
    - ceejayoz 2y ago
      > The two examples you gave... Include liquid water. This specific planet spends half its orbit in said zone. Here on Earth, we have creatures like https://en.wikipedia.org/wiki/Mudskipper https://en.wikipedia.org/wiki/Mudskipper that can survive severe dry spells, and fish that can happily freeze sold in ice for months. Europa spends zero time in our solar system's "habitable zone", but because of its conditions, may still possess large amounts of liquid water. It's a perfect example of why the "zone" may be overly narrowly defined, even for Earth-like water-dependent life. > It is entirely possible there is some other form of life that does not require liquid water, but we have yet to discover it. And we certainly won't if we only look in Earth-defined "habitable" zones.
  - dylan604 2y ago
    You seem to be deliberately trying to pervert the definition of habitable zone. Just because there are regions on a planet in the habitable zone that contains ice does not mean it is not in the habitable zone. If it were further out beyond the habitable zone, there would be no liquid water at the surface. To quote my friend Andy Dufresne, "How can you be so obtuse?...Is it deliberate?"
    - ceejayoz 2y ago
      > You seem to be deliberately trying to pervert the definition of habitable zone. No, I'm saying an Earth-life centric metric is a bit of an odd choice when evaluating extrasolar planets. It's like an African elephant declaring Norway uninhabitable.
      - pc86 2y ago
        Earth is the only environment in which we've found life, so it makes sense to first focus on other Earth-like planets. Your point is not without merit but taken to the extreme it would be like sending exploratory teams to the Mariana Trench to look for un-contacted human tribes. We have incontrovertible evidence that water + carbon + time sometimes equals life. We have no evidence of any other non-carbon or non-water chemistries resulting in life so why wouldn't we focus on locations potentially rich in water and carbon first?
        ceejayoz 2y ago
        The first exoplanet detection was in 1992; in my lifetime, "there are no planets outside our solar system" was roughly as supportable as "there is no life outside our solar system" is today. Here on Earth, we can barely decide if viruses are life or not, and discover new things within our own bodies pretty regularly, despite... a lot of direct access to them. (Example: https://www.science.org/content/article/it-s-insane-new-viruslike-entities-found-human-gut-microbes https://www.science.org/content/article/it-s-insane-new-viru...) We should be casting a pretty wide net.
        2y ago
  - throwup238 2y ago
    > Parts of our own Earth aren't in the habitable zone, by that definition. What parts would that be? Even the polar caps have huge liquid water oceans underneath. Unless you’re talking about the mantle or molten core, there are no uninhabitable areas on earth as per astrobiology (not even miles underground). > Not all life in the universe may require liquid water, nor require it 24/7. You might as well be talking about leprechauns and unicorns and Horta. Water is the universal solvent and has at least five unique properties that are as critical to life as carbon’s ability to form four chemical bonds. You’re correct that moons experiencing tidal heating can contain liquid water, but that’s irrelevant to a planet. The habitable zone is specifically talking about planets (rocky ones at that), not any arbitrary satellite. It’s a term of art in astronomy, not a colloquialism.
    - ceejayoz 2y ago
      > Unless you’re talking about the mantle or molten core, there are no uninhabitable areas on earth as per astrobiology (not even miles underground). We've found microbes that can survive at 120 Celsius, -25 Celsius, very high and very low pH, large amounts of ionizing radiation, intense pressures, etc. Habitability is a wide range encompasing scenarios not conducive to liquid water. > Water is the universal solvent and has at least five unique properties that are as critical to life as carbon’s ability to form four chemical bonds. None of that rules out life on other chemistries. It makes water+carbon-based life the most likely scenario on planets with liquid water, but hardly rules out other potential biologies. > You’re correct that moons experiencing tidal heating can contain liquid water, but that’s irrelevant to a planet. The habitable zone is specifically talking about planets (rocky ones at that), not any arbitrary satellite. But we should absolutely be looking at planet-sized moons with potentially habitable conditions, which we believe to be quite common. They are, after all, more common than the single "habitable zone" planet even within our own system.
      - throwup238 2y ago
        Dude, just read the Wikipedia article: https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry#Non-water_solvents https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemi... It’s not impossible, but we’ve got a ton of evidence why it’s extremely unlikely. It’s a long list including stuff like possible quantum transition states enabling biochemistry, reactivity with oxygen (the third most abundant element), and spectroscopic transparency. It’s an active area of research that keeps coming up with dead ends. Ammonia and methane are the best candidates but those would only be possible at low temperatures that preclude lots of other reactions.
- connorgutman 2y ago
  Regardless of the official definition, the word “habitable” is highly subjective. Extremophiles like tardigrades can survive being frozen and/or completely dehydrated. A planet with an eccentric orbit like this one could hypothetically support species capable of entering some form of extreme hibernation during part of their year.
  - hajola 2y ago
    While it's possible for conditions for life to emerge or sustain itself to be present beyond the habitable zone (e.g. there's likely a subsurface ocean orbiting the farthest plant from the Sun on Triton), afawk it is more probable that life forms in the habitable zone. That is the only one we have a data point for.
    - ceejayoz 2y ago
      A sample size of one tells us it it possible, but nothing about what’s most likely.
      - hajola 2y ago
        Well, we also know where we haven't found signs of life. So from that perspective we have more data.
  - glenstein 2y ago
    >Regardless of the official definition, the word “habitable” is highly subjective Well, one constructive way to take it out of the realm of subjectivity is to put forward a specific definition.
  - ziddoap 2y ago
    >the word “habitable” is highly subjective. Sure, but not in the context of "habitable zone" which is a specific term of art in astrobiology.
    - ceejayoz 2y ago
- steve_adams_86 2y ago
  Given the mass of the planet, if there's a lot of water it's entirely possible there could be oceans which stay warm due to a hot core.
nirav72 2y ago
Reminds me of the planet inhabited by Arachna spider species in Vinge's A Deepness in the sky.
xelxebar 2y ago
The terminology was probably chosen specifically to be somewhat clickbait, so it's probably not worth picking apart the words "habitable zone". The core idea really boils (heh) down to water, _i.e._ the "universal solvent". You can certainly argue that liquid water may not be necessary for life, but it's hard to argue that water's presence isn't a decent prior for potential life. But directly detecting liquid water in extrasolar planets is _hard_. So we do the next best thing and try to use whatever indirect signals we got. We know that liquid water can only exist within some range of temperatures and pressures. So let's just start with temperature. What things can affect the surface temperature of a planet? Amount of energy received from the parent star (i.e. stellar irradiance), geothermal heating, tidal forces between a moon and planet, and probably many others. Stellar energy stands out as being the biggest contributor of energy and, fortunately, the easiest one to measure. Of course, you could have localized sources of favorable conditions, like thermal vents or whatever, but those kinds of things are _way_ beyond our ability to detect with current tech. So, we've narrowed down our focus to _one big contributing factor for potential life_, the amount of energy received from a planet's host star. But how can we relate energy to temperature? This is effectively where all the physics and astronomy come in via thermodynamics, orbital mechanics, and stellar physics. Suffice it to say that all the effects combine to give a range of possible orbital radii and planet sizes where liquid water has a good chance of existing on the planteary surface. This range of radii and planet sizes is the concept that matters. The name for this idea is "habitable zone", which suggests why we might care, compared to the more precise "orbital and planetary mass parameters favorable to liquid water formation at average planetary surface".

K0balt 2y ago

This kind of resource variability seems likely to favor the development of intelligence, so there’s that. But I m sure we will find that the planet has issues that make complex life unlikely, just on a statistical basis. Simple life seems increasingly likely to propagate through panspermia, based on what we find deep inside the crust of our planet. Life forms that feed off of radioactive decay especially seem promising for panspermia. I wouldn’t be surprised at all if we discovered that for habitable zone, earth-like planets , the presence of simple life forms deep inside the crust turns out to be the rule rather than the exception, at least in our corner of the galaxy.

UltraSane 2y ago

in Vernor Vinge's novel A Deepness in the Sky the alien planet freezes for part of the year and the intelligent aliens have evolved to survive being frozen and thawed. One group develops technology to say unfrozen while their enemies are frozen and this gives them a huge advantage. Great book and I highly recommend it. Also has concepts of realistic mind control that is VERY creepy and the ultimate in distributed computing based on smart dust.

dmix 2y ago
How do they evolve when they are frozen part the year before evolution?
- rmsaksida 2y ago
  Life in that planet evolved to essentially hibernate during their long winter. Presumably the processes that resulted in the very earliest life forms happened countless times until some surfaced that had that feature.
UncleOxidant 2y ago
So kind of like living in Minnesota?
- mcswell 2y ago
  Ya' know, Oly was very happy to find his farm was in Iowa, rather than Minnesota. When his friend Sven asked him why, given that taxes were higher in Iowa, Oly replied "Vell, now I don't have to put up vith those lousy Minnesota vinters no more!"
ZYbCRq22HbJ2y7 2y ago
This general idea is explored in many other pieces of science fiction literature, but it has also recently been visualized in https://en.wikipedia.org/wiki/3_Body_Problem_(TV_series) https://en.wikipedia.org/wiki/3_Body_Problem_(TV_series)

pmontra 2y ago

> Its distance from its star changes significantly, causing the planet to move from the outer edge of the habitable zone to the inner edge throughout its year Too bad that the year is relatively short. If it were hundreds of Earth years that could be like Helliconia https://en.m.wikipedia.org/wiki/Helliconia https://en.m.wikipedia.org/wiki/Helliconia