Let's have a better Sun
Discussion
Every science programme on TV tells us how the odds are stacked against life starting on any planet and that we are probably unique. I more or less agree with this PoV but does it go for all stars?
Is our Sun the best star for the emergence of life?
Is there a better one for the emergence of life, one where the solar wind would not strip atmosphere's of planets without a sufficiently strong magnetic field? How about stablility? What about a smaller star, one with a longer life span and maybe more stable? This would, one assumes, give a longer time for life to emerge.
We also need a massive magnetic field from the Sun to protect us from galatctic radiation. Would something much smaller than ours be too pathetic>
Is our Sun the best star for the emergence of life?
Is there a better one for the emergence of life, one where the solar wind would not strip atmosphere's of planets without a sufficiently strong magnetic field? How about stablility? What about a smaller star, one with a longer life span and maybe more stable? This would, one assumes, give a longer time for life to emerge.
We also need a massive magnetic field from the Sun to protect us from galatctic radiation. Would something much smaller than ours be too pathetic>
Much of the 'odds against' stuff is based on a misguided view of our significance. It does not matter at all that we are as we are or where we are; if we were green gaseous clouds on the fifth planet of a Red Giant there would be some clouds asking 'What are the odds of us being green? Wow! Cosmic!'
If you relax the criteria to 'sentience' there is probably quite a bit of it in the Universe. If evenly spread out is likely to be very, very far away, but for all we know it's like buses!
If you relax the criteria to 'sentience' there is probably quite a bit of it in the Universe. If evenly spread out is likely to be very, very far away, but for all we know it's like buses!
Generally, yes.
The larger the mass of a star the quicker it uses up its hydrogen reserves.
So, I think there is quite a range of possible life supporting stars. The main criteria is reasonable stability of energy and radiation output. If you have a star that is all over the shop regarding how much energy it spews out, it makes the environment around the star a bit unpredictable.
The larger the mass of a star the quicker it uses up its hydrogen reserves.
So, I think there is quite a range of possible life supporting stars. The main criteria is reasonable stability of energy and radiation output. If you have a star that is all over the shop regarding how much energy it spews out, it makes the environment around the star a bit unpredictable.
There's an interesting article on this topic in Scientific American this month, written by a respected astrobiologist. According to this guy, the often quoted fact that we're in an ideal situation for life is wrong - we're actually on the edge, not in the middle, of the 'goldilocks zone', and our sun is not ideal either. He says that a dwarf star would be better than our sun for life, because it would have a less variable output over a longer period of time.
Moving away from that side of things (zone for liquid water etc), the other point worth bearing in mind is that we have evolved to suit our the conditions of the earth, so to ponder why we're so ideally suited to living on earth is, as Douglas Adams once put it, like a puddle pondering why it fits in its hole so well!
My personal opinion having read articles such as that one and lots of others, is that there's a fair chance life elsewhere in our galaxy, and an extremely good chance of life elsewhere in the Universe.
Moving away from that side of things (zone for liquid water etc), the other point worth bearing in mind is that we have evolved to suit our the conditions of the earth, so to ponder why we're so ideally suited to living on earth is, as Douglas Adams once put it, like a puddle pondering why it fits in its hole so well!
My personal opinion having read articles such as that one and lots of others, is that there's a fair chance life elsewhere in our galaxy, and an extremely good chance of life elsewhere in the Universe.
RobM77 said:
There's an interesting article on this topic in Scientific American this month, written by a respected astrobiologist. According to this guy, the often quoted fact that we're in an ideal situation for life is wrong - we're actually on the edge, not in the middle, of the 'goldilocks zone', and our sun is not ideal either. He says that a dwarf star would be better than our sun for life, because it would have a less variable output over a longer period of time.
Moving away from that side of things (zone for liquid water etc), the other point worth bearing in mind is that we have evolved to suit our the conditions of the earth, so to ponder why we're so ideally suited to living on earth is, as Douglas Adams once put it, like a puddle pondering why it fits in its hole so well!
My personal opinion having read articles such as that one and lots of others, is that there's a fair chance life elsewhere in our galaxy, and an extremely good chance of life elsewhere in the Universe.
The idea of a red dwarf seems to me to be wrong as they have (if memory servies) the habit of ejecting great amounts of dangerous radiation (gamma ray bursts?) at times.Moving away from that side of things (zone for liquid water etc), the other point worth bearing in mind is that we have evolved to suit our the conditions of the earth, so to ponder why we're so ideally suited to living on earth is, as Douglas Adams once put it, like a puddle pondering why it fits in its hole so well!
My personal opinion having read articles such as that one and lots of others, is that there's a fair chance life elsewhere in our galaxy, and an extremely good chance of life elsewhere in the Universe.
Further, if the star was much smaller then would the gamma ray output be greater as the size of our sun dictates that gamma rays are more or less knackered by the time they escape and come towards us.
I accept that we have evolved for our environment, but is life more likely to appear around smaller, less energetic stars, or would it increase the odds if it was a bigger star with a greater distance.
Stephen Baxter's novel "Proxima" envisages a habitable planet orbiting Proxima Centauri - which is a red dwarf. The planet is within the goldilocks zone for the star and the radiation from the star is not that much of an issue. However, one effect of having to be close in to a low output star is the fact that you will end up with a planet which is tidally locked to the star. In other words, the planet keeps one face towards the star all the time.
This creates unusual and dramatic weather patterns - and also creates a permanently bright side and a permanently dark side to the planet.
This creates unusual and dramatic weather patterns - and also creates a permanently bright side and a permanently dark side to the planet.
Eric Mc said:
Stephen Baxter's novel "Proxima" envisages a habitable planet orbiting Proxima Centauri - which is a red dwarf. The planet is within the goldilocks zone for the star and the radiation from the star is not that much of an issue. However, one effect of having to be close in to a low output star is the fact that you will end up with a planet which is tidally locked to the star. In other words, the planet keeps one face towards the star all the time.
This creates unusual and dramatic weather patterns - and also creates a permanently bright side and a permanently dark side to the planet.
Oddly enough, I've just got Proxima out of the library this morning. Now you've spoiled it for me.This creates unusual and dramatic weather patterns - and also creates a permanently bright side and a permanently dark side to the planet.
There's lots of factors, dwarfs will live much longer, but the planet needs to be much closer to the star, so potentially tidal locking and radiation exposure.
Big stars live too short a life so they are probably out.
However there may be other factors:
1. Size of the planet.
2. Density of atmosphere.
3. Molten planetary core and associated magnetic field and that fields strength.
4. Atmospheric composition.
At the moment it's the only one we know of that is capable of supporting life, let alone human life.
Big stars live too short a life so they are probably out.
However there may be other factors:
1. Size of the planet.
2. Density of atmosphere.
3. Molten planetary core and associated magnetic field and that fields strength.
4. Atmospheric composition.
At the moment it's the only one we know of that is capable of supporting life, let alone human life.
Derek Smith said:
RobM77 said:
There's an interesting article on this topic in Scientific American this month, written by a respected astrobiologist. According to this guy, the often quoted fact that we're in an ideal situation for life is wrong - we're actually on the edge, not in the middle, of the 'goldilocks zone', and our sun is not ideal either. He says that a dwarf star would be better than our sun for life, because it would have a less variable output over a longer period of time.
Moving away from that side of things (zone for liquid water etc), the other point worth bearing in mind is that we have evolved to suit our the conditions of the earth, so to ponder why we're so ideally suited to living on earth is, as Douglas Adams once put it, like a puddle pondering why it fits in its hole so well!
My personal opinion having read articles such as that one and lots of others, is that there's a fair chance life elsewhere in our galaxy, and an extremely good chance of life elsewhere in the Universe.
The idea of a red dwarf seems to me to be wrong as they have (if memory servies) the habit of ejecting great amounts of dangerous radiation (gamma ray bursts?) at times.Moving away from that side of things (zone for liquid water etc), the other point worth bearing in mind is that we have evolved to suit our the conditions of the earth, so to ponder why we're so ideally suited to living on earth is, as Douglas Adams once put it, like a puddle pondering why it fits in its hole so well!
My personal opinion having read articles such as that one and lots of others, is that there's a fair chance life elsewhere in our galaxy, and an extremely good chance of life elsewhere in the Universe.
Further, if the star was much smaller then would the gamma ray output be greater as the size of our sun dictates that gamma rays are more or less knackered by the time they escape and come towards us.
I accept that we have evolved for our environment, but is life more likely to appear around smaller, less energetic stars, or would it increase the odds if it was a bigger star with a greater distance.
It's a very good point. I haven't finished the article yet, but I'll post back if he mentions. As far as I understand it, bursts of radiation are indeed seen in red dwarfs, but are much rarer on other dwarf stars, but I'm not well enough versed in dwarfs to know much about how, for example, brown or white dwarfs, exhibit the phenomena.RobM77 said:
It's a very good point. I haven't finished the article yet, but I'll post back if he mentions. As far as I understand it, bursts of radiation are indeed seen in red dwarfs, but are much rarer on other dwarf stars, but I'm not well enough versed in dwarfs to know much about how, for example, brown or white dwarfs, exhibit the phenomena.What about globular clusters? My (hopefully not pathetic) understanding is some stars in them have been around for more than twice as long as our sun yet are still shining, and have a long life expectancy. They haven't got SM black holes in their centre and have led a placid life.
Did I read that that we have photographed globular clusters out in inter-glactic deep space?
Planets around such stars might well have been in existence for 10bn yrs or more. If the stars are more stable than ours . . .
Would a sentient being on one of them be musing about how dramatic the night sky would appear to a being on a planet about a third of the way from the centre of an average galaxy?
Derek Smith said:
RobM77 said:
It's a very good point. I haven't finished the article yet, but I'll post back if he mentions. As far as I understand it, bursts of radiation are indeed seen in red dwarfs, but are much rarer on other dwarf stars, but I'm not well enough versed in dwarfs to know much about how, for example, brown or white dwarfs, exhibit the phenomena.What about globular clusters? My (hopefully not pathetic) understanding is some stars in them have been around for more than twice as long as our sun yet are still shining, and have a long life expectancy. They haven't got SM black holes in their centre and have led a placid life.
Did I read that that we have photographed globular clusters out in inter-glactic deep space?
Planets around such stars might well have been in existence for 10bn yrs or more. If the stars are more stable than ours . . .
Would a sentient being on one of them be musing about how dramatic the night sky would appear to a being on a planet about a third of the way from the centre of an average galaxy?
Too dynamic an environment I would have thought, as Wikipedia confirms:
Wikipedia said:
However, they [GCs] are not thought to be favorable locations for the survival of planetary systems. Planetary orbits are dynamically unstable within the cores of dense clusters because of the perturbations of passing stars. A planet orbiting at 1 astronomical unit around a star that is within the core of a dense cluster such as 47 Tucanae would only survive on the order of 108 years.[30] There is a planetary system orbiting a pulsar (PSR B1620−26) that belongs to the globular cluster M4, but these planets likely formed after the event that created the pulsar.
http://en.wikipedia.org/wiki/Globular_clusterRobM77 said:
Too dynamic an environment I would have thought, as Wikipedia confirms:
Thanks for that.Wikipedia said:
However, they [GCs] are not thought to be favorable locations for the survival of planetary systems. Planetary orbits are dynamically unstable within the cores of dense clusters because of the perturbations of passing stars. A planet orbiting at 1 astronomical unit around a star that is within the core of a dense cluster such as 47 Tucanae would only survive on the order of 108 years.[30] There is a planetary system orbiting a pulsar (PSR B1620-26) that belongs to the globular cluster M4, but these planets likely formed after the event that created the pulsar.
http://en.wikipedia.org/wiki/Globular_clusterI'll
unpack my bags.
RobM77 said:
There's an interesting article on this topic in Scientific American this month, written by a respected astrobiologist. According to this guy, the often quoted fact that we're in an ideal situation for life is wrong - we're actually on the edge, not in the middle, of the 'goldilocks zone', and our sun is not ideal either. He says that a dwarf star would be better than our sun for life, because it would have a less variable output over a longer period of time.
Derek Smith said:
RobM77 said:
It's a very good point. I haven't finished the article yet, but I'll post back if he mentions. As far as I understand it, bursts of radiation are indeed seen in red dwarfs, but are much rarer on other dwarf stars, but I'm not well enough versed in dwarfs to know much about how, for example, brown or white dwarfs, exhibit the phenomena.Eric Mc said:
Do you think it strange that all the planets are called Kepler? Must make them a lot easier to find.40% more heat. That seems a lot to me. I accept the polls might be habitable but where would you snowboard?
Derek Smith said:
Eric Mc said:
Do you think it strange that all the planets are called Kepler? Must make them a lot easier to find.40% more heat. That seems a lot to me. I accept the polls might be habitable but where would you snowboard?
I'd love to live on one of these super earths like in the Sci-Am article! It was very revealing reading how far from ideal the earth is for life - of course it's good, but it certainly could be better.Gassing Station | Science! | Top of Page | What's New | My Stuff