@ahaco said in #20:
> For a star it is cold. For example surface of Sun has 5778K and it's rather average temperature.
that was a joke
> For a star it is cold. For example surface of Sun has 5778K and it's rather average temperature.
that was a joke
It would be terrible it would be a binary solar system and both the stars will kill us no matter how big or small they are
@buzzywasps said in #1:
> A binary star while the planets revolve around them... Imagine Jupiter actually turned into a star when it was born, which in reality it couldn't
He is called a failed star
> A binary star while the planets revolve around them... Imagine Jupiter actually turned into a star when it was born, which in reality it couldn't
He is called a failed star
@ahaco said in #16:
> It depends on many factors, like the size of the second star, its brightness, temperature, mass, where it would orbit and even the magnetic field of this star (a stronger magnetic field would make solar flares more intense, which could disturb radio waves and, in the case of an even stronger magnetic field, solar wind could pass through the atmosphere and damage living forms).
>
> There are four main scenarios:
> - second star is a white dwarf, a small, very dense dead star;
> - second "star" is a brown dwarf. Brown dwarfs are actually substars as they don't have enough mass to sustain hydrogen fusion, and they usually have a mass of 20–80 Jupiters;
> - second star is a red dwarf, the most common type of star in our galaxy, which has a very low mass (0.08-0.8 of Sun's mass) and is very cold (2000K-3500K);
> - second star is a yellow dwarf, a star with a mass and temperature similar to the Sun (the Sun is a yellow dwarf).
> Bigger stars (especially giants), and neutron stars would quickly destroy life on Earth, so they are not considered.
>
> In the first scenario, if a white dwarf was very close to the Sun, it would accrete matter from the Sun, which would result in changes in the Sun's brightness, which could cause mass extinctions (Earth organisms aren't adapted to it). If the mass of the white dwarf exceeded 1.4 masses of Sun it would explode as a type 1a supernova, killing all life on Earth. If white dwarf was further from Sun it could impact Earth orbit, pushing it out of habitable zone, which also would be fatal for life (white dwarfs can be heavier than Sun). To prevent destroying life on Earth the system would need to be stable and Earth would need to orbit Sun with higher speed.
>
> Brown dwarf wouldn't change much. If it was further from the Sun (like planets), it could change the orbits of asteroids just like Jupiter does. It would prevent or cause asteroid impact on Earth, which could lead evolution to create different life forms from what we know. In some configurations it would be very easily seen from Earth, which could make human kind (or different intelligent life forms, as human might not evolve due the butterfly effect) faster interest in space and result in faster technological progress.
>
> Red dwarf would change much. It would impact Earth's orbit, so in order for life to appear, Earth should have orbited the Sun at a slightly different velocity and distance. Life almost certainly would evolve in different way: surface temperature could be minimally higher and less stable, so protection from cold would be a bit less necessary, temperature of light would also be slightly different (red dwarfs aren't very bright, but in a binary system with Sun they would make daylight a bit more orange), so eyes would probably evolve to less care about red color and plants would get a little more light. These changes may seem minor, but over years (life on Earth exists for about 4 billion years), they would accumulate. Although life on such a planet would be different from ours, it might be similar in some ways because many traits would still be profitable. However, intelligent life forms like humans would probably not emerge at all, as evolution would go in different direction and intelligent life forms are very rare. If red dwarf would orbit beyond Earth orbit it could completely change day cycle on Earth (as Earth would be illuminated from both sides). This would completely change evolution, probably making emerging more complex life impossible, however if intelligent life would somehow emerge it probably have very small knowledge about astronomy, because in such case observing space would be very hard (sky at "night" often would be similar to sky at day, because of red dwarf beyond Earth orbit). Earth could also orbit a red dwarf, which would orbit the Sun like Proxima-b orbits Proxima Centauri, which orbits Alpha Centauri A and Alpha Centauri B. In that case, if Earth was in dwarf habitable zone, Earth year would be much shorter (as Earth would orbit with much slower velocity), leading to faster changing of seasons. Hypothetical life would be very different from what we know.
>
> The last scenario is adding a star that is similar to the Sun to Solar System. It would impact the Earth's orbit, so to allow life to appear, the Earth should be further from the Sun. The greater the distance between these two stars, the less stable the Earth's temperature would be. So, some configurations would result in a bit less predictable weather, others - very long or short harsh winters and summers, making life impossible to emerge. If Earth were between these two stars, there wouldn't be any nights. Some configurations would let life survive, and evolution (once again) would lead to different life forms from what we know.
>
> Would human are survive if second star suddenly started orbiting the Sun? If it would be brown dwarf (which actually is not a star, but a substar), yes we probably wouldn't have many problems. If it would be red dwarf - rather yes if the earth would suddenly sped up a bit and the system would be stable, but in some cases it would raise average temperature on earth, leading to even worse global warming. And if second star were beyond earth orbit it would change day cycle, which may be bad for humanity and even worse for various ecosystems. If it would similar to our sun - if earth orbit would immediately adapt - it depends, system would have to be stable and doesn't cause extreme climate events.
Wow did you write this by yourself or copy-paste it?
> It depends on many factors, like the size of the second star, its brightness, temperature, mass, where it would orbit and even the magnetic field of this star (a stronger magnetic field would make solar flares more intense, which could disturb radio waves and, in the case of an even stronger magnetic field, solar wind could pass through the atmosphere and damage living forms).
>
> There are four main scenarios:
> - second star is a white dwarf, a small, very dense dead star;
> - second "star" is a brown dwarf. Brown dwarfs are actually substars as they don't have enough mass to sustain hydrogen fusion, and they usually have a mass of 20–80 Jupiters;
> - second star is a red dwarf, the most common type of star in our galaxy, which has a very low mass (0.08-0.8 of Sun's mass) and is very cold (2000K-3500K);
> - second star is a yellow dwarf, a star with a mass and temperature similar to the Sun (the Sun is a yellow dwarf).
> Bigger stars (especially giants), and neutron stars would quickly destroy life on Earth, so they are not considered.
>
> In the first scenario, if a white dwarf was very close to the Sun, it would accrete matter from the Sun, which would result in changes in the Sun's brightness, which could cause mass extinctions (Earth organisms aren't adapted to it). If the mass of the white dwarf exceeded 1.4 masses of Sun it would explode as a type 1a supernova, killing all life on Earth. If white dwarf was further from Sun it could impact Earth orbit, pushing it out of habitable zone, which also would be fatal for life (white dwarfs can be heavier than Sun). To prevent destroying life on Earth the system would need to be stable and Earth would need to orbit Sun with higher speed.
>
> Brown dwarf wouldn't change much. If it was further from the Sun (like planets), it could change the orbits of asteroids just like Jupiter does. It would prevent or cause asteroid impact on Earth, which could lead evolution to create different life forms from what we know. In some configurations it would be very easily seen from Earth, which could make human kind (or different intelligent life forms, as human might not evolve due the butterfly effect) faster interest in space and result in faster technological progress.
>
> Red dwarf would change much. It would impact Earth's orbit, so in order for life to appear, Earth should have orbited the Sun at a slightly different velocity and distance. Life almost certainly would evolve in different way: surface temperature could be minimally higher and less stable, so protection from cold would be a bit less necessary, temperature of light would also be slightly different (red dwarfs aren't very bright, but in a binary system with Sun they would make daylight a bit more orange), so eyes would probably evolve to less care about red color and plants would get a little more light. These changes may seem minor, but over years (life on Earth exists for about 4 billion years), they would accumulate. Although life on such a planet would be different from ours, it might be similar in some ways because many traits would still be profitable. However, intelligent life forms like humans would probably not emerge at all, as evolution would go in different direction and intelligent life forms are very rare. If red dwarf would orbit beyond Earth orbit it could completely change day cycle on Earth (as Earth would be illuminated from both sides). This would completely change evolution, probably making emerging more complex life impossible, however if intelligent life would somehow emerge it probably have very small knowledge about astronomy, because in such case observing space would be very hard (sky at "night" often would be similar to sky at day, because of red dwarf beyond Earth orbit). Earth could also orbit a red dwarf, which would orbit the Sun like Proxima-b orbits Proxima Centauri, which orbits Alpha Centauri A and Alpha Centauri B. In that case, if Earth was in dwarf habitable zone, Earth year would be much shorter (as Earth would orbit with much slower velocity), leading to faster changing of seasons. Hypothetical life would be very different from what we know.
>
> The last scenario is adding a star that is similar to the Sun to Solar System. It would impact the Earth's orbit, so to allow life to appear, the Earth should be further from the Sun. The greater the distance between these two stars, the less stable the Earth's temperature would be. So, some configurations would result in a bit less predictable weather, others - very long or short harsh winters and summers, making life impossible to emerge. If Earth were between these two stars, there wouldn't be any nights. Some configurations would let life survive, and evolution (once again) would lead to different life forms from what we know.
>
> Would human are survive if second star suddenly started orbiting the Sun? If it would be brown dwarf (which actually is not a star, but a substar), yes we probably wouldn't have many problems. If it would be red dwarf - rather yes if the earth would suddenly sped up a bit and the system would be stable, but in some cases it would raise average temperature on earth, leading to even worse global warming. And if second star were beyond earth orbit it would change day cycle, which may be bad for humanity and even worse for various ecosystems. If it would similar to our sun - if earth orbit would immediately adapt - it depends, system would have to be stable and doesn't cause extreme climate events.
Wow did you write this by yourself or copy-paste it?
What if you had three butt cheeks?
@KNIGHT_c4 asks the question all astronomers must ponder: "What if you had three butt cheeks?"
The answer, after consulting a quality ephemeris, is "you'd have your choice of seats."
The answer, after consulting a quality ephemeris, is "you'd have your choice of seats."
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