Stars & Colours
Discussion
Hiya,
My science knowledge s very minimal and looking at some of the threads and I couldn't find an answer to my question. Basically, while looking up at stars on the fortunate occasions of clear skies, some appear to 'twinkle' more than others. Some seem to also change colours. I have seen with the naked eye some stars shimmer in various colours most prominently red, orange, yellow...and just wanted to know if i am looking at anything special like the end of a star, a reaction of light through the atmosphere or if it is just eyes playing tricks on me.
Sorry for the s
tty science 101 basic thread content, but it has always got me thinking...
Thanks
My science knowledge s very minimal and looking at some of the threads and I couldn't find an answer to my question. Basically, while looking up at stars on the fortunate occasions of clear skies, some appear to 'twinkle' more than others. Some seem to also change colours. I have seen with the naked eye some stars shimmer in various colours most prominently red, orange, yellow...and just wanted to know if i am looking at anything special like the end of a star, a reaction of light through the atmosphere or if it is just eyes playing tricks on me.
Sorry for the s
tty science 101 basic thread content, but it has always got me thinking...Thanks
i was under the impression that the stars 'twinkle' because of the atmosphere.
i don't know about the naked eye, but i also believe that stars are different colours depending on how hot they are, i seem to remember reading about a brown dwarf star that is so cool on the surface you could walk on it, if it were solid?
i don't know about the naked eye, but i also believe that stars are different colours depending on how hot they are, i seem to remember reading about a brown dwarf star that is so cool on the surface you could walk on it, if it were solid?
Stars are indeed different colours which depends on their temperature (hotter stars appear blue - whilst colder stars appear orange).
This can be seen quite easily with the naked eye in the constellation of Orion.
The top Left star is Betelgeuse and is an M class red giant. It has an obvious orange hue.
The bottom right star is Rigel - which is a B class blue/White super giant and has an obvious blue/white hue.
Any colour change or twinkling you observe is due to atmospheric scintillation and works on the same principle as heat haze.
This can be seen quite easily with the naked eye in the constellation of Orion.
The top Left star is Betelgeuse and is an M class red giant. It has an obvious orange hue.
The bottom right star is Rigel - which is a B class blue/White super giant and has an obvious blue/white hue.
Any colour change or twinkling you observe is due to atmospheric scintillation and works on the same principle as heat haze.
Even the closest stars will only ever appear to our eyes as a single point of light. In fact, the most powerful telescopes in the world will only ever show a single point of light.
Planets appear as a single point of light to the naked eye but will show a disc through even modest telescopes or binoculars - especially Jupiter and some of the closer ones like Mars or Venus.
Twinkling is purely caused by our own atmosphere distorting the light. The more turbulent and thicker the atmosphere, the more the star (or planet) will twinkle. That is why a star or planet low down in the sky will twinkle more than one directly overhead - as the light is coming through more atmosphere.
Twinkling can cause the light from the star or planet to change colour as sometimes the light is refracted like through a prism. Again, this is nothing to do with the star or planet itself but is entirely due to our atmosphere.
HOWEVER, stars do have genuine colour differences due to the wide variety of types of stars there are. The colour generally denotes the surface temperature of the star with blue being the hottest and red being the coolest.
A good place to spot the colour differences in a star is in the constellation or Orion. In the top left hand corner of the constellation is a red giant - Betelgeuse. In the bottom right hand corner, is a b blue giant, Rigel. Their colours are very obvious even to the naked eye.
Planets appear as a single point of light to the naked eye but will show a disc through even modest telescopes or binoculars - especially Jupiter and some of the closer ones like Mars or Venus.
Twinkling is purely caused by our own atmosphere distorting the light. The more turbulent and thicker the atmosphere, the more the star (or planet) will twinkle. That is why a star or planet low down in the sky will twinkle more than one directly overhead - as the light is coming through more atmosphere.
Twinkling can cause the light from the star or planet to change colour as sometimes the light is refracted like through a prism. Again, this is nothing to do with the star or planet itself but is entirely due to our atmosphere.
HOWEVER, stars do have genuine colour differences due to the wide variety of types of stars there are. The colour generally denotes the surface temperature of the star with blue being the hottest and red being the coolest.
A good place to spot the colour differences in a star is in the constellation or Orion. In the top left hand corner of the constellation is a red giant - Betelgeuse. In the bottom right hand corner, is a b blue giant, Rigel. Their colours are very obvious even to the naked eye.
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