pls help me ans these qes
pls help me ans these qes
Hi I'm Jingguo from SP Astro. I've a few qes to ask which bother me a little. 1st qes: About moon is bright because they reflect light from d sun,so y do other planets look so bright in d sky when they r so far away from d sun??? 2nd qes:Do stars revolve itself like our sun do??? thanks for helping me with all these qes.
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weixing
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Hi,
Your first question: The only planet that are bright and are further than us from the Sun are Mars, Jupiter and Saturn. Currently, visual magnitude of Moon is around -12.6, Mars around 0.6, Jupiter around -1.9 and Saturn is around 0.7. So Moon is around 2.5^(0.6 - (-12.6))=178,900 times brighter than Mars, 2.5^(-1.9 - (-12.6))=18,100 times brighter than Jupiter and 2.5^(0.7 - (-12.6))=196,100 times brighter than Saturn.
So the planets are actually a lots dimmer than the Moon. Also, Jupiter and Saturn are bright because they are big and got more surface area for reflection, and although Mars is a lot smaller, it is nearer to us compare to Jupiter and Saturn.
Your second question: Yes. I think astronomer haven't found any stars that won't rotate. Anyway, stars like the Sun spin from the original angular momentum that was there in the solar nebula from which it formed.
Hope answer your question and have a nice day.
Your first question: The only planet that are bright and are further than us from the Sun are Mars, Jupiter and Saturn. Currently, visual magnitude of Moon is around -12.6, Mars around 0.6, Jupiter around -1.9 and Saturn is around 0.7. So Moon is around 2.5^(0.6 - (-12.6))=178,900 times brighter than Mars, 2.5^(-1.9 - (-12.6))=18,100 times brighter than Jupiter and 2.5^(0.7 - (-12.6))=196,100 times brighter than Saturn.
So the planets are actually a lots dimmer than the Moon. Also, Jupiter and Saturn are bright because they are big and got more surface area for reflection, and although Mars is a lot smaller, it is nearer to us compare to Jupiter and Saturn.
Your second question: Yes. I think astronomer haven't found any stars that won't rotate. Anyway, stars like the Sun spin from the original angular momentum that was there in the solar nebula from which it formed.
Hope answer your question and have a nice day.
Yang Weixing
"The universe is composed mainly of hydrogen and ignorance."
"The universe is composed mainly of hydrogen and ignorance." -
Airconvent
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Re: pls help me ans these qes
Jingguo wrote:Hi I'm Jingguo from SP Astro. I've a few qes to ask which bother me a little. 1st qes: About moon is bright because they reflect light from d sun,so y do other planets look so bright in d sky when they r so far away from d sun??? 2nd qes:Do stars revolve itself like our sun do??? thanks for helping me with all these qes.
If I may add on to Weixing's response, actually, light is very resiliant.
in a virtual vacuum , light travels unimpeded (except for interstellar dust).
although the planets are small from where we see them, they are in fact very large and reflect alot of light. for example, you can actually see a candle many km away if the air is still and clear on earth.
as for stars...yes they ALL revolve. they have to as this was how the stars were formed in the first place, H2 atoms coagulate and their combined increase in gravity pulls in even more H2 atoms...resulting in more h2 atoms spiralling into the mass...
rich
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Captain, RSS Enterprise NCC1701R
United Federation of the Planets
Captain, RSS Enterprise NCC1701R
United Federation of the Planets
Hi Jingguo,
I hope I can help with a short reply to your first question.
Not all planets are actually that bright. They are very bright only when they are very near the sun (e.g. Venus), when they are very big (e.g. Jupiter), or very close to us (e.g. Saturn now and Mars in August '03). The further planets are actually not that bright at all.
I hope I can help with a short reply to your first question.
Not all planets are actually that bright. They are very bright only when they are very near the sun (e.g. Venus), when they are very big (e.g. Jupiter), or very close to us (e.g. Saturn now and Mars in August '03). The further planets are actually not that bright at all.