Originally posted by cheshirecatstevens The apparent expansion rate a nebula is 0.43 arcsec per year. The apparent size of the nebula is about 4 by 5.7 arcmin. If the expansion rate remains constant, calculate how long it will be until the long axis of the nebula has the same apparent size as the full moon (0.50 degree or 1800 arcsec).
Perhaps i am mistaken but this is one of those "looks hard but actually quite easy" problems.
60 arcsec = 1 arc min
We want long axis of apparent size of nebula to span 1800 arcsec, it currently spans 5.7*60 = 342 arcsec
Therefore apparent size of nebula needs to grow 1800 - 342 = 1458 arcsec
Apparent size grows at 0.43 arcsec/year
Therefore it will take 1458/0.43 = 3390.7 years give or take a few weeks.
Originally posted by AThousandYoung Maybe the star is in front. Ever thought of THAT, GENIUS?!?!?!??!
ðŸ˜
Thank you for the compliment, but I am not really a genius. 🙄
The moon is about 384 000 kilometres from earth. The nearest star, our sun, is about 150 000 000 kilometres from us. If any star would lie in front of the moon we would be burnt to ashes in a microsecond.
Oh, you made a joke? See? I'm not a genius after all! 😉
Originally posted by FabianFnas Thank you for the compliment, but I am not really a genius. 🙄
The moon is about 384 000 kilometres from earth. The nearest star, our sun, is about 150 000 000 kilometres from us. If any star would lie in front of the moon we would be burnt to ashes in a microsecond.
Oh, you made a joke? See? I'm not a genius after all! 😉
Astronomy?s
03 Dec '06 05:351 edit
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