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patrick t. cakes Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Jan-17-11 02:43 PM
Original message
Any science types in the lounge today? Help!
Edited on Mon Jan-17-11 02:44 PM by patrick t. cakes
I have a short essay to write on this topic, and I have no clue where to begin.
I'm taking an online (1 credit) course in astronomy and its over my head.

I'm a history major damn it! Can anyone walk me through this?

(a) Suppose that the tilt of the earth were double what it actually is. Which of the following would be affected: The dates of the equinoxes; the declination of the sun at the equinoxes; the declination of the Sun at the solstices. Explain!

(b) What observations could an observer at the Earth's equator make to determine the declination of the Sun?
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AngryAmish Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Jan-17-11 02:49 PM
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1. declination of the sun at solstices
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patrick t. cakes Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Jan-17-11 02:51 PM
Response to Reply #1
2. yes, your right.
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rug Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Jan-17-11 02:53 PM
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3. Astronomy is over my head too.
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patrick t. cakes Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Jan-17-11 02:55 PM
Response to Reply #3
4. pun intended?
:)
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Ptah Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Jan-17-11 03:07 PM
Response to Reply #3
5. Astronomy is looking up.
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patrick t. cakes Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Jan-17-11 03:18 PM
Response to Reply #5
6. I knew the lounge was a crap shoot
:) :-) x( :-( :( ;-) ;) :o :D }( ;( :P :9 :* :+
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Lionel Mandrake Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Jan-17-11 04:57 PM
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7. It's a trick question
to see if you know the definitions of "equinox", "solstice", and "declination". The etymology of these words is the best mnemonic device for remembering their meanings. This approach should appeal to a history major.

By definition, the declination of the sun is zero at the equinoxes. The declination of the sun is plus or minus the "tilt of the earth" (i.e., the obliquity of the ecliptic) at the solstices.

The dates of the equinoxes would also change if the tilt of the earth changed, because the equinoxes precess at a rate that depends on the "tilt of the earth". This has to do with the torque exerted on the spinning earth by the sun and moon. You are probably not expected to know this.

By the way, It is because of this precession that the sun moves from one "sign of the zodiac" to another on different dates now than it did when western astrology was invented. There was a recent thread about the resulting disagreement among astrologers. Of course, both points of view are equally ridiculous.
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HopeHoops Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Jan-17-11 05:58 PM
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8. Simple: The earth is flat so the question is pointless.
:evilgrin:

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petronius Donating Member (1000+ posts) Send PM | Profile | Ignore Mon Jan-17-11 07:16 PM
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9. For B, the observer would need to measure noon-time sun angle,
and whether it was to the north or south. For an observer on the Equator, the declination latitude would be 90 minus the sun angle above the horizon. You could also observe the azimuth angle of sunrise and sunset, but the equation would be a bit more complicated...
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