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Post by @@ »

ive just been playing around on stellarium and forwarded the year to 4008 and polaris has moved almost 20 degrees from the pole, then around the year 9000 it starts moving slowly back is this true?
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Post by stella »

No, by 9000 A.D. it is still moving away.
It will be around 15000 A.D. before the Pole-Polaris
distance starts to decrease.
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Post by 12dstring »

I kept going past 9000 and it was still slowly moving away from the pole (although it had slowed right down) - then it broke at 10,000 :roll:

The effect is called precession, and is caused by a very slow rotation of the Earth's axis (if you imagine a spinning top as it slows down and starts to wobble). This has a cycle of about 25,765 years - so in 25,765 years time, Polaris should be back where it is now, ignoring that the start itself would have travelled through space in this time.
It figures that around the year 15000 (it reaches its closest to the pole at around the year 2100) it should be at its furthest - and will then move back.

EDIT: What Stella said :D beat me to it. Still, Stellarium conks out at 10000 A.D so it's hard to tell from it exactly when it starts returning.

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Post by MartintheMartian »

i love knowing quirky little things about the earth that nobody else knows haha.

i heard somewhere that Vega in Lyra will be a pole star at one point, or it has been at somepoint in history, its odd to think that novice astronomers will one day be struggling to polar align their scopr to Vega =P

does this mean polaris is wrongly named :S
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Post by 12dstring »

You're absolutely right Martin.

Vega has been the pole star, and will be again - in about 12,000 years time I believe.

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Post by FrankB »

As will Thuban although neither it or Vega will get as close to due north as Polaris.

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Post by Ric »


Will Stellarium get me back to 3000 BCE please?

Feel like Dr Who asking such a question! :-o

Thanks ;)

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Post by nealeh »

12dstring wrote:Vega has been the pole star, and will be again - in about 12,000 years time I believe.
I'll add that to my diary right now.
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Post by Vega »

So when people say to me... "isn't the pole star the brightest star in the sky?"... they will be at least 'Almost' right, give or take a few :lol:
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Post by Sarah »

Well, in my case, I was going past 9000 and was still shifting slightly away from the pole. However, it broke apart when it reached 11000. I think 12dstring has already mentioned as to what the case is. It is nothing but precession which is caused by the minutest rotation of Earth’s axis.
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Post by brian livesey »

Welcome to the Forum, Sarah. Fifteen-thousand-years is a long time to wait, better keep taking the vitamins. :wink:
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Post by nas76 »

Around the time of Jesus Polaris was at about 80deg, luckily for the mariners who first traversed the Atlantic it has been close enough to the true pole to use as a simple navigational aid. Polaris will get closest to true north in the year 2104, when it will be about half a degree away.
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Post by Cliff »

Dear al(L)
Not quite so distant in time as this topic is mainly discussing,but still a while back along the line. I sometimes wonder if Polaris becoming a proper reliable Pole Star in late medeval times I think, was a big factor in triggering off Europeans exploration (?).
But perhaps not ? - I don't recall reading much ever said about it !!!! ?!!!!!
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Post by Brian »

Dear Cliff,

If the North Atlantic Cloud Cover then was anything like it is nowadays, I doubt that Polaris was accessible on sufficient occasions to make it useful in navigation :)

Anyway, didn't mariners have lodestone compasses from the Viking days to find north with? Maybe Polaris is overrated for navigational purposes,

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Post by Paul Sutherland »

I'm not an expert on Stellarium (or much else) but such planetarium programs are often unable to deal with events such a long way in the past or future due to the extra levels of data/complexity/precision that would be required. These would bloat the software and slow down its performance in normal use.
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