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"Earth's axis meets the sky at the North Celestial Pole (NCP), and as the axis precesses, the NCP changes. Right now, the NCP is less than 1 degree from the North Star, Polaris, and a century from now the NCP will be slightly closer to polaris. Then the NCP will move on. Five centuries ago, when Columbus sailed the ocean blue, Polaris was 3.5 degrees from the NCP, and sailors had to make allowances for this offset when navigating. At the time of the birth of Christ, Polaris was 12 degrees from the NCP and not a useful pole star at all. Almost thirty centuries earlier, Thuban - a faint star in Draco - was the pole star. Through the millennia, Earth has had several pole stars - but most of the time there has been no bright star near the NCP. Our present pole star is the best Earth will ever have. No other star is ever as bright and as close to the celestial pole as ours will be for the next two hundred years. It's one of those little things we just take for granted." Excerpt from the Starry Night Companion: Your Guide to Understanding the Night Sky, by John Mosley.
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∙ 15y ago
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Why isn't Polaris always the pole star?
This is because of the precession of the Earth's equinoxes as well as the motion of the stars, themselves. The precession of the equinoxes takes around 25,770 years before returning to the same position.
Why isn't polaris always the north star?
This is because of the precession of the Earth's equinoxes as well as the motion of the stars, themselves. The precession of the equinoxes takes around 25,770 years before returning to the same position.
Why does the answer say Currently the north star is Polaris?
Because in the future, due to a wobble in how the earth rotates on its axis, known as precession, what we now see as the north star, which we all Polaris, will no longer appear to be in that position.
Why pole star stays as it?
The pole star (Polaris) is not constant. The Earth's precession creates a continually varying point in space where the North Pole points. Right now, it is within a degree of Polaris, but there is a 26,000 year period where Polaris will not always be the pole star.
What cause the north star to change between the stars vega polaris and thuban?
The Earth is like an enormous gyroscope, spinning in space. We think of gyroscopes as always pointing in the same direction, but all gyros wobble a little bit, with a motion called "precession". The Earth's precession causes the north pole to move VERY SLOWLY. The north pole of the Earth is currently pointed to the star Polaris, but it hasn't always been, and won't always be. The cycle is 25,800 years long.As the centuries pass, the Earth's precession will cause the north pole to slowly move away from Polaris, and in about 12,000 years will point somewhere near Vega. In another 14,000 years, the north pole will be pointed somewhere near Polaris again - except that Polaris itself is moving. In 26,000 years, Polaris will be about 5 degrees away from the pole.
Why will the Polaris not always be the pole star?
That's because of precession. In other words, the position of Earth's axis of rotation in space changes over time.
How long will Polaris be our noth star?
Due to the precession of the equinoxes, Polaris will no longer be above the North Pole by the end of the 21st Century. Around the 40th Century, the Earth's rotational axis will pass close to Alrai (Gamma Cephei).
How long will Polaris be our north star?
Due to the precession of the equinoxes, Polaris will no longer be above the North Pole by the end of the 21st Century. Around the 40th Century, the Earth's rotational axis will pass close to Alrai (Gamma Cephei).
Was there ever a north star other than polaris?
Yes. Due to precession, Earth's axis doesn't always point in the same direction, so at times, the star we now know as "Polaris" will actually be quite far from the sky's North Pole.
Is Polaris the north star?
It is currently but 5,000 years ago the North star was Vega. This is because the Earth's axis wobbles (precession) every few thousand years.
What has the greatest effect on the precession of the Earth's axis?
It causes the set of constellations visible on any particular night each year to change over many years. It slowly changes which star is nearest to the north pole of the sky. So, Polaris will not always be the "pole star".
When Polaris is not the main star will Earth be different and how?
No Earth will not be different, Polaris has no effect on the Earth whatsoever.
