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lighthouse1234
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Why is it that I can still use my 10 year old planisphere, if the stars are in motion?
Are the stars of the constellations stationary?
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In summary, the relative positions of the 'fixed stars' change very slowly, so you do not notice it in your lifetime, unless you are an astronomer.
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Baluncore
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Because the relative positions of the "fixed stars" change very slowly, so you do not notice it in your lifetime, unless you are an astronomer.
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lighthouse1234
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Someone wrote this to me: From that moving position these 'fixed stars' seem to be stationary,
hence are actually moving, even if they seemingly do not.
hence are actually moving, even if they seemingly do not.
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Baluncore
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Is that a question?
As the Earth orbits the Sun, the relative position of the nearest stars, move back and forth every 6 months, against the distant background. That is how we identify and measure the distance to nearby stars.
As the Sun moves through and with the galaxy, the relative positions of the fixed stars gradually move against the distant background.
From what moving position?lighthouse1234 said:
As the Earth orbits the Sun, the relative position of the nearest stars, move back and forth every 6 months, against the distant background. That is how we identify and measure the distance to nearby stars.
As the Sun moves through and with the galaxy, the relative positions of the fixed stars gradually move against the distant background.
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The stars in constellations are so far away that they can be moving tremendously fast and we will not be able to notice it with the naked eye in our lifetime. The nearest star in Orion is Bellatrix, which is 250 light years away. A light year is 5.8 trillion miles. The farthest star in Orian is Alnilim, which is 1360 ly away. So the change in angle will be small unless/until they move very far sideways or up and downlighthouse1234 said:
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Vanadium 50
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There's a source!lighthouse1234 said:
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The visible star with the largest proper motion is 61 Cygni. In 10 years, it moves about 2-1/2 arc-seconds. That's 0.15% of the apparent size of the moon.
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Drakkith
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If I stand far away from the train tracks near my house and watch a train go by, the train appears to move very slowly. If I hold my thumb up it takes about a second for the train to 'cross' behind it. But if I stand next to the tracks the train will cross behind my thumb in a small fraction of a second.lighthouse1234 said:
The same is true for stars. They may be moving very quickly relative to us, but they are so far away that they don't appear to be moving hardly at all.
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berkeman
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"There's that guy again, trying to hitch a ride on our train..."Drakkith said:
Related to Are the stars of the constellations stationary?
Are the stars of the constellations stationary?
No, the stars in constellations are not stationary. They are moving through space, but their immense distances from Earth make their movements appear very slow to us. Over long periods of time, these movements can alter the shapes of constellations.
Why do constellations appear to stay the same over human lifetimes?
Constellations appear to stay the same over human lifetimes because the stars are so far away that their movements are imperceptible over short time periods. It takes thousands to millions of years for noticeable changes in their positions relative to each other.
Do stars within a constellation move together?
Stars within a constellation do not necessarily move together. They are not gravitationally bound to each other and can be at vastly different distances from Earth. Their apparent grouping into constellations is a result of our line of sight from Earth.
How do astronomers measure the movement of stars?
Astronomers measure the movement of stars using techniques such as astrometry, which involves precise measurements of a star's position in the sky over time. They also use Doppler shifts in the star's spectrum to determine its motion toward or away from us.
Will the constellations look different in the distant future?
Yes, the constellations will look different in the distant future. As stars move through space, the shapes of constellations will gradually change. In tens of thousands to millions of years, the familiar patterns we see today will be significantly altered.
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