[Physics] How does the view of night sky change as the Sun orbits around the Milky Way

Question

I know that the Sun and hence the Solar System orbits around the galactic center of the Milky Way. Does this rotation cause any visible change in the night sky?

I know that human life span is negligble compared to the time it takes the Sun to go around the galaxy, but will we ever see any change in the night sky if we record the the observations over few generations? Will we ever see a new start or constellations? Or a different view as we go around the Milky Way?

I am assuming (and hoping), given enough time to make considerable progress of the Sun around the Milky Way, there has to be some change, we may get to see another galaxy or something 🙂

Now, don't tell me that the Milky Way itself is going around something even bigger 🙂

(I am glad I found this site, there was a question that I always wanted to ask but did not know where.)

Answer 1

As it takes the sun about 250 million years (250 My) to orbit the galaxy, the proper motion of stars relative to the Sun will be the dominant effect of changes in the sky. The visible effects of the rotation will be far slower.

All stars move in the sky, some faster some slower, and in more or less random directions, not just moving around the galaxy. For example, Vega moves about 1 degree every 11,000 years. Around 12,000 BCE it was the pole star, and will be so again around 14,000 CE. Between now and then, other stars like Gamma Cephei and Iota Cephei will temporarily take the role of Polaris.

By 250 million years most stars will be far from their current position in the sky, but because of uncertainties it's impossible to say just where they'll be. For example, if the estimate of 250 My is wrong by just 1% (or 2.5 My), that means about 100 periods of Vega. Hence by that time Vega could be anywhere at all even if it stays in our general neighbourhood - which is certainly not guaranteed.

Galaxies move as well, but because they are much further away, their apparent position changes much slower than that of stars. It will be mainly our rotation around the galaxy that moves them in the sky.

Using telescopes we have already seen differences in the positions of the closer stars. In 10,000 years many changes will be visible to the naked eye. By the year 250 My, the sky won't look even remotely like the present.