Astronomy/Stars

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QUESTION: Are we ever going to see new constellations, or are the ones we see now always be there?

ANSWER: Hi Maria,

When you say "we", I assume you mean in your lifetime. In that case, the constellations you see will not change.

But if you mean "the human race", we will see new constellations simply because the earth's axis wobbles in space (termed 'precession of the equinoxes'). It takes 23,000 years for a complete wobble, so new constellations will come into view - peaking in 13,000 years. Polaris is now within one degree of the North Celestial Pole, but in 13,000 years, it will be about 23.5 degrees from the Pole. So some Southern constellations will slowly become visible.

Besides precession, all stars are moving - they have "proper motion". But they're so far away that it takes a long time to notice their movement. An interesting site is www.wired.com/2015/03/gifs-show-constellations-transforming-150000-years. This site gives the appearance of some constellations over the past 150,000 years.

Hope that helps.

Prof. James Gort
    

---------- FOLLOW-UP ----------

QUESTION: Thanks so much. That's really interesting. So do you know what other consolations the human race will see?
Have you done research about the other constellations the people in the way past might have seen?

Answer
Hi Maria,

No, astronomers are not very concerned with the way constellations will appear in the future, although they are very concerned with the positions of stars (and their positions do make up the constellations). In fact, star atlases always have an "epoch", or the date at which the positions of stars (the "constellations") are accurate. Some atlases have an epoch of 1950, 2000, or 2050. I've never seen an atlas with an epoch of 2100 or later, but astronomers can calculate how the positions of stars will change for any date in the future (or the past), and how the appearance of constellations will change.

This site gives a bit of the early history of star maps - https://en.wikipedia.org/wiki/Star_chart. Some constellations were apparently drawn at least 32,000 years ago, and those drawings appear to show constellations very similar to the constellations of today.

In the sky, things change very slowly!

Prof. James Gort  

Astronomy

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James Gort

Expertise

Questions on observational astronomy, optics, and astrophysics. Specializing in the evolution of stars, variable stars, supernovae, neuton stars/pulsars, black holes, quasars, and cosmology.

Experience

I was a professional astronomer (University of Texas, McDonald Observatory), lecturer at the Adler Planetarium, professor of astrophysics, and amateur astronomer for 42 years. I have made numerous telescopes, and I am currently building one of the largest private observatories in Canada.

Publications
StarDate, University of Texas, numerous Journal Publications

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