Astronomy/Speed

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Expert: - 10/26/2006


Question
I  know the earth travels about 67.000 mph around the sun to make it all the way around each year.  How fast does the earth move around the galaxy and how long does it take to complete that trip?  Thanks for considering the question.  

Answer
Hi Tom,

There is new data coming in on this all the time, mainly from the Hippararchus satellite.  But a good current estimate is that the sun is travelling at 250 km/s around the galactic center, and the trip takes 220 million years.  The earth's speed varies by season, of course, but it's almost the same as the sun's - the difference is relatively small.

Hope that helps.

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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