What are the Average Distances Between Stars and Between Galaxies?

-- Niall | January 19, 2021

Question:

Hi there

I worked out, very roughly, that stars in the Milky Way are about 5-10 Light years apart(if evenly distributed) and as stars are only about a few light minute sin diameter then Galaxy is very sparse. Also I work out that the Galaxys in the Universe are(very roughly) 200b to 5m Light years apart. So relatively closely packed.

Are these two items about right?
ps It occurred to me that the observable Universe is only 140,000 times the diameter of the Milky Way which I thought was a small number!

Thanks – great site!

-- Niall

Answer:

Your estimate for the average distance between stars is reasonable. Your estimate for the average distance between galaxies is also a good estimate, which agrees with the information given on Physics Stack Exchange to a similar question. In fact, the answer provided on Physics Stack Exchange provides some nice background information that you might find interesting.

-- Jeff Mangum

Facebook

Twitter

The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.
	Founded in 1956, the NRAO provides state-of-the-art radio telescope facilities for use by the international scientific community. NRAO telescopes are open to all astronomers regardless of institutional or national affiliation. Observing time on NRAO telescopes is available on a competitive basis to qualified scientists after evaluation of research proposals on the basis of scientific merit, the capability of the instruments to do the work, and the availability of the telescope during the requested time. NRAO also provides both formal and informal programs in education and public outreach for teachers, students, the general public, and the media.
	The National Science Foundation (NSF) is an independent federal agency created by Congress in 1950 "to promote the progress of science; to advance the national health, prosperity, and welfare; to secure the national defense..."
	AUI collaborates with the scientific community and research sponsors to plan, build, and operate cutting-edge facilities. We cultivate excellence, deliver value, enhance education, and engage the public.