help

How Far Away From Earth Could We See the Sun with the Unaided Eye?

-- Chris | January 1, 2024

Question:

If I were standing on a exoplanet from another solar system and looked up at the night sky; how many light years could you make out our suns light? Basically how far can we see our suns light without the aid of an instrument if looking back?

-- Chris

Answer:

The Sun’s absolute magnitude, which is its brightness if it were located at a distance of 10 parsecs (about 32.6 light years), is about 4.83. The human eye can see stars down to about apparent magnitude 6 or so. Using the relationship between apparent (m) and absolute (M) magnitude:

M = m – 5*log10(d(pc)) + 5

…we can calculate that our Sun’s absolute magnitude of 4.83 would appear to be as bright as a star with apparent magnitude 6 if it were at a distance of about 17.1 pc, or about 55.8 light years.

-- Jeff Mangum

Facebook

Twitter

The National Radio Astronomy Observatory is a facility of the U.S. 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 U.S. 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.