Astronomical distances

Eta Carinae

Light years and parsecs

Special units of measurement are needed to cope with the Universe's vast distances - light years, for example. A light year is the distance light travels in one year through a vacuum, about 9.46 trillion km.

A parsec is 3.26 light years, as Chris Lintott explains.

An astronomical unit is the mean distance between the Earth and the Sun, about 150 million km.

So the star Eta Carinae is an estimated 7,500 light years, 2,301 parsecs or 474,308,078 astronomical units from the Sun.

Image: An X-ray image of the star Eta Carinae (credit: NASA/CXC/SAO)

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Eta Carinae


What is a light year?

About Astronomical distances

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