Did you know that looking at the stars is a look back in time?
The light we see from the stars is incredibly ancient, and some of the stars we observe may already no longer exist, but their light continues to travel across the vastness of space, reaching us and offering a glimpse into the distant past. We use the term “light year” to measure the distance light travels in one year.

Some of the stars we observe may already no longer exist

The farthest individual star visible without any aids is V762 Cassiopeiae. It is situated approximately 16,300 light-years away and even though it is over 100,000 times brighter than the Sun, it appears only faint due to its great distance.

Image: H. Raab, CC-BY-SA-4.0

This means that we are seeing the star as it was 16,300 years ago, while the light from the most distant star known to us has travelled some 19 million light years to be detected by the Hubble telescope.

(For comparison, the light from the Sun takes only about 8 minutes to reach Earth, so we see it as it was 8 minutes ago.)

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Image header: Anim shrest, CC-BY-SA-4.0

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