Learning about the very first galaxies that formed after the big bang, like this one, helps us understand what the early universe was like. This picture shows hundreds of very old and distant galaxies.
The oldest one found so far in GN-z11 shown in the close up image. The image is a bit blurry because this galaxy is so far away. Oesch Yale University , G. Illingworth University of California, Santa Cruz. What Is a Light-Year? More to explore What Is a Galaxy? How Far Away Is the Moon? What Is a Nebula?
If you liked this, you may like: What Is a Barycenter? What Is the Big Bang? What Is a Galaxy? To quantify the vastness of the cosmos, astronomers often refer to things being a certain number of light-years away. What does that really mean? Though seemingly contrary to how it sounds, a "light-year" is a measure of distance, rather than time. A light-year is the distance light travels in a year.
Specifically, the International Astronomical Union defines a light-year as the distance light travels in In a similar vein, you could describe 60 miles as a car-hour the distance a car travels in an hour on a highway. In fact, we often tell people distances in terms of time — "I'm 10 minutes away," for instance. The term "light-year" was invented because, simply put, the equivalent distances in miles, meters or kilometers were huge.
How huge? Light moves at , miles per second, or , That's The distance to the nearest star is 4. A diagram depicting 12ly. Credit: Atlas of the Universe. What is a Light Year? So how big is the Observable Universe? Image from NASA. Leave a Reply Cancel reply You must be logged in to post a comment.
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