Not everyone celebrated Black Friday by standing in line to buy a flat-screen TV; NASA decided to declare it BlackHoleFriday, and spent the day sharing fun and interesting facts about the strange cosmic phenomena.

Using the hashtag #BlackHoleFriday, @NASA tweeted a series images and interesting facts about the objects in the center of galaxies whose gravity is so strong not even light can escape.

"For retail, it's #BlackFriday. For us, it's #BlackHoleFriday. Today, we'll post info & images all about black holes. pic.twitter.com/jsk9vUjcr4

- NASA (@NASA) November 29, 2013"

"A black hole is a region in space where the pulling force of gravity is so strong that light is not able to escape. The strong gravity occurs because matter has been pressed into a tiny space. This compression can take place at the end of a star's life. Some black holes are a result of dying stars," NASA explained.

This was the second year the space agency has celebrated BlackHoleFriday.

In keeping with a day that would see video games flying off the shelves, NASA even tweeted about a game with a black hole theme.

Need rescuing from #BlackFriday? Play 'Black Hole Rescue' now: [flash req'd] http://t.co/gvUbBA0qlC #BlackHoleFriday pic.twitter.com/NpNnGaxQgV

- NASA (@NASA) November 28, 2014

Some scientists believe black holes come in all sizes, NASA tweeted, perhaps as small as an atom, although they are so dense such a "mini black hole" would have as much mass as a large mountain on Earth.

Throughout the day, NASA provided dozens of tweets and retweets about black holes.

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