As a senior at UNLV, Christina Castellanos earned a chair in the Las Vegas Philharmonic.

Today is National Unfriend Day.

There's a holiday for practically everything -- even pruning your collection of friends on social media. Sunday is National Unfriend Day, which was started in 2010 by late-night TV host Jimmy Kimmel. Shrinking your social circle has a number of benefits, according to Natalie Pennington, a communications professor at the University of Nevada, Las Vegas, whose dissertation, cited in a university release, focuses on the effects of unfriending and unfollowing through social media.

The oldest Runnin' Rebel was the toast of homecoming ceremonies Friday night.

The oldest Runnin' Rebel was the toast of homecoming ceremonies Friday night.

The holiday encourages users of Facebook and other social networking platforms to examine how close or superficial their online relationships are, and unfriend those who ignore a status update pleading for volunteers to help move.

American astrophysicist and associate professor of physics and astronomy at the University of Nevada, Las Vegas Jason Steffen joins Matt Bubala to address the true meaning of a black hole. Jason is known for his work on the discoveries of several exoplanets. Matt and Jason go in depth of the true definition of a black hole and give insight on what really happens to you if you were to enter.

Former Las Vegas resident and comedian Jimmy Kimmel has created a holiday to help you end superficial relationships online. National Unfriend Day is Nov. 17 and a UNLV professor agrees with Kimmel.

More than half its population is non-white, including a third of residents who are Latino. It has huge masses of rural space but is still the third most urbanized state in the nation. Its growing senior population raises concerns about retirement security, while speedy growth is putting a crunch on affordable housing. Immigration, labor unions, education and health care are all major issues here.