The Big Bang Theory Season 8
Sheldon and Penny in The Big Bang Theory season 8 episode 21 promotional picture CBS

An all new episode of The Big Bang Theory season 8 airs tonight, 16 April at 8pm on the CBS Television Network.

Episode 21 is titled The Communication Deterioration, where Sheldon and his team work on an Alien assignment.

Click here to watch the episode via live stream online on CBS Go or click here to watch the episode online.

The synopsis of episode 21 reads as follows:

When Raj is asked to create a message in case a NASA mission discovers alien life, the guys fight over what he should do. Also, Penny is torn between auditioning for a movie or keeping her successful pharmaceutical sales job, on The Big Bang Theory.

In the episode, the guys split up into teams to work on a project to communicate with aliens, while Penny considers auditioning for Kevin Smith's movie, Clerks 3.

In a new sneak-peek of the episode, Leonard shows up at Rajesh's house to help him with a Nasa alien project. They discuss why they did not want to include Sheldon and Howard in her project, as the two would boss over them. They then are seen discussing who is the Alpha male, but later get confused on how to start the project.

In another sneak-peek, the whole gang come together for lunch, and Sheldon starts to sing a song that he had penned to get attract children towards science. Later, Sheldon asks Leonard if he knew Beyonce, as he wanted her to sing the chorus of his song.

A third promo shows Penny knocking on Sheldon's door, to talk to him about her acting carrier. Penny is unsure whether she should quit her job as a pharmaceuticals representative to resume her acting career.

Meanwhile, reports suggest that in the upcoming episode, real aliens might see Sheldon's video, and conclude that he is declaring a war on them, and they decide to attack planet Earth. Although it seems like the described scene could be a dream.

So, what do you think, will Penny quit her job and resume her acting career? Will Sheldon really make contact with aliens? To know the answers, watch The Communication Deterioration, that airs tonight on CBS.