Before I can talk about Stargate Universe, I have to explain a bit of how we got here...
In 1994, a movie titled Stargate opened a whole new universe to movie-goers. Conceived by Roland Emmerich and Dean Devlin, the film took the Chariots of the Gods premise from Erich von Daniken that ancient civilizations were given advanced technologies by aliens welcomed as gods, dusted it off, and made it a huge science fiction success to the tune of nearly $200 million at the box office.
In the film, the idea is that ancient Egypt was enslaved by an alien calling himself the god Ra. This alien and his alien friends (other "gods") flew in pyramid-shaped spacecraft and were able to traverse intergalactic distances through devices known as "Stargates" which used stable, temporary wormholes to instantaneously transport goods and people wherever they needed them. Eventually the natives on Earth grew restless and overthrew their alien masters, burying the gate deep in the sand with a stone inscribed with a warning to future generations not to open it again.
Of course, that's just the beginning of the story. When it's uncovered in 1928 by an archaeologist, it takes another nearly 70 years to find someone who can decipher its mysteries. Dr. Daniel Jackson (James Spader), Egyptologist, figures it out and goes on the adventure of a lifetime with a U.S. Air Force team led by Colonel Jack O'Neil (Kurt Russell). They find themselves on an alien world fighting a battle against an alien race with evil intentions and advanced technology. But never fear, the good guys win in the end!
Three years later, Brad Wright and Jonathan Glassner created a TV series based on the film that picks up where it left off. Stargate: SG1 (or just SG1 for short) aired for nearly 10 years and 214 episodes, becoming a huge phenomenon with Richard Dean Anderson and Michael Shanks taking over the roles of Russell and Spader. Together, they explore the universe jumping from gate to gate, finding new friends and fighting new enemies every step of the way.
In 2004, Wright and Robert C. Cooper spun off Stargate: Atlantis, opening up a whole new universe for a new team to explore. It aired for nearly five years and 100 episodes and was also quite successful.