Some of the sci-fi series currently on the air

“V,” ABC, Tuesdays at 7 p.m.

The world is stunned when Earth is suddenly visited by 29 alien ships, filled with attractive, seemingly peaceful aliens. The aliens say they need only water and an Earthly mineral, and will share their advanced technology in return. But it wouldn't be much of a show unless they were lying, would it? Impressive ratings and a huge marketing campaign gave this show a good start. Time will tell if it can be maintained.

“Fringe,” Fox, Thursdays at 8 p.m.

The FBI's Fringe Division tests the limits of possibility — the fringes of science — to explore the unexplained and terrifying. Special Agent Olivia Dunham enlists the help of scientist Walter Bishop and his son Peter to solve crimes that go beyond the limits of known reality. The show plays as a more extreme “X-Files” but is developing an interesting mythology all its own. Creator-writer J.J. Abrams has the support of fans, but low ratings threaten to end the show's run.

“FlashForward,” ABC, Thursdays at 7 p.m.

When everyone in the world blacks out at the same time, the chaos that ensues leaves much of society in shambles. But an even bigger issue is what everyone saw during the blackout: two minutes and 17 seconds of their own future. With a widely acclaimed pilot, the show started very strong, but critics say it needs to move, well, forward to maintain an audience. Strong cast is also a plus.

“Caprica,” Syfy, series begins Jan. 22 at 8 p.m.

The follow-up to one of the most beloved sci-fi shows of all time, “Caprica” begins its story 50 years before the cataclysmic events that began “Battlestar Galactica.” The series will follow two powerful families, the Graystones and the Adamas, as the planet Caprica starts its journey to oblivion. The series already had a powerful start, with a movie/test-pilot of the same name released on DVD earlier this year to strong reviews. Fans of “Galactica” wait with bated breath.