MADISON (WKOW) -- Time is running out on the last season of "Lost." And time travel may be the key to the finale.
Alternate realities, the grandfather paradox and magnetic fields are all elements of time travel in ''Lost'' that aren't all that far fetched. One moment they're on the island. The next moment they're safe in the states. Then it's back to the island in the 1970s.
Clearly, time travel is a big part of the "Lost" mystery. The question is, can it be possible?
"From a pure empirical point of view, it's very difficult. That's why you need to make some conjectures," according to UW Physics professor Daniel Chung. He says basically, that means making your best educated guess, which is something "Lost" fans are used to.
Einstein's theory of relativity seems to prove that traveling forward in time is possible.
But going backwards could lead to the grandfather paradox where you could kill the very man who's indirectly responsible for your existence. But physics has a theoretical answer to that.
"Once you find a consistent theory with time travel," says Chung, "you find equations that are self consistent which means you'll never find a situation where you killed your parents." Time will heal itself.
Such a theory could be responsible for why so many people who die in "Lost" keep coming back to life. But Chung says there's another possibility, alternate realities.
"You could actually have both histories happen in some universe so there are interpretations of quantum mechanics in which there are many parallel universes."
But what fun would that be if "Lost" ends up with an infinite number of endings?
The show suggests that the island is a giant time machine with an underground on switch and a massive magnet to curve time.
But Chung says to curve time, you'd need to take all the mass in the earth and scrunch it into a 10-centimeter ball. "Typical magnetic fields in the lab are a godzillion times smaller energy density and it's not going to do anything to space and time."
Of course, Hollywood isn't obligated to the constraints of science. And sometimes it's free thinking helps spur good science.
"That's the fun of it," says Chung, "that it's so challenging even for the small pay and long hours and your wife complaining that you spend all your time at the office. It's just intrinsically important and interesting."
Lots of people feel that way about the mystery's of "Lost."
Only, unlike physics professors, they know they'll get the answers they seek by the end of the season.