Perhaps it can cure jet lag -- introducing Entrain: a new iPhone app that calculates how travelers can adjust to new time zones faster.

Humans have an internal mechanism called circadian rhythm, a master biological clock that synchronizes bodily functions to the 24-hour pattern of the Earth's rotation. Also, it is regulated by the bodily sense, which depends much on how the eye perceives light and dark.

When people work late or travel to different time zones, the body clock falls out of sync, causing the feeling of jet lag, due to the fact that the light a body expects to see, compared to how long the person has been awake, is different. Therefore, the circadian rhythm has to reset itself with light exposure being its strongest regulator.

In a study partially funded by the Air Force, the researchers are now claiming that they have developed mathematical formulas that calculate light exposure. They have used two equations proven to predict one's circadian rhythm, and calculated different schedules of light exposures for more than 1,000 possible trips, with computer modeling.

"If you get light in the wrong time or wrong way, it'll send you the wrong direction," said Daniel Forger, a math professor, who led the research at University of Michigan.

If the app really works, the travelers on long flights will be able to use the free smartphone app to figure out how much daylight they need to be exposed to and when to change their biological clocks quicker.