1. The disappearing star
The star known as Epsilon Aurigae seems to disappear from time to time and the reason for that has remained elusive. Astronomers know that Epsilon Aurigae is eclipsed by a dark companion object every 27 years, but don't know why.
Observations from NASA's Spitzer Space Telescope this week have raised two possible answers to the mystery. According to NASA's Jet Propulsion Lab, one theory holds that the bright star is a massive supergiant, periodically eclipsed by two tight-knit stars inside a swirling, dusty disk. The second theory holds that the bright star is in fact a dying star with a lot less mass, periodically eclipsed by just a single star inside a disk.