Astronomers studying satellites orbiting the Earth have discovered Earth has multiple moons at any given time. Most of these objects are just a few meters across though, and typically stay in Earth's orbit for just 10 months.
"At any given time, there should be at least one natural Earth satellite of one-meter diameter orbiting the Earth," Granvik, Jeremie Vaubaillon and Robert Jedicke wrote in "The Population of Natural Earth Satellites," a paper published in online physics journal ArXiv.org.
In other words, at this very moment, our planet likely has a secret moon orbiting us (no word as to whether it's a blue moon). Such objects typically stay for about 10 months, making three revolutions around the planet.
Given that these tiny captured orbitals are only a meter or two in diameter, it may seem a stretch to officially call them "moons" -- but the scientific implications of the discovery are vast. Outside of assisting private spaceflight and exploring deep space, the other major thing on NASA's list of things to do is send astronauts to an asteroid.