美国康奈尔大学的研究人员称，月亮不是唯一围绕地球轨道运行的天体。其它更小一些的物体也一直有规律的运行在地球轨道上，有时它们会离开几个月，但仍然会回来继续绕地运行。

Researchers at Cornell University say that what we know as the Moon is in fact not the only one orbiting our planet at any given time. Smaller objects regularly inhabit the Earth's orbit, usually leaving after a few months to continue on their celestial¹（天上的） journeys.

The discovery is considered a major breakthrough for space research because scientists had been working toward visiting asteroids²（小行星） outside of Earth's orbit for research. While these temporary moons are too small for a shuttle landing, they are prime for research from a relatively³ close distance.

However, it's still to be determined⁴ whether the announcement will capture the public's attention like previously⁵ revealed New Moons. Either way, it should be a decidedly more pleasant experience for all involved.

The new paper titled "The population of natural Earth satellites," from Cornell University's Mikael Granvik, Jeremie Vaubaillon and Robert Jedicke states that these "secret moons" enter and exit the Earth's orbit without notice.

"At any given time, there should be at least one natural Earth satellite of 1-meter diameter orbiting the Earth," Granvik writes.

Scientists have confirmed at least one such temporary moon, discovered by the Catalina Sky Survey in Arizona in 2006.

"Our results are consistent with the single known natural [temporarily-captured orbiter] 2006 RH120, a few-meter diameter object that was captured for about a year starting in June 2006," the report says.