Asteroid 2024 PT5 was dubbed Earth's temporary 'second moon' because of its size and lingering presence so close to our planet. 

Astronomers collected data on the asteroid as it circled Earth, finding it may be a chunk of our moon that was broken off in one of the collisions that left the lunar surface marred by craters. 

The leading theory of lunar formation is the 'giant impact hypothesis,' which posits that the moon is actually an enormous, orbiting hunk of Earth. 

According to this theory, our planet collided with a Mars-sized planet roughly four billion years ago, and this triggered an explosion of material from Earth that shot into space and eventually condensed to form the moon. 

If the giant impact hypothesis and the analysis of Asteroid 2024 PT5's origin are correct, that would mean our true moon is the parent of this mini moon, and Earth is its grandparent. 

The second moon will begin its journey away from Earth today as it gets pulled out into space by the sun's gravitational force. 

'There are multiple lines of evidence suggesting that this asteroid may have a lunar origin,' Carlos de la Fuente Marcos, study lead author and a professor at the Universidad Complutense de Madrid, told Space.com. 

'Current research favors its rapid rotation with a rotational period under one hour, to be expected if 2024 PT5 is either a large boulder from the surface of the moon or a fragment from a larger object.'

He and his brother, Raul de la Fuente Marcos the Universidad Complutense de Madrid, identified the asteroid's mini moon behavior. 

As it traveled around the outer-edge of Earth's orbit, the astrophysicists used telescopes in Spain's Canary Islands to collect hundreds of observations of the asteroid.

They analyzed its spectra, or the range of electromagnetic wavelengths that it emits. This data indicated that the asteroid's chemical composition matches that of lunar material previously brought back to Earth.