Space is a strange and interesting place, and while scientists can look millions of light-years into the universe's distant past, sometimes they don't have to look very far to start stretching their heads.
A team of astronomers discovered an object using the Pan-STARRS observatory in Hawaii dubbed 2023 FW13 in March of this year and believed it was orbiting Earth. The scientists first thought this object was orbiting Earth, but after follow-up observations, it was confirmed that it was actually orbiting the Sun and was an asteroid. According to the space news website Space & Sky Telescope, this object is an asteroid that is orbiting the Sun at a very similar pace as Earth, with our planet playing no role in the motion of the object or its orbit.
Alan Harris, a scientist specializing in near-Earth objects at the Space Science Institute, spoke to Sky & Telescope and said that considering the newfound characterization of the asteroid, it's technically called a "quasi moon", or a "fake moon" as its not associated with Earth other than by chance. So, what makes this fake Moon special? Typically, quasi-moons only trail planets for several decades before separating out into other regions of space.
However, 2023 FW13 is different as data collected by astronomers indicates that it has been orbiting the Sun since 100 BC, or for more than 2,000 years. To put that into perspective, 100 BC was when Julius Caesar was born.
So, how big is 2023 FW13? According to measurements made by several observatories, such as Minor Planet Center at the International Astronomical Union, 2023 FW13 is approximately 65 feet long, which is about the size of a semi-truck, and despite its vicinity to Earth, our planet has minimal effect on it. Reports indicate that 2023 FW13 comes within 9 million miles of Earth, and by comparison, the Moon comes within 223,693 miles of Earth.
Astronomers have gone back through archival data on 2023 FW13 and have found sightings of the space rock dating back to 2013. According to Sky & Telescope's David Chandler, 2023 FW13 will remain a quasi-satellite of Earth until at least A.D 3700. If that is true, Chandler suspects that will make 2023 FW13 the most stable quasi-satellite of Earth ever discovered.
If you were wondering, 2023 FW13 doesn't seem to pose any threat to Earth. Space rocks need to be much larger than 65 feet long to make it to the surface of Earth. If you are interested in reading more about this story, check out this link here.