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The moon gains company once again, this time for the next 58 years.
Our moon, that was formed 4.5 billion years ago, has been with us since long before there was any life on Earth. Now, it seems that our planet has gained a new friend, that scientists have classified a temporary moon to Earth.
Labelled as 2025 PN7, the asteroid was first observed a few months ago on August 2nd by the Pan-STARRS observatory located at Hawaii’s Haleakala volcano. According to those involved in its discovery, it has been in Earth’s proximity since the 1960s. Interestingly, our new moon would be so until 2083.
According to Carlos de la Fluente, who was attached to the team that discovered the asteroid, the moon had escaped telescopes due to its small nature. Thus, it could only be captured by the currently available telescopes when it gets close to the planet, as it did in August.
However, though its proximity is close enough to Earth to gain the title of a moon, its actual distance estimate is around 4 million km away from Earth. For a rough measure, our OG moon is only 384,000 km away.
As fascinating as this undoubtedly is, many might be confused as NASA often comes forward revealing that the Earth has obtained a temporary moon every now and then.
What is classified as a moon?
A moon is essentially a natural satellite, and its most fundamental classification is that it has to be in stable orbit around a larger celestial body that is not the Sun. Moreover, the motion of the satellite is always highly dependent on the planet it orbits.
This requirement is best defined by the Hill Sphere, which defines the region where a planet’s gravity outweighs the gravitational pull of the Sun. To put it simply, think of the Earth’s gravity as a ‘gravitational well’. For the moon to stay in stable orbit, it has to maintain its position within this ‘well’.
Now, here’s where the trippy part comes: the Earth’s hill sphere extends to 1.5 million km, so why is 2025 PN7 considered a moon if its way farther from Earth’s gravitational reach?
