Starting today and going until Nov. 25, Earth will have a second moon, as “slow moving” asteroid 2024 PT5 will temporarily come under the influence of Earth’s gravitational field. The object will not even make a complete orbit around Earth, only seeing its own orbit around the Sun slightly altered by the Earth’s pull. Too small to be seen by the naked eye, 2024PT5—at 33 feet (9 meters) in diameter—is still large enough, were it not on its present trajectory, to cause damage to Earth. However, its orbit is far beyond that of Earth’s Moon.
Notably, this is not the first time this has happened and won’t be the last. Two years ago, Asteroid 2022 NX1 made a similar fly-by, and astronomers have determined that it had also visited us in 1981. Our present visitor, Asteroid 2024 PT5, is expected to re-visit Earth in 2055. While NASA’s capabilities in this area is being steadily expanded, these “gentle” encounters only serve to emphasize the need for a full-fledged multinational Defense of Earth program.
Detected by NASA’s Asteroid Terrestrial-Impact Last Alert System (ATLAS) in August 2024, PT5 comes from the Arjuna asteroid belt, the source of many, slow-moving asteroids with a solar orbit. ATLAS now has four telescopes at its base in Hawaii “specially designed to detect objects that approach very close to Earth—closer than the distance to the Moon, about 240,000 miles or 384,000 km away,” according to a 2022 NASA article. NASA wrote: “To date the ATLAS system has discovered more than 700 near-Earth asteroids and 66 comets, along with detection of 2019 MO and 2018 LA, two very small asteroids that actually impacted Earth.”
