Earth has a new ‘MOON’, scientists reveal – and it’s here to stay for at least 1,500 years
Earth has a new moon — or at least a “quasi-moon,” a new study has revealed.
A quasi-moon is a space rock that orbits the Earth, but gravitationally bound by the Sun.
Named 2023 FW13, this quasi-moon was discovered by experts using the Pan-STARRS telescope at the top of Hawaii’s Haleakala volcano, and is one of the few known quasi-moons.
Experts believe the ancient cosmic companion has been near Earth since 100 B.C. and will continue to orbit our planet for at least another 1,500 years, until 3,700 A.D.
Fortunately, neither 2023 FW13 nor a similar quasi-moon called 469219 Kamoʻoalewa are believed to pose any danger to humans on Earth.
Astronomers have discovered a new ‘quasi-moon’ – a space rock that orbits the Earth but is gravitationally bound by the sun. Several candidates for Earth’s second moon have been proposed, but none have been confirmed
What Are Quasi-Moons?
2023 FW13 is a quasi-moon – a subcategory of near-Earth asteroids that orbit the sun but remain close to Earth.
Quasi-moons follow elliptical (not perfectly circular) orbits around the sun that are very similar to Earth’s.
They often look as if they are orbiting the Earth, like the Moon, but in fact remain gravitationally bound to the Sun rather than the Earth.
Quasi-moons, also called “quasi-satellites,” often look as if they are orbiting our planet, much like our natural satellite the moon (affectionately known as “Luna”).
But they get the prefix “quasi” because they are gravitationally bound to the Sun rather than the Earth, rather than the other way around, as is the case for Luna.
2023 FW13 differs from our moon because it orbits well outside Earth’s “Hill sphere,” the area around a planetary body where its own gravity is the dominant force that attracts satellites.
Earth’s Hill sphere has a radius of 932,000 miles (1.5 million km), while 2023 FW13’s radius from Earth is quite a bit larger — about 1.6 million miles.
“The size of the loop — about 0.18 astronomical units in radius — is so large that Earth plays essentially no part in its motion,” said Alan Harris, a senior research scientist at the Space Science Institute in Boulder, Colorado. Sky & Telescope.
‘[2023 FW13 is] associated with the earth in no other way than by chance.’
Generic quasi-satellite orbit diagram. The satellite orbits both the sun and a nearby planet — but is gravitationally bound to the sun, not the planet
An online simulator shows the orbit of 2023 FW13 in relation to the satellite, the sun and other planets in the solar system
It was discovered using the Pan-STARRS telescope, located on top of Haleakala, a dormant volcano on the Hawaiian island of Maui
2023 FW13 was first observed on March 28 by PanSTARRS before its existence was confirmed by several other telescopes.
After being confirmed, 2023 was FW13 noted by the Minor Planet Center of the International Astronomical Union (IAU).
While the size of 2023 FW13 is unconfirmed, asteroid specialist Richard Binzel estimates its diameter to be about 10 to 15 meters.
This is only a small fraction of the diameter of our moon, which is 3,400 kilometers (although a moon is classified as such by its orbital characteristics rather than its size).
2023 FW13’s orbit around the sun takes almost exactly the same time as Earth – 365.42 days (1.0005 Earth years).
As it circles Earth on its orbital journey, this orbit is so elongated that it reaches halfway to Mars and halfway to Venus.
Earth has several known cosmic companionsmany of which are quasi-satellites, although as 2023 FW13 demonstrates, many more are likely to be discovered.
Quasi-satellites tend to follow a “stable” path around the Earth for more than a few decades before finally leaving the planet’s orbit.
2023 FW13 is special because it has been in its quasi-state for centuries and will remain so for many centuries to come, said amateur astronomer Tony Dunn.
Kamo’oalewa, whose name refers to a progeny that travels alone, was discovered in 2016 by the PanSTARRS telescope in Hawaii. Its orbit relative to the Earth and Sun is depicted
A online simulator created by Dunn shows the orbit of 2023 FW13 in relation to the moon, sun and other planets in the solar system.
Another famous quasi-satellite, known as 469219 Kamo’oalewa or 2016 HO3, was also discovered by PanSTARRS in April 2016.
469219 Kamo’oalewa, up to 330 feet in diameter, will only be in this orbit for about 300 years in the future, according to Renu Malhotra, an expert from the University of Arizona.
Malhotra wrote a recent study showing that 469219 Kamo’oalewa could be an ancient fragment of our moon.
Analysis of light reflected from the space rock suggested it is made of the same material as minerals found in moon rocks from NASA’s Apollo missions.
Explained: the difference between an asteroid, meteorite and other space rocks
A asteroid is a large chunk of rock left over from collisions or the early solar system. Most are located between Mars and Jupiter in the Main Belt.
a comet is a rock covered with ice, methane and other compounds. Their orbits take them much further out of the solar system.
a meteor is what astronomers call a flash of light in the atmosphere when debris burns.
This debris itself is known as a meteoroid. Most are so small that they evaporate into the atmosphere.
If one of these meteoroids reaches Earth, it will become one meteorite.
Meteors, meteoroids, and meteorites normally originate from asteroids and comets.
For example, if Earth passes through the tail of a comet, much of the debris in the atmosphere burns up and forms a meteor shower.