Forget Planet Nine! Scientists say an Earth-like world could be hiding within our Solar System
For years, astronomers teased the concept of another world in our solar system, commonly referred to as Planet Nine.
But there could be a whole other “Earth-like” planet to be discovered much closer to home, Japanese astronomers now reveal.
They think this new planet is hiding in the Kuiper Belt; the doughnut-shaped ring of objects extends just beyond Neptune’s orbit.
This so-called Kuiper Belt Planet (KBP) is located up to 500 astronomical units (AU) from the sun — 500 times the distance between Earth and the sun, and closer than Planet Nine.
KBP is up to three times more massive than Earth, experts say, but temperatures are probably too cold to sustain life as we know it.
Astronomers in Japan believe there may be an Earth-like world lurking in our solar system, waiting to be discovered (file photo)
The research was conducted by Patryk Sofia Lykawka of Kindai University in Osaka, Japan and Takashi Ito of the National Astronomical Observatory of Japan in Tokyo.
“We predict the existence of an Earth-like planet,” they say in their paper, published in The astronomical magazine.
“It is plausible that a primordial planetary body like KBP could have survived in the distant Kuiper Belt, since many such bodies existed in the early solar system.
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The Kuiper Belt is known to contain millions of icy objects, known as trans-Neptunian objects (TNOs) because they are beyond Neptune.
TNOs are believed to be the remnant of the solar system’s formation and are made up of mixtures of rock, amorphous carbon, and volatile ices such as water and methane.
“The orbits of trans-Neptunian objects (TNOs) may indicate the existence of an undiscovered planet in the outer solar system,” the Japanese team says.
“These rock and ice bodies are the remnants of planet formation in the outer solar system.”
NASA describes the Kuiper Belt as an “area of remnants from the early history of the solar system.” The experts think the Earth-like planet is in the belt, closer to the sun than the supposed location of planet Nine
An Earth-like planet could explain three fundamental properties of the distant Kuiper belt, including a “significant population of high-inclination objects” (pictured)
The team noted that some of these objects have “peculiar orbits” that indicate they are gravitationally influenced by something larger nearby.
The belt also contains a significant population of high-inclination objects; objects with a large tilt as they orbit the sun.
Computer simulations suggested that the hypothetical KBP could be responsible for these effects.
“We found that an Earth-like planet in a distant and inclined orbit can explain three fundamental properties of the distant Kuiper belt,” they write.
“(These are) a prominent population of TNOs with orbits beyond the gravitational influence of Neptune, a significant population of high-inclination objects, and the existence of some extreme objects with singular orbits.”
The experts note that they predict rather than confirm that the planet Kuiper Belt exists, as more research will be needed.
They also emphasize that their proposed planet is different from the already hypothesized Planet Nine, which is much more massive and presumably in a more distant orbit.
Planet Nine was first theorized by experts at Caltech in 2014, when they similarly found that the orbits of the farthest TNOs were disrupted or disrupted.
Astronomers still argue that this could be explained by the gravitational pull of a ninth planet in our solar system, which orbits 20 times farther from our sun than Neptune.
So far, however, astronomers have only circumstantial evidence for the existence of Planet Nine – and some are not at all convinced that it exists.
If it exists, Planet Nine will be in the outer regions of our own solar system, outside the Kuiper Belt, rather than inside it.
Planet Nine could have formed in the inner solar system at birth and then been expelled by interactions with Jupiter, another team of researchers said in 2020.
Another study published earlier this year suggested that Planet Nine could be surrounded by 20 hot moons, which could help experts find them.