"Discovery of Alien, Mars-Sized Planets Beyond Pluto"
The outer Solar System may harbor alien, Mars-sized planets that have been captured by the Sun's gravity, according to theoretical astrophysicist Amir Siraj of Princeton University. His calculations suggest there could be 1.2 planets with a mass greater than Mars, 2.7 with a mass comparable to Mars, and 5.2 with a mass comparable to Mercury. These planets, potentially from distant stars, could be lurking beyond Pluto, and the upcoming Vera C. Rubin Observatory may be able to spot them when it commences science operations in 2025.