There are hundreds of Pluto-sized worlds in the Kuiper Belt and potentially up to 200,000 in the Oort Cloud! While estimates of Earth-sized objects in the Oort Cloud vary, simulations predict about five Earth-sized bodies—some scientists predict many more. Bottom line, it’s possible future Homo sapiens will never have to leave our solar system even after our Sun expands, engulfs Earth, and collapses in about 5 billion years. The Oort Cloud likely provides more than enough resources for trillions of years of growth, evolution, fighting, etc.
Our Moon is really big for a moon; it is about 1/4 the size of Earth, which is the largest moon-to-planet size ratio in the solar system! I know, a super-geeky trivia question. Pluto is a bit smaller, and Charon, one of Pluto’s moons, is large for its planet at about 1/2 the size of Pluto. However, Pluto is a dwarf planet, so it has satellites, not moons.
I love the image above that shows the size of Pluto in human terms. This image depicts the Moon in the sky high above a mountain range with Pluto orbiting it. Although smaller than the Moon, it would appear much bigger when it passes in front of the Moon and much smaller when it passes behind it. It humanizes the ideas of size and volume. The Moon’s diameter is about 1/4 that of Earth’s diameter, representing size, and approximately 49 Moons could fit within the Earth’s volume. The Moon is roughly 5.6 times the volume of Pluto, which is about 32% smaller in diameter, representing size. This means that approximately 3.4 Plutos could fit within the Moon’s volume.