The asteroid belt holds about 3% of the Moon's mass, and it is mostly empty space. See the facts, the myths, Ceres and the missions…
The leading theory says a Mars-sized planet called Theia hit the young Earth 4.5 billion years ago. See the evidence, the puzzles and the rival…
The Moon is 384,400 km away on average and drifting off 3.8 cm a year. See how laser ranging measures distance to the millimetre, and…
Venus is so hot, about 465 °C at the surface, because its thick carbon dioxide atmosphere traps heat in a runaway greenhouse effect. That makes…
Enceladus has a salty ocean with phosphorus and hydrogen. Titan has methane lakes and rich organic chemistry. Compare both moons and the missions heading there.
Saturn's rings are mostly water ice, possibly only 100 to 400 million years old, and slowly raining into the planet. See how they formed and…
Saturn has 285 moons, Jupiter 101, Uranus 29, Neptune 16, Mars 2, Earth 1. Mercury and Venus have none. See the full count and why…
Ground telescopes fix atmospheric blur by reshaping a mirror up to 1,000 times a second, using an artificial star made with a laser. Here's how.
A 2.4-meter mirror, a famous 1990 mistake, and five repair missions — here's how Hubble actually captures images sharper than most ground telescopes.
Launched in 1977, Voyager 1 and 2 are still sending data from interstellar space in 2026 — kept alive by an engineering trick NASA calls…