Blog

Learn what a meteoroid is, how it differs from a meteor and meteorite, and why these small space rocks matter.

Learn how planets are classified by the International Astronomical Union, by composition, orbit, size, and planetary system role.

Explore the main processes that strip planetary atmospheres and why some worlds keep their gases while others become barren.

Explore how the Moon shapes Earth’s tides, rotation, stability, and ecosystems through gravitational forces and long-term planetary effects.

Learn how astronomers determine planet size using transits, imaging, and density measurements, and why the result is often more complex than it looks.

Learn how planets develop atmospheres, from volcanic outgassing and impacts to gravity, magnetic fields, and atmospheric loss.

Learn how the Oort Cloud works, why it matters for comets, and what scientists know about the Sun’s farthest suspected boundary.

Mercury is the smallest planet in the solar system, but its size hides unusual extremes in temperature, orbit, and surface geology.

Scientists infer planetary composition from starlight, spectra, gravity, density, and spacecraft data—without ever needing to touch most worlds.

Learn what an asteroid is, how it differs from comets and meteoroids, where asteroids come from, and why they matter to Earth.