Mercury Is Shrinking — the Whole Planet Is Getting Smaller
As its giant iron core cools, Mercury contracts, wrinkling its crust into cliffs hundreds of kilometers long. The planet has lost up to 14 km of diameter.
Solar System Secrets
Mars Has a Volcano So Big You Couldn't See It While Standing On It
Olympus Mons is nearly three times the height of Everest and the size of an entire country — so wide its slopes would hide beyond your horizon.
We Only Ever See One Side of the Moon — the Other Was Hidden Until 1959
The Moon is locked so that the same face always points at Earth. Humanity never saw its far side until a Soviet probe photographed it in 1959.
Sunsets on Mars Are Blue — the Exact Opposite of Earth's
On Earth, sunsets glow red and the sky is blue. On Mars it's reversed: the daytime sky is butterscotch, and the Sun sets in a cool blue glow.
Halley's Comet Returns Every 76 Years — Most People See It Once, If Ever
The most famous comet swings past Earth roughly once a human lifetime. It last appeared in 1986; the next visit is 2061. Mark Twain lived and died by it.
It Literally Rains Diamonds Inside Neptune and Uranus
Thousands of kilometers below the clouds of the ice giants, extreme pressure squeezes carbon into diamonds that fall like hail toward the core.
Saturn Is Slowly Losing Its Rings — They're Raining Down Onto the Planet
Saturn's iconic rings are being pulled into the planet as a dusty 'ring rain.' On cosmic timescales they're a temporary feature we're lucky to see at all.
Saturn Has a Perfectly Hexagonal Storm Bigger Than Earth
At Saturn's north pole sits a six-sided jet stream 30,000 km across that has held its geometric shape for over 40 years. Nothing else like it exists.
A Single Day on Venus Lasts Longer Than Its Entire Year
Venus takes 243 Earth days to spin once but only 225 to orbit the Sun. On Venus, your birthday comes around faster than sunrise.
Venus Is Hotter Than Mercury — Even Though Mercury Is Closer to the Sun
Mercury sits twice as close to the Sun, yet Venus is the hottest planet in the solar system. The reason is a runaway greenhouse effect gone mad.