Why does Mercury have such extreme temperature swings, reaching -180 degrees C at night and 430 degrees C during the day?

Mercury spins so fast that temperatures swing rapidly Mercury is made of metal, which heats and cools quickly Mercury has almost no atmosphere to trap heat at night or spread it around the planet Mercury is too close to the Sun for any temperature to be stable

Which planet is the hottest in our solar system?

Mercury Venus Earth Mars

What makes Venus the hottest planet despite not being closest to the Sun?

Venus has a very dark surface that absorbs more sunlight Venus's volcanic activity produces enormous amounts of heat Its thick carbon dioxide atmosphere creates a runaway greenhouse effect that traps enormous amounts of heat Venus orbits much closer to the Sun than it appears on diagrams

How does the atmospheric pressure on Venus compare to Earth's?

About the same as Earth's About 10 times greater About 90 times greater — equivalent to being nearly 1 km underwater on Earth About 1,000 times greater

In which unusual way does Venus rotate?

Venus rotates extremely fast, completing a day in just a few hours Venus does not rotate at all Venus spins backward (retrograde) compared to most planets, so the Sun rises in the west and sets in the east Venus rotates sideways, like Uranus

How long is one day on Venus compared to one year on Venus?

A Venus day is about 24 hours, similar to Earth A Venus day (243 Earth days) is longer than a Venus year (225 Earth days) A Venus year is about 10 times longer than a Venus day A Venus day and Venus year are exactly the same length

Which spacecraft radar-mapped the surface of Venus, revealing its volcanoes and highlands?

Voyager 2 Cassini The Magellan spacecraft The Hubble Space Telescope

Which spacecraft has mapped Mercury's surface in detail?

Cassini New Horizons MESSENGER Juno

What is surprising about Mercury's iron core?

Mercury has no iron core — it is too small Mercury's core is entirely liquid, unlike Earth's Mercury's core is made of gold, not iron It is unusually large — making up about 85% of the planet's radius, more than any other planet

How does Mercury's rotation relate to its orbit? It rotates 3 times for every 2 orbits — what is this relationship called?

A random wobble caused by Jupiter's gravity A 3:2 spin-orbit resonance, caused by the Sun's gravity locking Mercury's rotation to its orbital period A magnetic lock that keeps one side always facing the Sun Mercury rotates freely with no relationship to its orbit

Venus and Earth are often called twins. What is the main way they are similar?

They have the same average temperature They both have one large moon They are nearly the same size and made of similar rocky material They rotate at the same speed