Mercury
The smallest planet in our solar system and nearest to the Sun.
From the surface of Mercury, the Sun would appear more than three times as large as it does when viewed from Earth, and the sunlight would be as much as seven times brighter. Despite its proximity to the Sun, Mercury is not the hottest planet in our solar system – that title belongs to nearby Venus, thanks to its dense atmosphere.
Because of Mercury's elliptical – egg-shaped – orbit, and sluggish rotation, the Sun appears to rise briefly, set, and rise again from some parts of the planet's surface. The same thing happens in reverse at sunset.
The information published here was produced by NASA.
Please visit NASA Space Place for more kid-friendly facts.
NASA Space Place: All About Mercury
10 Need-to-Know Things About Mercury
#1 - Small World
Mercury is the smallest planet in our solar system – only slightly larger than Earth's Moon.
#2 - Inside Track
Mercury is the planet that orbits the closest to the Sun.
#3 Fastest Planet
Mercury is the fastest planet in our solar system – traveling through space at nearly 29 miles (47 kilometers) per second. The closer a planet is to the Sun, the faster it travels. Since Mercury is the fastest planet and has the shortest distance to travel around the Sun, it has the shortest year of all the planets in our solar system – 88 days.
#4 - Rough Surface
Mercury is a rocky planet, also known as a terrestrial planet. Mercury has a solid, cratered surface, much like the Earth's moon.
#5 - Can't Breathe There
Mercury's thin atmosphere, or exosphere, is composed mostly of oxygen (O2), sodium (Na), hydrogen (H2), helium (He), and potassium (K).
#6 - Moonless
Mercury has no moons.
#7 - Ringless
There are no rings around Mercury.
#8 - Tough Place for Life
It is unlikely that life as we know it could survive on Mercury due to solar radiation, and extreme temperatures.
#9 - Big Sun
Standing on Mercury's surface at its closest approach to the Sun, our star would appear more than three times larger than it does on Earth.
#10 - Robotic Visitors
Two NASA missions have explored Mercury: Mariner 10 was the first to fly by Mercury, and MESSENGER was the first to orbit. ESA's BepiColombo is on its way to Mercury.
Further information for the curious Star-sailors
We Are NASA
The Formation of the Solar System
NASA Skywatching
A short introductory video to the National Aeronautics and Space Administration
NASA Skywatching
The Formation of the Solar System
NASA Skywatching
Updated daily with information for stargazers and skywatchers
The Formation of the Solar System
The Formation of the Solar System
The Formation of the Solar System
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Our Solar System in the wiki
Our Solar System in the wiki
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