Starship Asterisk*

Mercury is the smallest planet in our solar system—only slightly larger than Earth's Moon.

Source: NASA

It is the closest planet to the Sun at a distance of about 36 million miles (58 million kilometers) or 0.39 AU.

Source: NASA

One day on Mercury (the time it takes for Mercury to rotate or spin once with respect to the stars) takes 59 Earth days. One day-night cycle on Mercury takes 175.97 Earth days. Mercury makes a complete orbit around the Sun (a year in Mercury time) in just 88 Earth days.

Source: NASA

Mercury is a rocky planet, also known as a terrestrial planet. Mercury has a solid, cratered surface, much like the Earth's moon.

Source: NASA

Mercury's thin atmosphere, or exosphere, is composed mostly of oxygen (O2), sodium (Na), hydrogen (H2), helium (He), and potassium (K). Atoms that are blasted off the surface by the solar wind and micrometeoroid impacts create Mercury's exosphere.

Source: NASA

Mercury has no moons.

Source: NASA

There are no rings around Mercury.

Source: NASA

No evidence for life has been found on Mercury. Daytime Temperatures can reach 430 degrees Celsius (800 degrees Fahrenheit) and drop to -180 degrees Celsius (-290 degrees Fahrenheit) at night. It is unlikely life (as we know it) could survive on this planet.

Source: NASA

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.

Source: NASA

The two spacecraft of ESA-JAXA's BepiColombo are en route to Mercury. NASA's Mariner 10 was the first mission to explore Mercury. NASA's MESSENGER was the first to orbit the innermost planet.

Source: NASA

Thank you for brief and comprehensive information about Mercury I became interested in space exploration since I was 10 and wanted to add one more fact about the smallest planet in Solar System that I remember from childhood: many people think that Mercury is the hottest planet in the solar system because it is closer to the Sun than other planets. However, Venus is the real record holder in this matter. The surface of Mercury, which faces the Sun, heats up to 427 ° C (800 degrees Fahrenheit), while the opposite side of the planet can be as low as -173 ° C (-290 degrees Fahrenheit). This is due to the fact that the planet does not have a dense atmosphere to regulate temperature.

I want to add some more interesting facts about Mercury:
Mercury has a faint comet-like tail, two and a half million kilometers long.
There are clouds at the poles of Mercury.
The largest crater on its surface, the Zhara Plain, has a diameter of about one and a half thousand kilometers.
One of the earliest mentions of Mercury dates back to around 3000 BC.

Here's another interesting fact about Mercury:
Mercury has an iron core, which could only be possible if it was a larger planet. It is assumed that, during the early times of the Solar System, Mercury was once larger, maybe closer to the size of Mars, before something caused it to shrink.