SOLAR SYSTEM

Mercury

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*These images are satellite photos sourced from NASA's Flickr Commons and are used for educational and informational purposes.
~1/3 SIZE OF EARTH
43M FARTHEST DISTANCE TO THE SUN
-333°F MEAN TEMPERATURE
88 DAYS IN A MERCURY YEAR

Discovery

  • Mercury has been recognized for several millennia.

  • It’s close enough and bright enough to be seen by the naked eye, often being one of the brightest objects in the sky.

  • The earliest known record comes from the Assyrian MUL.APIN Tablets, around 1400 BC, where it is referred to as ‘The Jumping Planet’.

We also have records from the ancient Babylonian, Greek, Chinese, and Mayan civilizations showing various observations on its movement and speculation about its composition. The first telescopic observations came in the 1600s from Galileo and Thomas Harriot. Using this new technology, Johannes Kepler was able to not just predict, but also observe Mercury transiting in front of the sun in 1631. Being so close to the sun, it was a long time before detailed observations were made. Currently we know more about Mercury thanks to landers, probes, and orbiters.

Exploration

  • Reaching the surface of Mercury is quite challenging due to the thin atmosphere and gravitational acceleration so close to the Sun.

  • NASA has managed to get 2 orbiters to study Mercury.

  • Mariner 10 made 3 close pass-bys of the planet between 1974-1975 before being shut down due to a lack of fuel.

In 2011 Messenger spacecraft entered Mercury’s orbit and spent the next two years fully mapping the surface before crashing into the planet. Current exploration efforts are underway from a joint mission with ESA and JAXA. BepiColombo was launched in 2018 and expects to enter Mercurian orbit in 2025. Perhaps someday we will find an efficient way to slow down a lander to successfully land on this rocky planet.

WHAT WE KNOW

  • Mercury is not just the closest planet to the Sun, but it’s also the fastest in the whole solar system.

  • It takes just 88 days to orbit the sun.

  • This rocky planet has almost no atmosphere at all, letting it get bombarded with meteorites and cosmic radiation.

Mercury has minimal atmosphere to blanket the surface, so visitors would experience extreme temperature shifts as the sun sets and rises. However, there is only one sunrise every 180 days, due to the slow rotation. This allows the sunlit side to heat up to nearly 800 degrees Fahrenheit, but cool down without sunlight to -290 degrees Fahrenheit. Just a little bit larger than our own moon, this is now the smallest planet in our solar system.

We will have additional information on this planet coming soon.
Last updated September 15, 2023. Content written by Trevor Macduff.