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The first planet from the Sun in the solar system. Mercury orbits the Sun at an average distance of 0.4 times Earth’s distance. The planet is just five percent as massive as Earth, and it about 50 percent larger than the Moon. It is made of solid, rocky material that is heavily cratered, and it has no significant atmosphere. Mercury has no moons.


Mercury March 7, 2006

Radio Programs

Mercury and Regulus A planet sneaks up on the lion July 28, 2023

Venus and Mercury Two planets that just make sense July 21, 2023

Mercurial Encounter A spacecraft puts on the brakes June 19, 2023

Morning Mercury A hard place to live May 21, 2023

Evening Mercury Lining up a bright neighbor April 2, 2023

Venus and Mercury Changing the surface of a planet December 27, 2022

Morning Mercury An elusive visitor in the dawn sky October 6, 2022

Morning Mercury A hot planet with a cold cap June 13, 2022

Morning Mercury A planet with double sunrises and sunsets February 10, 2022

Moon and Mercury Twisting around the Sun’s closest planet November 2, 2021

First Glimpse A first glance at a final destination October 1, 2021

Moon and Mercury Angling in on the planet Mercury May 13, 2021

Evening Mercury Questions for a future explorer May 9, 2021

Mercury and Jupiter Crossing paths in the dawn sky March 2, 2021

Evening Mercury An evening planet that’s in a hurry January 18, 2021

Morning Mercury Moon and Regulus November 8, 2020

Morning Mercury Peeling away the skin of Mercury July 22, 2020

Evening Mercury Lighting up some evening planets February 8, 2020

Moon, Mars, Mercury M&M&Ms in the dawn sky November 23, 2019

Mercury Transit Crossing the face of the Sun November 8, 2019

Morning Mercury A bowling ball in the dawn sky August 8, 2019

Evening Mercury A planet with an artistic flair February 27, 2019

Mercury Bound Starting the long trip to Mercury October 4, 2018

Mercury in the Morning Lining up a bright morning planet August 24, 2018

Mercury in the Evening Looking for a reticent planet July 5, 2018

Morning Mercury Building a little planet April 20, 2018

Moon and Mercury A bowling-ball planet January 24, 2017

Featured Images

Just Passing By June 21, 2023

BepiColombo image of Mercury, June 23, 2022

Getting Acquainted June 28, 2022

Composite image showing sites of possible ice deposits on Mercury

Icy Darkness November 24, 2019

2006 Mercury transit

Seeing Spots November 8, 2019

On Its Way October 20, 2018

Artist's concept of BepiColombo arriving at Mercury in 2025

Heading for Mercury October 4, 2018

Mercury transits the Sun, May 2016

Little Black Dot May 10, 2016

2006 transit of Mercury

Spotty Sun May 6, 2016

Colorful Caloris April 15, 2016

View of Mercury from Messenger spacecraft

Dark Planet October 10, 2015

The Messenger spacecraft's final image of the surface of Mercury

The End April 30, 2015