Does Mercury Have Water?
You might think the surface of the closest planet to the Sun would be the last place we’d find water, but the surface of Mercury actually has ice! This is because there is almost no atmosphere. Air is great at holding on to heat, which is why winter coats are puffy. Sunlight heats up Mercury's surface to 430°C (806°F) during daytimes that last nearly 3 Earth months, but without an atmospheric blanket, the surface loses all that heat to space and drops to -180°C (-292°F) during the equally long nighttime. That’s well below the freezing point of water. How would ice survive the daytime, though? It wouldn’t, but at the poles where the Sun stays near the horizon as the planet turns, the bottoms of deep craters are forever in shadow. Data collected by NASA’s MESSENGER spacecraft and the Arecibo Observatory in Puerto Rico have confirmed water ice deposits on the floors of these polar craters that never see the light of day. Read More
Latest News About Mercury
BepiColombo Mio and Earth's GEOTAIL show shared wave frequency properties across planetary magnetospheres
January 19, 2026
This opens the way to comparative studies across multiple planets. Read more
Mercury: The planet that shouldn't exist
December 28, 2025
Mercury has long baffled astronomers because it defies much of what we know about planet formation. Read more
Collision between two bodies of similar mass may explain the formation of Mercury
September 22, 2025
A new study proposes an alternative explanation for the formation of Mercury. Read more
How much has Mercury shrunk?
August 17, 2025
Mercury is still shrinking as it cools in the aftermath of its formation, and new research estimates how much. Read more
Scientists detect lithium in Mercury's exosphere using magnetic wave analysis
July 18, 2025
Mercury's surface has been enriched with volatile elements through continuous meteoritic impacts Read more
Mercury's 'missing' meteorites may have finally been found on Earth
July 6, 2025
Meteorites may be the only practical way to study Mercury's surface directly. Read more
See Mercury at greatest elongation, its farthest from the sun in the evening sky this week
July 2, 2025
The rocky world will be visible for a brief window after sunset Read more
A mission that could reach Mercury on solar sails alone
April 4, 2025
The proposal would harness solar winds to propel a spacecraft all the way to Mercury Read more
Mercury looks stunning in images from BepiColombo spacecraft's 6th and final flyby
January 9, 2025
All six of its flybys of Mercury have given us invaluable new information about the little-explored planet Read more
Why Mercury remains a mystery: three key exploration challenges
December 14, 2024
Mercury is the least explored of the four rocky planets in the inner Solar System Read more
BepiColombo probe captures haunting Mercury image on 5th of 6 gravity assist flybys
December 2, 2024
During recent flyby, the probe was once again able to generate an image of the planet Read more
BepiColombo probe captures stunning Mercury images in closest flyby yet
September 6, 2024
It is a world of extremes and contradictions, so I dubbed it the ‘Problem Child of the Solar System’ Read more
How the MESSENGER mission transformed our understanding of Mercury
August 13, 2024
The probe was the first to map the entire surface and find water ice in its polar craters Read more
Mercury has a layer of diamond 10 miles thick
July 24, 2024
The solar system's tiniest planet may be hiding a big secret Read more
Japanese-European spacecraft bound for Mercury weakened by thruster glitch
May 16, 2024
The spacecraft is set to make a flyby of Mercury in September Read more
The seven most amazing discoveries we’ve made by exploring Mercury
April 16, 2024
Only two robotic missions have made it there, but they were crucial for upending many false assumptions Read more
The Solar System's smallest planet may once have been as large as Earth
April 14, 2024
The Mercury we see today may be nothing more than the kernel of the planet that was once there Read more
Mercury slammed by gargantuan eruption from the sun's hidden far side, possibly triggering 'X-ray auroras'
March 12, 2024
It's often blasted due to its proximity to the Sun Read more
Salt may have carved out Mercury’s terrains, including glacierlike features
January 4, 2024
The surface might not be quite so terra firma, at least on geologic timescales Read more
Are glaciers on Mercury a link to life?
December 28, 2023
Salty regions on the closest planet to the Sun may hint at extremophiles Read more
The origin of Mercury’s structure and chemical composition and their astrobiological implications
October 17, 2023
There's high concentrations of sulfur, carbon, potassium, sodium, and chlorine Read more
Mysterious 'singing' plasma waves detected around Mercury
October 16, 2023
Around planets that have a magnetosphere, something magical happens Read more
Mercury is still shrinking
October 14, 2023
Yes, Mercury’s surface is boiling, but the interior isn’t Read more
Mercury’s surface and atmosphere mapped by solar wind study
September 17, 2023
It's the first to examine the impact on the surface in terms of geographic location Read more
The mysterious origins of Mercury’s hollows might answer bigger questions
September 5, 2023
Enigmatic vapors that waft from the lowlands Read more
Cumulate overturn on Mercury may have produced varied mantle source regions
August 8, 2023
Its composition suggests it is an endmember case for magma ocean evolution Read more
Mercury appears to have its own strange aurora after all
July 19, 2023
Auroral processes take place in spite of a practically nonexistent atmosphere Read more
Chromium on Mercury hints at planet’s offbeat chemistry
July 13, 2023
It's the first time chromium has been detected and mapped on a planetary surface Read more
A trio of images highlight BepiColombo’s third Mercury flyby
June 20, 2023
The closest approach took place about 236 km above the planet’s surface Read more
Maps of solar wind plasma precipitation onto Mercury’s surface
May 19, 2023
It’s magnetic field shields the surface from 90% of the solar wind Read more
Fascinating Facts About Mercury
- The Sun appears more than three times as large in Mercury's sky as it does from Earth, and sunlight is about 11 times brighter.
- It takes Mercury 59 Earth days to rotate once around its axis. However, because this rotation is so slow compared to its orbit around the Sun, it takes 176 Earth days to go through one day/night cycle, which is twice as long as a year on Mercury.
- Mercury's craters are named after famous writers, artists, musicians, composers, and choreographers.
- Unlike all other major planets, Mercury has no atmosphere. Sunlight and meteor impacts create an exosphere, a diffuse cloud of gas around the planet made of oxygen, sodium, hydrogen, helium and potassium.
- Mercury has a tail, kind of like a comet. It has barely any magnetic field to protect it, so the intense solar wind blows some of its exosphere out into space.
- With no atmosphere to hold on to heat, temperatures plummit at night and in shadows. Water ice has been found at the poles at the bottom of deep craters that sunlight never reaches.
- Since Mercury’s orbit is within Earth’s orbit, it only appears in our sky near to the Sun, either just before dawn or just after sunset. It's very difficult to spot due to its small size, dark surface, position just over the horizon, and the sun-brightened sky around it.
Source: NASA
Missions
BepiColombo (2018)
A pair of orbiters that will study the surface, internal composition and magnetosphere of Mercury
MESSENGER (2004)
Imaged and mapped almost the entire surface of Mercury, measured the chemical composition of the rocks, and studied the interior
Mariner 10 (1973)
This was the spacecraft to fly by Mercury and image the surface up close