Mercury is the smallest and innermost planet in the Solar System, located 0.39 astronomical units from the Sun. It has a diameter of 4,880 kilometers and a mass of 3.3 x 10^23 kilograms, making it only slightly larger than Earth's moon. Mercury is a rocky, terrestrial planet with a heavily cratered surface and a thin atmosphere composed mostly of helium and trace amounts of other gases. The planet has a slow rotation and completes three rotations for every two orbits around the sun, resulting in a day that is longer than its year. Mercury has no moons or rings and is the second hottest planet after Venus, with a maximum temperature of 800 degrees Fahrenheit (430 degrees Celsius) on its daytime side due to its proximity to the sun. Mercury was first observed and studied by ancient civilizations, including the Babylonians and Greeks, and has been explored by multiple spacecraft in recent decades, including NASA's MESSENGER mission.
Find it in the Sky
Chose a date & time and view the position of Mercury in the sky on our interactive planetarium.
In Evidence
Mercury
Mercury is in the constellation of Cancer, at a distance of
Finder Charts
The sky charts below show, at different resolutions, the position of Mercury in the sky. Click on each chart to access the interactive star map tool.
The following map uses photographic imagery from the Digitized Sky Survey (DSS) to realistically visualize the precise position of Mercury against the stars in the background. The horizontal size of the map measures 60 arcminutes. Click on the image to access a more detailed full-screen view.
Equatorial Coordinates
Apparent
J2000
Additional Information
Rise and Set Times
The following table lists today's rise, transit and set times of Mercury from Greenwich, UK (all times relative to the local timezone Europe/London):
If you need to access this information frequently for your observations, you can create a simple customized Quick Access page, so that you can easily bookmark it in your browser favorites or add a shortcut to your mobile phones' home screen.
Distance from Earth
The distance of Mercury from Earth is currently
The following graph shows the distance of Mercury from Earth as a function of time. In the chart the distance is measured in Astronomical Units and the data is sampled with an interval of 1 day.
Note: The values in this chart may not be entirely accurate around the time of closest approach for objects passing very close to Earth at high speed (e.g., Near-Earth Objects).
The value of the distance of Mercury from Earth is also available as a real time updated value in the live position tracker.
Closest Approach to Earth
In the period between January 1, 1600 and December 30, 2499, the closest approach of Mercury to Earth will happen on Monday 6 June 2416 at a distance of 0.548876 Astronomical Units, or 82,110,662 kilometers:
Note: the values for the closest approach are computed with a sampling interval of 1 day.
Light Curve
The following chart shows the light curve of Mercury, i.e., its apparent magnitude as a function of time. The curve is calculated using the latest ephemerides provided by JPL Horizons. The magnitude data is sampled with the interval of 2 days. Because of this sampling, inaccuracies may occur for objects that have large variations of brightness over a few days. For comets, large discrepancies can arise between the calculated brightness and the observations due to their highly dynamic, and not always precisely predictable, behavior.
Physical Properties
The table below lists the known key physical properties of Mercury.
| Physical Parameter | Value | Relative to Earth |
|---|---|---|
| Diameter | 4879.4 km | 0.3829 |
| Mass | 0.330104 x 1024 kg | 0.0553 |
| Density | 5.427 gr/cm3 | 0.9843 |
| Escape Velocity | 4.25 km/s | 0.3798 |
| Sideral Rotation | 1,407.5088 hours | 58.8068 |
| Absolute Magnitude | -0.6 | |
| Geometric Albedo | 0.106 |
15 Days Ephemeris
The following table lists the ephemerides of Mercury computed for the past and next 7 days, with a 24 hours interval. Apparent celestial coordinates are provided.
| Date | Right AscensionR.A. | DeclinationDec. | MagnitudeMag | Apparent DiameterDiameter | Constellation |
|---|---|---|---|---|---|
| Jul 10 2025 | 09h 00m 20s | +15° 42’ 47” | 0.82 | 9.0” | Cancer |
| Jul 11 2025 | 09h 02m 22s | +15° 19’ 40” | 0.89 | 9.2” | Cancer |
| Jul 12 2025 | 09h 04m 06s | +14° 57’ 27” | 0.96 | 9.4” | Cancer |
| Jul 13 2025 | 09h 05m 33s | +14° 36’ 14” | 1.04 | 9.5” | Cancer |
| Jul 14 2025 | 09h 06m 43s | +14° 16’ 08” | 1.13 | 9.7” | Cancer |
| Jul 15 2025 | 09h 07m 34s | +13° 57’ 16” | 1.23 | 9.9” | Cancer |
| Jul 16 2025 | 09h 08m 08s | +13° 39’ 45” | 1.34 | 10.0” | Cancer |
| Jul 17 2025 | 09h 08m 23s | +13° 23’ 44” | 1.47 | 10.2” | Cancer |
| Jul 18 2025 | 09h 08m 20s | +13° 09’ 17” | 1.61 | 10.4” | Cancer |
| Jul 19 2025 | 09h 07m 58s | +12° 56’ 33” | 1.77 | 10.5” | Cancer |
| Jul 20 2025 | 09h 07m 17s | +12° 45’ 37” | 1.95 | 10.7” | Cancer |
| Jul 21 2025 | 09h 06m 18s | +12° 36’ 35” | 2.16 | 10.8” | Cancer |
| Jul 22 2025 | 09h 05m 01s | +12° 29’ 34” | 2.39 | 11.0” | Cancer |
| Jul 23 2025 | 09h 03m 26s | +12° 24’ 38” | 2.65 | 11.1” | Cancer |
Additional Resources on TheSkyLive
- Mercury: Complete reference information on TheSkyLive.com.
- Where is Mercury?: Key information on where to find Mercury in the sky.
- Distance of Mercury from Earth: Find out how far Mercury is from Earth right now.
- How Bright is Mercury?: Current visual brightness (magnitude) and apparent size.
- Rise and Set Times: Rise and set times of Mercury from your location.
- Interactive Sky Map: Planetarium-style interactive visualization of Mercury's position in the sky.
- Live Position Tracker: High precision real time tracker of Mercury's position using deep space imagery.
- Ephemeris: 15 days Mercury's computed ephemeris.
- Physical Data: Detailed information about physical properties of Mercury.