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.
The current Right Ascension of Mercury is 18h 08m 19s and the Declination is -25° 42’ 56” (topocentric coordinates computed for the selected location: Greenwich, United Kingdom ). The current magnitude of Mercury is -0.39 (JPL).
- Mercury is above the horizon from Greenwich, United Kingdom .
- Right now it is placed in the South direction at an altitude of 13° above the horizon.
- Given its current magnitude, Mercury is visible to the naked eye, even from highly light polluted areas.
- Go to interactive sky chart
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.
Mercury Position and Finder Charts
Below we provide Mercury finder charts showing where the object is right now in the sky with respect to the brightest stars. The first finder chart has a field of view of 50 degrees, while the second one has a field of view of 10 degrees. Click on each finder chart to access a full screen interactive Online Planetarium.
Higher precision deep sky finder chart, 60 arcmin wide, showing where Mercury is right now. Click on the image to see a more detailed fullscreen tracker view.
Also check out Where is Mercury?, a page that provides all the information needed to find Mercury in the sky and additional links to sky charts.
Mercury Distance from Earth
The following chart shows the distance of Mercury from Earth as a function of time. In the chart the distance data is measured in Astronomical Units and sampled with an interval of 1 day.
The value of the reported distance might be somewhat inaccurate around the times of closest approach for objects passing extremely close to Earth. The value of the distance of Mercury from Earth is also available as a real time updated value in the Live Position and Data Tracker.
Closest Approach of Mercury to Earth
Between 1 January 1600 and 30 December 2499, the closest approach of Mercury to Earth happens on Mon Jun 6 2416 at a distance of 0.548876 Astronomical Units, or 82,110,662 kilometers:
NOTE: values for the closest approach are computed with a sampling interval of 1 day.
Mercury Brightness and Light Curve
The following chart is the predicted light curve (visual magnitude as a function of time) of Mercury, according to the most recent ephemerides data. Magnitude data is sampled with a 2 days interval and there might be inaccuracies for objects changing brightness very rapidly during the course of a few days. For comets there could be large discrepancies between the observed and predicted brightness because of their highly dynamic behaviour.
Mercury Physical Data
The following shows the known values of the most important physical parameters of Mercury. Source: JPL Small-Body Database
|Physical Parameter||Value||Relative to Earth|
|Mass||0.330104 x 1024 kg||0.0553|
|Escape Velocity||4.25 km/s||0.3798|
|Sideral Rotation||1,407.5088 hours||58.8068|
Mercury 15 Days Ephemeris
The following table lists the ephemerides of Mercury computed for the past and next 7 days, with a 24 hours interval. Click on each row of the table to locate Mercury in our Online Planetarium at the chosen date.
|Date||Right AscensionR.A.||DeclinationDec.||MagnitudeMag||Apparent DiameterDiameter||Constellation|
|2023 Nov 26||17h 26m 42s||-25° 40’ 26”||-0.45||5.7”||Ophiucus|
|2023 Nov 27||17h 32m 39s||-25° 45’ 21”||-0.45||5.8”||Ophiucus|
|2023 Nov 28||17h 38m 30s||-25° 48’ 52”||-0.45||5.9”||Ophiucus|
|2023 Nov 29||17h 44m 15s||-25° 51’ 00”||-0.44||5.9”||Sagittarius|
|2023 Nov 30||17h 49m 51s||-25° 51’ 42”||-0.43||6.1”||Sagittarius|
|2023 Dec 01||17h 55m 18s||-25° 50’ 58”||-0.42||6.2”||Sagittarius|
|2023 Dec 02||18h 00m 36s||-25° 48’ 51”||-0.41||6.3”||Sagittarius|
|2023 Dec 03||18h 05m 39s||-25° 45’ 20”||-0.40||6.4”||Sagittarius|
|2023 Dec 04||18h 10m 30s||-25° 40’ 27”||-0.38||6.6”||Sagittarius|
|2023 Dec 05||18h 15m 02s||-25° 34’ 13”||-0.35||6.7”||Sagittarius|
|2023 Dec 06||18h 19m 17s||-25° 26’ 40”||-0.32||6.9”||Sagittarius|
|2023 Dec 07||18h 23m 09s||-25° 17’ 53”||-0.28||7.0”||Sagittarius|
|2023 Dec 08||18h 26m 36s||-25° 07’ 54”||-0.24||7.2”||Sagittarius|
|2023 Dec 09||18h 29m 36s||-24° 56’ 48”||-0.18||7.4”||Sagittarius|