Mercury
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.
Mercury is currently in the constellation of Pisces, at a distance of 97,935,525 kilometers from Earth.
View interactive star map
Today's rise, transit and set times of Mercury from Greenwich, United Kingdom (all times relative to the local timezone Europe/London):
- Mercury is above the horizon from Greenwich, United Kingdom .
- Right now it is placed in the South direction at an altitude of 43° above the horizon.
- Given its current magnitude, Mercury is visible to the naked eye, easy and bright under dark skies, might be more difficult from heavily 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.
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 distance of Mercury from Earth is currently 97,935,525 kilometers, equivalent to 0.654659 Astronomical Units. Light takes 5 minutes and 26.6777 seconds to travel from Mercury and arrive to us.
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 |
|---|---|---|
| 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 |
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 |
|---|---|---|---|---|---|
| 2024 Apr 20 | 01h 02m 12s | +06° 43’ 18” | 3.01 | 11.4” | Pisces |
| 2024 Apr 21 | 01h 01m 06s | +06° 18’ 43” | 2.68 | 11.3” | Pisces |
| 2024 Apr 22 | 01h 00m 16s | +05° 56’ 18” | 2.40 | 11.2” | Pisces |
| 2024 Apr 23 | 00h 59m 44s | +05° 36’ 12” | 2.15 | 11.0” | Pisces |
| 2024 Apr 24 | 00h 59m 30s | +05° 18’ 34” | 1.93 | 10.9” | Pisces |
| 2024 Apr 25 | 00h 59m 33s | +05° 03’ 29” | 1.74 | 10.7” | Pisces |
| 2024 Apr 26 | 00h 59m 53s | +04° 50’ 59” | 1.58 | 10.5” | Pisces |
| 2024 Apr 27 | 01h 00m 29s | +04° 41’ 05” | 1.43 | 10.4” | Pisces |
| 2024 Apr 28 | 01h 01m 23s | +04° 33’ 48” | 1.30 | 10.2” | Pisces |
| 2024 Apr 29 | 01h 02m 34s | +04° 29’ 06” | 1.19 | 10.0” | Pisces |
| 2024 Apr 30 | 01h 04m 00s | +04° 26’ 53” | 1.09 | 9.8” | Pisces |
| 2024 May 01 | 01h 05m 41s | +04° 27’ 10” | 1.00 | 9.6” | Pisces |
| 2024 May 02 | 01h 07m 37s | +04° 29’ 49” | 0.92 | 9.5” | Pisces |
| 2024 May 03 | 01h 09m 48s | +04° 34’ 49” | 0.85 | 9.3” | Pisces |