How far away is Mercury now?
Last Updated: Today
Where does this distance data come from?
I source Mercury‘s distance from Earth via the Horizon JPL API. It is a free service provided by NASA’s Jet Propulsion Laboratory (JPL) that offers access to ephemeris (positional) data and related information for celestial bodies, such as planets, asteroids, and comets. The system can be accessed through various interfaces, including a web interface, a telnet interface, and an email interface.
This API contains the precise distance between Mercury and Earth from each day of the next few hundred years.
So I simply created a system to check for today’s date, then go retrieve the accurate distance value directly from NASA’s database. The up-to-date value is then displayed on this page.
How do scientists calculate the real-time distance between Mercury and earth?
Scientists calculate the live distance between Mercury and Earth using a combination of mathematics, astronomical data, and the principles of celestial mechanics.
The positions of Earth and Mercury in their respective orbits are constantly changing due to their elliptical orbits and different orbital periods around the Sun.
Mercury's orbital parameters
Orbital parameters describe the way objects move around in space, such as planets, moons, and satellites. These parameters include the size, shape, and tilt of the orbit, as well as the object’s position and speed within the orbit.
They help scientists understand and predict the paths of celestial bodies, which is crucial for planning space missions, observing astronomical phenomena, and monitoring satellites.
| Property | Definition | Mercury | Earth | Ratio (Mercury/Earth) |
|---|---|---|---|---|
| Semimajor axis (106 km) | The longest radius of an elliptical orbit | 57.909 | 149.598 | 0.387 |
| Sidereal orbit period (days) | The time it takes for the planet to complete one full orbit around the Sun, as observed from the stars | 87.969 | 365.256 | 0.241 |
| Tropical orbit period (days) | The time it takes for the planet to go from one vernal equinox to the next | 87.968 | 365.242 | 0.241 |
| Perihelion (106 km) | The closest distance from the planet to the Sun during its orbit | 46.000 | 147.095 | 0.313 |
| Aphelion (106 km) | The farthest distance from the planet to the Sun during its orbit | 69.818 | 152.100 | 0.459 |
| Synodic period (days) | The time it takes for a planet to return to the same point in its orbit as observed from Earth | 115.88 | – | – |
| Mean orbital velocity (km/s) | The average speed of the planet along its orbit | 47.36 | 29.78 | 1.590 |
| Max. orbital velocity (km/s) | The maximum speed of the planet along its orbit | 58.97 | 30.29 | 1.947 |
| Min. orbital velocity (km/s) | The minimum speed of the planet along its orbit | 38.86 | 29.29 | 1.327 |
| Orbit inclination (deg) | The tilt of the planet’s orbit relative to the ecliptic plane | 7.004 | 0.000 | – |
| Orbit eccentricity | The measure of how much the planet’s orbit deviates from a perfect circle | 0.2056 | 0.0167 | 12.311 |
| Sidereal rotation period (hrs) | The time it takes for the planet to complete one full rotation on its axis, as observed from the stars | 1407.6 | 23.9345 | 58.785 |
| Length of day (hrs) | The time it takes for the planet to rotate once on its axis relative to the sun (sunrise to sunrise) | 4222.6 | 24.0000 | 175.942 |
| Obliquity to orbit (deg) | The angle between the planet’s rotational axis and its orbital axis | 0.034 | 23.44 | 0.001 |
| Inclination of equator (deg) | The angle between the planet’s equator and the plane of its orbit | 0.034 | 23.44 | 0.001 |
Mercury's greatest elongations (list for the next 5 years)
Greatest elongation is the term used in astronomy to describe the maximum angular separation of a planet from the Sun as viewed from Earth. In simpler terms, it refers to the point at which a planet appears farthest from the Sun as seen from our perspective on Earth.
As an inferior planet (meaning it orbits closer to the Sun than Earth), Mercury goes through phases similar to the Moon, as well as various positions relative to Earth and the Sun. These positions include inferior and superior conjunctions, and greatest elongations.
| Date | Type of Elongation | Visual Magnitude | |||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Jan 30, 2023 | Greatest Elongation (West Morning) | 0°59′ | |||||||||||||||||||||||||||||||||
| May 29, 2023 | Greatest Elongation (West Morning) | -3°31′ | |||||||||||||||||||||||||||||||||
| Sep 22, 2023 | Greatest Elongation (West Morning) | 0°50′ | |||||||||||||||||||||||||||||||||
| Jan 12, 2024 | Greatest Elongation (West Morning) | 1°35′ | |||||||||||||||||||||||||||||||||
| May 9, 2024 | Greatest Elongation (West Morning) | -3°08′ | |||||||||||||||||||||||||||||||||
| Sep 5, 2024 | Greatest Elongation (West Morning) | 0°02′ | |||||||||||||||||||||||||||||||||
| Dec 25, 2024 | Greatest Elongation (West Morning) | 2°03′ | |||||||||||||||||||||||||||||||||
| Date | Type of Elongation | Visual Magnitude |
|---|---|---|
| Apr 11, 2023 | Greatest Elongation (East Evening) | 2°43′ |
| Aug 10, 2023 | Greatest Elongation (East Evening) | -1°40′ |
| Mar 24, 2024 | Greatest Elongation (East Evening) | 2°25′ |
| Jul 22, 2024 | Greatest Elongation (East Evening) | -0°55′ |
| Nov 16, 2024 | Greatest Elongation (East Evening) | -2°38′ |
| Feb 19, 2026 | Greatest Elongation (East Evening) | 1°10′ |
| Jun 15, 2026 | Greatest Elongation (East Evening) | 1°00′ |
| Oct 12, 2026 | Greatest Elongation (East Evening) | -2°54′ |
| Feb 3, 2027 | Greatest Elongation (East Evening) | 0°23′ |
| May 28, 2027 | Greatest Elongation (East Evening) | 1°55′ |
| Sep 24, 2027 | Greatest Elongation (East Evening) | TBD |
Just for fun, how long would it take to reach Mercury via different transportation means
The average distance between Earth and Mercury is 48 million miles (77 million km), so based on that distance, I have calculated the time it would take to reach the closest planet to the Sun at the speed of different means of transportation.
- On foot (3 mph): Approximately 1,827.85 years
- Bicycle (15 mph): Approximately 365.97 years
- Horse (galloping at 25 mph): Approximately 219.18 years
- Motorbike (average speed of 70 mph): Approximately 78.25 years
- Boat (cruising speed of 20 knots): Approximately 238.08 years
- Car (60 mph): Approximately 91.32 years
- High-speed train (200 mph): Approximately 27.4 years
- Commercial airplane (575 mph): Approximately 9.52 years
- Concorde supersonic jet (1,350 mph): Approximately 4.06 years
- SpaceX Starship (projected average speed of 16,777 mph): Approximately 0.33 years
Bonus Fact: On average it takes about 3.2 minutes for light from Mercury to reach Earth.
How far away are the other planets of the solar system?
I have developed a webpage that monitors the real-time distances between Earth and each planet of the solar system (work in progress):
- Real-time distance between the Moon and Earth
- Real-time distance between Mars and Earth
- Real-time distance between Venus and Earth
- Real-time distance between Jupiter and Earth
- Real-time distance between Saturn and Earth
- Real-time distance between Uranus and Earth
- Real-time distance between Neptune and Earth
- How Far Away Is Earth From The Sun?
I’ve been fascinated by space and astronomy from a very young age. When I’m not watching space-themed documentaries, movies or TV series, I spend most of my free time in my backyard admiring the planets and galaxies with my telescope.