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How far away is Mercury from the Sun? The average distance from Mercury to the Sun is 58 million km, or 36 million miles.

This number is an average, which astronomers call the semi-major axis. But Mercury actually follows an elliptical orbit around the Sun. Sometimes it's closer than 58 million km, and sometimes it's further. At its closest point, which astronomers call perihelion, Mercury gets within 46 million km. And then it orbits out to its most distant point from the Sun, called aphelion, where it's 70 million km from the Sun.

Another way to describe distances in the Solar System is using astronomical units. 1 astronomical unit, or AU, is the average distance from the Earth to the Sun, or approximately 150 million km. So Mercury's average orbit from the Sun is 0.387 AU. Its perihelion is 0.308 AU, and its aphelion is 0.467 AU.

We have written many articles about Mercury for Universe Today. Here's an article about the orbit of Mercury, and here's an article about new mysteries unveiled on Mercury.

If you'd like more info on Mercury, check out NASA's World Book on Mercury. And you should also visit the NASA/JPL Solar System Exploration Guide.

We have also recorded an entire episode of Astronomy Cast all about Mercury. Listen here, Episode 49: Mercury.

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Mercury is the planet that orbits closest to the Sun, at an average distance of only 58 million km. It actually follows an elliptical path around the Sun, getting closer and more distant from the Sun. At its closest point, Mercury is only 46 million km from the Sun, and it gets out to 70 million km from the Sun.

A day on Mercury lasts 59 Earth days. This is only a little shorter than Mercury's year, which lasts 88 days.

Although it's the closest planet to the Sun, Mercury isn't the hottest planet in the Solar System. That's because it doesn't have an atmosphere to absorb the Sun's radiation. The side facing the Sun rises to a temperature of 450°C, and then the side facing away from the Sun dips down to -170°C. The hottest planet in the Solar System is actually Venus with its thick atmosphere of carbon dioxide.

When seen from orbit, Mercury looks very similar to the Earth's moon. It has a surface covered in ancient lava flows and impact craters. The interior of Mercury is much denser than the Moon, though. Fully 40% of Mercury's interior is a metal core, surrounded by a rocky mantle and thin crust.

Seen in a telescope, Mercury appears to go through phases, just like the Earth's moon. This is because Mercury orbits closer to the Sun than the Earth, and so we can see parts of the planet in shadow. You can also see Mercury with your own eyes or through a small telescope. You can find the planet close to the Sun. Look to the west after sunset, or to the east before sunrise and you might be able to see it.

NASA is the only space agency to actually send spacecraft to Mercury, to study the planet up close. Their first mission was Mariner 10, which arrived at the planet in 1974 and completed 3 flybys of the planet, eventually imaging half of the planet. Then no spacecraft visited Mercury until NASA's MESSENGER spacecraft arrived at the planet in 2008. It has completed 3 flybys and will eventually go into orbit around Mercury in 2011.

Unlike most planets in the Solar System, Mercury doesn't have any moons and it doesn't have any rings.

We have written many articles about Mercury for Universe Today. Here's an article with interesting facts about Mercury, and here's an article about missions to Mercury.

If you want more Mercury info, I highly recommend you check out the MESSENGER mission website. This is where they release all their latest discoveries about Mercury.

We've also recorded an episode of Astronomy Cast all about Mercury. Listen here, Episode 49: Mercury.

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Here are some amazing Mercury pics.

Here's a global mosaic of Mercury, showing the planet in great detail. This isn't one picture, but it's actually a huge collection of images taken by NASA's MESSENGER spacecraft. They were stitched together by Jason Perry, who works on the Cassini imaging team.

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This is an image of Mercury taken by NASA's Mariner 10 spacecraft. Mariner 10 was the first spacecraft to ever reach Mercury, making the first of 3 flybys in 1974.

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Here's another high resolution pic of Mercury captured by NASA's MESSENGER spacecraft. It shows how much the planet looks like the Earth's moon, with its crater-strewn landscape.

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This is an image of the Caloris Basin, the largest crater on Mercury. It measures 1300 km across, and has two concentric rings from two different impacts.

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This is an artist's impression of the upcoming BepiColumbo mission to Mercury. If everything goes well, this spacecraft will launch to Mercury in 2014.

If you'd like more images of the Solar System, here are some pictures of Mars, and here are some pictures of Venus.

And the best place to get the latest Mercury pics is from the mission page from NASA's MESSENGER spacecraft.

We have also recorded an entire episode of Astronomy Cast all about Mercury. Listen here, Episode 49: Mercury.

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Most of the planets in the Solar System, but Mercury has no moons.

But for a little while astronomers did think it had a moon. Back in 1974, when NASA's Mariner 10 spacecraft was just about to make its flyby of the planet, astronomers detected a spike of ultraviolet radiation from the planet. They thought this spike of ultraviolet radiation might have come from radiation reflected off of Mercury's moons. But when Mariner 10 arrived at Mercury, it found no moons, and astronomers realized that the flood of ultraviolet must have come from a more distant star that happened to be lined up at the time.

Mercury's surface is heavily cratered, just like the Earth's moon. It's possible that it might have had moons billions of years ago, just like some planets have captured asteroids as moons. But any moons would have crashed to the surface long ago, joining the countless impact craters on the surface of Mercury.

We've written many articles about the moons for other planets in the Solar System. Here's an article about which planet in the Solar System has the most moons, and here's an article about asteroids with moons.

Want more information about Mercury's lack of moons? Here's NASA's short, sweet page on this, and here's a table of moons in the Solar System.

We've also recorded an entire episode of Astronomy Cast just about Mercury. Listen here, Episode 49: Mercury.

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The distance from the Sun to Mercury is approximately 58 million km, or 36 million miles. The exact number is 57,909,100 km.

But keep in mind that this number is an average. Sometimes Mercury is closer to the Sun than 58 million km, and other times it's more distant, depending on its point in orbit. At its closest point to the Sun, which astronomers call perihelion, Mercury is only 46 million km from the Sun. And then at its most distant point, called aphelion, Mercury gets out to 70 million km from the Sun.

Astronomers use another term called "astronomical units" to measure distance in the Solar System. 1 astronomical unit, or AU, is the average distance from the Earth to the Sun – that's about 150 million km. So we can also measure the distance from Mercury to the Sun in astronomical units. Mercury's average orbital distance is 0.387 AU. Its closest distance is 0.307 AU; and it's furthest distance is .467 AU.

We have written many articles about Mercury for Universe Today. Here's an article about new mysteries unveiled on Mercury, and here's an article about the surface of Mercury.

NASA has some great resources for Mercury. One place to go is the MESSENGER mission page. This is where you can get the latest images of Mercury. You should also check out NASA's World Book on Mercury.

We have also recorded an episode of Astronomy Cast all about Mercury. Listen here, Episode 49: Mercury.

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Mercury is the closest planet to the Sun, and so Mercury's distance from the Sun averages 58 million km (36 million miles). It completes one orbit around the Sun every 88 days. Just to compare, Earth has an average distance of 150 million km from the Sun.

But this number is actually an average. Mercury travels in an elliptical orbit around the Sun. Mercury's closest point in its orbit is called the perihelion, when Mercury is only 46 million km (28.5 million miles) from the Sun. At its most distant point in its orbit, called the aphelion, Mercury gets to a distance of 70 million km from the Sun. Mercury has an orbital eccentricity of 0.205, the greatest of all the planets in the Solar System.

Mercury gets as close as 77.3 million km (48 million miles) to Earth during its orbit around the Sun.

We have written many articles about Mercury for Universe Today. Here are some interesting facts about Mercury, and here's how far the rest of the planets are from the Sun.

If you'd like more info on Mercury, check out NASA's World Book on NASA. And I'd also recommend you look at NASA's Solar System Exploration Guide to Mercury.

We've also recorded an entire episode of Astronomy Cast just about planet Mercury. Listen here, Episode 49: Mercury.

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Mercury is the closest planet to orbit the Sun in the Solar System. Orbiting the Sun at a distance of only 58 million kilometers, Mercury completes an orbit once every 88 days. Mercury is also the smallest planet in the Solar System, with a diameter of only 4,879 kilometers.

Mercury actually has one of the most elliptical orbits around the Sun. At its closest point, Mercury gets within 46 million km from the Sun, and then it swings out to 70 million km at its furthest point. And Mercury gets as close as 77 million km from Earth.

A day on Mercury lasts 59 days. That's how long Mercury takes to complete one rotation on its axis. The problem is that Mercury only takes 88 days to go around the Sun. If you were able to stand on the surface of Mercury, you would see the Sun rise and then spend a total of 176 Earth days in the sky before setting again.

The surface of Mercury is either incredibly hot or incredibly cold. That's because Mercury lacks any kind of atmosphere, and so it radiates heat back into space. The side of Mercury in sunlight rises to an average temperature of 450° C, while the side in shadow dips down to -170° C. Venus, with its thick carbon dioxide atmosphere, is the hottest planet in the Solar System.

If you could stand on the surface of Mercury, you would experience about 1/3rd the gravity you feel on Earth. This is surprisingly high for such a small planet, and comes from the fact that the interior of Mercury is very dense. 60% of the volume of Mercury is made up of its metallic core. This core is surrounded by a rocky mantle and then a thin solid crust.

Want to see Mercury with your own eyes? No problem, it's easy to see if you know where to look. Mercury is usually lost in the glare of the Sun, but at the times when it's at its greatest visual distance from the Sun, you can see it. Just look to the west after sunset, or look to the east before sunrise, and you might be able to see it as a bright star near the horizon. If you can see Mercury through a telescope, you'll see a world that goes through phases, just like the Moon.

Unfortunately, Mercury doesn't have any moons, nor does it have any rings.

We have written many articles about Mercury for Universe Today. Here's an article about new mysteries unveiled on Mercury, and here's an article about how Mercury is soft in the middle.

Want more information about Mercury? Check out this resource from Windows on the Universe. I also recommend you check out NASA's MESSENGER mission website. This is where they release all the latest photos taken of Mercury.

We've also recorded an episode of Astronomy Cast all about Mercury. Listen here, Episode 49: Mercury.

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The planet Mercury is the closest planet to orbit the Sun, with an average distance from the Sun of only 58 million km. It orbits so close to the Sun that it only takes 88 days to go around the Sun. Mercury is also the smallest planet, with a diameter of only 4,879 km. Saturn's moon Titan and Jupiter's moon Ganymede are larger than Mercury.

Because it's so close to the Sun, you might think that Mercury is the hottest planet in the Solar System, but it's not. That honor goes to Venus, because of its thick atmosphere of carbon dioxide. On Mercury the daytime temperatures can reach 450° C, but then they dip down to -170° C in the shadows.

A day on Mercury lasts 59 Earth days; this is a rotation speed slower than any other planet in the Solar System except for Venus. But since a year on Mercury lasts 88 days it creates a very strange situation on Mercury. The Sun rises on Mercury, moves through the sky for 176 days before setting.

Mercury is also the second densest planet in the Solar System (after the Earth). This is because the metal core of Mercury accounts for 60% of the planet. This is surrounded by a rocky mantle and then the hardened crust. This high density means that Mercury's gravity is higher than you might expect. If you could stand on the surface of Mercury, you would experience about 1/3rd the gravity you feel on Earth.

The first spacecraft to ever visit Mercury was NASA's Mariner 10 mission. It arrived at the planet in March, 1974 and made a total of 3 flybys over the course of a year. During its three flybys, Mariner 10 was able to image only half the planet. It wasn't until 2008, when NASA's MESSENGER spacecraft made more three flybys of the planet and completed our high resolution view of Mercury.

You might be surprised to know that you can see Mercury with your unaided eyes; you just need to know where to look. For most of the time, Mercury is lost in the glare of the Sun. But sometimes Mercury is visible just after sunset in the west, or just before sunrise in the east. You need a really clear view to the horizon to be able to see it, though.

Mercury doesn't have any moons, and it doesn't have any rings either.

We have written many articles about Mercury for Universe Today. Here's an article about planet Mercury for kids, and here's how to find Mercury in a telescope.

If you'd like more information on the planet Mercury, there are several great resources from NASA. I highly recommend NASA's World Book on Mercury. And you should also check out the mission website for NASA's MESSENGER spacecraft.

We have also recorded an entire episode of Astronomy Cast that's all about Mercury. Check it out, Episode 49: Mercury.

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Here are some cool Mercury photos:

This amazing Mercury image is actually a mosaic of Mercury photos taken by NASA's MESSENGER spacecraft. Jason Perry put together 65 images of Mercury captured during Mercury's most recent flyby into this high resolution image.

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This is an image of the Caloris Basin on Mercury, the site of the largest impact crater on the planet, measuring 1,300 km across. The impact was so large that astronomers think seismic waves traveled through the planet and caused volcanic eruptions on the opposite side of the planet.

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When NASA's Mariner 10 spacecraft first visited Mercury in 1974, it was only able to image about half of the planet during its 3 flybys. The hidden side of Mercury wasn't seen until NASA's MESSENGER spacecraft returned to Mercury in 2008. We now have hig resolution images of the entire planet.

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Although Mercury is small, it's actually the second densest planet in the Solar System (after Earth). This is because 60% of the planet is made up of its metallic core. This core is surrounded by a rocky mantle and a thin crust.

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This is an artist's impression of the BepiColumbo mission. If all goes well, this European spacecraft will launch for Mercury in 2014.

We have written many articles about Mercury for Universe Today. Here's an article about some features of Mercury. And here's an article about the location of Mercury.

If you'd like more information about Mercury, check out NASA's World Book on Mercury. And if you'd like more Mercury photos, I recommend you take a look at the MESSENGER mission website. That's where all the new images taken by the spacecraft are released.

We have also recorded an entire episode of Astronomy Cast that's just about Mercury. Listen here, Episode 49: Mercury.

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Here are some cool Mercury images.

This is actually a mosaic of Mercury, made up of 65 images taken by NASA's MESSENGER spacecraft during its recently flyby in 2009. It was compiled together by Jason Perry, who actually works on the imaging team for NASA's Cassini spacecraft.

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This was one of the first Mercury images ever gathered from close up. It's also a mosaic of images, captured by NASA's Mariner 10 spacecraft which made the first planetary flyby of Mercury in 1974.

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This is the Caloris Basin, the largest impact crater on Mercury . It measures 1,300 km across. The impact that created this crater was so large that astronomer think seismic waves traveled through the planet and deformed the surface on the opposite side of the planet.

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This is an image of the interior of Mercury which shows its large metal core. This core accounts for 60% of Mercury's mass, and explains why the planet has a very high density, compared to the other terrestrial planets.

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This Mercury image shows a bright spot on the surface of the planet. Because Mercury has no atmosphere, meteorites are able to strike the surface without being slowed down. Over the billions of years since Mercury's formation, these impact craters have gone on to cover the surface of the planet.

We have written many articles about Mercury for Universe Today. Here's an article about the geology of Mercury, and here's an article about the composition of Mercury.

If you'd like more information on Mercury, check out NASA's World Book on Mercury. And if you want to get many more Mercury images, visit the homepage for NASA's MESSENGER spacecraft.

We have also recorded an episode of Astronomy Cast all about Mercury. Listen here, Episode 49: Mercury.

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Here's some Mercury information. Mercury is the planet in the Solar System that orbits closest to the Sun, at a distance of only 58 million km. Just for comparison, Earth orbits at an average distance of 150 million km from the Sun. Mercury completes one full orbit around the Sun every 88 days, giving it the shortest year in the Solar System. And Mercury is also the smallest planet, with a diameter of only 4,879 km; that's even smaller than Saturn's moon Titan and Jupiter's moon Ganymede.

Mercury rotates very slowly on its axis, completing a single day every 59 Earth days. But this is just how long it takes for Mercury to turn once on its axis. Because a day on Mercury is almost as long as a year on Mercury, it would make the length of day very long. If you could stand on the surface of Mercury, you would see the Sun rise and not set for another 176 Earth days.

The surface of Mercury is very much like the surface of the Moon. There are fields of lava from ancient volcanic eruptions, as well as impact craters littering the surface of Mercury. The largest impact crater on Mercury is the Caloris Basin, measuring 1,300 kilometers across.

Mercury has a negligible atmosphere, made up of particles captured from the solar wind. Without this atmosphere, it's unable to trap the intense heat from the Sun. The side of Mercury that faces the Sun gets as hot as 450° C, while the side away from the Sun dips down to -170° C.

The first spacecraft to ever make the voyage to Mercury was NASA's Mariner 10 mission, which made its first flyby in 1974. It made two more flybys over the course of the next year, eventually mapping out about half of the planet's surface. One of NASA's newest spacecraft, MESSENGER, recently returned to Mercury with its own flybys. But this time MESSENGER is going to be going into orbit around Mercury to help scientists learn much more about the smallest planet.

You might be surprised to know that you can see Mercury with your unaided eyes; you just need to know where to look. Most of the time, Mercury is lost in the glare of the Sun. But there are times in its orbit when Mercury is visible when the Sun is down. Look to the east for a bright star near the horizon before sunrise, or to the west after sunset and you might be looking at Mercury. If you have a small telescope, you'll be able to know better because Mercury appears to go through phases, like the Earth's moon.

Mercury doesn't have any moons, and it doesn't have any rings.

We've written many articles about Mercury for Universe Today. Here's an article about what's inside Mercury, and here's an article about how many moons Mercury has (hint: none).

If you'd like more Mercury information, check out NASA's World Book on Mercury and the NASA/JPL Solar System Exploration Guide to Mercury.

We have also recorded an entire episode of Astronomy Cast just about Mercury. Listen here, Episode 49: Mercury.

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When you look at an image of Mercury, it looks like a dry, airless world. But you might be surprised to know that Mercury does have an atmosphere. Not the kind of atmosphere that we have here on Earth, or even the thin atmosphere that surrounds Mars. But Mercury's atmosphere is currently being studied by scientists, and the newly arrived MESSENGER spacecraft.

Mercury's original atmosphere dissipated shortly after the planet formed 4.6 billion years ago with the rest of the Solar System. This was because of Mercury's lower gravity, and because it's so close to the Sun and receives the constant buffeting from its solar wind. Its current atmosphere is almost negligible.

But Mercury does have a tenuous atmosphere made up of hydrogen, helium, oxygen, sodium, calcium, potassium and water vapor. Astronomers think this current atmosphere is constantly being replenished by a variety of sources: particles of the Sun's solar wind, volcanic outgassing, radioactive decay of elements on Mercury's surface and the dust and debris kicked up by micrometeorites constantly buffeting its surface. Without these sources of replenishment, Mercury's atmosphere would be carried away by the the solar wind relatively quickly.

In 2008, NASA's MESSENGER spacecraft discovered water vapor in Mercury's atmosphere. It's thought that this water is created when hydrogen and oxygen atoms meet in the atmosphere.

We have written many articles about Mercury's atmosphere for Universe Today. Here's an article about how magnetic tornadoes might regenerate Mercury's atmosphere, and here's an article about the climate of Mercury.

If you'd like more information on Mercury, check out NASA's World Book on Mercury, with an entry on the planet's atmosphere. You can also learn more at NASA's Solar System Exploration Guide.

We have also recorded an entire episode of Astronomy Cast all about atmospheres. Listen here, Episode 151: Atmospheres.

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This is the symbol that astronomers use for the planet Mercury. It's also the same symbol that medieval alchemists used for the substance Mercury. The symbol is similar to the sign for female, with the circle above a cross. But then it has the horns above the circle. It's thought to represent the winged hat worn by the Greek god Hermes, the messenger of the gods.

We have written many articles about Mercury for Universe Today. If you'd like, there are symbols for all the planets in the Solar System. And here's an article about how to build a model of the Solar System.

Here's more information on the symbol for Mercury from the MESSENGER website.

We've also recorded an entire episode of Astronomy Cast just about Mercury. Listen here, Episode 49: Mercury.

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Here are some cool Mercury pictures.

This is an amazing mosaic of Mercury that was put together by Jason Perry. He compiled together 66 images taken by the MDIS camera on NASA's MESSENGER spacecraft during a recent flyby.

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This is a high resolution image of Mercury's northern horizon taken by NASA's MESSENGER spacecraft. The surface of Mercury is ancient, virtually unchanged for billions of years, except for the occasional asteroid impact and volcanic eruption.

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This is an amazing double-ringed crater on the surface of Mercury. It was photographed by NASA's MESSENGER spacecraft during its 3rd flyby of the planet. The crater measures 290 km across.

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When NASA's Mariner 10 spacecraft first visited Mercury in 1974, it was only able to image approximately half of the surface of Mercury during 3 flybys. The other half of Mercury had never been seen in high resolution until the MESSENGER spacecraft made its own series of flybys starting in 2008. This image shows that previously hidden side of Mercury in incredible detail.

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This was one of the first Mercury pictures ever taken. It was photographed by NASA's Mariner 10 spacecraft.

We have written many articles about Mercury for Universe Today. Here's an article about how Mercury actually isn't the hottest planet, and here's an article about Mercury's magnetic field.

If you'd like more info on Mercury, as well as some amazing Mercury pictures, check out the MESSENGER mission website.

We have also recorded an entire episode of Astronomy Cast dedicated to Mercury. Listen here, Episode 49: Mercury.

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Mercury is the closest planet to orbit the Sun in the Solar System; orbiting at a distance of only 58 million km (just for comparison, Earth orbits at 150 million km). It has a diameter of 4,879 km, making it the smallest planet in the Solar System. In fact, Mercury is actually smaller than some of the largest moons in the Solar System.

Mercury orbits the Sun in a highly elliptical orbit, varying its distance to the Sun depending on where it is orbit. At its closest point, called perihelion, Mercury gets within 46 million km, and then it gets to 70 million km at aphelion. At its closest point, Mercury gets within 77 million km from Earth. Mercury takes only 88 days to complete an orbit around the Sun.

Even though you can see Mercury without a telescope, it's hard to find it because it's lost within the glare of the Sun most of the time. When Mercury is visible, you'll be able to see it to the west just after sunset, or to the east just before sunrise. When you do see Mercury through a telescope, it appears to go through phases like the Moon, depending on its point in orbit.

Astronomers used to think that Mercury was tidally locked to the Sun, always presenting the same face to the Sun. But radio astronomers in 1965 were able to bounce radar signals off the surface of Mercury and determine that a day on Mercury lasts 59 Earth days.

In photographs captured by spacecraft, Mercury looks very similar to the Moon. It has a surface of ancient lava flows and numerous impact craters. But beneath the surface, Mercury the planet is much more dense than the Moon. It has a large core of metal surrounded by a rocky mantle and a thin crust. The largest crater on Mercury is the Caloris Basin, which measures 1,300 km across.

Mercury is arid and dry. It has essentially no atmosphere to trap the heat from the Sun. So the side that faces the Sun reaches a temperature of 450° C, while the side in shadow dips down to -170° C. Venus is actually much hotter than Mercury because of its thick carbon dioxide atmosphere.

The first spacecraft to reach Mercury was NASA's Mariner 10 mission. It made its first flyby on March 29, 1974, and then two more flybys over the next year. During its mission, Mariner 10 was able to photograph approximately half the surface of Mercury. The next spacecraft to visit Mercury was NASA's MESSENGER spacecraft, which arrived at Mercury in 2008 and went into orbit in 2011.

Mercury doesn't have rings or any moons.

We have written many articles about Mercury for Universe Today. Here's an article about magnetic tornados on Mercury might regenerate its atmosphere, and here's an article about missions to Mercury.

If you'd like more info on Mercury, check out the mission page for the MESSENGER spacecraft. There's also NASA's World Book on Mercury.

We've also recorded an episode of Astronomy Cast all about Mercury. Listen here, Episode 49: Mercury.

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