# How Far is Mercury from Earth? Facts About Mercury

In this article we are going to answer the question, how far is Mercury from Earth? Mercury is 48 million miles (77.3 million kilometers) away from Earth when they are at their closest. The maximum distance between the two when they are on opposite ends of their orbits is 137 million miles (222 million kilometers). The actual distance at any given moment varies all the time depending on where they are in their respective orbits.

## How far is Mercury from the Sun?

Mercury’s orbit is 36 million miles (57.9 million kilometers) away from the sun on average. It is the equivalent of 0.4 Astronomical Units (AU) where one AU is the distance between the Earth and the sun.

Since the orbit is elliptical and not circular, sometimes it is farther from the sun, and sometimes it is closer. When it is at its farthest, Mercury is 43 million miles (70 million kilometers) from the sun and when it is at its closest, it is 29 million miles (46 million kilometers) from the sun.

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Mercury takes 88 earth days to orbit around the sun. That’s approximately three months (90 days) to us. If you lived on the tiny planet, you would host your birthday party four times per normal (earth) year.

## How long does it take light to travel to Mercury?

Sunlight takes 3 minutes to reach Mercury. Light can travel from Earth to Mercury in 4.3 minutes when they are at their closest.

## What are the diameter and circumference of Mercury?

Mercury is the smallest planet in our solar system, now that Pluto’s planet status has been revoked, and is only slightly bigger than our own Moon.

Mercury: 3,032 miles (4,879 kilometers) diameter and 9,525 miles (15,329 kilometers) circumference.
Earth: 7,918 miles (12,742 kilometers) diameter and 24,901 miles (40,074 kilometers) circumference.

## How long would it take to travel to Mercury?

Using the fastest spacecraft ever launched, a mission to outer space named New Horizons, it would take 40 days. Nevertheless, the amount of time depends on the purpose of the flight. If it is just a flyby, it would take a short time because you would maximize speed. If you wanted to orbit the planet and save on fuel, you would take longer.

• The first mission, Mariner 10, took 147 days to reach Mercury.
• The second mission, MESSENGER, which was meant to orbit Mercury took three and a half years because it did two flybys of Venus, and one of Earth in order to use the gravitational pull of the two planets for a boost (less fuel needed then).

## What would you find when you get to Mercury?

Mercury has a dark gray surface because it is covered in carbon dust. It has a heavily cratered surface.
We can observe Mercury a couple of times every year from the earth with the naked eye. It takes the form of a small dot during sunset or sunrise – it is brighter than your ordinary star and sometimes it appears together with Venus (as a significantly bigger dot).

You can only see it when it is farthest from the sun because the rest of the time, the sun is too bright to let you see it. While it is true you can see Mercury with the naked eye, of a telescope is without question the best way to do it. Be sure to check out this article for everything you need to know before  buying your first telescope.

### The Atmosphere:

Mercury does not have a normal atmosphere (with air or clouds) which explains why it achieves freezing temperatures on the side hidden from the sun despite being so close to the sun (cannot trap heat).

In fact, what it has is technically an exosphere; a combination of atoms of potassium, sodium, hydrogen, oxygen, calcium, and helium that are blown onto the planet by solar winds. Some of the components of the exosphere are elements like helium from the surface spewed off from the radioactive decay of planetary elements.

There are no signs of life on Mercury because no known life form would stand a chance in those conditions.

### The Seasons:

Mercury spins relatively slowly on its axis given its small size. One rotation takes about 58.7 earth days. It turns so slowly that it completes three spins after it has done two full trips around the sun. Compare that to the 365 and a quarter spins Earth does by the time it finishes one full trip around the sun.

It does not experience seasons because the axis is tilted by only two degrees relative to the plane of its orbit (compared to Earth’s 23.5 degrees). Seasons are caused by a tilt in the axis.

The temperature fluctuations on Mercury’s surface are drastic; alternating between extremely hot when facing the sun, and freezing when facing away from the sun. The temperature varies between -290 degrees Fahrenheit (-180 Celsius) and 800 degrees Fahrenheit (430 Celsius).

Even though Mercury is the closest planet to the sun it is still not the hottest; that honor goes to Venus because it has an atmosphere that traps heat (unlike Mercury) and it is still pretty close to the sun.

### The Terrain:

The terrain is full of craters (large and small). Mercury has had an unfair share of bombardment by numerous bodies in its billions of years of existence because it has no atmosphere to protect its surface.
The most notable crater is called the Caloris Basin. It measures 960 miles (1545 kilometers) wide.

There are volcanic plains that were formed a long time ago. There are also cracks and ridges that were formed as the surface cooled after the planet was formed.

## How many moons does Mercury have?

Mercury, like Venus, has no moons or rings. This is most likely due to their close proximity to the Sun. Any moons that could form would have to be extremely close to the parent planet as the gravitational pull from the Sun would likely swallow them up. That said, if the moon formed too close to the planet it would likely be destroyed by tidal gravitational forces.

## Is there water on Mercury?

Mercury does not have water on its surface. It only has traces of ice at its poles snuggled in craters where it is sheltered from the sun. The ice is thought to have been deposited by comets flying near the planet.

## How much would you weigh on Mercury?

The Mass of mercury is about 5.5% that of earth. The core is made of molten iron which accounts for 55% of the planet’s volume. The crust is made up of silicates and other metals. Due to its low mass, the gravitational strength of the tiny planet is just 1% that of Earth. If you weighed 100 lbs. on earth, the scale would read 38 lbs. on Mercury.

## Man’s Missions to Mercury

Exploring the planet closest to the sun is a tall order. Therefore, we haven’t explored it extensively.
That being said, the first spacecraft we sent to the tiny planet was Mariner 10 (NASA) which took photos of the surface between 1974 and 1975.

We sent another mission called MESSENGER (NASA). It orbited the planet between 2011 and 2015 before it was deliberately crashed onto the planet. It captured most of the high-quality images of the tiny planet we enjoy today.