April 15, 2019



How to View Planet Mercury in the Sky




Do you want to see Mercury?

Mercury is difficult to observe from Earth because it is always near the Sun. It can therefore only be observed in the evening shortly after sunset or at dawn.


In the spring, Mercury is easier to observe in the evening sky, in the autumn in the morning sky. Of course, this is only possible if Mercury is currently on the ‘right’ side of the sun, so in the spring only after the sun goes down and in the autumn before the sun rises over the horizon.


On the other hand, it is difficult to find in the morning sky until early in the morning, and in the autumn it is barely to be discovered in the evening sky. This is due to the position of the ecliptic in these seasons.


View the Changing phases

If you want to observe the little Mercury, it is best to use binoculars, even better a small telescope. Then you can not only watch his waning or increasing sickle but even find him in the daytime sky. However, the view must be very clear – and the sun should be covered by clouds. Or you use the shadow of a building. Its frequent transits from the sun can also be observed well, but only with a telescope – and always with a special protective film for telescopes!

If you want to see Mercury in the daytime, you need to use a telescope applying an orange or light red filter to cut down the sky’s bright light to a significant proportion!

In addition, if you want to see the surface of Mercury, you need to magnify your telescope at least 200 times!

Mercury’s average distance from the Sun is 57,909,170 km, which is just 38% of Earth’s distance from the Sun.

At its closest from the Sun, the distance remains only 460,000,000 km and its farthest point, the distance between Mercury and the Sun goes to as high as 70,000,000 meaning its orbit is highly elliptical among all the planets of our solar system!

Due to its proximity with the Sun, Mercury is also known as the innermost planet in our solar system! If you could view the Sun from Mercury’s surface, then the Sun would appear three times larger than what we can see from Earth.

Do you know that Mercury completes its one orbit around the Sun in just 88 days?

When Mercury is the farthest from the Sun, it moves the slowest. Precisely at this time, it appears to have a retrograde movement when viewed from Earth. This occurs once every three and a half months.

Currently, during April and until the first half of May 2019, you can see Mercury in the morning sky. If you want to see Mercury in the evening sky, you will have to wait until June 3.

Celestial objects become visible with the increasing darkness after the Sunset and do you know that the sky catches up total darkness only when the Sun dips almost 18°from the horizon?

But, you can start spotting Mercury when the Sun goes at least 6° below the horizon!

Mercury is best visible when its angular separation from the Sun is at its maximum, which is also called maximum elongation!

Usually, it can be spotted 45 to 50 minutes before Sunrise from any high-rise building with unclogged views of horizons!

It is difficult to spot Mercury because the Earth and Mercury both orbit in almost the same plane; especially, if you are located above the 45-degree latitude, the visibility of Mercury becomes even more difficult.

This also means that viewing Mercury is relatively easier for those who stay closer to the equator than those who are located away from the equator!

In other words, the finest and sharpest visibility comes when Mercury reaches a maximum elongation of 27.2° from the Sun!

For the state of complete darkness, as discussed before, the Sun has to reach 18° below the horizon and then Mercury will still be 9° up and above the horizon and can be spotted with naked eyes.

Surprisingly, Mercury has no moons or rings; it is endowed with a weak magnetic field in comparison to many other planets in our solar system.

Another interesting aspect is that Mercury passes between Earth and the Sun 13 times in one century. This is also known as a transit of Mercury!

During that time it appears as a small black spot on the Sun’s disk; the last transit of Mercury occurred in May 2016, which was seen in many parts of the world.

Some More Facts about Mercury

Due to its closeness to the Sun, the surface temperature reaches as high as 450° Celsius. Mercury does not have much atmosphere needed to trap heat; a very small amount of hydrogen, helium, oxygen forms its atmosphere. Because of this, at night, the temperature falls to as low as 170° Celsius.

This temperature difference is one of the highest among all planets of our solar system!

Despite Mercury’s proximity to the Sun, it is not the hottest planet in our solar system; that credit goes to Venus, the closest neighbor of Earth. Thanks to the greenhouse effects on Venus!

You might be surprised to know that Mercury is the densest planet in our solar system after Earth!

As such, three distinct layers such as a crust, mantle, and core form its interiors.

While the crust is 100-300 kilometers in thickness, its mantle is said to be 600 kilometers thick. Its core presents an interesting study for having a much higher density than many other planets and moons in the solar system.

Two months in the evening, two months in the morning in the sky

The innermost planet is moving fast: Mercury races around the sun in only 88 days – four times in each year of the earth. As we also turn around the sun during this time, Mercury overtakes us three times a year. Three times he wanders exactly between us and the sun through its lower conjunction – from the evening to the morning sky. Mercury revolves around the sun at a small distance and therefore always stands near it in our sky – at most a constellation to the west or east of it.


Its orbit is so elliptical that its distance from the sun varies widely. For westerly or easterly elongation, its angular distance may reach 28 degrees, when at the same time it reaches the aphelion of its orbit, the most remote point. This happens exactly twice a year: in the spring west of the sun, in the autumn east of it. Mercury could, therefore, be found in the first case in the morning sky, in the second case in the evening sky.


Mercury is the innermost planet orbiting the Sun at an average distance of 58 million km. It takes only 88 days to complete one round.


But just at these times, the ecliptic, the planetary plane, runs very flat across our sky. Although Mercury is 28 degrees from the Sun in the sky, but only slightly above the horizon in the diffused dim light, it would be better to see it at the same time as the ecliptic is very steep – during dusk in spring and in the morning in autumn. But then, for the greatest elongation, Mercury only reaches an angular distance of 18 degrees to the sun, because it is in the perihelion, the nearest point in the sun’s orbit.

According to the astrophysicists, its core is not only liquid but slightly larger than the core of our moon. Its diameter is estimated at 4,879 kilometers, almost 40 percent of Earth’s diameter.

Mercury revolves around the Sun at the velocity of almost 180,000 km per hour which is the fastest among all planets in our solar system.

Mercury rotates on its axis very slowly; for this reason, its day is significantly longer equal to 58.6 Earth days!

For the gravitational pull of Mercury is only 38% of that exerted by the Earth; our top jumpers can conveniently make jumps as high as 20 ft there assuming they jump 8ft high on the Earth.

The fact is that the lower gravitational pull makes Mercury incapable of holding the atmosphere!

No atmosphere in Mercury means meteors enter and fall on its surface unabated – without being burned at all!

That is why while viewing with powerful telescopes you can see battered surfaces and soaring cliffs instead of plains.

Mercury in Mythology

Our ancestors knew about mercury and that is why it has found a place in mythology too. In Greek, Mercury was known as the messenger of the gods – Hermes and Apollo.

In Roman mythology, Mercury was also known as the god of the merchants invoking the same attributes as found in the Greek god Hermes.

In Rome, during 400-500 BC, people would worship Mercury with great awe.

To the Sumerians dating back to almost 3,000 BC, Mercury was known as Gud – the God who brings not only rains but also supports agriculture.

In Hindu mythology, Mercury is called Budh associated with trade and business. The word ‘buddhi’ – the intellect is derived from Budh, which is also central to all worldly affairs. In Hindu and Jain mythology, Budh is worshipped from ancient times.

No need to say that Mercury is deeply associated and mentioned across most ancient cultures!