Planet Mercury – What to Expect in a Telescope Study of Planet Mercury?

If you are planning to observe the planet Mercury from your telescope, you might want to do some research beforehand and come up with certain facts that you did not of. As we have read in our science books that Mercury is the first planet in the solar system. But how do we designate it as the first planet?

Well, since it is the closest planet to the Sun, we call it the first planet of the Solar System.

Surprisingly, it is closest to the Sun, but it does not have the highest temperatures. It is the smallest planet of the most solar system – and the structure is somewhat similar to the Earth.

Discovery of Planet Mercury

Galileo Galilei first discovered Mercury in the early 17th Century. Although Mercury could be seen without the use of a telescope, Galileo saw it with the aid of a telescope. Galileo was not able to observe the phases of Mercury with his crude telescope, however, an astronomer Giovanni Zupi in 1639 was able to do so. He discovered and claimed that the planet Mercury had similar phases to Moon and Venus.

The Mourning and Evening Star

In the older times, Mercury was considered as two different objects as it appeared in the sky. One phase of it was known as the Mourning Star and the other one as the Evening Star. Little did the scientists know that it was the same planet showing different phases of its lifecycle.

Closest Planet to the Sun

Mercury being the closest planet to the Sun is at a distance of approximately 35.98 miles away from it. It takes only 3.2 minutes for the sunlight to travel from the Sun to Mercury.
Fastest Planet

Mercury is the fastest planet of our Solar system, orbiting the Sun at a speed of 29 miles per second – hence it was named Mercury after a certain God.
It completes a trip around Sun in 88 days (as Earth does in 365 days). Thus, a year at Mercury has 88 years only – making it the shortest year of the planetary calendar.

The surface of the Mercury

Mercury does not have its satellites or rings. On the basis of surface, it appears quite similar to our Moon – implying that it has not been very active for many years.

The surface of mercury exhibit many impacts from comets or meteoroids. These craters are mostly named after deceased artists. There are a few basins, such as the Caloris Basin, having magma similar to the Moon.

Mercury’s surface is a mix of folds and criss-cross plains with wrinkled ridges and rugged terrain.

According to a hypothesis, Mercury does not have a Moon because of its proximity to the Sun. The Sun’s gravity could pull any object towards itself – depriving Mercury of anything that comes around it.


Just as Earth has a layer of Atmosphere around it, Mercury being an exoplanet, has an exosphere. It is a thin layer made up of atoms detached from the surface by strong solar winds and meteoroids.

The exosphere is composed of oxygen, hydrogen, sodium, helium, and potassium.

Temperature Fluctuations on Mercury

The temperatures vary widely – reaching up to 430 degrees Celsius in the daytime to -180 degrees Celsius during the nights. Hence, it is unfavorable to support life on the planet.

The main reason for such a drastic transition in temperature is due to the fact that it has no atmosphere that could retain the heat. These changes are the sharpest in the entire Solar System.

Mercury’s Magnetic Field

Although the magnetic field strength on the surface of Mercury is only 1.1% as compared to the magnetic field of the Earth, it is somehow able to join up with the Sun’s magnetic field leading to severe and intense tornadoes.

Layers of Planet Mercury

Mercury has three main layers, namely: core, mantle, and crust. The crust has no tectonic plates (responsible for Earthquakes on Earth). Its iron core is vast – making 85% of its radius, whereas the other two layers account for the rest of 15%

The planet has around 70% metallic and 30% silicate material, which makes it the second-highest density planet of the whole solar system. The density also represents the fact that its colossal core is rich in iron.

Life Supportability of Mercury

The absence of the exosphere and the planet’s ability to retain temperature within a specific range makes it highly unfavorable to support life. Human life is not possible on any planet with such extreme temperatures – whether hot or cold.

Observing Mercury Through a Telescope

Mercury is one of the least studied and observed planets because of its close proximity to the Sun. However, we can easily see it through a reflective telescope when it is at its most significant distance from the Sun. In terms of Astronomy, we call it “greatest elongation.”

Attempting to locate Mercury during the daytime is mere foolishness. Due to its closeness to the Sun, it provides scarce chances to be found. Hence, it would be best to observe it during the night to prevent the risk of eye damage.

Certain star charts help you to spot planets more easily. So do not hesitate to use the help of any such magazine, books, visual guide, or application.

Mercury being an inferior planet, is closer to the Sun than it is to the Earth. Therefore, it shows phases just like the Moon, which are viewable through a Reflective telescope. However, Mercury is badly reputed to give a challenging time when locating it. However, hard work and patience pay off.

Once you locate it, you can easily see some of the details on the surface if you use larger aperture telescopes. However, resolving craters would be almost impossible provided that the size of Mercury is very small.

Wrapping Up

If you are actually fond of Astronomy and want a deep dive into the sky and planets, you would definitely take it as a challenge to locate Mercury in the sky. So grab your set up of reflective telescope and accessories and get started!