You might be wondering why I have kept this type of title? What does it mean? How is it related to Mercury? You will get to know the answers in the post and I will be telling you about Mercury. So let's get started...
Mercury was named after the Roman God, Mercurius. Mercurius was the Messenger of Roman Gods and was also known for his speed. Mercury was first seen by a Greek Astronomer Timocharis in 200 BC. At that time it was believed that mercury was a star and it revolves around the Earth but, in 1537 a great mathematician and astronomer, Nicolaus Copernicus made the model of solar system and as per that model, sun was in center and the planets were revolving around it. Later, Galileo Gallie, an Italian astronomer saw the space using his telescope, and proved that the model of Copernicus was correct.
Mercury is the first and the innermost planet in the Solar System. It is the closest planet to the Sun, positioned at a distance of about 58 million kilometres. It is the fastest spinning planet, it takes 87.97 days for this little planet to complete it's orbit around the Sun and it takes 58.6 days to complete one rotation. Therefore, 1 Mercury year is equal to 88 Earth days. Mercury doesn't have any natural satellite.
As Mercury is the closest planet to the Sun, it should be the hottest planet but, it isn't. So what is the reason behind it? The reason behind it is that, Mercury almost doesn't no atmosphere but a thin layer of exosphere is present, that cannot hold heat and keep the planet warm, the temperature drops down to -183.2°C (297.7°F) during nights. But due to its close proximity to the Sun, the temperature rises to 430°C (806°F) during the daytime. Thus, half of the Murcury will be too much hot and the rest half will be very cold.
With the diameter of 4.879 km, Mercury is the smallest planet of our Solar System. Mercury is about one third of Earth! Mercury consists of 70%metallic and 30% silicate material. Unlike Earth, it has three layers, the core, the mantle and the crust but, it doesn't have tectonic plates. The iron core is the the densest of all these layers, that makes up around 85% of its radius while the core of earth only makes 55% of its radius. The core of Mercury has also a big contribution towards its weight, making it the most iron-rich planet in the Solar System. But with time this iron loaded core is cooling down, resulting in the wrinkling and shrinking of this planet. Now you might be thinking that, if the planet has shrunk? Yes, the planet was shrunk 4.4 miles(7.7 km).
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Unlike Earth, Mercury is also a terrestrial planet. What is Terrestrial Planet? So Terrestrial planet means that the planet has compact rocky surface and Mercury is a Terrestrial Planet. Mercury's surface closely resembles the surface of Moon as it is heavily cratered. Just wait, what's the meaning of crater? A crater is a depression in the surface of a planet, natural satellite, or other solid body in the Solar System or elsewhere, formed by the hypervelocity impact of a smaller body. Now the question arises, how these small bodies came into Mercury? The reason behind it, is also the absence of atmosphere. As the atmosphere is absent, it's easy for the body to enter the planet without melting so. One of these largest crater till know is the Caloris Basin of 1,550 km diameter. Researchers believe that this crater is caused by an object nearly 100 km wide, which is a way bigger than an asteroid.
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| Caloris Basin |
All these interesting facts about this tiny planet makes us curious to know about it. But due to its orbit near to the sun, it is difficult to observe through telescopes. So we have sent only sent two spacecraft to the surface of Mercury. The first spacecraft to visit Mercury was NASAs Mariner 10 (1974-75). Mariner 10 provided the first close up images of Mercury's surface, going closest to within 327 km of the surface. Many years later in 2004, a second NASA Mission to Mercury named MESSENGER (Mercury Surface, Space Environment, Geochemistry and Ranging) was launched in August 2004 as the first robotic NASA spacecraft orbiting the planet Mercury. By March 2012 it has collected close to 100,000 images ending it's one year primary mission and entered an extended mission scheduled to last until March 2013.
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| Mariner 10 |
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| MESSENGER |