Have you ever wondered what Mercury is made of, what is different about it, and when it has been observed? Well, now you’ll know because I will be talking all about Mercury.
There have been two spacecrafts that visited Mercury in between 1974 and 2011. The first spacecraft was Mariner 10. Mariner 10 imagined 45 percent of Mercury. The second spacecraft was MESSENGER. MESSENGER stands for: Mercury Surface, Space Environment, Geochemistry, and Ranging. MESSENGER went around Mercury to predict what it would be like. It flew around the planet three times in 2008 to 2009 and was orbiting Mercury from 2011 to 2015. The entire planet has now nearly been completely imagined, revealing that it has been shaped by volcanic activity and meteor impacts.
The temperatures on Mercury’s surface can reach up to 800 degrees Fahrenheit (430 degrees Celsius). Even though the temperatures can be so high, MESSENGER observers have shown that there is ice water in deep craters. In addition, nighttime temperatures can drop to -290 degrees Fahrenheit (-180 degrees Celsius). In 2007 researchers used ground-based radars to study the core of Mercury, and found out that it is partly liquid. Since the core is partly liquid, Mercury’s outer shell is only about 250 miles (400 km) thick.
Even though there are large smooth areas on Mercury’s surface, there are also cliffs that go for miles. Mercury’s surface is like Earth’s Moon, it has had many impact craters from collisions with meteoroids and comets. Instead of an atmosphere, Mercury has a thin surrounding called an exosphere which is made up of atoms blasted off the surface by the solar wind, and strong micrometeoroids.
If someone could stand on the surface of Mercury when it is close to the Sun, the Sun would appear more than three times as large as it does when viewed from Earth. Since Mercury is close to the sun, it is hard to view from Earth except when it is dawn or twilight. Mercury can be as close to the Sun as 29 million miles (47 million km) when it is circulating close to the sun, or as far as 43 million miles (70 million km) when it is circulating away from the sun. One Mercury solar day equals approximately 175.97 Earth days.
In 1631, Thomas Harriott and Galileo Galilei observed Mercury with the newly invented telescope. Mercury makes an appearance 13 times each century. When this happens, people can view Mercury pass across the face of the sun. This is called a transit. The first person to watch a transit was Pierre Gassendi using a telescope in 1631. The first two transits in the 21st century happened the 7th of May in 2003 and the November 8th, 2006. The recent one was on May 9th, 2016. The next transit is expected to happen in November 11th, 2019.
Now that you have read about Mercury, maybe you’ll be even more curious and want to investigate even deeper about this amazing planet.