Spaceship Earth, Meet the Neighbours "Mercury"
As we begin to head out into the cosmos, it's important to begin looking around to see what's 'out there' and where mankind might end up.
From ancient times man has looked up, into the skies and wondered just what, or who was 'out there' watching us.
As he looked into the sky, he began to see things moving around our sun, he wasn't sure what they were, so somehow in his state of wonder he began to give these objects names, names he already associated with the divine.
Blame the Romans
It was the Romans who gave the planets the names they have today, or at least the five that they could see with the naked eye.
Looking into the sky just before the dawn, he saw an orb, or sphere, it looked pink from where he was looking, warm and inviting, he called it after the goddess he already associated with love, he called in Venus.
That same sky at night showed him an angry-looking sphere, one that looked as if it was blood red, it reminded him of the blood spilled on Battlefields, so he called that one after the god of war, its name was Mars.
But there were others he saw, much larger than those two were two more, 'the biggest must be the boss' he surmised, so that one got the name 'Jupiter' and the second biggest got the name 'Saturn' after the god of agriculture.
But the fastest planet around our sun reminded them not of a 'god' but of their messenger Mercury, and that was named after him!
Mercury, "Messenger of the gods"
Back in ancient times, it was thought that the sun, moon and stars all revolved around the Earth, this wasn't at first a Christian idea but came from the likes of Plato and Aristotle that the early church took on board.
It made sense really, if the Earth was flat, as they thought it was back then (despite the ancient Egyptians working out that the Earth was actually round, and even working out the approximate size of the Earth as far back as 400 BCE!) then it made sense that they were all moving around the Earth, and one of them was 'scampering around' the sun moving faster than all the rest, so he must be the messenger of the gods.
For most of human history, only five planets were known about, besides the one that we live on, and our five nearest neighbours, and it's to these five that our first explorers are likely to go when we start to explore the heavens by sending people.
Actually two we certainly won't go to, one we will and two others we're probably going to go to the moons surrounding them, but going to the planets themselves, no thanks, we're not going there!
Our system, a very special place
The Earth is 93 million miles from the sun, but inside that orbit lie two other planets. Venus is actually closer to us than Mars is, but very different to Earth, closer still to the sun is Mercury.
Mercury lies about 30 million miles from the sun and is much smaller than the Earth but don't let its lack of size fool you, the composition of the planet is much denser than all of the other planets. Except for one that is, EARTH is the densest!
Astronomers use the distance of the Earth from the sun as a unit of measurement to indicate how far things are from our sun, they call the 93 million miles one Astronomical unit or AU for short.
Mercury is 0.38 of an AU from the sun and at that short of a distance for a long time it was thought to be so bound by the sun's gravity that it was 'Tidal locked' with the same side always facing the sun.
In 1965 it was discovered that Mercury wasn't actually tidally locked, but its day is actually twice as long as it's year!
It takes Mercury 88 Earth days to orbit the sun, but 176 Earth days for it to rotate a full 'day' making it the longest day in the solar system, and during that time the temperature will rise from -173 degrees centigrade to around 400 degrees centigrade, but it isn't the hottest planet in our solar system, that honour belongs to Venus!
Battered by the sun
Being so close to the sun Mercury bears the full brunt of the solar storms that erupt every so often, anything living on the surface of Mercury would have little or no warning of solar flares erupting, these are massive plumes of plasma that streak out into the solar system and even at our distance from the sun have been known to knock out communication satellites.
Back in 1859, just as we were learning how to build telecommunication systems (the telegraph) a solar flare erupted that destroyed all electronic communication in half of the Eastern United States and Canada, these flares erupt every eleven years, and while we insulate against the normal ones, we can't plan for the bigger ones, they still destroy communication systems.
Mercury is right in the 'firing line' for these, we have sent probes close to Mercury, but they stay in orbit as landing on the surface with that kind of heat around would cause them to malfunction (keeping them in orbit we can swing them around the planet allowing them to cool off).
How big is it?
With a diameter of just under three thousand miles the planet is about one third the size of Earth, but with the difference that Mercury has no moon to help protect it, though recently Ice was actually discovered.
Yep, that's right, the planet with a daytime temperature of 400 degrees Celcius actually has places where the ice never melts!
Located at the North pole of the planet are some deep craters where one space probe showed permanently dark regions, these dark areas were realised to be always in the shade even when in the daylight, scientists did a few more tests and realised that even in the scorching heat of the 'daytime' there was ice in these areas, and not just a little but maybe as much as a few hundred billion tons of the stuff, not only that, but there is also organic material there, we just don't know what!
Ice on Mercury
Don't believe me about this? Read the article then.
And that's all for tonight folks
Here are just a few interesting facts about the nearest planet to our sun, I hope you enjoyed them
Till next time then