This week our 5 Facts series continues with our home planet! Read on to learn more about our Earth.

  • Earth is the only planet not named after a God

The other planets in our Solar System are named after Roman and Greek Gods, but not our Earth! The word “Earth” comes from an 8th Century Anglo-Saxon word “Erda”, which meant soil or ground. We didn’t use the word to describe our planet until the 1400s. Academics eventually nicknamed Earth Terra Mater, after the Roman Goddess, which translated to Mother Earth. As we discovered our planetary neighbours, we named them after gods: Mercury is named after the roman messenger to the Gods, Venus after the Roman Goddess of Love, Mars after the Roman God of War, Jupiter after the Roman God of Thunder, Saturn after the Roman God of Wealth and Agriculture, Uranus after the Grecian God of The Sky and finally Neptune after the Grecian God of The Sea!

Image of Earth from Apollo 15
Big Blue: Earth photgraphed by the crew of Apollo 15 (Image credit: NASA)
  • Earth has a magnetic field

Earth has a magnetic field that encircles our entire planet – and spreads out into space! This magnetic field is generated by electrical currents from below our Earth’s crust. Within Earth’s outer core there is molten iron that moves around similarly to the way water moves in our seas on the surface – this creates the field! Our magnetic field is good because it helps protect us from the solar wind from our Sun, as well as cosmic rays that would destroy our upper atmosphere. The upper part of our atmosphere is extremely important as it protects our planet from harmful ultraviolet radiation. 

Earth’s Magnetic Sphere. Credit: NASA
  • Earth is struck by lightning 100 times per second!

That equates to 8 million lightning strikes per day and 3 billion each year! Lightning is least likely to occur in the poles whilst most likely to occur in the stormier climates of the tropics. You can see real time lightning strikes via this website: https://www.lightningmaps.org 

Lightning doesn’t just occur on Earth though! Jupiter has famously has lightning storms on its cloud tops.

Lightning on Jupiter’s Northern Pole. Credit: NASA
  • Earth was once believed to be the very centre of the entire universe 

When early astronomers looked up into the sky they could see what appeared to be the sun, moon, stars moving around us. In view of the greatest wisdom on their time, it was suggested that our planet Earth was actually at the centre of the whole universe. This is called the Geocentric Model and was believed by most people until the 17th Century! This grew to be known as the Ptolemaic Model.

The Ptolemaic Model named after astronomer from Ancient Greece, Claudius Ptolemaeus. Image: WikiCommons

However, as far back as the 1600s, many astronomers were seeking to prove that the Earth moved around the sun, rather than the opposite. This was controversial as this Geocentric Model of our universe was upheld by many religious institutions until the 1800s. Famously in 1633 Galileo Galilei in a moment of freedom said “and yet it moves”, after being forced by religious leaders to say the Sun moved around the Earth. 

If you think this is long behind us, you are mistaken! In 2006 a poll revealed that 20% of US citizens stated that they believe the Sun moves around the Earth. Shhh, no one tell Galileo…

Galileo pretending he didn’t see that poll. Image sourced from Britannica. Galileo, oil painting by Justus Sustermans, c. 1637; in the Uffizi Gallery, Florence.
  • Earth is not round

But don’t worry – it’s certainly not flat! Earth is a bit like a squashed sphere, there is a bulge around the middle. The bulge around the middle is small but significant – the middle sticks out around 42km more than a perfect sphere would. This is about the distance between the top of Mount Everest and the bottom of Marianas Trench.

Credit: NASA

Isn’t a bit unsettling to think that Earth isn’t perfectly round?! And if you don’t like that image, you certainly won’t like the look of Earth if there were no tides to pull our oceans (remember to say thank you to the moon tonight!).

That’s one lumpy planet. Source: WIKICommons

And there you have some facts about Earth – did you know them all? Our home planet certainly has some secrets even after all this time. Stay tuned for Mars next week!


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