10 Things you never knew about the Earth

10 amazing things you didn't know about the Earth 10. Secret ocean Scientists have discovered a vast reservoir of water located 660 kilometers beneath the Earth’s surface. The underground ocean is hidden inside a blue rock called ringwoodite, which acts like a sponge, trapping hydrogen and water. There is enough water beneath the Earth’s surface to fill the Earth’s oceans three times over. Scientist Steve Jacobsen suggests that the Earth’s surface oceans were first formed when trapped water was driven to the surface by geological activity. This contradicts the widely accepted theory that icy comets deposited water onto Earth. Sources: The Guardian, New Scientist 9. Uneven gravity Many people assume that gravity is distributed evenly on Earth, but there are certain places, such as Hudson Bay in Canada, that actually experience less gravity than other regions of the globe. In Hudson Bay this occurs because there is only a small amount of land mass, due to retreating glaciers on the surface and swirling magma in the Earth’s core. A satellite called the ‘Gravity Field and Steady-State Ocean Circulation Explorer’ was sent into space in 2009 to create a map of the planet’s gravitational field. It mapped Earth’s gravity with extraordinary accuracy and is used by geophysicists to measure ocean circulation, sea-level change, and ice dynamics. Sources: Live Science, New Scientist, Space Daily 8. Longer Earth days Around 620 million years ago, there were only 21.9 hours in a day. Ocean tides generated by the Moon and Sun's gravity have added 1.7 milliseconds to the length of a day each century, because they alter the planet’s rotational momentum. The length of the day can also be affected by natural events such as the 2011 earthquake in Japan, which actually shortened the length of each Earth day. The quake changed the distribution of the Earth’s mass causing it to rotate slightly faster, decreasing our day by about 1.8 microseconds. Sources: Scientific American, NASA 7. Pangaea Pangaea was a supercontinent that existed during the late Paleozoic and early Mesozoic eras, 300 million years ago. Formed by the movement of Earth's tectonic plates, it began to break apart about 175 million years ago. At this time most of the dry land on Earth was joined in one huge land mass that covered nearly a third of the planet's surface. Geologists believe that due to tectonic plate movements, in 250 million years the Earth’s continents will be merged again into one giant land mass, form ‘Pangaea Ultima.’ Currently each year Hawaii, which sits on the Pacific Plate, moves nearly three inches closer to Alaska. Sources: Universe Today, BBC, The Blaze 6. Hot in here Over the next 1.1 billion years, scientists predict that the Sun will get progressively brighter and hotter by about 10% compared to now. In 4 billion years, our oceans will evaporate, resulting in a runaway greenhouse effect that will send temperatures soaring above 750 degrees Fahrenheit, rendering life on Earth impossible. In 7.5 billion years, Earth will become a vast desert similar to Mars today and the Sun will expand into a red giant. At this point, scientists predict that the Sun will engulf Earth altogether, meaning the definite end of our planet. Sources: Howitworksdaily, BBC 5. Earth used to be purple There is an astrobiological hypothesis that suggests that Earth used to be purple. Scientists believe that before plants as we know them became dominant, ancient microbes might have used a molecule other than chlorophyll to harness the Sun's rays. The molecule, called retinal, gave Earth’s organisms a violet hue. According to Shil DasSarma, a microbial geneticist from the University of Maryland, chlorophyll gradually replaced retinal because it is more efficient at absorbing light, and thus purple became green. Sources: Astrobio, livescience, Dawn 4. How did life on Earth begin? There are around 8.7 million different species on Earth, but scientists are still not entirely sure how life on Earth began. Most scientists believe that living things developed from molecules that were able to replicate themselves, rather like DNA does. These molecules either came from somewhere further out in space, or they were produced by the conditions on Earth at the time. A new study suggests the latter and argues that the building blocks of life, such as the compounds that would be necessary to create DNA, existed on Earth prior to the creation of the first life forms. Sources: BBC, Live Science, Time, Phys.org 3. Earth is a bumpy globe Despite countless photos of Earth depicted as a perfect sphere, Planet Earth is actually an imperfect bumpy globe. This is because the force of Earth’s rapid rotation on its axis causes it to push outwards at the equator, making it look like a squashed ball. Due to the Earth’s uneven shape, Mount Everest isn’t actually the tallest mountain. If measured from sea level, Everest would top the list, but measuring from the center of the Earth, Mount Chimborazo takes the crown. Sources: Scientific American, Independent 2. Underwater mountain range The longest mountain range on Earth is actually 90% underwater. It is called the mid-ocean ridge system and was formed by the movement of plate tectonics. Surveyed in detail in the 1950s, it stretches for 80,000 kilometers all around the world and is nearly 20 times longer than the longest range on the surface, the Andes Mountains. Furthermore, it consists of thousands of individual volcanoes that sporadically erupt. Around 20 volcanic eruptions occur each year and this causes the formation of 2.5 kilometers of new seafloor. Sources: BBC, Ocean Service 1. Geomagnetic Reversal The Earth’s magnetic field is becoming less stable. Researchers believe that the planet’s inner core is slowly growing, as the outer core cools and solidifies, resulting in more frequent flips of Earth’s magnetic field. In other words, if the polarity of today’s magnetic field were reversed, the North and South markings on all compasses would be 180 degrees wrong. Using fossil records from hundreds of past magnetic polarity reversals, scientists have determined that the reversal of the magnetic poles should not have a dramatic effect on human life. However, some animals, such as pigeons and whales, use the Earth’s magnetic field for a sense of direction. So, if a reversal occurs in their lifetime, they might have to develop different methods of navigation. Sources: NASA, geomag, BBC

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