1. There are some facts about life that are hard to imagine, like the fact that you were once a tiny egg just 0.1mmacross.
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2. And in a single ejaculation between 40 million and 1.2 billion sperm cells raced to fertilise that egg.
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3. That fertilised egg eventually became you. And then you became one of over 7 billion people currently on this planet.
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4. Even though that number sounds enormous, if every single person was placed in a heap in the Grand Canyon it would barely fill it.
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5. And that number doesn’t compare to the amount of tiny atoms each adult is made up of: Around 7 octillion!
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6. To put that into perspective, if you compare an atom to the size of an apple, it’s about the same as comparing an apple to the size of the planet.
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7. It’s difficult to get your head around how enormous our planet is. Earth has a diameter of 7,926 miles. And at the equator it has a circumference of roughly 24,902 miles.
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8. Although about 71 percent of the Earth’s surface is covered in water, researchers estimate that less than 5% of it has been seen by human eyes. The rest of it remains a mystery.
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9. But our planet is really tiny compared to other stuff in the universe. For example, the sun has a circumference of roughly 2,713,406 miles.
10. 109 Earths could be lined up across the diameter of the sun.
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11. Earth looks even tinier compared to the blue Hypergiant ‘Pistol Star’, which is one of the most luminous stars known.
12. And even tinier compared to VY Canis Majoris, the largest known star in the milky way galaxy.
13. The diameter of the observable universe is estimated to be 93 billion light years. But the size of the entire universe is thought to be so gigantic that scientists are unable to put a number on it.
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This is an infrared image of the entire observable universe.
14. There’s no evidence to suggest that the universe has an edge. Even if it does, we’ll probably never reach it.
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15. But there are still so many unanswered questions about life and humanity on Earth. For example, researchers still don’t know exactly why humans dream.
16. No one knows exactly why humans produce tears of laughter, joy, and sorrow. There are many different types of tears, but emotional tearing is thought to be unique to humans.
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Although other animals shed tears, there has only been anecdotal evidence for emotional tearing in species other than human beings. Scientifically, since animals can’t speak, it’s difficult to tell whether an animal is crying emotionally, or simply producing tears for the purpose of lubrication, or due to irritation.
17. And even though time is such a significant part of life, no one can explain when it began or whether it will end. Some believe time is an illusion constructed by humans, and others believe that time existed long before humans recorded it.
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18. Our planet has been around for a very long time. Scientists have estimated the age of the earth to be 4.55 billion years old.
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