How many atoms are there in the vacuum of space? Technically, in a true vacuum, there would be zero atoms, but it is impossible to make a completely true vacuum. There will always be some atoms. In intergalactic space, there are 0.3 atoms per cubic meter, on average. Obviously, some areas of space have an
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Why can’t we see the far side of the universe? We can’t see the other side of the universe because there hasn’t been enough time since the beginning of the universe for that light to reach us, and the universe is expanding faster than the light can travel. The first reason we can’t see the
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What is the conservation of energy? Conservation of energy is the principle behind the First Law of Thermodynamics. The Law of Conservation of Energy says that you can change the state of energy, but energy can never be created and energy can never be destroyed. Before we look at this question, I think we need
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How do the phases of the moon happen? The phases of the moon happen because only one side of the moon faces the Earth at any one time and as the moon rotates we can’t see the lit side. This question was surprisingly difficult for me to get my head around. For the longest time,
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What is escape velocity? Escape velocity is the minimum speed an object needs for it to be able to escape the gravitational pull of a celestial body. Everything in the universe has gravity. Even dark matter has gravity, which is how astronomers know it is there even though they can’t see it. The gravity of
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What happens to the human body in space? Astronauts in space lose bone mass and their muscles weaken. Their blood volume decreases, and their heart can shrink. They are exposed to radiation, and they may have mental changes as well. People have only been going into space for 64 years. The first person in space
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When will the Milky Way and Andromeda collide? The Milky Way Galaxy and the Andromeda Galaxy will collide in about 4.5 billion years. None of us, nor our sun, will be here to see it. We might still be in the Milky Way, but we certainly won’t be here on Earth. The Milky Way Galaxy
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Is it possible to deflect an asteroid? It is, to a certain extent. The deflection has to happen early enough, and the asteroid has to be small enough for it to work. Earth has been hit by countless asteroids over the eons. We are hit by over 17,000 meteors a year. Meteors are pieces of
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What is a quasar? A quasar is a very bright energy source at the center of a young, newly formed galaxy. All of the quasars we can see are incredibly far away from us. The word quasar is the shortened form of quasi-stellar radio source and they were named by an astrophysicist called Hong-Yee Chiu
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Which of the planets have an atmosphere? All of the planets in our solar system except for Merucry actually have an atmosphere, but they vary in thickness. We all obviously know that our planet has an atmosphere and what it is made of. It is 78% nitrogen, 21% oxygen, 0.9% argon, and the rest is
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