About a century ago, we didn’t even know that galaxies existed. Mai Lam/The Conversation NY-BD-CC, CC BY-SA

Curious Kids: will the universe expand forever, or contract in a big crunch?

Curious Kids: will the universe expand forever, or contract in a big crunch? About a century ago, we didn’t even know that galaxies existed. Mai…

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For the Earth, which is shaped like a ball, the force of gravity pulls you to the centre from every point on the ground. Cindy Zhi/The Conversation NY-BD-CC, CC BY-SA

Curious Kids: If Australia is at the bottom of the world, why are we the right way up?

Curious Kids: If Australia is at the bottom of the world, why are we the right way up? For the Earth, which is shaped like…

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Astronaut Peggy Whitson aboard the International Space Station. NASA

Curious Kids: Where does the oxygen come from in the International Space Station, and why don’t they run out of air?

Curious Kids: Where does the oxygen come from in the International Space Station, and why don’t they run out of air? The first piece of…

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Flight Engineer Peggy Whitson suits up ahead of a spacewalk. Vomiting inside a spacesuit during a spacewalk could be fatal for astronauts. NASA, CC BY

Curious Kids: Do astronauts get space sick when they travel from Earth to the International Space Station?

Curious Kids: Do astronauts get space sick when they travel from Earth to the International Space Station? Flight Engineer Peggy Whitson suits up ahead of…

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Without satellites, modern technologies such mobiles phones and GPS would not exist. Flickr/NASA Goddard Space Flight Center, CC BY-SA

Curious Kids: How do satellites get back to Earth?

Curious Kids: How do satellites get back to Earth? Without satellites, modern technologies such mobiles phones and GPS would not exist. Flickr/NASA Goddard Space Flight…

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The mass of the Earth is big enough that the gravitational force it creates can pull the hard shape of ice, rock and metal into a sphere. NASA Earth Observatory images by Joshua Stevens, using Suomi NPP VIIRS data from Miguel Román, NASA's Goddard Space Flight Center

Curious Kids: Why is the Earth round?

Curious Kids: Why is the Earth round? The mass of the Earth is big enough that the gravitational force it creates can pull the hard…

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