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What is a Comet? – Astronomy – Space

By |2019-04-18T05:32:51-07:00August 17th, 2017|Physics|

A comet in the night sky What are comets made of? Comets are balls of leftover rock and ice in space. They started out when a star exploded into a supernova. What is a supernova? More about ice All our space articles When were the first comets? A nebula formed, and then most of the material in our nebula merged together, about [...]

What is water made of? Molecules and chemistry

By |2017-06-02T18:02:44-07:00June 2nd, 2017|Chemistry|

A big ocean wave The first molecules of water formed out in space, about 14 billion years ago, as part of the nebula left over after an early star exploded in a supernova. There were a lot of hydrogen and oxygen atoms floating around in these nebulae, and when they stuck together that [...]