space

« Back to Glossary Index

Space (def): The term “space” in astronomy refers to the region outside the atmosphere of the Earth, i.e., it starts about 100 kilometers or 60 miles above Earth – a vast 3-dimensional region of blackness with too few oxygen molecules to produce the sky blue effect we see when the Sun illuminates Earth’s atmosphere. It is a vacuum because molecules are too far apart to transmit sound.

« Back to Glossary Index