won't much matter in 5 billion years - the sun has a hydrogen burning lifetime of about 10 billion years - and it is about 4.6 billion years old now - when it runs out of hydrogen and has to start burning helium and becomes a red giant, the sun will expand to include the orbit of Mars - and Mercury through Mars including the moon won't be planets anymore either by this definition, or as much to look at..
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won't much matter in 5 billion years - the sun has a hydrogen burning lifetime of about 10 billion years - and it is about 4.6 billion years old now - when it runs out of hydrogen and has to start burning helium and becomes a red giant, the sun will expand to include the orbit of Mars - and Mercury through Mars including the moon won't be planets anymore either by this definition, or as much to look at..