20
How long
will Sun’s fuel last?
•Luminosity of sun: 3.8 ´ 1026 J/s
•H
burned rate:
•H atoms available:
•Lifetime:
•In reality not all the atoms we start with are H, and
only those near the
center are available for fusion.
The structure of
the sun will change when about 10% of the above total have been used, so after about 10 billion years.
