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Expert: - 2/18/2005


Question
I was wonderomg, what is the average life span of a star? How long has our sun been around? How much longer has it got? (I am assuming that it will stick around at least until I'm shoved into the ground) Thanks for taking the time to help me!  

Answer
Hello Amanda,

The average life span for a star depends on the type of star (e.g. distinguished in terms of mass, and color).

Thus, a massive blue star (very hot) will last only a relatively short time, while a lesser mass "yellow dwarf star" - like the Sun, may last for nearly ten billion years.

The difference arises because of the *rate* of nuclear fusion reactions in the star's core. Heavier, hotter stars feature reactions that consume more of the star's mass faster - and it will end in a violent (supernova) explosion.

Lower mass stars (like the Sun) consume their mass (convert it into energy based on Einstein's famous equation - E = mc^2) at a much slower rate. And, because their starting mass is too low - will *not* end in explosion. But rather as a white dwarf.

Our Sun has been around at least 4.6 billion years, and will be around for at least another 4.5 - 4.8 billion more.

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Philip Stahl

Expertise

I have forty years of experience in Astronomy, specifically solar and space physics. My specialties include the physics of solar flares, sunspots, including their effects on Earth and statistics as applied to astronomical investigations.

Experience

Astronomy: more than forty years experience starting with construction of my own simple telescopes. Worked at university observatory in college, doing astrographic measurements. M.Phil. degree in Physics/Solar Physics and more than ten years as researcher.

Organizations
American Astronomical Society (Solar Physics and Dynamical Astronomy divisions), American Mathematical Society, American Geophysical Union

Publications
Solar Physics (journal), The Journal of the Royal Astronomical Society of Canada, The Proceedings of the Meudon Solar Flare Workshop (1986), The Proceedings of the Caribbean Physics Conference (1985). Books: 'Selected Analyses in Solar Flare Plasma Dynamics', 'Physics Notes for Advanced Level'.

Education/Credentials
B.A. Astronomy, M. Phil. Physics

Awards and Honors
American Astronomical Society Studentship Award (1984), Barbados Government Award for Solar Research

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