Astronomy/Star vs. Planet

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Expert: - 7/19/2007


Question
My cousin asserts that all stars are planets. I say he is incorrect. Who is correct?

Thank you,

Aaron

Answer
Hello,

Alas, your cousin needs to improve his basic understanding of astronomy.

Stars and planets are totally separate categories of astronomical object. Stars are self-generating energy spheres, with a high temperature core capable of sustaining nuclear reactions. They are seen by virtue of generating their own light.

Planets, on the other hand, are only visible by virtue of the light from a star reflected off their surfaces. They have no self-sustaining energy sources similar to stars. In other words, without a bright star nearby - a planet wouldn't be seen.

Thus, you are correct.

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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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