Astronomy/distance

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Expert: - 5/3/2006


Question
how many kilometres from the sun to earth? from earth to venus and earth to mercury?

Answer
Hello.

You do not stipulate what specific distances you want, so I will assume you want the mean distance (in the case of the Sun to the Earth) and also the mean theoretical distance from the Earth to Venus, and to Mercury.

The mean distance (in km) of each planet to the Sun can be expressed in astronomical units (AU):

Earth - Sun    =    1.0  AU   = 1.5 x 10^8 km

Mercury - Sun  =    0.39 AU  

Venus - Sun     =   0.72 AU

Therefore it is possible to work out the distances from Earth to Venus and Earth to Mercury:


Earth to Venus:

1.0 AU  -  0.72 AU  =   0. 28 AU  

(e.g. the distance of Earth to Sun minus the distance of Venus to Sun equals the distance of Earth to Venus)

and 0.28 AU  =   0.28 (1.5 x 10^8 km)  = 4.2  x 10^ 7 km

or 42 million kilometers

Earth to Mercury:

1.0 AU   - 0.39 AU   =  0.61 AU

(e.g. the distance of Earth to Sun minus the distance of Mercury to Sun equals the distance of Earth to Mercury)

and 0.61 AU  =  0.61 (1.5 x 10^8 km)  = 9.15 x 10^7  km

or 91.5 million kilometers

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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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