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Q & A: sun and other stars

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Most recent answer: 09/26/2013
Q:
If the sun is a star and produces heat and plays a role in photosynthesis; how is it that other stars in space are not held accountable for process on earth. I have a theory that through spectrum stars participate in process such as the grizzly caterpillar. I just have a strong belief that stars through light transmission aid process on earth. The sun can't be the only star that works.
- Candace (age 27)
Byram, mississippi
A:

Many stars are just like our sun, some even much bigger and brighter.  However, they do not contribute much to the energy input to the earth simply because they are very very distant.  It is well known that radiation of all kinds is diminished by the square of the distance between the source and the illuminated object.  For example consider the average surface temperatures of Venus, Earth and Mars, which are respectively 480,  14,  and 0.63 °C (or in absolute temperatures, 753 K, 287 K, and 274 K) .  The respective  distances to the sun are, approximately, 100, 154 and 228 million kilometers.  So the farther away from the sun, the colder the planets.  

The nearest stars are several light-years distant.   You can imagine the amount of electromagnetic energy they contribute to the earth: it is miniscule. 

LeeH


(published on 09/26/2013)

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