Subject: Introduction
*sci.astro* is a newsgroup devoted to the discussion of the science of
astronomy. As such its content ranges from the Earth to the farthest
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However, certain questions tend to appear fairly regularly. This document
attempts to summarize answers to these questions.
This document is posted on the first and third Wednesdays of each month to
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(both ftp and Web) is also available. (As a general note, many other FAQs
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<URL:ftp://rtfm.mit.edu/pub/usenet/news.answers/>.)
Questions/comments/flames should be directed to the FAQ maintainer, Joseph
Lazio <jlazio@patriot.net>.
Section Contents
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with stars, then every direction you looked would eventually end on
the surface of a star, and the whole sky would be as bright as the
surface of the Sun.
Why would anyone assume this? Certainly, we have directions where we look that are dark because something that does not emit light (is not a star) is between us and the light. A close example is in our own solar system. When we look at the Sun (a star) during a solar eclipse the Moon blocks the light. When we look at the inner planets of our solar system (Mercury and Venus) as they pass between us and the Sun, do we not get the same effect, i.e. in the direction of the planet we see no light from the Sun? Those planets simply look like dark spots on the Sun.
Olbers' paradox seems to assume that only stars exist in the universe, but what about the planets? Aren't there more planets than stars, thus more obstructions to light than sources of light?
What may be more interesting is why can we see certain stars seemingly continuously. Are there no planets or other obstructions between them and us? Or is the twinkle in stars just caused by the movement of obstructions across the path of light between the stars and us? I was always told the twinkle defines a star while the steady light reflected by our planets defines a planet. Is that because the planets of our solar system don't have the obstructions between Earth and them to cause a twinkle effect?
9-14-2024 KP