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Top Document: [sci.astro] Stars (Astronomy Frequently Asked Questions) (7/9) Previous Document: G.10 What happens to the planets when a planetary nebula is formed? Do they get flung out of the solar system? Next Document: G.12 Do star maps (or galaxy maps) correct for the motions of the stars? See reader questions & answers on this topic! - Help others by sharing your knowledge This question can have a few answers. 1. The Milky Way galaxy is about 120,000 light years in diameter. We're about 25,000 light years from the center. Thus, the most distant stars that are still in Milky Way galaxy are about 95,000 light years away, on the opposite side of the center from us. Because of absorption by interstellar gas and dust, though, we cannot see any of these stars. 2. The most distant object known has a redshift of just over 5. That means that the light from this object started its journey toward us when the Universe was only 30% of its current age. The exact age of the Universe is not known, but is probably roughly 12 billion years. Thus, the light from this object left it when the Universe was a few billion years old. Its distance is roughly 25 billion light years. 3. Existing observations suggest that the Universe may be infinite in spatial extent. If so, then the farthest star would actually be infinitely far away! User Contributions:Comment about this article, ask questions, or add new information about this topic:Top Document: [sci.astro] Stars (Astronomy Frequently Asked Questions) (7/9) Previous Document: G.10 What happens to the planets when a planetary nebula is formed? Do they get flung out of the solar system? Next Document: G.12 Do star maps (or galaxy maps) correct for the motions of the stars? Part0 - Part1 - Part2 - Part3 - Part4 - Part5 - Part6 - Part7 - Part8 - Single Page [ Usenet FAQs | Web FAQs | Documents | RFC Index ] Send corrections/additions to the FAQ Maintainer: jlazio@patriot.net
Last Update March 27 2014 @ 02:11 PM
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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