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Top Document: [sci.astro] Galaxies (Astronomy Frequently Asked Questions) (8/9) Previous Document: H.01.2 How many galaxies in the Universe? Next Document: H.01.4 How many open clusters? See reader questions & answers on this topic! - Help others by sharing your knowledge We are on firmer ground with this one, since globular clusters are fairly large and luminous. The only places where our census in the Milky Way is incomplete are regions close to the galactic disk and behind large amounts of absorbing dust, and for the fainter clusters that are farthest from the Milky Way just now. The electronic version of the 1981 Catalogue of Star Clusters and Associations. II. Globular Clusters by J. Ruprecht, B. Balazs, and R.E. White lists 137 globular clusters in and around the Milky Way. More recent discoveries have added a handful, especially in the heavily reddened regions in the inner Galaxy. As a rough estimate accounting for the regions that cannot yet be searched adequately, our galaxy should have perhaps 200 total globulars, compared with the approximately 250 actually found for the larger and brighter Andromeda galaxy. User Contributions:Comment about this article, ask questions, or add new information about this topic:Top Document: [sci.astro] Galaxies (Astronomy Frequently Asked Questions) (8/9) Previous Document: H.01.2 How many galaxies in the Universe? Next Document: H.01.4 How many open clusters? 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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[sci.astro] Galaxies (Astronomy Frequently Asked Questions) (8/9)
Section - H.01.3 How many globular clusters in the Milky Way?
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[sci.astro] Galaxies (Astronomy Frequently Asked Questions) (8/9)
Section - H.01.3 How many globular clusters in the Milky Way?
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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