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Top Document: [sci.astro] Cosmology (Astronomy Frequently Asked Questions) (9/9) Previous Document: I.15. Why is the sky dark at night? (Olbers' paradox) Next Document: I.17 Since energy is conserved, where does the energy of redshifted photons go? See reader questions & answers on this topic! - Help others by sharing your knowledge A common objection to the Big Bang model is that redshifts do not measure distance. The logic is that if redshifts do not measure distance, then maybe the Hubble relation between velocity and distance is all wrong. If it is wrong, then one of the three pillars of observational evidence for the Big Bang model collapses. One way to show that redshifts do not measure distance is to find two (or more) objects that are close together on the sky, but with vastly different redshifts. One immediately obvious problem with this approach is that in a large Universe, it is inevitable that some very distant objects will just happen to lie behind some closer objects. A way around this problem is to look for "connections"---for instance, a bridge of gas---between two objects with different redshifts. Another approach is to look for a statistical "connection"---if high redshift objects tend to cluster about low redshift objects that might suggest a connection. Various astronomers have claimed to find one or the other kind of connection. However, their statistical analyses have been shown to be flawed, or the nature of the apparent "bridge" or "connection" has been widely disputed. At this time, there's no unambiguous illustration of a "connection" of any kind between objects of much different redshifts. User Contributions:Comment about this article, ask questions, or add new information about this topic:Top Document: [sci.astro] Cosmology (Astronomy Frequently Asked Questions) (9/9) Previous Document: I.15. Why is the sky dark at night? (Olbers' paradox) Next Document: I.17 Since energy is conserved, where does the energy of redshifted photons go? 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