Monthly Archives: September 2013

Radial Extent of Last Scattering Shell at CMB Recombination

Question:  At CMB recombination (z=1090), what is the radial extent of the last scattering “shell”? a) Delta(z) = …. b) Delta(comoving angular distance)= ….Mpc The WMAP first-year parameters give Delta(z) = 195. Is this still correct?  – Rene Answer:  I … Continue reading

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How Did the First Galaxies Form?

Question:  From where did this initial cloud of gases and dust come? In other words, how did the cloud form? Why were these gases and this dust together in a cloud? I read on another website that the cloud began … Continue reading

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Time Dilation and the Speed of Light

Question:  T or F: Since gravitational time dilation has been confirmed to exist. The speed of light cannot be constant since speed = distance÷ time and if the denominator changes then the speed must also change? Or atleast the distance … Continue reading

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How Much Longer Will We Be Able to Detect Voyager 1?

Question:  The space probe “Voyager 1″ has now left our solar system and is venturing into interstellar space. This in itself is magnificent achievement but for how much longer will Voyager 1 be able to gather data and transmit it … Continue reading

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How to Tell the Difference Between an Extrasolar Planet and a Star Spot

Question:  I am a retired PhD chemist..interested in amateur astronomy.  Recently a lot of exo planets have been discovered using a “transit” method of observing brightening and dimming of stars.  How do we know these are planet transits, and not … Continue reading

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What Skills Are Needed to be an Astronomer?

Question:  What basic training is needed to become an astronomer?  – Adeshina Answer: I have assembled pointers to several sources for this information on my Student Resources page.  You might also want to consult my previous posts on this subject.  … Continue reading

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