Semi-protected edit request on 10 September 2014
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I sent an edit request for this article before.But I made a mistake.Actual mistake I was referring to , is about nationality of "Ibn al-Haytham(Alhazen) ".In Galaxy article he is refereed as an Arab astronomer which is wrong.So I want to ask a review about alhazen nationality.According to history(non Arab ones of course) he is a PERSIAN SCIENTIST who born in Basra(Iraq). thank you 184.108.40.206 (talk) 15:10, 10 September 2014 (UTC) 220.127.116.11 (talk) 15:10, 10 September 2014 (UTC)
Could you please supply a source? See WP:VERIFICATION for more information on Wikipedia's requirements. Marteau (talk) 15:27, 10 September 2014 (UTC)
Not done: see above Cannolis (talk) 04:23, 11 September 2014 (UTC)
Stars, stellar remnants, interstellar gas and dust, and dark matter.
"dust" seems to be a separate item, so the commas and "and"s look weird.
Should be liek this: stars, stellar remnants, dark matter, and interstellar gas and dust
In 1912, Vesto Slipher made spectrographic studies of the brightest spiral nebulae to determine their composition. Slipher discovered that spiral nebulae have high red shifts, indicating that they are moving away from the Milky Way at a rate exceeding the Milky Way's escape velocity. Thus, they are not gravitationally bound to the Milky Way, and are unlikely to be a part of the galaxy.
I checked Slipher's publications through 1921 and he made no such assertion regarding the escape velocity of the Milky Way, or whether the spiral nebulae were gravitationally bound. All he noted was that the spiral nebulae have higher velocities than those observed for stars, and (by 1921) that the majority were moving away from us. I think the paragraph should be re-written:
In 1912, Vesto Slipher made spectrographic studies of the brightest spiral nebulae to determine their composition. Slipher discovered that spiral nebulae have high doppler shifts, indicating that they are moving at a rate exceeding the relative velocity of stars. He also discovered that the majority are moving away from us.