The Andromeda and Milky Way galaxies are moving toward each other due to mutual gravitational attraction. This mutual gravity…
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Does a Gravitational Lens Really Magnify Objects?
In fact, the magnification due to a gravitational lens is directly analogous to the magnification of objects that one…

Would Colors Be Perceived Differently By Humans On a Planet Orbiting a Different Type of Star Than Our Sun?
Although it is true that the sensitivity of the human eye to different frequencies of light is consistent with…

How Does Atmospheric Extinction Affect the Brightness of Stars?
Michael Richmond has provided an excellent description of the physics of atmospheric extinction (and refraction) on his Atmospheric Effects:…

How to Determine if a Planet is Moving Retrograde
I believe that this question has been answered on the Physics StackExchange forum. Observationally, if you can measure the…

Do Radio Waves Make “Noise”?
In fact, “radio waves” are defined as a section of the electromagnetic spectrum, or light, that represents wavelengths of…