Your answer is electricity, light and magnetism. They can be determined usinf elecromagnetic radioation.
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Even the energy can't be detected by our eyes, there are a lot of measurement instruments that can measure infrared (IR), gamma rays, radio or X-rays or ultraviolet (UV)</span>
A nebula is gas, dust, and other things that form and form some sort of clould like thing. It also looks cool because of the colors it produces. I'm sure you could do a web search to find more about it, I don't take astronomy hahaha
Image from a far away object formed by a concave mirror
I have no idea but this is my best guess as a sophomore in college
12.5 times 14 and convert to meters its 1.75 meters per second
