Space

JaneiR36 wrote: »

Also, I have a question about "seeing" the Milky Way galaxy. Since that's our galaxy, how does one see it? The way I understand it, it would be like seeing earth. Since we're on planet earth, it wouldn't look like a sphere from here, right?

The galaxy is way less like a sphere than the Earth, it's closer to a dinner plate, but bulging in the middle. At least that's the current understanding. But it doesn't look like a circle from inside, it looks more like a thick line across the sky.



I've posted this before but it's probably useful right now. This is the Milky Way from Slate Peak in the North Cascades. The camera is more sensitive than the eye, so it's a little bit dimmer and it's less colorful too, when you're standing there.

I don't think I explained that very well at all. If you were able to make any sense of it, my hat's off to you.

Another thing, if anybody is interested in the physics of light and vision.

Here are some pictures of a 50 mm lens at different apertures:



You can plainly see that more light will pass through the lens at f/1.8 (first) than at f/22 (last). Smaller numbers mean a bigger opening, and more light gathering power - more brightness.

Your eyes work the same way. Your pupils dilate when it's dark, and when you're under the influence of certain drugs. They close down when it's bright out. That's why you can see well enough to walk under a full moon, or at noon at the beach. The lens in the pics above can open to f/1.8 and it can close to f/22, it can't get brighter or darker than that.

A 50 mm f/1.8 lens like this one costs about $100. A 50 mm f/1.4 lens is almost 2x brighter, weighs almost 2x as much, and costs $400. A 50 mm f/1.2 lens is brighter, heavier, and costs $1,500.

I don't know which one is most similar to human vision, but people can't go to the store and buy cat eyes. You sort of can do that with cameras. That's a huge part of why photos of the Milky Way look different than standing outside looking at it.