Monday, February 15, 2016

Where Are the Stars?

In order to counter the many pictures of Earth from space, ranging from low-orbit satellite photos and International Space Station video, to distant photos taken from the moon, to the "Pale Blue Dot" image taken from 3.7 billion miles away, flat-Earthers have to claim that all such pictures are faked.

Most of their "proof" comes down to, "it looks fake to me," or more commonly, "come on, you don't think that's real, do you?" But the one argument they make that might, at first blush, sound plausible is: "Where are the stars?"

In the famous "Blue Marble" photo taken from Apollo 17 in 1972, there are no stars visible in the space surrounding the Earth. Most pictures taken from the International Space Station also fail to show stars. Doesn't that show that they weren't actually taken from space?

Only if you've watched too many movies.

Stars are very bright. But they are also very far away. If you're out in an isolated area on a very dark night, you can see perhaps as many of 5000 stars in the sky. Any light pollution, from the moon, from lights in a nearby city, and the number drops off very sharply. And your eyes can discern a much wider range of light and dark than any photographic system.

I don't know if you've done enough star-gazing to recognize the difference between the planets and the stars in the sky (assuming you believe in planets), but if you have, you know that the closer and larger planets appear brighter in the night sky, and they don't twinkle nearly so much.

That's because, although the planets are smaller by far than stars (well, Jupiter is almost big enough to be a star), and shine by reflected light instead of producing their own light, they are simply much, much closer to Earth than the stars are.

So back to the photography. If you are taking a picture of something big and bright against a background of black plus some lights that are relatively dim (in this case because they are so far away), the dim lights in the background just won't show up. If you want to get them to show up, you have to expose for them.

Which means you are vastly overexposing for the big bright object, which means it will register as a big white circle, and maybe a big white circle that's very fuzzy around the edges.

So why, in the movies, do we see lots of stars in the background? Because it looks cool, that's why. And also because we expect to see them there, something that art directors figured out many decades ago. The producers of Star Trek did a lot of tests with shots of the Enterprise using information from astronomers to make it look as realistic as possible, including having no "whoosh" sound when the ship sped by in the opening credits, as would be true in space.

It didn't work. Nobody thought it looked real. With no experience in space, we have preconceived notions of what it would be like to be in space, to watch a spaceship zip by, and they just don't match the reality.

Which brings me, briefly, to another topic: the moon in front of the clouds. I've seen a lot of footage that purports to show the moon (or the sun) in front of the clouds, and so thus much lower than we've been told.

Two problems with that. First, the moon is not is front of the clouds; it's an illusion caused by overexposing the moon. If you expose the moon so that you can see all its features, then the clouds will also be visible drifting in front of it (it only works with relatively thin cloud cover).

The second problem is that having the moon closer than the clouds also violates the flat-Earth model, at least as far as most understand it. It's something that's not often brought up, but if any flat-Earther tried to claim that the moon is closer than the clouds, especially because plenty of people have flown above the clouds in an ordinary jetliner, they would suddenly have a lot of explaining to do, even more so than they do now,

We like to think that our everyday experience can tell us the real from the fake, but that's only true if our everyday experience takes place in the realm of what we're trying to judge. We can't judge what outer space looks like, because flew of us have been there. We can't judge what the microscopic world looks like, because we don't live at that scale.

Sometimes, and I know this is an uncomfortable idea for some, you have to trust the people whose job it is to actually explore those realms, and who, because of the time they've spent at it, know much more about it than you do.

You can't trust everything that everyone says. But the fact is that most people are telling you the truth.

2 comments:

  1. And the claim that stars are seen in the crescent, which is likely due to dust in the optics.

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