Those Big Telescopes

I might need up to be updated on the lastest on spy scopes because the last answer I read was posted in 1987, (archives).If we can see the deepest regions of the universe, like all the way across almost, why shouldn’t we be paranoid that “they” can see right down to my mail I am reading?

LINK TO COLUMN: Can spy satellites read the headlines of a newspaper on a park bench? - The Straight Dope

Distance is easy. You can see things (well, a thing) two and a half million lightyears away, with your own naked eye. But you can’t read a newspaper at that distance. That takes resolution, which is much more difficult, especially when you’re looking through the atmosphere.

Because the things we see way across the universe are *really *big. Like, huge. Like bigger than that. No bigger. No, bigger.

Hubble had to be put into space to get outside our pesky interfering atmosphere. Earth based giant telescopes have since had some success with systems observing and adjusting for atmospheric disturbances, but they add a lot of complexity and there’s no way the combination will be a part of a spy satellite any time soon.

As long as you make sure you stay within the atmosphere, “they” will have to put the camera close to you if they want to read your email.

Welcome to the Straight Dope Message Boards, Dave L, we’re glad to have you with us.

When you start a thread, it’s helpful to other readers if you add a link to the column you’re commenting on. Saves search time, and helps keep us all on the same page. I think I’ve found the one you meant, and I’ve added a link for you. (If I got it wrong, please email me or let me know and I’ll fix it, with apologies.) Meanwhile, no biggie, and you’ll know for next time.

You’re quite right, however: that’s an old column, and computer techniques have improved enormously since then. I’ll put this before Cecil and see whether he’d like to update the column.

The farthest thing easily seen by the naked eye is the Andromeda Galaxy which is about 2.5 million light-years away. You don’t even need a telescope to see something very, very far away. But can you read a newspaper from 20 feet? (NY Daily News headlines aside.)