Whenever I get the chance, I like to sleep outside under the stars. On a clear, dark night, far away from the city…it takes me out of ordinary day-to-day life and plunks me down where I really am: clinging to a tiny rock floating around somewhere in an immense and complex Universe. It gives me perspective.
Several times, though, while I’ve been looking up and pondering all the countless other stars and planets Out There, I’ve had a strange sensation of reverse-vertigo, almost as if gravity were letting go and I was floating up into the limitless black of the night sky.
It’s a weird feeling of falling up.
Falling up is an unsettling feeling…but in a good way, kind of like riding a roller coaster. I’m sure it stems from somewhere in my inner-ear—something about losing sight of the horizon. Or maybe it’s just the starry sky… a reminder of just how small I am and how big the Universe really is.
How far out into space can we see?
Last week on this blog, we pondered Andromeda, the most distant thing any of us can see with our naked eyes—a mere 2.5 million light years away. But with a wide variety of different telescopes, we can look much farther, as far as 13.7 billion light years.
Looking into space is not always a visual “seeing”, especially at the greater distances. (Remember how limited the “visual” portion of the electromagnetic spectrum is?) Often, we are detecting other wavelengths that are invisible to our eyes but detectable by a variety of telescopes: infared, radio, ultraviolet, gamma rays, microwave, etc.
How big is the Universe?
13.7 billion light years is the farthest distance we have detected. At that point, all we detect is microwave background ‘noise’ left over from the Big Bang. We’re basically looking back to the beginning of time. But we’re not seeing all there is…the Universe is likely at least 160 billion light years in size. Or bigger.*
And as far as we can tell… it’s probably flat.**
And it may be only one of many, many, many Universes.***
I’m falling up again. How about you?
PS – Happy Birthday Voyager 1!
Today is Voyager’s 35th birthday.
The most-distant human-made objects, Voyager 1 and Voyager 2 are on their way out of the solar system. Sometime soon, they will enter interstellar space, where they will wander our galaxy, the Milky Way until one of the following happens:
a. they get picked up by some extraterrestrial life form
b. our entire galaxy gets swallowed into a black hole
For more information:
Go ahead, make my day…leave a comment! Anything at all…ask a question, make an observation, tell me if you’ve ever fallen up, or down, or sideways…