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Distance
Every now and then I think of a new way of looking at the universe. The scale of the thing always astounds me.
Consider this. Before the twentieth century the farthest apart any two humans could ever get was 12,756.2 kilometers, that’s 7,926.41 miles, the diameter of Earth at the equator. (I suppose it’s possible that mountains could add a little to that, but we’ll ignore that possibility because it really won’t matter.) The first manned orbiters extended this by a couple hundred kilometers, but it was the moon missions that really changed it.
At perigee, when it’s closest to Earth, the Moon is 362,631 kilometers away. Frank Borman, James A. Lovell, Jr. and William A. Anders, the first people to orbit the Moon, were more than 28 times farther away from other humans than any other human ever had been.
I wonder if that distance weighed on their minds, or if they kept too busy to think about it.
It amazes me that as big and filled with fascinating things as this world is, it’s a tiny place even by the standards of its own satellite system.
On average, the Sun is about 39o times farther away than the Moon. And we’re one of the near planets, close to our star.
The most distant machine we’ve ever made is Voyager I, which is now 122 Astronomical Units away from our homeworld, 122 times as far from us as we are from the Sun. Traveling at lightspeed, a radio signal from Earth takes 16 and a quarter hours to reach our farthest creation. And it’s still within our solar system.
Which is one of hundreds of billions in our galaxy. Which is one of hundreds of billions in the known universe.
And on that awesome thought, I’m going to bed. Goodnight, Earth.
Forged in the heart of a star
In my last post I mentioned our connection to the stars and the universe, and I’ve been thinking about that some more. Consider for a moment that every atom that makes up your body was part of a star once. Think about some of the implications.
There’s a young Earth creationist group whose favorite tactic is the phrase “Were you there?” They train children to ask this question in schools, at museums, anytime someone talks about something happening millions of years ago. It’s every bit as childish and annoying as you imagine, all the irritation of a four year old repeatedly asking “why?” with none of the actual curiosity.
The thing is, from a certain point of view it’s a perfectly honest answer to say “Yes”. Yes, I was there when the dinosaurs died out, and so were you. The atoms that make up my body were already here, in the air, the ground, the oceans, and the plants and animals, even in the dinosaurs themselves. Scattered across the world, unbinding from one molecule and binding into another, and passing down through the ages until the time when, for a brief while, they would come together to form me. The same is true of you and everyone else who’s ever lived. Read the rest of this entry
Full of stars
Phil Plait of Bad Astronomy has once again blown my mind. If you never click another link on this blog, click this one. It’s a pan & zoomable hi res image of the Milky Way disc. There are a billion stars in that picture.
Pick any random spot and zoom in and feel amazed. I liked zooming in on the galactic core, but there’s no boring spots that I saw (except for the blacked out sections hiding the alien civilizations ;þ). There’s so much going on in there, and every pixel represents an area vastly larger than that ever occupied by humans throughout our entire history.
Naturally, it had to be taken from Earth, since we can’t get any cameras far enough away to make any difference. Which means there’s still much more of our galaxy not visible in that image. Read the rest of this entry
Home Sweet Home
Bad Astronomy featured this pic today, which came from the ESA spacecraft Rosetta.
Crescent Earth from 633,000 km away.
Breathtaking, isn’t it? For all the wonders of this vast universe, there are few sights as beautiful as our home. The little water world that’s named, with seeming irony, after dirt, and is home to all the life we’ve ever found. It’s lovely to see it as a place with phases like the moon, to challenge our usual perception. Read the rest of this entry
Happy Perihelion!
That’s right, tonight we’re as close to the Sun as we get. Tomorrow we start the long six month slog back to Aphelion, three million miles above us and a hundred and eighty-five million miles below us. It’s statements like these that make it clear that English was not developed with orbital mechanics in mind.
What’s the appropriate way to celebrate perihelion?
The Adventures of Leo Tarvi 