There are many ways to celebrate Earth Day, from sustainability efforts (and check out our new blog, Guilty Planet) to simply appreciating nature.

And while this is a beautiful shot of Forest Park right here in Portland, it doesn't compare -- in my eyes -- to the perfection of Earth as seen from so far away.

In October of 1946, a V-2 missile was launched from New Mexico, straight up into the air. And at its maximum height of 65 miles (just barely into what was then considered outer space), it snapped the first photographs of the Earth from Space. (And you can click every image on this page to enlarge it.)

It wasn't until Apollo 8, 22 years later, that the first color photograph of Earth was taken. The sole idea of Apollo 8 was to orbit and take photographs of the Moon, but when William Anders saw Earth rising over the Moon, he snapped the most famous photo of the mission, known simply as "Earthrise."

And now, in the 21^st Century, we've got a myriad of satellites, shuttles, spacecraft and rockets to choose from if we want to photograph the Earth. And there are some beautiful shots out there, such as from the International Space Station's 7th expedition.

The IMAGE satellite captured the Aurora Australis over the southern hemisphere after a record-setting Solar Flare in 2005 (and movies are available here).

While, on the other side of the Earth, the United States' Space Shuttle photographed this shot of the Aurora Borealis in 2007.

But for the very last photo I'll leave you with, I'd like to remind you of how tiny we are once you get just a little ways away. The Cassini spacecraft, out at Saturn, took this photograph of the Earth in September 2006. The Earth is the tiny, bluish dot on the right of the image, just inside the outermost, diffuse ring.

Notice how, in the close-up inset in the upper left-hand corner, there's a little blur on the upper left hand corner of the Earth? Say hello to the Moon, as seen from Saturn.

That's us, folks. That's our wet, little rock, that nobody cares about (yet) except us Earthlings. So appreciate it, be aware of it, and -- most of all -- enjoy living on it! Happy Earth Day.