Eugene Cernan

I was born just in time to say that I am a child of the Apollo era (except for arriving too late for Apollo 11, but I really don’t mind as it beats the alternative). Among my very early memories are those of the tail end of the program, and ultimately the very end with Apollo 17 in 1972 (1)Sure there was Apollo-Soyuz but it was more of a coda than an end.

That mission was commanded by Eugene Cernan, Captain, USN. Cernan was pilot of Gemini 9, Lunar Module pilot of Apollo X (which got him to within 47,000 feet of the lunar surface), and commander of Apollo 17, which closed the remaining 47,000 feet. I found this clip on YouTube which summarized Cernan’s last mission:

Until Apollo 17, every NASA astronaut was a current or former military test pilot. But this final mission included NASA’s first scientist-astronaut, Harrison “Jack” Schmidtt, a geologist. I love the genuine excitement in Schmidtt and Cernan’s voices as they find the orange rocks they were hoping to find in the Taurus–Littrow valley.

Capt Gene Cernan, USN, in the Taurus–Littrow valley, Moon. December, 1972. Credit: NASA:

“We leave as we came, and, God willing, we shall return, with peace and hope for all mankind.” — Cernan’s closing words on leaving the moon at the end of Apollo 17

Eugene Cernan was the last man to ever walk on the Moon; the last human being to ever walk on another world. And now he has left this world one final time.

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1. Sure there was Apollo-Soyuz but it was more of a coda than an end

The Moon and Earth

China’s Chang’e 5-T1 is the latest in a series of robotic missions to eventually return a lunar sample to Earth. Its mission is to “simply” travel to the Moon and return to Earth. Just a little run around the neighborhood. But as it was coming around the far side of the Moon, it snapped this image that should make us all stop and marvel:

The Chang'e 5 test vehicle captured this beautiful view of Earth over the far side of the Moon on October 28, 2014. Credit: CNSA
Earth over the far side of the Moon on October 28, 2014. Full size image. Credit: CNSA

You’ve got to click to see the full-sized image. It’s a perspective that’s unlike anything I’ve ever seen before. Yes, similar views were captured during the Apollo program, but nothing quite like this. Our Moon’s far side is so very different from its near side that it almost looks like an alien world. Most of the maria regions are on the near side, and thanks to tidal forces, we can never see the far side of the Moon from Earth. And yet, it’s our Moon. And there we are, on that small blue/white sphere in the distance.

I first spotted this image on the Planetary Society’s blog and it’s cool to see it getting passed around. I think images like these are crucial to our survival. Hopefully, as we continue to “grow up” as a species, we’ll better understand how finite our planet really is, how alone in the dark we really are. And how lucky we are to be alive to see it like this.

There’s enough room between the Earth and Moon for all of the planets

The Moon is our nearest celestial neighbor, but it’s tempting to think it’s much closer to Earth than it really is. The Moon has an average distance from Earth of 384,399 kilometers (or 238,854 miles if you prefer). We know that’s far, but how far is that really? It turns out it’s far enough to fit every other planet in the solar system with room to spare. Check it out:

All ur planets belong to us: The planets of the solar system can fit between Earth and the Moon. Credit: Astronomy Foundation
All ur planets belong to us: The planets of the solar system can fit between Earth and the Moon. Credit: Astronomy Foundation

I spotted this image on Twitter and thought it was a perfect illustration of the actual distance between the Earth and the Moon. But even then I needed a double-check so I went to Wikipedia, found the equatorial diameter of each of the planets and added them up. Sure enough, they came out to less than the average Earth-Moon distance:

[table id=PlanetsDiameter /]

As you can see, the average distance (or semi-major axis) between the Earth and Moon can accommodate all of the planets with room to spare! But perhaps the most dramatic example of the actual distance to the Moon is to simply just show it to scale:

The Earth and Moon to scale.
The Earth and Moon to scale. Click to embiggen, it’s pretty amazing!

Space is big. It’s really, really big. So big that it’s hard to not end this post with a quote from Douglas Adams:

Space is big. Really big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space.

— Douglas Adams, The Hitchhiker’s Guide to the Galaxy