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

We Landed on the Moon

Today, the Chinese Space Agency’s Chang’E-3 spacecraft successfully touched down on the surface of the Moon. A few hours later, a small rover called Yutu (Jade Rabbit, in Chinese) successfully set foot onto the lunar surface.

Screen caps taken from a Chinese state television feed show the view from a side-looking camera mounted to the lander of the Yutu rover deploying from a ramp onto the surface of the Moon on December 14, 2013 CNSA / CCTV / Emily Lakdawalla
Screen caps taken from a Chinese state television feed show the view from a side-looking camera mounted to the lander of the Yutu rover deploying from a ramp onto the surface of the Moon on December 14, 2013
CNSA / CCTV / Emily Lakdawalla

Incredible! Emily Lakedewalla has more animations like this on her blog, and I highly recommend checking it out.

Chang’E-3 and Yutu aren’t alone at the Moon. Orbiting above are the Lunar Reconnaissance Orbiter and the recently-launched Lunar Atmosphere and Dust Environment Explorer (LADEE). That means that as of today, we have multi-national, peaceful, scientific exploration of our Moon.

As Sean Carroll noted, the Chinese certainly deserve credit for this accomplishment, becoming only the third nation in the history of humanity to soft-land a spacecraft on the Moon.  But I admit to a certain twinge of frustration that this accomplishment comes at a time when the United States is seriously considering a budget that slashes funding for NASA, particularly its planetary exploration program. There’s simply no sensible reason the world’s richest and most technologically advanced nation – the only one to ever send humans to the Moon, for crying out loud – to be considering such a cut in funding like this.

Who knows, perhaps China’s lunar landing will spurn public pressure on Congress and the administration to reconsider the proposed budget for NASA.  In the meantime, I’m glad that other countries like China are stepping up and advancing the frontier.

Yes, the Chinese are proud, and they deserve to be. But we should all be proud because this is first and foremost a human endeavor. This is what we are capable of when we choose to do great things. This is humanity at its best.