I was at the SXSW tech conference over the weekend to be on a panel about 2012 doomsday nonsense. Right after, Helen Popkin of MSNBC interviewed me about this stuff:

[If the video above doesn't load, hit refresh; I've found that happens sometimes and refreshing usually fixes it.]

The panel was fun — I gave an overview to and quickly debunked a bunch of 2012 claims, while JPL scientists Don Yeomans and Veronica McGregor talked about asteroid impacts, and what NASA is doing to calm unfounded fears about them. Asteroids are indeed a threat, but that danger is routinely exaggerated way beyond reality by lots of folks (YouTube fearmongers, I’m looking at you). There’s no real danger of the Earth ending in 2012, Mayan calendar-wise or otherwise — but the real danger is the overhyped fear of nonsense.

Forewarned is forearmed. Be aware of the reality of the situation, and save yourself a lot of trouble.

I’m a fan of simple infographics: illustrations that make a point clearly and cleanly. The folks at mgmt. design have made one for US manned spaceflight that does just that.

Click that to enboosternate it; I’ve put just a portion of it here. I like it because you can see a few things instantly, for example how short the Apollo program was compared to the total amount of time we’ve been space traveling.

Even more obvious are the gaps in flights. The biggest is post-Apollo and pre-Shuttle, when the Saturn V was essentially decommissioned before the Shuttle was anywhere near being ready. That might be something to keep in mind during the current gap in the US capability to put humans in space.

Also obvious are the pauses after Challenger and Columbia, when the safety of the Shuttle was reassessed. Now, of course, we’re in the second long gap.

I wonder how long it will last? And perhaps more importantly, just how it will end?

Last week, I was interviewed by my friend Ken Plume for his "A Bit of a Chat" series (which has a pretty stellar list of geeky guests, I must say). That interview is online for your earball pleasure. We talked Dragon*Con, quiz shows, being a little dirty, Bill Corbett (hi Bill!), and then NASA. Oh boy, and then NASA. I spouted off pretty good on that particular topic.

And if hearing me blather for way over an hour isn’t enough, you can also listen to the time he interviewed me back in May 2010.

On March 2, 2012, I was the guest on the live Nerdist podcast recorded in Boulder, my hometown. We did the show to a full house (700+ folks) and had a lot of fun. And now, for your brain-melty pleasure, the episode is now online!

Now listen — and I’m serious here — this podcast is Not Safe For Work. I mean seriously and holy cow really really NSFW. There is much swearing, and much humor that would not be fit for primetime TV, say. I’m only marginally sweary, but Chris, Matt Mira, and Jonah Ray — the Nerdist crew — are very much so. And before anyone calls child services on me, in the podcast Jonah misspoke: my daughter is in fact older than 14, and she’s a big fan of the podcast.

Anyway, it was a great experience. I’ve known Chris for a few years now, and finally got a chance to meet Matt and Jonah, who were funny and lovely. And the audience! They were amazing. I could tell they were having a good time, and afterwards the line to talk to the Nerdist folks was so long we were there until nearly 2:00 a.m. And man, do they love Chris — they brought presents, drawings, Dalek cupcakes… it was amazing.

If you’re curious about the topics we covered, we went over marijuana, living in Boulder, conspiracy theories, the Transformers movies, the Moon Hoax, my work on Hubble, poop jokes, life as a nerd, supernovae, quantum superposition, colors in Hubble pictures, Fiske planetarium, and much more. Come to think of it, I’m surprised in hindsight we didn’t totally dork out over Star Trek and Doctor Who! That’s actually pretty shocking.

So, if you’re not easily offended, gird your ears and give it a listen. And I hope, given the caveats, you enjoy your burrito.

The Lunar Reconnaissance Orbiter has been circling our nearest neighbor since 2009, taking amazing high-resolution images of the Moon’s surface. When it was first proposed, I remember wondering if it would get good shots of the Apollo sites… and boy howdy, did it. Then, in 2011, NASA decided to lower the mapping orbit from its usual 50 km (30 miles) down to an incredible 25 km (15 miles) — an orbit they can’t sustain, since variations in the density of the Moon would soon crash the spacecraft. But for those short periods, they got amazing images of the Apollo landing sites, including this stunner from Apollo 15:

[Click to onesmallstepenate.]

LRO has looked at the Apollo 15 site before (see the links at the LRO page for more), but never this clearly! The lander descent stage is labeled (the ascent stage took Dave Scott and James Irwin back up to the Command Module, which then brought them home), and is pretty clear (the shadow’s cool too). To the upper left is the ALSEP (Apollo Lunar Surface Experiments Package, containing scientific instruments), and the the right is the rover (LRV). And connecting them all, you can clearly see the astronauts’ bootprints! Arrows point out the fainter ones.

[Cripes, the news is coming so fast I can hardly keep up: in between writing this post and putting it up, the folks at LRO released an image from the Apollo 11 landing site too, and it's also just flippin' amazing.]

That’s not the first time we’ve seen those boot tracks, but still. It gives me chills: human beings walked on the Moon.

And we’ll do it again, I just know it. Soon, I hope. But it will happen.

Image credit: NASA/GSFC/Arizona State University

- LRO spots Apollo 12 footsteps
- Apollo 17, then and now
- LRO spots Apollo landing sites in high res
- Apollo 16 site snapped from orbit
- One Giant Leap seen again
- APOLLO LANDING SITES IMAGED BY LRO!

Over the weekend, I posted about asteroid 2012 DA14, which is not the threat some people are claiming it is (at least not right away). And now I have to tell you about an asteroid that might be a threat in the year 2040. Most likely it won’t be, but it’s something we need to look at carefully.

There’s some background I have to give you so this all makes sense, but let me sum up here: the odds of an impact from asteroid 2011 AG5 are low, but not easily dismissed. If it passes us at just the right distance in 2023, it’ll swing back again and impact the Earth in 2040. We don’t know the orbit of it well enough to say either way just yet, and it may be late 2013 before we can be sure. An asteroid expert at NASA says waiting until next year for more observations is not a problem, but another asteroid expert is saying that waiting that long is a bad idea: we should start analyzing a possible deflection campaign for this rock now. I’m personally leaning toward the idea that getting moving on the initial analysis now is not such a bad idea. If you prefer, I have a list of bullet points at the conclusion of this post with summarized information.

[In the interest of full disclosure: Below, I will be talking about Rusty Schweickart and Don Yeomans. I've known Rusty for several years, and Don and I will be on a panel together talking about asteroid impacts at SXSW next week. I honestly like both Rusty and Don. They're good men, very intelligent and honest, and I have a lot of respect for both of them.

Also, because of the length and nature of this post, I strongly urge everyone to read the whole thing, carefully, before commenting. Thank you.]

The rock

The asteroid, called 2011 AG5, was discovered in early 2011 by a telescopic survey of the sky designed to look for asteroids that can get near the Earth. Although its exact size is unknown, it’s roughly 140 meters across — the size of a football stadium. As you can see from this diagram, it orbits the Sun on an elliptical path that brings it out past the orbit of Mars and inside the orbit of Earth. It circles the Sun once every 1.7 years.

As it happens, the orbit of AG5 brings it close to Earth every few orbits. In 2023, it will pass us at a distance of about 1.6 million km (1 million miles). That’s a safe distance, with no chance of it hitting us at all. However, you have to appreciate the gravity of this upcoming situation.

The keyhole

When AG5 passes us in February 2023, the Earth’s gravity will bend its orbit a little bit, changing the path the rock takes. If it passes close to the Earth the orbit changes a lot; if it’s too far the orbit changes only a little. But if AG5 passes us at just the right distance, the orbit will change just the right amount to put it on a collision course with Earth. This region of space is called a “keyhole”, and in this case, should AG5 slip through it, it will hit us 17 years later, in 2040. That collision, though not global in scope, would be catastrophic: equal to about a 100 megaton explosion, twice that of the largest nuclear weapon ever detonated.

The problem is, we don’t know the orbit of AG5 well enough to know if it will travel through the keyhole or not. As I pointed out in the article about the asteroid 2012 DA14, it can be tricky to try to predict asteroid orbits too far into the future. The orbit of an asteroid is determined by making measurements of its position over time, and because of various effects (like blurring due to our atmosphere) it is impossible to get exactly precise positions. They can be good enough to get an accurate orbit for the next few years, but the farther into the future you look, the fuzzier that path gets.

In the case of AG5 we know its orbit well enough to know for sure it’ll miss us by a million miles in 2023, but we don’t have the accuracy yet to know if it will thread the eye of this keyhole, which is very roughly 360 km (240 miles) across. It’s like standing by the side of a road and knowing a car driving down it will safely miss you by 10 meters, but you can’t be sure if that exact distance will be 10.004 meters or 9.996 meters. And that’s the sort of accuracy we need for AG5.

The odds

At the moment, given the observations we have, the odds of AG5 passing through the keyhole in 2023 are about 1 in 625. For an asteroid impact, that’s actually pretty high as these things go, but still pretty low in realistic terms. Let me be clear: any professional poker player will tell you never to bet on an inside straight, and the odds of getting the card you need in that case are only 1 in 13 or so. The odds of AG5 hitting us are much lower than that!

Moreover, since the orbit of the asteroid is uncertain, as we get better observations the predicted path is likely to change, to move. In that case — which is almost certainly the way things will play out — the predicted orbit will move away from the keyhole and we’ll be safe from a 2040 impact. This sort of thing has happened several times before with asteroids as their positions are observed over time, and the orbital paths clarified.

Still, a 1 in 625 chance is high enough that we need to be sure. So how do we do that?

(more…)

Wanna know what the Moon will look like at any time this year? And I mean what it really looks like, shadows and all?

Then go to the NASA Goddard Science Visualization Studio, where they have an amazing applet that shows you the Moon’s appearance on an hourly basis for the entire year!

Most times, websites showing you the phase of the Moon do it in big time chunks, like once per day or even per week, or they have a low-res image of the Moon with the dark part blacked out. But this one from NASA lets you enter the date and hour, for very high time resolution photo-realistic pictures.

The images are based on observations by the Lunar Reconnaissance Orbiter, which has been taken super-high-res images and altimetry data since it went into orbit our satellite in June 2009. The images show far more than just the lunar phase. For one thing, using the LRO altimeter data, it can calculate the lengths, directions, and positions of all the shadows of mountains, crater rims, and so on, knowing the angle of the Sun over the horizon.

After seeing it, my first thought was, "Someone should string these all together to make a video." I looked down the NASA page, et voila! They had! So I made it into a video on YouTube which I annotated. I also added music by Kevin MacLeod I rather like.

That weird rocking and tilting motion is real. It’s called libration. The Moon’s orbit around the Earth is elliptical, so sometimes it moves faster in its orbit than other times. However, the Moon’s spin is constant. The geometry of these two things add together, allowing us to sometimes peek a little bit over the eastern and western horizons. Not only that, the Moon’s orbit is tilted a bit with respect to our Equator, so we sometimes get a little peak over the north and south poles too.

I’ll note that these views of the Moon are not designed for people at different latitudes; for example, from Australia the Moon looks upside-down compared to how I’m used to seeing it in Boulder! Instead, these views show the Moon as if you are at the center of the Earth with your head pointed toward the north pole. Still, it’s an amazing thing, and well worth bookmarking. When I need to know what phase the Moon is in — and it happens several times a month for me — this is where I’ll check.

Image credit: NASA/Goddard Space Flight Center Scientific Visualization Studio. Music for the video is "Five Armies" by Kevin MacLeod.