Tag: Lunar Reconnaissance Orbiter

Moon bounce

By Phil Plait | November 9, 2012 7:00 am

Of all the amazing pictures returned from the moon by the Lunar Reconnaissance Orbiter – and I may include the Apollo landing sites among them – I think my favorites are the ones showing boulders that rolled down slopes.

Did I say rolled? I mean bounced!

[Click to enselenate.]

This shot from LRO shows the floor of crater Shuckburgh E, an impact crater about 9 km (~6 miles) across. The image shows a region about 655 meters (0.4 miles) across. The crater floor here is not level; it’s tilted up from left to right, and also has contours. Boulders dislodged for some reason (a seismic event, or a nearby impact) on the right have rolled down to the left… and some actually skipped along, bouncing and bounding as they did.

The two biggest trails are dashed, indicating the boulders had a bit of a rollicking time before coming to rest. You can see both boulders at the left of the trails, where they came to a stop. Note that the sunlight is coming from the bottom of this picture, which can play tricks on perspective. I see the boulders looking almost like craters and the skidding trails they left like little mounds. If you flip the picture over it may look better to you.

As always, pictures like this are a strong reminder that even on the Moon, where time stretches long and processes are slow, changes do occur. Maybe not often, and maybe not recently, but given enough time you have to think of the Moon as a dynamic place.

Image credit: NASA/GSFC/Arizona State University


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CATEGORIZED UNDER: Astronomy, Cool stuff, Pretty pictures

Excavating a long-dead lunar fire fountain

By Phil Plait | September 18, 2012 7:00 am

Although it may seem rather obvious now, for a long time there was a debate over craters on the Moon. Were they from impacts, or big volcanoes?

We now know that the vast majority are from objects slamming into the Moon. There’s a lot of junk floating around out there in space, and without an atmosphere the Moon suffers impacts from even the smallest chunk of rock.

However, you can’t completely disregard lunar volcanoes! Although long dead, they’ve been seen as well, though in far, far smaller numbers. And then, sometimes, you get a crater and a volcano just to mix it up. And I mean that literally.

Here is a very cool image from the Lunar Reconnaissance Orbiter showing just such a thing:

[Click to vulcanimpactenate.]

This odd-looking feature took me a few minutes to figure out, even after reading the description page. What you’re seeing is an impact crater about 170 meters (185 yards) across – the whole image is 450 meters (500 yards) in width. But what’s all that black stuff in the middle?

The picture inset here is an overview of the region (about 200 km across), and you can see the big blanket of darker material on the somewhat lighter lunar surface. The asterisk marks the location of the above picture. The dark stuff is pyroclastic – ash and other material that’s been blown out of volcanic vents in what are called fire fountains. In this inset picture it looks dark, but when it was fresh it was even darker. Over the eons, blasting by subatomic particles in the solar wind – think of it as cosmic erosion – has lightened it. Either that, or nearby impacts blew lighter-colored material over it.

Either way, it’s lightened up. But then something roughly the size of a tennis court, probably an asteroid, slammed into the middle of that region. It churned up pyroclastic material under surface, excavating it. This material still retains its fresh dark look, so the surrounding landscape looks positively gray in comparison.

Mind you, this is only one small part of a much larger image showing this region in high-resolution. I really suggest you take a look at the full image, where you can scan and zoom and really see what’s what. Seriously, it’s an amazing swath of lunar real estate. It’s very flat – as you might expect from an area inundated with volcanic flow – but peppered to near-saturation with small craters. This one crater with the dark material in it really stands out, as much due to its size as to its color and composition. It’s quite lovely.

Oh, that Moon of ours. We’ve sent twelve humans there, and dozens of various probes, and there’s still a whole lot left to explore.

Image credit: NASA/GSFC/Arizona State University.


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CATEGORIZED UNDER: Astronomy, Cool stuff, Pretty pictures

… and the flags *ARE* still there!

By Phil Plait | July 31, 2012 7:00 am

One of the more enduring questions about the Apollo Moon missions is seemingly simple: after 40+ years, are the flags the astronauts planted on the lunar surface still there?

It’s an interesting question. Buzz Aldrin claims he saw the flag blow over when the ascent module carrying him and Neil Armstrong lifted off from the Moon – which was never confirmed (until now; hang on for that), but the fates of the flags from the other five missions have never been ascertained. In 2009 there was tantalizing evidence the flags from Apollo 17 was still standing, but the images were just barely too fuzzy to know for sure.

But now, apparently, we do know: the Lunar Reconnaissance Orbiter has now confirmed that the flags at all the landing sites are still there, except for Apollo 11. It looked like Buzz was right!

Here’s an image showing the Apollo 16 flag:

The flag itself is visible in the picture – LRO’s angle on it shows the shadowed side, which is slightly darker than the lunar surface – and the shadow it casts on the surface is obvious.

I have to admit, I’m surprised*. The flags were made of simple nylon, which can disintegrate when exposed to ultraviolet light. I figured that after all this time they’d be nothing more than red, white, and blue powder at the base of their poles. I guess I was wrong. And I’m happy to be! [UPDATE: In the comments below, BABloggee Maxx points out that polymers need oxygen to be degraded by UV light, so this may be why the flags haven’t disintegrated.]

That picture from Apollo 16 is impressive, and I have to admit, that’s my favorite flag of the missions. It’s where Charlie Duke took a picture of John Young doing a "big Navy salute" – Young jumped up, and Duke snapped the photo while Young was still off the surface (not while he was in the air, of course, since that’s a commodity the Moon lacks):

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CATEGORIZED UNDER: Cool stuff, NASA, Pretty pictures

Map and measure a million Moon craters!

By Phil Plait | April 30, 2012 9:16 am

I give talks about asteroid impacts quite often, and sometimes people ask me why we should worry about them. I reply, "Go outside and look at the Moon. Then tell me we don’t need to worry about asteroid impacts!" The Moon is covered in craters, and it really brings home — literally — the fact that we need to understand impacts better.

I’m not being facetious, either. Looking at the Moon is a great way to learn about craters. By measuring their size, position, and shape, we can find out a lot about the history of impacts in the Earth-Moon system. The problem is there are so many craters — billions, if you look at high enough resolution. How on Earth — haha — can any scientist or team of scientists possibly look at them all?

Well, it depends on how big the team is. Enter citizen science: non-professional-science people who nevertheless love science. If you’re reading my blog — and you are — then that means you! CosmoQuest.org is a group of astronomers, run by my friend Dr. Pamela Gay, who have created a series of projects where people like you can perform needed tasks that are real science… in this case, measuring craters on the Moon! Using MoonMappers, you can identify and measure craters using images from the Lunar Reconnaissance Orbiter, a spacecraft currently circling our Moon and taking thousands of high-resolution pictures.

I signed up and started right in, and find it somewhat addicting. You’ll need to register first through the CosmoQuest forum, which takes one minute and is free. Once you’ve done that, just go back to Moonmappers and dive in. I was able to identify dozens of craters in just a few minutes. Here’s a typical scene:

The blue circles are craters found using automated software. The green ones mark craters I found. The task is really simple: you can mark craters with your mouse, dragging the circle to match its size. If you miss a bit, you can easily adjust the circle’s position to re-center it. You only need to find craters bigger than 18 pixels in size, so it’s not an impossible chore! You can also flag odd features like linear cliffs, boulders, and so on, if you happen to see any. Several of the images I went through had them. One had lovely striations in an old lava flow, so you never know what you’ll see.

Sound like fun? It is! But hurry: right now, CosmoQuest has issued a Million Crater Challenge, to get 1,000,000 craters identified by full Moon, which is on May 5, just days away. As I write this they’re still a long way from their goal. How many can you find?

And remember: this isn’t just fooling around, this is real science. How are craters made? Why are they different shapes? How many are 10 meters across versus 20 versus 30 versus 100? All these questions are important in understanding impacts… especially that last one. Getting the scales of impacts, and how the numbers of them increase as the size gets smaller, is critical in being able to predict how often they happen. At some point, we’ll see a small asteroid headed toward Earth, and we’ll have to decide if it’s big enough to worry about and spend hundreds of millions of dollars deflecting it. The work you do here, quite seriously, can help inform that decision.


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CATEGORIZED UNDER: Astronomy, Cool stuff, Pretty pictures

Desktop Project Part 6: Psychedelic topographic Moon

By Phil Plait | March 31, 2012 7:00 am

[Over the past few weeks, I’ve collected a metric ton of cool pictures to post, but somehow have never gotten around to actually posting them. Sometimes I was too busy, sometimes too lazy, sometimes they just fell by the wayside… but I decided my computer’s desktop was getting cluttered, and I’ll never clean it up without some sort of incentive. I’ve therefore made a pact with myself to post one of the pictures with an abbreviated description every day until they’re gone, thus cleaning up my desktop, showing you neat and/or beautiful pictures, and making me feel better about my work habits. Enjoy.]

The Lunar Reconnaissance Orbiter, one of my favorite space probes ever, takes amazing high-res pictures of the lunar surface. But more than that, it can map the elevations of lunar features using shadows as a guide. Knowing the angles of the Sun, the Moon, and its viewing position, it can accurately gauge the elevations of the Moon’s surface as it takes image after image, orbit after orbit.

The scientists on LRO used that information to put together a wild topographic map of the Moon’s far side:

In this map, red represents stuff higher up, blue lower down. The resolution is decent: 100 meters across the surface (NSEW) and 20 meters vertically. Not enough to keep you from stubbing your toe if you’re walking across Mare Orientale, but enough to get pretty good info on the geological history of our nearby cosmic neighbor.

Of course, the picture I’ve displayed here — and even the embiggened version if you click it — doesn’t really convey the scale of this map. For that, you really need to check out the pan-and-zoom version. That lets you drill down into the data and see just how detailed this map really is.

And stay tuned. In a few months the LRO team will release a new version of this map; the spacecraft is still plugging away over the Moon, and there’s more way cool stuff yet to come.

Image credit: NASA/GSFC/DLR/Arizona State University


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Desktop Project Part 1: A weird Moon crater

By Phil Plait | March 26, 2012 7:00 am

[Over the past few weeks, I’ve collected a metric ton of cool pictures to post, but somehow have never gotten around to actually posting them. Sometimes I was too busy, sometimes too lazy, sometimes they just fell by the wayside… but I decided my computer’s desktop was getting cluttered, and I’ll never clean it up without some sort of incentive. I’ve therefore made a pact with myself to post one of the pictures with an abbreviated description every day until they’re gone, thus cleaning up my desktop, showing you neat and/or beautiful pictures, and making me feel better about my work habits. Enjoy.]

First up in my Desktop Project is a weird crater on the Moon, seen by the Lunar Reconnaissance Orbiter:

What a strange little thing! [Click to enlunenate.]

It’s about 140 meters across the rim, and it’s located in Plato, a big, relatively flat walled plain — basically, a crater that got mostly filled in with lava long ago — about 110 km (70 miles) across. You can see rubble and other debris scattered around it (in this image, sunlight is coming from below and to the left), and the interior is just odd.

This is called a bench crater, where you get roughly concentric features inside the crater itself. It’s probably from a high-velocity impact by a small (5-meter or so) asteroid, and the terrain where it hit probably has a thin layer of compacted regolith — the powdery surface material covering a lot of the Moon. This loose material blasted out more than the harder rock below, so you get this weird two-tiered structure.

Craters can be pretty complex; you might think you just get bowl, but in fact the impact speed, angle, the terrain, and the overall size of the impactor make a huge difference in crater structures.

Also? The first thing I thought of when I saw this picture was that it looked like the plaster cast they made of the giant ant footprint in one of my favorite movies of all time, "Them!" And that makes me a bigger dork than you can ever hope to be.

Image credit: NASA/GSFC/Arizona State University

CATEGORIZED UNDER: Astronomy, Pretty pictures

The Moon's history of violence

By Phil Plait | March 14, 2012 1:53 pm

The Lunar Reconnaissance Orbiter is a NASA space probe that’s been orbiting the Moon since June 23, 2009. On March 19 it will mark its 1000th day in orbit! To celebrate, NASA released this cool animation showing the history of the Moon:

According to current thinking, the Moon itself formed after a planet roughly the size of Mars slammed into the Earth at a glancing blow. This colossal impact threw billions of gigatons of debris into space. Some of that fell back onto Earth, and some formed a huge disk around the (now once again liquefied) planet. This material eventually coalesced to form the Moon.

But the story wasn’t done: with impact after impact, wave after wave of bombarding material shaped and reshaped the Moon’s surface. The animation above is a bit fanciful – it has sound, of course, and it shows time as a variable that flows at different rates – but gives a lovely overview of the violent past of our satellite. I like how I could see various features forming, knowing eventually they would be the familiar sites (and sights) I see through my telescope eyepiece. It’s a good reminder that the way we see things now is not the way they’ve always been, and that sometimes the forces that shape our current circumstances are not necessarily gentle or subtle.

[My congrats to everyone on the LRO team for 1000 days of amazing science! If you want to see more about LRO, I’ve written about it dozens of times, and you can also check the Related Posts below.]


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LRO spots Apollo landing sites in high res

By Phil Plait | September 6, 2011 11:27 am

NASA’s Lunar Reconnaissance Orbiter has been circling the Moon for the past few years, snapping away, taking hi-res pictures of the lunar surface from a height of a mere 50 kilometers (30 miles). A few weeks ago, NASA commanded the probe to dip lower, allowing even closer, more detailed shots. Skimming the surface at a mere 21 km (13 miles), it took this amazing shot of a site where humans once walked on the Moon:

[Click to onesmallstepenate.]

That is Apollo 12, my friends, the location where humans showed that not only can we explore other worlds, but we can do it more than once.

The entire shot shown here is a little over 350 meters across (pictures from Apollo 14 and 17 are also available at on NASA’s website). Various highlights are labeled: the descent stage of the lunar module (left behind when the top half of the module blasted back up to orbit, docked with the command module, and returned home to Earth), the Apollo Lunar Surface Experiments Package (ALSEP), and even Surveyor 3, an unmanned lander that had touched down two years previously; one of the Apollo 12 mission goals was to land near it, examine it, and return pieces of it. Clearly, they nailed that.

The part of the picture showing the lander is really something. LRO took images of the site in 2009, but these new ones are more detailed due to the lowered orbit, and also a bit clearer due to the angle of the Sun being lower. You can see the lander’s shadow to the right far more clearly.

… and those squiggly lines? That’s where the dust was disturbed by the astronauts’ bootprints as they walked around.

Yup. You are actually seeing physical evidence of human beings walking on the surface of another world.

And there’s more.

Read More

Majestic mountains of the Moon

By Phil Plait | June 30, 2011 6:30 am

The Lunar Reconnaissance Orbiter takes amazing pictures of the Moon; I’ve posted dozens over the past couple of years. One of my favorite things is when the spacecraft snaps features I know: craters, mountains, winding valleys that I’ve seen myself behind the eyepiece. When I was younger I spent countless hours scouring the lunar surface with my telescope, and it’s still a fun target when I haul my ‘scope out to the end of the driveway.

And among the best of the best is the crater Tycho. You probably know it already; when the Moon is full the crater is bright, and the rays extending from it — plumes of material ejected radially during the impact that formed the crater — are extremely obvious. At 86 km (50 miles) across, it’s a decent-sized hole in the surface, with a beautifully-defined system of central mountain peaks 15 km (8 miles) across. So when LRO sets its sights on Tycho’s peaks, well… you get a gorgeous panorama like this:

You must click that to enlunenate it and see it in incredible detail. It’s truly spectacular!

That peak rises about 2 km (1.2 miles) about the crater floor. Look how steep it is! I was mentally comparing it to the local foothills of the Rockies near where I live in Boulder, and realized it’s not a bad analogy as far as size and shape go. In one way, hiking to the top of Tycho’s peak would be easier, since the gravity is only 1/6th of Earth’s… but while the air is thin here in Boulder, it’s literally nonexistent on the Moon. So I’m thinking hiking Tycho would be somewhat more taxing.

But what a sight when you reached the top! Sitting smack dab on that largest peak is a boulder I’d very much like to see up close:

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CATEGORIZED UNDER: Astronomy, Pretty pictures

I think the Moon watched Bad Universe

By Phil Plait | June 14, 2011 6:30 am

Nature imitates art! Kinda!

I am endlessly fascinated by impact craters. You might think they all look alike, but they don’t. They have different shapes, structures, shading, even (sometimes) colors. And these features can tell us a lot about the object that caused the impact as well as the structure of the surface they hit.

For example, here’s a nifty crater on the Moon as seen by the Lunar Reconnaissance Orbiter:

That image is 500 meters (.3 miles) across, so this is a decent-sized hole [click it to enlunanate]. Note the rubble; that’s a clear indication that the surface of the Moon where the object hit was rocky as opposed to sandy. You only get fractured boulders like that when the impacted surface has some cohesion. Most of the Moon is covered with a layer of dust called regolith, but here, under that powdery surface, was rock.

I’m not a geologist, so that wasn’t the first thing I thought of when I saw this picture. What I did think of was how familiar this crater looked to me. And it didn’t take me long to figure out why…

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