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[Music]

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♪ What the heck is that? ♪♪

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[Music fades]

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Hi everyone – I’m Noah Petro,

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the Project Scientist of NASA's Lunar Reconnaissance Orbiter Spacecraft

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which has been at the Moon for over a decade now,

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sending back a treasure-trove of data, including some spectacular images.

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Inevitably, whenever NASA publishes a photo

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or releases a video of ours showing the lunar landscape,

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we get emails, tweets, and online posts from viewers

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asking for us to further explain some of the weird looking visuals they are seeing.

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So today, we’re going to look at these strange and mysterious looking features on the Moon

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to answer the question: What the heck is that?

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So let's launch into this!

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In our video "Apollo 13 Views of the Moon" –

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many viewers wondered about this strange looking circle with dark lines.

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So what the heck is that?

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Well, for starters, this is not the remnants of an ancient lake,

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and apologies to the sci-fi crowd,

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it’s not a secret Moon base with runways for spacecraft.

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This is a geological feature known as Komarov Crater.

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It’s 80 kilometers wide, and it’s on the far side of the Moon,

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on the edge of Mare Moscoviense.

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The floor is covered with a network of rilles that make it look like Sun-dried mud.

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And it’s a great example of a floor-fractured crater, or FFC.

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So what made Komarov look like that?

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The leading idea among scientists is that FFCs are like

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volcanoes that didn't quite reach the surface.

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An impactor hits the Moon, forming the crater.

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And underneath the crater floor, the impact creates a zone of broken rock,

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called a breccia lens.

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Magma from deeper inside the Moon rises into the cracks in the breccia lens,

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but something stops it from getting all the way to the surface.

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So, it spreads out under the crater floor, forming what’s called a sill.

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The magma and hot gasses in the sill push on the crater floor from below,

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causing it to bulge and fracture like the top of a cake in the oven.

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The cracks you see are known as graben.

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[Release the graben!]

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Using data from Lunar Reconnaissance Orbiter,

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scientists have cataloged over a hundred floor-fractured craters just like Komarov.

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They are fascinating works of nature from billions of years ago.

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[Billions!]

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An image from the Apollo 11 mission has gotten a lot of attention over the years.

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Here you see a pair of craters known as Messier and Messier A.

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But they don’t look like the more typical round craters you see on the Moon.

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LRO has taken even more high definition shots of these two sights, showing us incredible detail.

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These oval shapes and areas of ejected rock do look like they could belong in Star Wars

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as the crash site of the Millennium Falcon.

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And actually, the way you might imagine a scene like that happening,

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with an object slamming and then skipping across the surface

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is what took place here - except with an asteroid.

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You see, at very low angels, an incoming asteroid can actually become decapitated,

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with the top part splitting off at impact

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and either escaping back into space or skipping to form a second crater.

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Think of it like skipping a stone across the water.

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Both laboratory impact experiments and computer modeling

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have demonstrated the physical affects of the oblique impact

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of a large asteroid on the Moon. And LRO's data helps prove

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the formation of these unusual features.

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[LRO!]

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Scattered across the lunar surface are these long winding features –

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which many viewers have correctly assumed are channels.

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On the Moon, these are called rilles.

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There is a prominent one here on the Aristarchus plateau.

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And if you were comparing to visuals on the Earth –

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you might be tempted to think about long river canyons,

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flowing in long, sweeping meanders –

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like the mighty Mississippi pouring out into the Gulf of Mexico.

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And if that’s what you’re thinking –

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erase it from your memory, because it’s wrong.

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Now to be fair, when these channels were observed on the Moon for the first time,

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there was an immediate thought that water may have carved these features.

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But, once we got actual samples from the Moon,

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combined with additional spacecraft data and studies over the years,

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we’ve come to understand that there was never flowing water on the Moon.

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So what could carve these sweeping features?

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If you said flowing liquid hot magma after it erupted onto the Moon's surface -

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you’d be correct!

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[Winner!]

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When lava flows across the surface, it erodes the crust,

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and slowly flows as it bends and turns, forming these beautiful channels.

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We have a great view of this in our Rima Prinz visualization.

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Here you see a long channel where lava once flowed

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from the Vera volcanic depression.

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Eruptions of lava fountains formed a lake of lava 300 meters deep

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and carved a lava channel one-hundred times deeper than anything found on Earth.

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These types of feature were so compelling

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that the Apollo 15 mission went and explored one in 1971,

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known as the Hadley rille.

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Future explorers may visit others, but they should leave their fishing rods at home.

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This visual is one of our most popular.  This is a picture of Tycho crater,

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and the famous central peak boulder, which is about 400 feet wide.

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That’s longer than a football field.

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How in the world did that wind up there?

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Well I have no idea!

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["Oh, daggum-it!"]

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We’re going to fly now into a spot on the near side to look at this weird feature,

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which has long defied an easy explanation.

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It’s known as Reiner Gamma.

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Those squiggles and swirls sure are bizarre.

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A combination of computer modeling and data gathered

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from numerous recent lunar missions, including Lunar Reconnaissance Orbiter,

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now sheds light on the origin of these unusual surface decorations –

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which we call lunar swirls.

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Now think of it this way -

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You’ve probably been told that when you go outside to put on your sunscreen.

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Well, these beautiful swirls are constant reminders

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that the Moon is no different from you and me.

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Except that it’s a Moon, and we’re humans.

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These swirls are examples of what happens when the Moon applies SPF three million.

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The Moon is constantly bombarded by radiation from the Sun and galaxy,

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as well as micro-meteorites that sand-blast the surface.

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These swirls, however, show what happens

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when the radiation is blocked from reaching the surface.

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Data suggests that small magnetic anomalies block radiation from reaching the surface,

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and therefore prevent the Moon from getting sunburned in these areas,

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which keep them as bright as they appear to be.

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So, the next time you put on sunblock to go lounge outside,

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think of the Moon and how it gets baked in the Sun just like you and me.

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[Aaaaaaah!]

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Thanks for watching today.

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Hopefully this video taught you more about the Moon,

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and that you aren’t left thinking, “What the heck was that?”

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I’m Noah Petro, signing off.