Smithsonian Voices National Air and Space Museum

The Moon: Earlier than We Knew

Voyages to Mars from the museum’s AirSpace Podcast is a mini-series to accompany NASA’s Perseverance rover on its journey from Earth to Mars. On the most recent installment of this literary mixtape, I learn choices from Mark Wick’s novel To Mars By way of the Moon.

As somebody who very a lot enjoys the moons of different planets, I’ve been actually excited to start learning Earth’s Moon. Within the final 12 months or two I’ve added our Moon to my assortment of photo voltaic system our bodies that I research (I’ve spent most of my profession wanting on the moons of the biggest planets in our photo voltaic system). Studying Wick’s phrases motivated me to replicate on how our considering of the Moon has modified as real-life science and know-how has advanced (versus Wick’s sci-fi brainstorms).

So, what have been scientists nonetheless questioning about earlier than we began sending spacecraft (and people) to discover our nearest neighbor? I pose (and reply) just a few questions that have been thought-about as NASA ready to ship astronauts to the Moon.

Is the Moon fluffy?

The Moon wasn’t understood in addition to we’d have hoped as NASA moved in direction of the (secure) arrival of Apollo 11. In fact, a lot planning had gone into the missions that led as much as the primary touchdown, together with the event of detailed maps and different analysis instruments.

We understood that most of the round floor options have been affect craters, however a priority remained: couldn’t billions of years of bombardment by meteorites result in a floor that was simply soiled fluffy affect ejecta threatening to swallow up an astronaut?

Check out the massive saucer formed toes of the Lunar Exploration Module: all that additional floor space was designed to present additional stability in case the terrain was fluffier than hoped (you understand, like lightning sand within the Princess Bride?). Scientists didn’t actually anticipate the lunar floor to be like lightning sand, however they needed to be ready. So, whereas the lunar floor is roofed with what we name regolith (a generally inches-thick, fluffy layer of unfastened materials) none of it was deep sufficient to do greater than seize iconic boot-prints and cling to spacesuits. [Hearken to half 1 of the AirSpace Podcast Walking on the Moon to listen to extra in regards to the ‘fluffy moon’].

Is there water on the Moon?

That is sort of a sure, then no, then yes-kind-of. (The thrill of science!) Lots of the broad darkish areas you see on the Moon are referred to as “mare/maria” which interprets to ocean. Early astronomers thought that these darkish, easy wanting areas resembled oceans on Earth. When know-how superior sufficient to see rilles (a fissure or slim channel) meander throughout the floor like rivers or streams, many questioned whether or not water flowed on the lunar floor sooner or later. This, after all turned out to not be the case. Options like sinuous rilles are far more simply defined by the presence of lava flowing on the floor or by way of lava tubes.

However what about ice? In 2009, the LCROSS mission (Lunar CRater Remark and Sensing Satellite tv for pc), as a part of the Lunar Reconnaissance Orbiter mission, despatched a part of its rocket (the Atlas V’s Centaur higher stage) crashing into the south pole of the Moon. The Moon’s south pole has some spots which might be completely shadowed, and scientists thought that if there was any water on the Moon, it was probably to be lurking in these completely shadowed areas. By making a contemporary affect crater utilizing the Centaur higher stage, the Lunar Reconnaissance Orbiter may observe the composition of the fabric blasted by the affect. LCROSS discovered water ice on the moon! So, is there water on the Moon? Sure, however not liquid, and it by no means flowed.

Is there life on the Moon?

Realizing so little in regards to the Moon earlier than Apollo, there was a concern that if there was some sort of microbial life on the Moon, it could possibly be introduced again to Earth by the astronauts and/or the lunar samples they collected. When Apollo 11 returned, the astronauts have been held in a specifically outfitted Mobile Quarantine Facility (a transformed Airstream trailer) whereas they have been transferred to the longer-term quarantine facility on the Lunar Receiving Laboratory in Houston, Texas. After Apollo 14, NASA felt assured in saying that there have been no lunar microbes, and Apollo astronauts returning house didn’t need to undergo an extended post-flight quarantine. Astronauts right now nonetheless quarantine, however earlier than their mission (not after) and solely to make sure that astronauts don’t get sick in area. The lunar samples returned by Apollo astronauts are nonetheless rigorously quarantined to guard all these nice rocks from being contaminated. [Hearken to our episode Mask, Gloves, Soap, Scrubs to listen to extra].

How did the Moon type?

Till the Apollo missions, we actually couldn’t show how the Moon shaped. Main as much as Apollo, there have been three widespread concepts about the place the Moon got here from:

1. The Moon shaped concurrently the Earth out of the identical cloud of stuff.
2. The Moon handed too carefully to Earth and couldn’t escape Earth’s gravitational pull so was captured into Earth’s orbit.
3. Early in Earth’s historical past, an object in regards to the dimension of Mars smashed into Earth making a bunch of particles. A few of that particles coalesced into the Moon and the remaining re-formed into the Earth.

The lunar samples that got here house with the Apollo missions confirmed that the Moon and Earth have been made up of the identical sorts of minerals, however the quantity of these minerals on the Moon have been barely totally different than on Earth. These outcomes proved {that a} large affect (idea 3) into our early Earth is what shaped our Moon, however the particulars of precisely how that each one labored remains to be a scorching matter in lunar science. [Hearken to Half 2 of Walking on the Moon to listen to extra about lunar samples].