What can lunar eclipses do for science?

On the night of July 27, 2018, the longest total lunar eclipse for the next 105 years will be visible across the regions of Europe, Africa, Asia and the Middle East. Australia. Six months later, on January 20, 2019, there will be the "Great American" lunar eclipse, where the whole is visible in the 50 states.

NASA's Lunar Reconnaissance Orbiter spacecraft has been studying the Moon's surface since 2009.
NASA's Goddard Scientific Visualization Studio

The Moon's Journey through the Shadow of the Earth produces one of the most spectacular and impressive sites of nature. But can it help us to deepen our understanding of nature?

Noah Petro is the Project Scientist for NASA's Lunar Reconnaissance Orbiter (LRO) mission, orbiting the moon since June 2009. We talked to him about what lunar eclipses can do for science – and why we should study the moon. 19659006] S & T: First of all, a brief overview. Is it true that you had a "moment of enlightenment" at the university that led you from the study of geology to the study of planetary geology?

NP: Yes, it was pretty much that. My father was involved in the Apollo program, so I was always interested in space exploration and the moon. Then, in high school, I had some Earth Science teachers who had me passionate about geology. That was a teacher from my undergraduate institution, Bates College, who said, "Noah, you like space and you love geology Did you know that you could do geology things in the world?" # 39; space? I thought, oh really? And that was it …

S & T: It's now 20 years later, and you're based at the Goddard Space Flight Center that works on LRO's mission. What were the most important results of the mission?

NP: It's a hard question to answer because we're learning a lot. LRO has been at the moon for almost nine years, and no mission has ever worked at the moon as long as that before. We are constantly rewriting our understanding of how the Moon works and changes. LRO has taken steps to constrain the rate at which new impacts are formed on the surface of the moon. We can map volatile substances on the lunar surface, including water. We can watch the moon with a high resolution camera and see features we have never seen before. We have identified volcanic deposits that look very young: tens of millions of years rather than billions of years. LRO inaugurated a new era of lunar science

From our gallery: The lunar eclipse on January 31, 2018.
Bill McGrath

S & T: During a lunar eclipse, the surface of the Moon shines bright sunlight in the dark and back in a few hours. How can scientists use this to learn more about the moon?

NP: We can use a thermal instrument to see how the temperature of the Moon's surface changes. Anyone who has visited a beach knows that the sand is very hot in hot weather and, when it cools, it cools quickly. We can therefore deduce the properties of the regolith from the Moon – the surface of the Moon – as a function of the speed or slowness of its cooling.

S & T: This is done with instruments onboard the LRO and telescopes on Earth

NP: In the most recent total eclipse, we did not not used the instruments because the spacecraft is older and we were worried about what would happen to the battery. We recharge the battery using solar energy, and when we are in eclipse, we are in the dark for a long period of time. We did not want to leave the instruments and empty the battery. What we are doing now is that we are making observations during partial eclipses, when the spacecraft is in the dark for a shorter period of time. We can always take measurements from the Earth if the telescope is clear

S & T: How to choose the areas of the Moon to study during an eclipse?

NP: It's a good thing. question. With LRO's observations we are essentially looking at what will happen under the spacecraft during a particular orbit during an eclipse. For telescopic observations, we do not have the same limitations, so we can point where we want. We know the interesting features of the Moon, whether it is a volcanic peculiarity or a small fresh impact crater. There are enough new mid-size impact craters that we can see from the Earth and that make valuable targets. And, in the end, we can look at this feature, then we'll look here. We can move around fascinating areas as the eclipse unfolds. The great thing about lunar eclipses is that they are beautiful, slow walks. There is nothing you need to move very fast

S & T: Why is it important to know more about the surface of the moon?

NP: Let's take three steps back. Imagine if a new continent appeared on Earth that revealed the first processes that occurred in the solar system. We would absolutely like to know everything about this place. Well, it happens to be the moon. It's in three days – it took three days for Apollo astronauts to get to the moon – and it's about the size of Africa in terms of area. And the Moon itself records the processes that have affected the entire solar system: impact craters, volcanism, tectonism, interactions with the space environment, they are all recorded on the lunar surface. Every continent here on Earth, some features of this continent tell us something about the functioning of the Earth. The moon is fabulous because it tells us something about the functioning of the planets.

So, here in our garden we have a representation of the whole range of types of objects in our solar system, with the exception of gaseous giants. We have the Earth, with water and an atmosphere, and we have the moon, with essentially no atmosphere and no water – there is water on the moon, but no rivers and water. Oceans and things like that. And so, where the disc does not exist on Earth, we use the Moon to understand what is happening on other objects

S & T: Final Thoughts for Readers S & T before the next eclipses?

lunar eclipse phases of our gallery
wcreech

NP: We can never underestimate the importance of showing people why looking at the sky is amazing. Whether during an eclipse when the moon turns red, or a beautiful clear night where the moon looks like the moon, use every opportunity for people to look at the moon, be curious about the moon , excited about it

I should also point out – because I know people here at Goddard would like me to do it! – that in October we have our International Observe the Moon Night . And, of course, we have all Apollo birthdays starting this year.

Roger Sinnott, Sky & Telescope, discusses Useful projects for a lunar eclipse : "You only need clear skies and very simple equipment. "(But remember that lunar eclipses can – and should – be savored without any observational equipment:" set aside some time to sit down and enjoy the eclipse, too! ")