Red Moon. Craters On The Moon

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1 Red Moon by Fraser Cain Most of the time, the Moon is a bright yellow color; it s reflecting light from the Sun. But sometimes the Moon can turn a beautiful dramatic red color. What s going on? What causes a red moon? scatter away the blue/green light and let the red light go straight through. During a lunar eclipse, the Moon passes fully into the shadow of the Earth and it s no longer being illuminated by the Sun; however, this red light passing through the Earth s atmosphere does reach the Moon, and shines on it. And that s how we can get a red moon. There are few situations that can cause a red moon. The most common way to see the Moon turn red is when the Moon is low in the sky, just after moonrise or before it s about to set below the horizon. Just like the Sun, light from the Moon has to pass through a larger amount of atmosphere when it s down near the horizon, compared to when it s overhead. The Earth s atmosphere can scatter sunlight, and since moonlight is just scattered sunlight, it can scatter that too. Red light can pass through the atmosphere and not get scattered much, while light at the blue end of the spectrum is more easily scattered. When you see a red moon, you re seeing the red light that wasn t scattered, but the blue and green light have been scattered away. That s why the Moon looks red. The second reason for a red moon is if there s some kind of particle in the air. A forest fire or volcanic eruption can fill the air with tiny particles that partially obscure light from the Sun and Moon. Once again, these particles tend to scatter blue and green light away, while permitting red light to pass through more easily. When you see a red moon, high up in the sky, it s probably because there s a large amount of dust in the air. A third and dramatic way to get a red moon is during a lunar eclipse. During a lunar eclipse, the Moon passes behind the Earth s shadow, which darkens it. If you could take a look at the Earth from inside its shadow, you would see that the atmosphere around the edge of the entire planet glows red. Once again, this is because large amounts of atmosphere will Craters On by John Carl Villanueva The Earth is so close to the Moon and yet the number of craters on the Moon are far more abundant. Have meteoroid and asteroid bombardments been selective? That is, have they been pounding the lunar surface but somehow sparing Earth s? Not really. Earth is definitely receiving its fair share of meteoroid and asteroid assaults. In fact, meteoroids rain nonstop on both the Earth and the moon every minute. However, our planet is protected by its atmosphere. The moon, unfortunately, doesn t have one. When small meteoroids pass through the atmosphere, friction causes them to ignite and ART 8.1: Page 1 of 5

2 disintegrate; the larger ones simply explode. The shooting stars and meteor showers that we see are the more visible ones. Surely you didn t think meteoroids only struck at night, did you? On the moon, even the tiniest meteoroids strike the surface unhindered, forming the smallersized craters on the moon. These tiny craters even leave marks on moon rocks and are easily spotted on the rock samples brought home by the Apollo missions. The tiny craters on the Apollo moon rocks are among the most substantial evidence that the Apollo landings actually took place. You can t hope to find rocks with the same features here on Earth. the Moon has any plate tectonic activity, it is believed that, if the Moon in fact has any such activity, the Earth s plate tectonic movement is still far more active. So far, we ve explained the presence of small craters on the Moon. How about the larger ones? The giant craters on the Moon were obviously formed by much larger astronomical objects, like asteroids or comets. Bombardments from comets or asteroids are not common both on Earth and on the Moon. However, why do we see more of them on the Moon s surface? The reason for this is because of the absence of water (in liquid form) and climates on the lunar surface. These factors cause erosions, which subsequently conceal the evidence of such major bombardments. It would be safe to say that the large lunar craters fashioned by asteroid and comet impacts were formed millions of years ago. This is consistent with the theory that the dinosaurs were wiped out by this kind of impact some 65 million years ago. While the evidence of such an impact, as well as even older impacts, are well preserved on the Moon, the same thing cannot be said for the Earth. The Earth s high plate tectonic activity is also one major factor that has concealed large craters. Although we are not yet sure whether Moon Landing Hoax by John Carl Villanueva The moon landing hoax is a conspiracy theory that gained prominence when Fox television featured a program titled Conspiracy Theory: Did We Land on The idea was that the landings were just productions a la Hollywood films. We know better, and there are numerous facts that back the real story. In fact, many of them are adjudged authentic by organizations outside NASA. Nevertheless, the moon landing hoax theory is an interesting one and we thought you d want to hear about it. However, we ve also included rebuttals from scientists to make sure you don t go to bed believing it. First point from the hoax believers Why aren t there stars in images showing the astronauts walking on The sky was dark but there were no stars. Shouldn t ART 8.1: Page 2 of 5

3 they have been very visible since the Moon doesn t have clouds? Expert photographers are quick to spot the reason here. You can t see lights in the background if the foreground object is very bright. The astronauts suits, which were white, served as very good reflectors of light coming from the sun. Also, since the landings were shot under daylight, it would be difficult even for the naked eye to spot the stars. Second point Why are the footprints well preserved when in fact the lunar dust is supposed to be very fine and devoid of moisture and strong gravity? Since the dust is silicate, they have the tendency to stick to gather together like that when in vacuum. The Mythbusters demonstrated this phenomena in the episode NASA Moon Landing. Third point The American flag flapped as it was planted but there is no wind on the moon! This can be explained by elementary physics. Anything that is initially set into motion will readily continue moving if no external force acts in the opposite direction. So when the astronauts were on the act of planting the flag, they were able to set the flag into motion. Naturally, under the sole influence of a very weak gravitational field, the flag appeared to flap. There are still many observations that the conspiracy theorists have pointed out and all of them have been rebutted substantially. Among the best evidences that the astronauts were able to bring home were the moon rocks. Studies conducted by various academic and research institutions on them revealed that their composition, characteristics and age are unlike those naturally found here on Earth. Color of the Moon by Fraser Cain If the Moon s up, go take a look and see what color it is. If you re looking during the daylight, the Moon will look faint and white surrounded by the blue of the sky. If it s night, the Moon will look bright yellow. Why does the color the Moon seem to change from white to yellow when you go from day to night. And why does the Moon look gray in many photographs, especially the ones from space? What color is The photographs of the Moon, taken from space are the best true-color views of the Moon. That gray color you see comes from the surface of the Moon which is mostly oxygen, silicon, magnesium, iron, calcium and aluminum. The lighter color rocks are usually plagioclase feldspar, while the darker rocks are pyroxene. Most of the rocks that you can see are volcanic, and were extruded from the inside of the Moon during volcanic eruptions. Some rare rocks called olivine are actually green. The dark regions you see on the Moon are called lunar maria, and they were formed by ancient volcanic eruptions. They re less reflective than the lunar highlands, and so they appear darker to the eye. The maria cover about 16% of the lunar surface, mostly on the side we can see from Earth. Astronomers think the lunar maria were formed about ART 8.1: Page 3 of 5

4 billion years ago, when the Moon was much more volcanically active. When you see the Moon from here on Earth, the atmosphere partially blocks your view. The particles in the atmosphere scatter certain wavelengths of light, and permit other wavelengths to get through directly. When the Moon is low in the sky, you re seeing its light go through the most atmosphere. Light on the blue end of the spectrum is scattered away, while the red light isn t scattered. This is why the Moon looks more red. As it goes higher in the sky, the Moon is obscured by less and less atmosphere, so it turns more yellow the same thing happens to the Sun as it rises in the sky. During the day, the Moon has to compete with sunlight, which is also being scattered by the atmosphere, so it looks white. Since the Earth s Moon doesn t have a significant atmosphere, nothing can stop even the smallest meteoroids from striking its surface. As a result, the lunar surface is heavily cratered. As a matter of fact, tiny craters are quite common even on lunar rocks. This was observed on the Moon rocks brought home by the Apollo missions. By contrast, small meteoroids that pass through the Earth s atmosphere are easily vaporized and hence are not able to form craters on the land below. The absence of liquid water on its surface has allowed the Moon to preserve much of its ancient geological features. Here on Earth, erosion can alter and cover formations over time. Plate tectonics, which is also absent on the Moon, is another big factor that makes the terrain of the two celestial bodies different. Here on Earth, plate tectonics cause volcanic activities, earthquakes, and sea floor spreading. Due to the lack of water and atmosphere, the lunar regolith (also called lunar soil ) is noticeably dry and devoid of air. It also does not contain anything organic. The regolith comes from meteor impacts that has plagued the Moon since its inception. Surface of the Moon by John Carl Villanueva Despite the close proximity between the Earth and the Moon, there s a big difference between the surface of the Moon and of Earth s. Much of the difference between the two celestial bodies is caused by the absence of the following attributes on the Moon: an atmosphere, bodies of water, and plate tectonics. Impact crater sizes on the lunar surface range from the tiny holes that mark lunar rocks to the really big ones like the South Pole Aitken Basin that has a diameter of approximately 2,500 km. Younger craters are superimposed over older ones. This characteristic is used by scientists to determine the relative ages of impact craters. Basically, it has been observed that the size of impact craters on the surface of the Moon have decreased over time. ART 8.1: Page 4 of 5

5 Other prominent geological features found on the surface of the Moon include maria, rilles, domes, wrinkle ridges, and grabens. The term regolith is any layer of material covering solid rock. It can be dust, soil and broken rock. Nearly the entire lunar surface is covered with regolith. Bedrock is only visible on the walls of very steep craters. regolith was formed over billions of years by constant meteorite impacts on the surface of the Moon. Scientists estimate that the lunar regolith extends down 4-5 meters in some places, and even as deep as 15 meters in the older highland areas. You can also use the term lunar soil to describe the lunar regolith, but many argue that the term isn t appropriate because the moon regolith doesn t have any organic material in it at all. The maria, which comprise about one-third of the Moon s near side, are made up of flows of basaltic lava formed from volcanic activities that occurred in the younger years of the Moon. They were once mistaken for seas on the surface of the Moon, hence the name. Maria is the Latin word for seas. The near side refers to the side of the Moon that is constantly facing Earth. Lunar Regolith by Fraser Cain When you re walking in the forest, what s that stuff beneath your feet? Here on Earth, we call it dirt, or soil. Take a look at dirt under the microscope, and you ll see a collection of particles of rock, sand, little critters, and organic matter. The surface of the Moon is covered with a fine powdery material that you might want to call dirt. But that s the wrong term. There s no organic material on the surface of the Moon, and so scientists call it lunar regolith instead. When the plans were put together for the Apollo missions, when the first humans would walk on the surface of the Moon, some scientists were worried that the lunar regolith was too light and powdery to support the weight of the lunar lander. Instead of landing on the surface, they were worried that the lander would just sink down into it like a snowbank. Landings by robotic spacecraft showed that the lunar soil was firm enough to support a spacecraft, and the astronauts later explained that the surface of the Moon felt very firm. As NASA is working on plans to send humans back to the Moon in the next decade, researchers are working to learn the best ways to work with the lunar regolith. Future colonists could mine minerals and even oxygen out of the lunar soil. Since real lunar regolith is hard to come by, you can purchase lunar regolith simulant, made here on Earth. ART 8.1: Page 5 of 5

6 Question 1. Why might the Moon appear red? Name: Period: Answer 2. What does the atmosphere do to sunlight that makes the Moon appear red? 3. Why does the Moon appear red during a lunar eclipse? 4. Why are there more impact craters on the Moon than Earth? 5. When were the large craters on the Moon formed? 6. What happened to old impact craters on Earth? 7. Why are there no stars in the sky of pictures of astronauts on 8. Why does the lunar soil preserve footprints so well? 9. Why did the flag appear to flap when there is no gravity on 10. What is the best evidence ART 7.1:

7 that astronauts visited Name: Period: 11. What produces the color of 12. Most of the rocks on the Moon are of what type? 13. What are the dark regions on 14. What two things make the surface of the Moon so different from that of Earth? 15. How common are craters on 16. What produces lunar regolith? 17. How do scientists determine the relative ages of craters? 18. Over time, what has happened to the size of impact craters on 19. Why do we not refer to lunar soil dirt? ART 7.1:

8 20. What is regolith? Name: Period: ART 7.1: