A few glass spherules and are evident. Agglutinates are hard to find in regolith breccias and there may be none in this section.
Sample is a very friable regolith breccia. It breaks apart easily and the clasts are easy to remove. I have done it. I think that it would not survive lunar ejection and terrestrial capture as a lunar meteorite.
In contrast, regolith breccia below is very coherent. Lunar meteorite NWA is a fragmental breccia. We are looking at a sawn slice. Again, note that the clasts are shades of gray, not brightly colored. Also, there are several different kinds colors and textures of clasts, which we would expect in a lunar regolith or fragmental breccia considering the diversity of rocks in the Apollo 11 and 16 regolith samples above.
In contrast, many terrestrial sedimentary rocks and basalts contain of clasts or phenocrysts of a single rock or mineral type. Notice that there is no preferred orientation of the clasts. Here, the regolith is formed and modified by impact processes, mass wasting, and space weathering , as on the surfaces of Mercury , most of the satellites, and the asteroids. The processes involved, however, vary over time cratering rate and impactor size , with gravity and the heliocentric distance kinetic energy and space weathering.
Skip to main content Skip to table of contents. This service is more advanced with JavaScript available. Encyclopedia of Astrobiology Edition. It is typically made up of material that is weathered away from the underlying rock. In addition to the chemical composition of bedrock, the texture that results as rock disintegrates also influences the characteristics of soil.
Unlike on Earth, there is no erosion by wind or water on the moon because it has no atmosphere and all the water on the surface is frozen as ice. Also, there is no volcanic activity on the moon to change the lunar surface features. The outer surface layer of the Moon is termed the regolith; it is a loose layer or debris blanket probably, up to 10 metres deep in places, continually churned up by the impacts of micrometeorites Figure 1.
The harmful properties of lunar dust are not well known. Based on studies of dust found on Earth, it is expected that exposure to lunar dust will result in greater risks to health both from acute and chronic exposure. The bulk of the regolith is a fine gray soil with a density of about 1.
About half the weight of a lunar soil is less than 60 to 80 microns in size. Nearly the entire lunar surface is covered with regolith, and bedrock is only visible on the walls of very steep craters.
The moon 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 meters in some places, and even as deep as 15 meters in the older highland areas. When the plans were put together for the Apollo missions, some scientists were concerned that the lunar regolith would be 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. However, landings performed by robotic Surveyor spacecraft showed that the lunar soil was firm enough to support a spacecraft, and astronauts later explained that the surface of the moon felt very firm beneath their feet. During the Apollo landings, the astronauts often found it necessary to use a hammer to drive a core sampling tool into it.
Once astronauts reached the surface, they reported that the fine moon dust stuck to their spacesuits and then dusted the inside of the lunar lander. The astronauts also claimed that it got into their eyes, making them red; and worse, even got into their lungs, giving them coughs. Lunar dust is very abrasive, and has been noted for its ability to wear down spacesuits and electronics. The reason for this is because lunar regolith is sharp and jagged. This is due to the fact that the moon has no atmosphere or flowing water on it, and hence no natural weathering process.
When the micro-meteoroids slammed into the surface and created all the particles, there was no process for wearing down its sharp edges. The term lunar soil is often used interchangeably with "lunar regolith", but some have argued that the term "soil" is not correct because it is defined as having organic content.
However, standard usage among lunar scientists tends to ignore that distinction. As NASA is working on plans to send humans back to the moon in the coming years, researchers are working to learn the best ways to work with the lunar regolith.
Future colonists could mine minerals, water, and even oxygen out of the lunar soil , and use it to manufacture bases with as well. Landers and rovers that have been sent to Mars by NASA, the Russians and the ESA have returned many interesting photographs, showing a landscape that is covered with vast expanses of sand and dust, as well as rocks and boulders. Compared to lunar regolith , Mars dust is very fine and enough remains suspended in the atmosphere to give the sky a reddish hue.
The dust is occasionally picked up in vast planet-wide dust storms, which are quite slow due to the very low density of the atmosphere. The reason why Martian regolith is so much finer than that found on the moon is attributed to the flowing water and river valleys that once covered its surface. Mars researchers are currently studying whether or not martian regolith is still being shaped in the present epoch as well. It is believed that large quantities of water and carbon dioxide ices remain frozen within the regolith, which would be of use if and when manned missions and even colonization efforts take place in the coming decades.
Mars moon of Deimos is also covered by a layer of regolith that is estimated to be 50 meters feet thick. Images provided by the Viking 2 orbiter confirmed its presence from a height of 30 km 19 miles above the moon's surface. The only other planet in our solar system that is known to have regolith is Titan, Saturn's largest moon. The surface is known for its extensive fields of dunes, though the precise origin of them are not known.
Some scientists have suggested that they may be small fragments of water ice eroded by Titan's liquid methane, or possibly particulate organic matter that formed in Titan's atmosphere and rained down on the surface. Another possibility is that a series of powerful wind reversals, which occur twice during a single Saturn year 30 Earth years , are responsible for forming these dunes, which measure several hundred meters high and stretch across hundreds of kilometers.
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