How are the rilles on the Moon formed?
Other rilles, such as Rima Ariadaeus, are believed to be faults that formed as a result of tectonic activity. Some scientists believe that the linear rilles might have formed after large impact events, while others believe that the rilles were formed as a surface manifestation of deep-seated dike systems when the moon was still volcanically active.
How are arcuate rilles formed?
Arcuate rilles likely formed as the mare basalts sagged under their own weight toward the center of the basin, causing the edges to pull apart; the rille shape follows the circular shape of the basin.
What is the origin of the rilles of Mars?
Some rilles, such as Vallis Schroteri, were formed by volcanic eruptions. Other rilles, such as Rima Ariadaeus, are believed to be faults that formed as a result of tectonic activity.
What is an example of a rille in architecture?
Rima Cauchy, below, is another beautiful example of a straight rille. The last type of rille is known as the arcuate rille. Typically curved formations, like a parentheses or a bow (without the arrow), these depressions are formed along the edges of maria within some basins.
How were rilles and faults formed?
Some rilles, such as Vallis Schroteri, were formed by volcanic eruptions. Other rilles, such as Rima Ariadaeus, are believed to be faults that formed as a result of tectonic activity.
How are linear rilles formed on the Moon?
Since normal faults are understood to be the products of extensional stresses (see yesterday's Featured Image post), we can assume this region of the Moon was "pulled apart" - creating these normal faults, dropping the middle blocks, and producing the linear rilles.
What are rilles associated with?
rille, any of various valleys or trenches on the surface of the Moon. The term was introduced by early telescopic observers—probably by the German astronomer Johann Schröter about 1800—to denote such lunar features.
Are rilles older than craters?
The endogenic crater (Feature 1) has is superposed on top of the arcuate rille (Feature 2), indicating that it is younger than the rille.
What are rilles in space?
Rille /ˈrɪl/ (German for 'groove') is typically used to describe any of the long, narrow depressions in the surface of the Moon that resemble channels. The Latin term is rima, plural rimae. Typically, a rille can be several kilometers wide and hundreds of kilometers in length.
What are linear rilles?
Definition. The term linear rille refers to linear, trench-like features on the surface of the Moon (Masursky et al. 1978), typically found in the highlands adjacent to mare-filled basins (Watters and Johnson 2010), though some are observed crosscutting basin maria.
What is the dust on the Moon called?
lunar regolithThe lunar surface is covered by a layer of unconsolidated debris called the lunar regolith (fig.
How do you pronounce rilles?
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Why do we only see one side of the moon?
It is because the moon spins on its axis once in precisely the same amount of time that it takes it to orbit the earth once that we only ever see one side of it.
Is maria or highlands older?
Compared to geology of the Lunar Highlands: ● Lunar highlands have more impact craters than the mare. So, the highlands are older.
Which is older mare or highlands?
Further, different parts of the surface of the Moon exhibit different amounts of cratering and therefore are of different ages: the maria are younger than the highlands, because they have fewer craters. The oldest surfaces in the Solar System are characterized by maximal cratering density.
Is rille a word?
n. 1. A long, narrow, roughly straight channel or groove on the surface of a solar system body like a planet or moon.
Is there a fault line on the Moon?
As the moon's interior cools, it shrinks, which causes its hard surface to crack and form fault lines, according to research sponsored by NASA. The moon has gotten about 150 feet skinnier over the last few hundred million years. NASA posted a video on Twitter showing fault lines on the moon's surface.
What are sinuous Rilles found on the lunar surface?
Lunar sinuous rilles (German for 'groove') consist of long, narrow depressions in the lunar surface that meander in a curved path across the surface and morphologically resemble terrestrial fluvial channels (Image 1). Sinuous rilles are generally up to several kilometers wide and hundreds of kilometers in length.
Which two geological processes have been most important in shaping the surface of the Moon as we see it today?
The primary geologic processes that shaped the moon are the formation of craters, volcanic activity, and tectonic activity. Each of these will be dealt with in their respective sections below. Craters cover the surface of the moon. They are the result of high velocity impacts on the surface by meteorites.
How did the maria form?
The maria basins were formed beginning about 3.9 billion years ago during a period of intense bombardment by asteroid-sized bodies. This was well after the lunar crust had cooled and solidified enough, following the Moon's formation, to retain large impact scars.
What is the name of the rille on Mars?
Mamers Valles rille on Mars. Rima Ariadaeus is categorized as a straight rille (graben) and is over 300 km in length. Hadley Rille at center is a sinuous rille visited by the Apollo 15 mission. Detail of part of Hadley Rille.
How deep is the Hadley Rille?
Sinuous rilles. According to NASA, the origin of lunar sinuous rilles remains controversial. The Hadley Rille is a 1.5 km wide and over 300 m deep sinuous rille. It is thought to be a giant conduit that carried lava from an eruptive vent far to the south.
What are sinuous rilles?
Sinuous rilles meander in a curved path like a mature river, and are commonly thought to be the remains of collapsed lava tubes or extinct lava flows. They usually begin at an extinct volcano, then meander and sometimes split as they are followed across the surface.
What are grabens in the crust?
Straight rilles follow long, linear paths and are believed to be grabens, sections of the crust that have sunk between two parallel faults. These can be readily identified when they pass through craters or mountain ranges. Vallis Alpes is by far the largest graben rille, indeed it is regarded as too large to be called a rille and is itself bisected by a linear rille; Rima Ariadaeus, west of Mare Tranquillitatis, is a clearer example.
Where are arcuate rilles found?
Arcuate rilles have a smooth curve and are found on the edges of the dark lunar maria. They are believed to have formed when the lava flows that created a mare cooled, contracted and sank. These are found all over the moon, examples can be seen near the south-western border of Mare Tranquillitatis and on the south-eastern border of Mare Humorum. Rima Sulpicius Gallus is a clear example in southwestern Mare Serenitatis.
Which rille is the largest?
Vallis Schröteri in Oceanus Procellarum is the largest sinuous rille, and Rima Hadley is the only one visited by humans, on the Apollo 15 mission. Another prominent example is Rima Herigonius. Arcuate rilles have a smooth curve and are found on the edges of the dark lunar maria.
How wide is a rille?
Typically, a rille can be several kilometers wide and hundreds of kilometers in length. However, the term has also been used loosely to describe similar structures on a number of planets in the Solar System, including Mars, Venus, and on a number of moons. All bear a structural resemblance to each other.
What are some examples of sinuous rille?
While sinuous rilles are a common lunar landform, there are similar, though typically much shorter, volcanic features on Earth that form when magma steadily emerges from a vent and forms a channelized flow. Rima Sharp is another example of a sinuous rille (controlled feature mosaic centered at 46°N Lat, 309°E Lon) with a total rille length ...
How did sinuous rilles form?
Sinuous rilles arethought to have formed as the result of surface lava flows, or collapsed lava tubes. Many have crater-like structures at their point of origin. These depressions are most likely vents where the magma reached the surface from mantle source regions below.
How do rilles form?
These valleys are graben, which form when the surface pulls apart under extensional stresses, and a block of the crust drops down to create the valley floor. The largest rille on the Moon is a straight rille known as Rima Sirsalis. It extends about 400 km across the lunar near side in Oceanus Procellarum, the Ocean of Storms. On a good night (when the moon is waning and the topography results in large shadows being cast), you may be able to find it with a telescope at home!
What are the three types of rilles?
Lunar scientists have categorized these structures into 3 distinct categories: sinuous, straight, and arcuate rilles. First, let's talk about sinuous rilles, the most common type found on the Moon. Vallis Schröteri, below, is a beautiful example.
What are the different types of craters on the moon?
These formations, which often look almost like dried riverbeds, have a variety of potential origins, and Controlled Feature Mosaics made from LROC Narrow Angle Camera (NAC) images allow for a closer look. Lunar scientists have categorized these structures into 3 distinct categories: sinuous, straight, and arcuate rilles.
Where is the largest rille on the moon?
It extends about 400 km across the lunar near side in Oceanus Procellarum, the Ocean of Storms. On a good night (when the moon is waning and the topography results in large shadows being cast), you may be able to find it with a telescope at home!
Hadley Rille (from Orbit)
This photo shows the Hadley Rille on the southeast edge of Mare Imbrium. It is fairly well known because Apollo 15 landed there (see next image). The rille begins at the curved gash in the bottom left corner, and is clearest in the rectangular, mare-floored valley shown here.
Hadley Rille (from Surface)
This is a photo of Hadley Rille from the lunar surface. Astronaut James Irwin is standing in the foreground by the lunar rover. At this point, the rille is nearly a mile wide (1.6 km). Note the many boulders on the Valley floor. These rocks have apparently rolled off of the Valley wall over time.
Posidonius Rille
This image shows a sinuous rille located in the crater Posidonius. The source of this rille is a shallow pit on the northern crater wall (arrow). The rille then meanders along the edge of the crater floor for over 60 miles (100 km). Finally, it reaches a hole in the crater rim and vanishes into Mare Serenitatis.
Lava Tubes
This image shows a chain of small pits and ridge segments. It marks the likely site of a partially collapsed lava tube in western Mare Imbrium. Here, instead of a surface lava channel, lava flowed through a buried tunnel in the mare. After the eruption stopped, the tunnel then emptied. Where the roof of the tunnel has fallen in, we see pits.
Schroter's Valley 1
This photo shows Schroter's Valley (arrow) and the Aristarchus Plateau. It lies between Mare Imbrium and Oceanus Procellarum. This valley is the largest (widest) sinuous rille on the Moon. It also has a smaller rille inside it (see next photo). Both rilles come from the same vent, but they probably reflect two separate eruptions.
What are the rilles formed by?
Some rilles, such as Vallis Schroteri, were formed by volcanic eruptions. Other rilles, such as Rima Ariadaeus, are believed to be faults that formed as a result of tectonic activity.
Why is the rille younger than the ridge?
For example, the rille cross-cuts a ridge in the middle-left of the WAC frame (near the arrow in the WAC image below); this relationship suggests that the rille is younger than the ridge, because the rille changed the shape of the ridge.
What are linear rills?
Most linear rilles are believed to represent tectonic faulting and can be used to determine stratigraphic relationships on a surface. Image width is 1.2 km (3/4 mi). Credit: NASA/Goddard Space Flight Center/Arizona State University. Rima Ariadaeus is one of several linear rille systems nestled in the highlands between Mare Vaporum ...
How wide is Rima Ariadaeus?
Rima Ariadaeus is 5 km (3.1 mi) wide and disrupts the preexisting geologic features. The stratigraphic relationships between the rille and other surface features can help determine whether the rille is older or younger than these features with respect to relative age.
Is Rima Ariadaeus a fault?
Experts agree that Rima Ariadaeus, about 300 km (18 6.4 mi) long, is a fault system similar to those on Earth. A large portion of Rima Ariadaeus is visible in this subset of an LROC frame (below), and the LROC NAC image (above) shows part of the rille fault scarp. A mare surface is visible in the southwest corner of the image, and a defined contact between the rille wall and the rille floor is visible in the northeast corner of the image. Rima Ariadaeus is 5 km (3.1 mi) wide and disrupts the preexisting geologic features.
