On June 10, 2011, NASA's Lunar Reconnaissance Orbiter spacecraft pointed the LRO Camera NACs to capture a dramatic sunrise view of Tycho crater.
Tycho crater's central peak complex, shown here, is about 9.3 miles (15 km) wide, left to right (southeast to northwest in this view).
A very popular target with amateur astronomers, Tycho is located at 43.37°S, 348.68°E, and is about 51 miles (82 km) in diameter. The summit of the central peak is 1.24 miles (2 km) above the crater floor. The distance from Tycho's floor to its rim is about 2.92 miles (4.7 km).
A very popular target with amateur astronomers, Tycho is located at 43.37°S, 348.68°E, and is about 51 miles (82 km) in diameter. The summit of the central peak is 1.24 miles (2 km) above the crater floor. The distance from Tycho's floor to its rim is about 2.92 miles (4.7 km).
This image shows an oblique (angled) view of the summit area of Tycho crater's central peak. The boulder in the background is nearly 400 feet (120 m) wide. The image itself is about 3/4ths of a mile wide.
The bottom of Tycho's crater is covered by blocks, boulders and impact melt textures. The impact melt deposits often show networks of fractures visible at the LROC WAC pixel scale of 100 meters. At NAC resolution with very high incidence angles (illuminated almost along the horizon), the extremely complicated and chaotic nature of the surface is striking.
Impact melts have extremely complicated thermal histories. When the impacting meteoroid's kinetic energy is large enough, the initial temperature of an impact melt can be much higher than that of normal magma, which is driven by volcanic activity. The melts are mixed together with ejecta debris, flow down slopes and puddle; loosing heat and increasing in viscosity with time.
Credit: NASA Goddard/Arizona State University, › View larger image
This LRO image mosaic shows Tycho crater under lighting conditions similar to those when the above "oblique" image was taken. North is up in this image, which is about 81 miles wide (130 km).
Credit:NASA Goddard/Arizona State University, › View larger image,
The bottom of Tycho's crater is covered by blocks, boulders and impact melt textures. The impact melt deposits often show networks of fractures visible at the LROC WAC pixel scale of 100 meters. At NAC resolution with very high incidence angles (illuminated almost along the horizon), the extremely complicated and chaotic nature of the surface is striking.
Impact melts have extremely complicated thermal histories. When the impacting meteoroid's kinetic energy is large enough, the initial temperature of an impact melt can be much higher than that of normal magma, which is driven by volcanic activity. The melts are mixed together with ejecta debris, flow down slopes and puddle; loosing heat and increasing in viscosity with time.
Once settled in the crater floor, solidification starts at the top and the bottom (chilled margins), and continues little by little to the melt volume interior. Any kind of deformation during this time (for example, the isostatic rebound of the crater floor, uneven thermal contraction, or late flows pushing pre-existing melts) will disturb the solidifying melt surfaces to make the chaotic patterns and sometimes cause local "eruptions" of melt onto the newly solid layer.
View larger image, Credit: NASA/GSFC/Arizina State University
The central farside crater Bhabha (64 km diameter) was named in honor of the physicist Homi Jehangir Bhabha (1909-1966), a nuclear physics pioneer in his home country of India. Bhabha Crater lies deep within the interior of the enormous South Pole-Aitken (SPA) Basin.
View larger image
Credit: NASA/GSFC/Arizona State University
Bhabha has a trio of central peaks that rise over a kilometer above the crater floor, and it has an intricate and complex system of rim terraces. Bhabha itself is a deep crater whose floor lies some 3 to 3.5 km below the crater rim.
Bhabha is of special interest because the impact that formed it penetrated deep into the SPA Basin floor, excavated materials of the SPA Basin impact-melt complex, and distributed these materials onto the surrounding plains. Even though this event happened long ago in the Moon's history, those materials are still present in the surrounding plains deposits waiting for a lunar explorer - whether robotic or human - to come along and return them to Earth.
Credit:NASA Goddard/Arizona State University
Many rock fragments ("clasts") ranging in size from some 33 feet (10 m) to hundreds of yards are exposed in the central peak slopes. Were these distinctive outcrops formed as a result of crushing and deformation of the target rock as the peak grew? Or do they represent preexisting rock layers that were brought intact to the surface?
Tycho's features are so steep and sharp because the crater is only about 110 million years old -- young by lunar standards. Over time micrometeorites and not-so-micro meteorites, will grind and erode these steep slopes into smooth mountains. For a preview of Tycho's central peak may appear like in a few billion years, look at Bhabha crater.
On May 27, 2010, LRO captured a top-down view of the summit (below), including the large boulder seen in the above image. Also note the fractured impact melt deposit that surrounds the boulder. And the smooth area on top of the boulder, is that also frozen impact melt? These images from the LRO Camera clearly show that the central peak formed very quickly: The peak was there when impact melt that was thrown straight up during the impact came back down, creating mountains almost instantaneously.
Or did the melt get there by a different mechanism? The fractures probably formed over time as the steep walls of the central peak slowly eroded and slipped downhill. Eventually the peak will erode back, and this massive boulder will slide such that the big boulder will meet its demise as it slides 1.24 miles (2 km) to the crater floor.
Tycho's features are so steep and sharp because the crater is only about 110 million years old -- young by lunar standards. Over time micrometeorites and not-so-micro meteorites, will grind and erode these steep slopes into smooth mountains. For a preview of Tycho's central peak may appear like in a few billion years, look at Bhabha crater.
On May 27, 2010, LRO captured a top-down view of the summit (below), including the large boulder seen in the above image. Also note the fractured impact melt deposit that surrounds the boulder. And the smooth area on top of the boulder, is that also frozen impact melt? These images from the LRO Camera clearly show that the central peak formed very quickly: The peak was there when impact melt that was thrown straight up during the impact came back down, creating mountains almost instantaneously.
Or did the melt get there by a different mechanism? The fractures probably formed over time as the steep walls of the central peak slowly eroded and slipped downhill. Eventually the peak will erode back, and this massive boulder will slide such that the big boulder will meet its demise as it slides 1.24 miles (2 km) to the crater floor.
This image shows a vertical view of the Tycho central peak summit, highlighting the same 400-foot-wide boulder as in the above image.
Credit: NASA Goddard/Arizona State University, › Larger image
Bhabha Sinks Into the Shadows: Last rays striking central peak of Bhabha crater just before sunset. View from the west looking east; image M133982125
The central farside crater Bhabha (64 km diameter) was named in honor of the physicist Homi Jehangir Bhabha (1909-1966), a nuclear physics pioneer in his home country of India. Bhabha Crater lies deep within the interior of the enormous South Pole-Aitken (SPA) Basin.
Full resolution view of summit of Bhabha central peaks.
Credit: NASA/GSFC/Arizona State University
Bhabha has a trio of central peaks that rise over a kilometer above the crater floor, and it has an intricate and complex system of rim terraces. Bhabha itself is a deep crater whose floor lies some 3 to 3.5 km below the crater rim.
Bhabha is of special interest because the impact that formed it penetrated deep into the SPA Basin floor, excavated materials of the SPA Basin impact-melt complex, and distributed these materials onto the surrounding plains. Even though this event happened long ago in the Moon's history, those materials are still present in the surrounding plains deposits waiting for a lunar explorer - whether robotic or human - to come along and return them to Earth.
These materials could then be used to address several important scientific questions, including age-dating the SPA Basin formation event, determining the nature of the materials that melted when SPA formed, and figuring out how deep the impact penetrated - perhaps through the lower crust and into the upper mantle of the Moon! Bhabha is truly a window deep into the interior of the Moon and deep into the ancient history of the Solar System.
View larger image, Credit: NASA/GSFC/Arizona State University
Look at those boulders on the summit. They may contain some of the deepest materials readily available from the Moon's crust. Imagine collecting samples of these precious materials yourself and returning them to Earth!
Full view across Bhabha crater.
Look at those boulders on the summit. They may contain some of the deepest materials readily available from the Moon's crust. Imagine collecting samples of these precious materials yourself and returning them to Earth!
LRO launched aboard an Atlas V rocket from Cape Canaveral, Fla., on June 18, 2009. LRO was built and is managed by NASA's Goddard Space Flight Center, Greenbelt, Md. The exploration phase was funded by NASA's Exploration Systems Missions Directorate in Washington, D.C. LRO operates under NASA's Science Mission Directorate.
Contacts and sources:
Arizona State UniversityRelated Link: Web page on the LROC site
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