By Gary Nugent

Google launched the highly anticipated full version of Google Earth, the search engine’s stand-alone global map utility on June 28th. The application [~10Mb] is available to download from http://earth.google.com.

This geographic search tool combines local search with satellite images and maps from around the globe.

Google Earth is a standalone application that’s essentially an enhanced and upgraded version of its Keyhole 3D satellite imagery product. As Google has done with several of its past acquisitions, the company has also made the application free to all users, dropping its annual subscription fee for the basic version. Google Earth Plus with additional features will cost $20 per year.

The program lets you do smooth sailing flybys of the entire Earth. You can easily fly to any spot on the globe, by entering any associated data, like street addresses, place names or lat/long coordinates. There are overlays that put additional information on the map, like roads, international boundaries, terrain, 3D buildings, crime statistics, schools, stadiums, any number of interesting stuff.

Currently, the application has detailed imagery for the U.S., Canada and the U.K. and 38 major cities in other countries, as well as medium to high resolution terrain imagery for the entire world.

You can do Local searches in the program, with icons on the map and a display on the side showing your results. You can leave notes, called “placemarks” all over the map, so you can remember where all sorts of places are. Searches and placemarks can be saved as bookmarks in “My Places”. Everything can be output in an XML format called KML, that will allow the vast popularity of Google Maps to continue in Earth. You can also email a JPEG of the map, or send a KMZ file if you know the recipient has Earth installed.

Google Earth Plus gives higher resolution images, GPS support, and more sophisticated annotation (like drawing on the map).

Google Earth is a broadband, 3D application that not all computers can run.

  • Apple Macintosh computers are not supported at this time (but they are working on it).
  • Windows-based desktop PCs older than 4 years old may not be able to run it.
  • Windows-based notebook PCs older than 2 years old may not be able to run it.

System Requirements:

Minimum configuration:

    Click for a larger view
  • Operating system: Windows 2000, Windows XP
  • CPU speed: Intel® Pentium® PIII 500 MHz
  • System memory (RAM): 128MB
  • 200MB hard-disk space
  • 3D graphics card: 3D-capable video card with 16MB VRAM
  • 1024×768, 32-bit true color screen
  • Network speed: 128 kbps (“Broadband/Cable Internet”)

Recommended configuration:

  • Operating system: Windows XP
  • CPU speed: Intel® Pentium® P4 2.4GHz+ or AMD 2400xp+
  • System memory (RAM): 512MB
  • 2GB hard-disk space
  • 3D graphics card: 3D-capable video card with 32MB VRAM or greater
  • 1280×1024, 32-bit true color screen
  • Network speed: 128 kbps (“Broadband/Cable Internet”)

Google has put together a Google Earth Sightseeing page with images of famous landmarks, and the KMZ files that will get you there.

Here are a few astronomical landmarks. You’ll need to have Google Earth running. Click on the required link, Clip “Open” on the dialog that will appear and then double-click on the doc.kml file:

  • Meteor Crater, U.S.A. – The origin of this classic simple meteorite impact crater was long the subject of controversy. The discovery of fragments of the Canyon Diablo meteorite, including fragments within the breccia deposits that partially fill the structure, and a range of shock metamorphic features in the target sandstone proved its impact origin.
  • Aorounga Crater, Chad, Africa – The impact of an asteroid or comet several hundred million years ago left scars in the landscape that are still visible in this spaceborne radar image of an area in the Sahara Desert of northern Chad. The original crater was buried by sediments, which were then partially eroded to reveal the current ring-like appearance. The dark streaks are deposits of windblown sand that migrate along valleys cut by thousands of years of wind erosion. The dark band in the upper right of the image is a portion of a proposed second crater. Scientists are using radar images to investigate the possibility that Aorounga is one of a string of impact craters formed by multiple impacts.
  • Roter Kamm, South West Africa/Namibia – Located in the Namibia Desert, the raised crater rim is clearly visible against darker background vegetation. Target rocks include primarily Precambrian crystalline rocks and modest amounts of younger sedimentary rocks. Outcrops of impact melt breccias are found exclusively on the crater rim. The crater floor is covered by broad, shifting sand dunes. The image can be tilted in Google Earth to see its profile against the landscape.
  • Mistastin Lake, Newfoundland and Labrador, Canada – a heavily eroded complex structure. Eastward moving glaciers have drastically reduced the surface expression of this structure, removing most of the impact melt sheet and breccias and exposing the crater floor. Glacial erosion has also imparted an eastward elongation to the crater that is particularly evident in the shape of the lake that occupies the central 10 kilometers (6 miles) of the structure. Horseshoe Island, in the center of the lake, is part of the central uplift and contains shocked Precambrian crystalline target rocks. Just beyond the margins of the lake are vestiges of the impact melt sheet that contains evidence of meteoritic features in quartz, feldspar and diaplectic glasses.
  • Manicouagan, Quebec, Canada – The Manicouagan impact structure is one of the largest impact craters still preserved on the surface of the Earth. The prominent 70 kilometers (43 miles) diameter, annular lake fills a ring where impact-brecciated rock has been eroded by glaciation. The lake surrounds the more erosion-resistant melt sheet created by impact into metamorphic and igneous rock types. Shock metamorphic effects are abundant in the target rocks of the crater floor. Although the original rim has been removed, the distribution of shock metamorphic effects and morphological comparisons with other impact structures indicates an original rim diameter of approximately 100 kilometers (62 miles).
  • Clearwater Lakes, Quebec, Canada – These twin circular lakes were formed simultaneously by the impact of an asteroidal pair which slammed into the planet approximately 290 million years ago. The lakes are located near the eastern shore of Hudson Bay within the Canadian Shield in a region of generally low relief in northern Quebec province. Notice that the larger western structure contains a ring of islands with a diameter of about 10 kilometers that surrounds the center of the impact zone. They constitute a central uplifted area and are covered with impact melts. The central peak of the smaller Clearwater Lake East is submerged. The lakes are named after their exceedingly clear water. Also notice that the surrounding terrain shows widespread scarring from glaciation. The multitude of linear and irregular shaped lakes (dark features) are the result of gouging or scouring action caused by the continental ice sheets that once moved across this area.
  • Gosses Bluff, Northern Territory, Australia – 142 million years ago, an asteroid or comet slammed into what is now the Missionary Plains in Australia’s Northern Territory, forming a crater 24 kilometers in diameter and 5 kilometers deep. Today, like a bull’s eye, the circular ring of hills that defines Gosses Bluff stands as a stark reminder of the event. The crater is located just south of MacDonnel Ranges (top of the picture). It is highly eroded. The circular ring of hills (5 kilometers or 3 miles diameter) is actually the results from differential erosion of the central uplift within this large complex crater. The crater rim is eroded to the point that it is no longer visible though it is probably located along the grayish colored drainage system outside the inner ring. The image can be tilted in Google Earth to see its profile against the landscape.
  • Kara-Kul, Tajikistan – The spectacular Kara-Kul structure is readily apparent in this image. Partly filled by the 25-kilometer (16-mile) diameter Kara-Kul Lake, it is located at almost 6,000 meters (20,000 feet) above sea level in the Pamir Mountain Range near the Afghan border. Only recently have impact shock features been found in local breccias and cataclastic rocks.
  • Goat Paddock, Australia – located within the semi-arid plains south of the Kimberley Plateau of northwestern Australia. The crater is expressed as a nearly circular depression open to the north. Its name is derived from its natural use as a paddock (a fenced pasture) for livestock. Goat Paddock’s diameter is very close to the transition diameter from simple bowl-shaped craters to more complex forms with central structures, flat floors, and slumped rim zones. Unfortunately, very little is currently known about this potentially insightful feature. The image can be tilted in Google Earth to see its profile against the landscape.
  • Goat Paddock, Australia – The Haughton Impact Crater is located on Devon Island, within the arctic archipelago of Canada’s Northwest Territories. Dry summers, harsh winters, and acidic soil conditions inhibit growth of vegetation and make this an ideal location for assessing lithological conditions via satellite image data. The crater formed in the Allen Bay Formation (OSA) but penetrated and excavated older rocks as deep as 1800 meters below the surface.
  • Gweni Fada, Chad – The Gweni Fada structure was first noted on Landsat images and aerial photography. Later (in the early 1990s), a team of French geologists visited the site and reported evidence of shock metamorphism within rock samples they had collected inside the structure. Erosion and infilling have modified the original crater topography, yet structural and lithological variations delineate the feature clearly. The most prominent expression of the crater is a bright crescent-shaped depression which encloses the southern two-thirds of an 8–10-kilometer-wide elevated region containing strongly disturbed blocks of sandstone; this probably corresponds to the eroded crater’s central peak. The crescent itself is ~12 kilometers in diameter and probably represents the vestiges of the original crater floor.
  • Acraman, South Australia, Australia – The existence of this impact structure was deduced from the discovery of its ejecta layer within late Precambrian shales of the 590-million-year-old Bunyeroo Formation in the Adelaide geosyncline, South Australia. This layer contains abundant shocked quartz grains and small shatter cones. The ejecta were found in outcrops and drill cores over several hundred kilometers. These outcrops led scientists to the Acraman structure in South Australia, which was shortly thereafter confirmed as an impact structure, and as the source crater of the Bunyeroo impact ejecta layer. The diameter of the Acraman structure is at least 90 kilometers, with some outer arcuate features at 150 kilometers diameter. Impact ejecta have been found at distances of up to 450 kilometers from the Acraman structure. The center of the structure is occupied by the 20-kilometer-diameter, hexagonal Lake Acraman, a dry salt lake (white feature slightly left of the center). It is not quite clear if the semicircular Lake Gairdner and Lake Everard, which can be seen in the upper part of the image, are part of the impact structure or not. If they are, Acraman would have a diameter of about 160 kilometers.
  • Vredefort, South Africa – The Vredefort structure is located near the center of the Witwatersrand Basin, about 100 kilometers from Johannesburg. It is expressed as a central core, about 40 kilometers in diameter, composed of old crystalline rocks. A deformed collar of uplifted and overturned younger sediments and lavas surrounds the core. Younger, flat-lying sediments resulting in the arcuate shape observed in this image bury much of the structure. The diameter of the collar rocks is approximately 80 kilometers, but reconstructions based on the distribution of shock metamorphic effects suggest an original crater diameter of up to 300 kilometers, encompassing the whole extent of the Witwatersrand Basin. It is very likely that the preservation of the gold deposits of the Witwatersrand Basin, the largest on Earth, is due to the structural constraints provided by the Vredefort impact structure. Formed about 2 billion years ago, it is the oldest and largest recognized impact structure on Earth.
  • Spider, Western Australia, Australia – The deeply eroded Spider structure occurs within sedimentary rocks of the semi-arid Kimberley plateau, northwestern Australia. The web-like radiating pattern of ridges that inspired the structure’s name is approximately 5 kilometers wide and is most probably the central uplift of an eroded large complex impact crater.
  • Teague (Shoemaker), Western Australia, Australia – This crater, in the desert of Western Australia, consists of a granitic uplifted core, about 10 kilometers diameter, surrounded by a dark crescent-shaped inner ring unit. An outer ring of Precambrian sediments has a diameter of about 20 kilometers. The appearance of this impact structure is complicated by salt deposits produced by shallow lakes that seasonally fill the depressions and evaporate. It has recently been renamed the Shoemaker impact structure, in honor of the late geologist Eugene M. Shoemaker, who was one of the founding fathers of impact research.
  • Ouarkziz, Algeria, Africa – This structure is situated in sedimentary rocks in the rocky desert of northwest Algeria. It displays a well-defined ring that is partly open to the south. The impact origin is suggested from the occurrence of planar deformation features within rocks returned 30 years ago from the only geologic expedition ever to visit the structure.
  • Ramgarh, India – This structure is situated in a semi-arid region in eastern Rajasthan. A ring of hills of about 3 kilometers in diameter and a small central peak are conspicuous. Although evidence of shock metamorphism that would prove an impact origin has not yet been presented, the surface morphology suggests that this is a likely impact crater. The image can be tilted in Google Earth to see its profile against the landscape.
  • New Quebec, Quebec, Canada – The 250-meter-deep circular lake that fills the New Quebec Crater is a relatively large, well-preserved crater. The interior topography of the crater is covered by lake sediments that inhibit a determination of whether the structure has a small central uplift. The rocks involved in this impact event are ancient and strongly deformed gneisses of the Precambrian shield. The jumbled and outwardly tilted rocks comprising the rim extend as much as 160 meters above the surrounding countryside, based on its morphological similarity to Meteor Crater in Arizona (slide #10). This was confirmed much later when diagnostic evidence of shock metamorphism was discovered in the minerals from gneiss samples collected from within the crater. Whereas the ejecta blanket has been removed by erosion, some isolated melt rocks have been found up to 2 kilometers from the crater rim.

You can enter the latitude and longitude of other features into Google Earth to have a look at them. The Earth Impact Database lists all known impact structures on Earth.

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Google Earth Videos:

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Filed under: Astronomy Articles