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Showing posts with label Colonisation. Show all posts
Showing posts with label Colonisation. Show all posts

Spectacular Drone Video Footage - Maasai Mara Wildebeest Migration

Last year, I embarked on an unforgettable 19 000km adventure that will stay with me for a very long time. I crossed the African continent alone on a motorcycle. The journey took about 6 months, as I took my time to learn more about the 15 African countries I was travelling through .


I tried to help where I could, particularly with charities for children and wildlife conservation. I also captured many images, many of which are on the Facebook page of Two Wheels Across and documented the entire journey in videos for my Youtube channel.


One of the exciting parts of my adventure was Casper the friendly drone, a Quadcopter that I used as often as I could to capture the beauty of Africa from the air.


I am excited to share one of the videos I filmed with you. I was fortunate to be in Kenya’s Maasai Mara during the migration and I captured the river crossing from the air. I also danced with an elephant, ran with wildebeests and kept three lions company for a few minutes. I hope you will enjoy the film!

 Guest Blogger in Animal Encounters                             Africa Geographic

How Much Water is Left on Earth

As you know, the Earth is a watery place. But just how much water exists on, in, and above our planet? About 71 percent of the Earth's surface is water-covered, and the oceans hold about 96.5 percent of all Earth's water. But water also exists in the air as water vapor, in rivers and lakes, in icecaps and glaciers, in the ground as soil moisture and in aquifers, and even in you and your dog.

Water is never sitting still, though, and thanks to the water cycle, our planet's water supply is constantly moving from one place to another and from one form to another. Things would get pretty stale without the water cycle!

 All Earth's water in a bubble

This drawing shows various blue spheres representing relative amounts of Earth's water in comparison to the size of the Earth. Are you surprised that these water spheres look so small? They are only small in relation to the size of the Earth. This image attempts to show three dimensions, so each sphere represents "volume." The volume of the largest sphere, representing all water on, in, and above the Earth, would be about 332,500,000 cubic miles (mi3) (1,386,000,000 cubic kilometers (km3)), and be about 860 miles (about 1,385 kilometers) in diameter.

The smaller sphere over Kentucky represents Earth's liquid fresh water in groundwater, swamp water, rivers, and lakes. The volume of this sphere would be about 2,551,000 mi3 (10,633,450 km3) and form a sphere about 169.5 miles (272.8 kilometers) in diameter. Yes, all of this water is fresh water, which we all need every day, but much of it is deep in the ground, unavailable to humans.

Do you notice that "tiny" bubble over Atlanta, Georgia? That one represents fresh water in all the lakes and rivers on the planet, and most of the water people and life of earth need every day comes from these surface-water sources. The volume of this sphere is about 22,339 mi3 (93,113 km3). The diameter of this sphere is about 34.9 miles (56.2 kilometers). Yes, Lake Michigan looks way bigger than this sphere, but you have to try to imagine a bubble almost 35 miles high—whereas the average depth of Lake Michigan is less than 300 feet (91 meters).

Water is on and in the Earth

The vast majority of water on the Earth's surface, over 96 percent, is saline water in the oceans. The freshwater resources, such as water falling from the skies and moving into streams, rivers, lakes, and groundwater, provide people with the water they need every day to live. Water sitting on the surface of the Earth is easy to visualize, and your view of the water cycle might be that rainfall fills up the rivers and lakes. But, the unseen water below our feet is critically important to life, also. How would you account for the flow in rivers after weeks without rain? In fact, how would you account for the water flowing down this driveway on a day when it didn't rain? The answer is that there is more to our water supply than just surface water, there is also plenty of water beneath our feet.

Even though you may only notice water on the Earth's surface, there is much more freshwater stored in the ground than there is in liquid form on the surface. In fact, some of the water you see flowing in rivers comes from seepage of groundwater into river beds. Water from precipitation continually seeps into the ground to recharge the aquifers, while at the same time water in the ground continually recharges rivers through seepage.

Humans are happy this happens because people make use of both kinds of water. In the United States in 2005, we used about 328 billion gallons per day of surface water and about 82.6 billion gallons per day of groundwater. Although surface water is used more to supply drinking water and to irrigate crops, groundwater is vital in that it not only helps to keep rivers and lakes full, it also provides water for people in places where visible water is scarce, such as in the desert towns of the western United States. Without groundwater, people would be sand-surfing in Palm Springs, California instead of playing golf.

Just how much water is there on (and in) the Earth? Here are some numbers you can think about:
If all of Earth's water (oceans, icecaps and glaciers, lakes, rivers, groundwater, and water in the atmosphere was put into a sphere, then the diameter of that water ball would be about 860 miles (about 1,385 kilometers), a bit more than the distance between Salt Lake City, Utah to Topeka, Kansas. The volume of all water would be about 332.5 million cubic miles (mi3), or 1,386 million cubic kilometers (km3). A cubic mile of water equals more than 1.1 trillion gallons. A cubic kilometer of water equals about 264 billion gallons.

About 3,100 mi3 (12,900 km3) of water, mostly in the form of water vapor, is in the atmosphere at any one time. If it all fell as precipitation at once, the Earth would be covered with only about 1 inch of water.

The 48 contiguous United States receives a total volume of about 4 mi3 (17.7 km3) of precipitation each day.

Each day, 280 mi3 (1,170 km3)of water evaporate or transpire into the atmosphere.
If all of the world's water was poured on the contiguous (lower 48 states) United States, it would cover the land to a depth of about 107 miles (145 kilometers).

Of the freshwater on Earth, much more is stored in the ground than is available in lakes and rivers. More than 2,000,000 mi3 (8,400,000 km3) of freshwater is stored in the Earth, most within one-half mile of the surface. But, if you really want to find freshwater, the most is stored in the 7,000,000 mi3 (29,200,000 km3) of water found in glaciers and icecaps, mainly in the polar regions and in Greenland.

 Where is Earth's water located?

For a detailed explanation of where Earth's water is, look at the data table below. Notice how of the world's total water supply of about 332.5 million mi3 of water, over 96 percent is saline. And, of the total freshwater, over 68 percent is locked up in ice and glaciers. Another 30 percent of freshwater is in the ground. Rivers are the source of most of the fresh surface water people use, but they only constitute about 300 mi3 (1,250 km3), about 1/10,000th of one percent of total water.
Note: Percentages may not sum to 100 percent due to rounding.
One estimate of global water distribution
(Percents are rounded, so will not add to 100)
Water sourceWater volume, in cubic milesWater volume, in cubic kilometersPercent of
Percent of
total water
Oceans, Seas, & Bays321,000,0001,338,000,000--96.54
Ice caps, Glaciers, & Permanent Snow5,773,00024,064,00068.71.74
    Fresh2,526,00010,530,00030.1  0.76
    Saline3,088,00012,870,000--  0.93
Soil Moisture3,95916,5000.050.001
Ground Ice & Permafrost71,970300,0000.860.022
Swamp Water2,75211,4700.030.0008
Biological Water2691,1200.0030.0001
Source: Igor Shiklomanov's chapter "World fresh water resources" in Peter H. Gleick (editor), 1993, Water in Crisis: A Guide to the World's Fresh Water Resources (Oxford University Press, New York).


Sources and more information

  • The Hydrologic Cycle, USGS pamphlet, 1984

Satellite Image - The Nile Illuminated at Night

Nile River Delta at Night
acquired October 28, 2010 download large image (606 KB, JPEG, 1440x960)
One of the fascinating aspects of viewing Earth at night is how well the lights show the distribution of people. In this view of Egypt, we see a population almost completely concentrated along the Nile Valley, just a small percentage of the country’s land area.

The Nile River and its delta look like a brilliant, long-stemmed flower in this astronaut photograph of the southeastern Mediterranean Sea, as seen from the International Space Station. The Cairo metropolitan area forms a particularly bright base of the flower. The smaller cities and towns within the Nile Delta tend to be hard to see amidst the dense agricultural vegetation during the day. However, these settled areas and the connecting roads between them become clearly visible at night. Likewise, urbanized regions and infrastructure along the Nile River becomes apparent (see also The Great Bend of Nile, Day & Night.)

Another brightly lit region is visible along the eastern coastline of the Mediterranean—the Tel-Aviv metropolitan area in Israel (image right). To the east of Tel-Aviv lies Amman, Jordan. The two major water bodies that define the western and eastern coastlines of the Sinai Peninsula—the Gulf of Suez and the Gulf of Aqaba—are outlined by lights along their coastlines (image lower right). The city lights of Paphos, Limassol, Larnaca, and Nicosia are visible on the island of Cyprus (image top).
Scattered blue-grey clouds cover the Mediterranean Sea and the Sinai, while much of northeastern Africa is cloud-free. A thin yellow-brown band tracing the Earth’s curvature at image top is airglow, a faint band of light emission that results from the interaction of atmospheric atoms and molecules with solar radiation at approximately 100 kilometers (60 miles) altitude.

Astronaut photograph ISS025-E-9858 was acquired on October 28, 2010, with a Nikon D3S digital camera using a 16 mm lens, and is provided by the ISS Crew Earth Observations experiment and Image Science & Analysis Laboratory, Johnson Space Center. The image was taken by the Expedition 25 crew. The image in this article has been cropped and enhanced to improve contrast. Lens artifacts have been removed. The International Space Station Program supports the laboratory as part of the ISS National Lab to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Caption by William L. Stefanov, NASA-JSC.
ISS - Digital Camera

City Lights Illuminate the Nile
acquired October 13, 2012 download large image (2 MB, JPEG, 3000x3000)
acquired October 13, 2012 download GeoTIFF file (5 MB, TIFF)
acquired October 13, 2012 download Google Earth file (KML)
The Nile River Valley and Delta comprise less than 5 percent of Egypt’s land area, but provide a home to roughly 97 percent of the country’s population. Nothing makes the location of human population clearer than the lights illuminating the valley and delta at night.

On October 13, 2012, the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite captured this nighttime view of the Nile River Valley and Delta. This image is from the VIIRS “day-night band,” which detects light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe signals such as gas flares, auroras, wildfires, city lights, and reflected moonlight.

The city lights resemble a giant calla lily, just one with a kink in its stem near the city of Luxor. Some of the brightest lights occur around Cairo, but lights are abundant along the length of the river. Bright city lights also occur along the Suez Canal and around Tel Aviv.

Away from the lights, however, land and water appear uniformly black. This image was acquired near the time of the new Moon, and little moonlight was available to brighten land and water surfaces.

Learn more about the VIIRS day-night band and nighttime imaging of Earth in our new feature story: Out of the Blue and Into the Black.
  1. References

  2. United Nations Environment Programme. (2008). Africa: Atlas of Our Changing Environment. Division of Early Warning and Assessment, United Nations Environment Programme, Nairobi, Kenya.
NASA Earth Observatory image by Jesse Allen and Robert Simmon, using VIIRS Day-Night Band data from the Suomi National Polar-orbiting Partnership. Suomi NPP is the result of a partnership between NASA, the National Oceanic and Atmospheric Administration, and the Department of Defense. Caption by Michon Scott.
NASA Earth Observatory

A History of the Landsat Science Satellite

Landsat 1 • Landsat 2 • Landsat 3 • Landsat 4 • Landsat 5 • Landsat 6 • Landsat 7 • Landsat 8

From the Beginning

“The Landsat program was created in the United States in the heady scientific and exploratory times associated with taming the atom and going to the Moon,” explains Dr. John Barker. In fact, it was the Apollo Moon-bound missions that inspired the Landsat program. During the early test bed missions for Apollo, photographs of Earth’s land surface from space were taken for the first time.

“This photography has been documented as the stimulus for Landsat,” explains Dr. Paul Lowman, who proposed the terrain photography experiment for the last two Mercury missions, the Gemini missions, and the Apollo 7 and 9 missions.

Thor-Delta rocket prepared to launch Landsat 1, 1972.
Thor-Delta rocket prepared to launch Landsat 1, 1972.

In 1965, director of the U.S. Geological Survey (USGS), William Pecora, proposed the idea of a remote sensing satellite program to gather facts about the natural resources of our planet. Pecora stated that the program was “conceived in 1966 largely as a direct result of the demonstrated utility of the Mercury and Gemini orbital photography to Earth resource studies.”

While weather satellites had been monitoring Earth’s atmosphere since 1960 and were largely considered useful, there was no appreciation of terrain data from space until the mid-1960s.
So, when Landsat 1 was proposed, it met with intense opposition from the Bureau of Budget and those who argued high-altitude aircraft would be the fiscally responsible choice for Earth remote sensing.

Concurrently, the Department of Defense feared that a civilian program such as Landsat would compromise the secrecy of their reconnaissance missions.
Additionally, there were also geopolitical concerns about photographing foreign countries without permission.

In 1965, NASA began methodical investigations of Earth remote sensing using instruments mounted on planes. In 1966, the USGS convinced the Secretary of the Interior, Stewart L. Udall, to announce that the Department of the Interior (DOI) was going to proceed with its own Earth-observing satellite program.

This savvy political stunt coerced NASA to expedite the building of Landsat. But, budgetary constraints and sensor disagreements between application agencies (notably the Department of Agriculture and DOI) again stymied the satellite construction process.
Finally, by 1970 NASA had a green light to build a satellite. Remarkably, within only two years, Landsat 1 was launched, heralding a new age of remote sensing of land from space.

The Landsat satellite record stretches from 1972 to the present. This gallery includes all Landsat images published on the Earth Observatory, Visible Earth, and Landsat Science web sites from all seven Landsat satellites (Landsats 1-8, Landsat 6 failed to achieve orbit). All of the images are in the public domain and may be used with attribution. The correct attribution for imagery obtained from this site is:

“Landsat imagery courtesy of NASA Goddard Space Flight Center and U.S. Geological Survey” or “USGS/NASA Landsat”

More History


Learn about the Landsat Legacy project        Landsat Science

Curiosity Mars Rover moves On - Alexander Hills

Within Rover's Reach at Mars Target Area 'Alexander Hills'

This view from the Mast Camera (Mastcam) on NASA's Curiosity Mars rover shows a swath of bedrock called "Alexander Hills," which the rover approached for close-up inspection of selected targets.

The mosaic of six Mastcam frames covers an area about 6 feet (2 meters) across. It shows details within the workspace accessible using the rover's robotic arm from the rover's location when the view was acquired. The component exposures were taken on Nov. 23, 2014, during the 817th Martian day, or sol, of Curiosity's work on Mars. The color has been approximately white-balanced to resemble how the scene would appear under daytime lighting conditions on Earth.

Figure A is an annotated version showing the location of three targets selected for study -- "Aztec," "Agate Hill" and "Cajon" -- and a 50-centimeter (20-inch) scale bar.

The location of Alexander Hills within the "Pahrump Hills" outcrop at the base of Mount Sharp is indicated on an earlier Mastcam view at http://photojournal.jpl.nasa.gov/catalog/PIA19039. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Science Laboratory Project for NASA's Science Mission Directorate, Washington. JPL designed and built the project's Curiosity rover. Malin Space Science Systems, San Diego, built and operates the rover's Mastcam.

Image Credit: NASA/JPL-Caltech/MSSS

Erosion Resistance at 'Pink Cliffs' at Base of Martian Mount Sharp
Erosion Resistance at 'Pink Cliffs' at Base of Martian Mount Sharp
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Ripples Beside 'Pahrump Hills' Outcrop at Base of Mount Sharp
Ripples Beside 'Pahrump Hills' Outcrop at Base of Mount Sharp
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Erosion Resistance at 'Pink Cliffs' at Base of Martian Mount Sharp
Erosion Resistance at 'Pink Cliffs' at Base of Martian Mount Sharp (Labeled)
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Fine-Grained Rock at Base of Martian Mount Sharp
Fine-Grained, Finely Layered Rock at Base of Martian Mount Sharp
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Fine-Grained Rock at Base of Martian Mount Sharp
Fine-Grained, Finely Layered Rock at Base of Martian Mount Sharp (Labeled)
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