The first picture is of the Mackinac Bridge. The Bridge spans a stretch of water five miles wide between Michigan’s lower and upper peninsulas. The strait connects Lakes Michigan (left) and Huron (right). The bridge is a combination of pier-supported spans with a high, central suspension sector that allows passage of lake steamers. The suspension sector is the longest in the Americas (8, 614 feet or 1.6 miles). Prior to construction of the bridge, the only passage across the straits was by ferryboat. The photo shows shipping lanes opened by ice breakers. A narrow passage connects the cleared shipping channel to the small town of St. Ignace at the north end of the bridge (Mackinaw City appears at the south end). The April view shows the ice broken into a series of irregular rafts that appear gray against bright water. The whitish appearance of the water is not snow or ice, but instead is sunlight glinting off the water back to camera. The shipping channel is maintained even through remnants of the ice mass, but the ice ridges can be hazardous to shipping until the last of the ice breaks up.
Astronauts obtained this detailed image of the summit caldera of Mauna Loa volcano, called Mokuaweoweo Caldera. Mauna Loa is the largest volcano on our planet—the summit elevation is 4,170 m (over 13,600 ft), but the volcano’s summit rises 9 km above the sea floor. The sharp features of the summit caldera and lava flows that drain outward from the summit are tribute to the fact that Mauna Loa is one of the Earth’s most active volcanoes. The most recent eruption was in 1984. The straight line that cuts through the center of the crater from top to bottom is a rift zone—an area that pulls apart as magma reaches the surface. A weather observatory run by NOAA’s Climate Monitoring & Diagnostics Lab is on the volcano’s north slope at 11,000 ft (3397 m). This facility, known as the Mauna Loa Observatory, is the site where scientists have documented the constantly increasing concentrations of global atmospheric carbon dioxide.
Other resources about Mauna Loa:
http://wwwhvo.wr.usgs.gov/maunaloa/
http://www.cmdl.noaa.gov/obop/mlo/
The snow-covered peaks of the Alps can be seen in this near-nadir view. Cut by numerous gaps and passes, the Alps do not form a complete climax or strategic barrier, as is evidenced by the similarities of air, people, and animals on either side of the system. Permanently snow capped peaks rise above the snowline - located between 8000 and 10000 feet (2440 to 3050 meters) - and valley glaciers form the headwaters of many Alpine rivers. Glaciation was quite extensive around 13000 years ago and carved a distinctive mountain landscape of cirques, Matterhorn's, u-shaped and hanging valleys, and long moraine-blocked lakes. Below the snowline is a treeless zone of pastures that have for generations been used for summer grazing. Tourism, based on the scenic attractions of the Alps and the mountaineering and winter sports they provide, is a major source of income for the region. Near the bottom center of the image, the famous resort city of Innsbruck is discernible. The Winter Olympic Games were held in Innsbruck in 1964 and 1976.
The twin cities of Sault Ste Marie are located across the St. Mary’s River that forms part of the international boundary between Canada (Province of Ontario) and the United States (State of Michigan). This astronaut photograph highlights the two cities, together with the region of lakes and islands that separates Lakes Huron and Superior, two of the Great Lakes of North America. Smaller lakes include Lake George to the west; the large forested islands of St. Joseph and Drummond are visible at image upper left. The Sault Ste Marie urban areas (image lower left) have a distinctive gray to white coloration in the image, contrasting with the deep green of forested areas in Ontario and the lighter green of agricultural fields in Michigan. The coloration of water surfaces in the lakes and rivers varies from blue to blue-green to silver, and is likely caused by varying degrees of sediment and sun glint – light reflecting back to the astronaut observer on the International Space Station from the water surface, much as light reflects from a mirror. Prior to formalization of the US/Canada border in 1817, Sault Ste Marie was a single community. Archaeological evidence suggests that the region had been occupied by Native Americans at least five hundred years ago. A mission – the first European settlement in Michigan - was established there in 1668 by the French Jesuit Father Jacques Marquette. Today, shipping locks and canals in both urban areas are an important part of the Great Lakes shipping traffic system.
The Grand Canyon, one of the deepest canyons in the world with a depth of 1 mile (1.6 kilometers), can be seen in this spectacular, west-looking, low-oblique photograph. The Colorado River cut through rocks billions of years old to create this canyon. The Grand Canyon is 277 miles (466 kilometers) long and averages nearly 10 miles (16 kilometers) in width. The snow-covered, forested Kaibab Plateau (north of the canyon) and the Coconino Plateau (south of the canyon) are visible. The western portions of the Painted Desert can be seen east of the canyon where the Little Colorado River joins the Colorado River.
And the skies of night were alive with light, with a throbbing, thrilling flame; Amber and rose and violet, opal and gold it came. It swept the sky like a giant scythe, it quivered back to a wedge; Urgently bright, it cleft the night with a wavy golden edge. — “The Ballad of the Northern Lights.”
In describing auroras as he saw them in the far north in 1908, poet Robert Service captured the sense of fluid motion, the vivid color, and the fiery, flame-like qualities one sees from the ground. His description works just as well in the southern hemisphere and when looking down from above.
Astronauts on the International Space Station (ISS) used a digital camera to capture several hundred photographs of the aurora Australia, or “southern lights,” while passing over the Indian Ocean on September 17, 2011. Solar panels and other sections of the ISS fill some of the upper right side of the photograph. Auroras are a spectacular sign that our planet is electrically and magnetically connected to the Sun. These light shows are provoked by energy from the Sun and fueled by electrically charged particles trapped in Earth’s magnetic field, or magnetosphere. In this case, the space around Earth was stirred up by an explosion of hot, ionized gas from the Sun—a coronal mass ejection—that left the Sun on September 14, 2011. The pressure and magnetic energy of the solar plasma stretches and twists the magnetic field of Earth like rubber bands, particularly in the tail on the night side. This energizes the particles trapped in our magnetic field; that energy is released suddenly as the field lines snap the particles down the field lines toward the north and south magnetic poles. Fast-moving electrons collide with Earth’s upper atmosphere, transferring their energy to oxygen and nitrogen molecules and making them chemically “excited.” As the gases return to their normal state, they emit photons, small bursts of energy in the form of light. The color of light reflects the type of molecules releasing it; oxygen molecules and atoms tend to glow green, white or red, while nitrogen tends to be blue or purple. This ghostly light originates at altitudes of 100 to 400 kilometers (60 to 250 miles).
The Northern Hemisphere Jet Stream can be seen crossing Cape Breton Island in the Maritime Provinces of Eastern Canada. The Jet Stream is a narrow zone of high-speed winds typically found at altitudes of 4 to 8 miles (8-12 km) above the earth. They result from temperature contrasts between polar and tropical regions. The strongest Jet Stream winds are found in the winter when the contrast between polar and tropical regions is the greatest. Wind speeds can reach 90 to over 180 miles per hour (145 to over 290 km/h) from west to east. Jet Streams are found between latitudes 20 to near 55 north and south. During the winter months over the United States and southern Canada, the path taken by the Jet Stream can have a large influence on the weather conditions of this region.
Astronauts aboard the International Space Station took this digital photograph of the eye of Hurricane Igor at 10:56 Atlantic Daylight Time (13:56 UTC) on September 14, 2010. The storm was a category four hurricane on the Saffir-Simpson scale of intensity. At the time of the image, Igor was centered in the Atlantic Ocean near 18° N 52° W and slowly moving west-northwest at 11 kilometers (7 miles) per hour, according to the U.S. National Hurricane Center. Maximum sustained winds of 213 km (132 mi.) per hour, with gusts to 259 km (161 mi.) per hour.
Eruption of Cleveland Volcano, Aleutian Islands, Alaska is featured in this image photographed by an Expedition 13 crew member on the International Space Station. This image, acquired shortly after the beginning of the eruption, captures the ash plume moving west-southwest from the summit vent. The eruption was short-lived; the plume had completely detached from the volcano summit two hours later. Ash plumes from Cleveland Volcano have reached heights of 12 kilometers and can present a hazard to trans-Pacific jet flights. The fog bank visible at image top center is a common feature of the Aleutian volcanoes. Cleveland Volcano, situated on the western half of Chuginadak Island, is one of the most active of the volcanoes in the Aleutian Island chain extending west-southwest from the Alaska mainland. At a summit elevation of 1,730 meters, this stratovolcano is the highest in the Islands of the Four Mountains group. Carlisle Island to the north-northwest, another stratovolcano, is also part of this group. Magma that feeds eruptions of ash and lava flows from the volcano is generated by subduction of the northwestward-moving Pacific Plate beneath the North American Plate. As one tectonic plate subducts beneath another, melting of materials above and within the subducting plate produce magma that can eventually move to the surface and erupt through a vent (such as a volcano). Cleveland Volcano claimed the only known eruption-related fatality in the Aleutian Islands during 1944.
The crew of the International Space Station took this dramatic image of the fires in Australia on the morning of January 18, 2003. Brisk winds are sweeping smoke plumes eastward off the Australian coast north of Cape Howe. The agricultural valleys of the Murrumbidgee and Murray Rivers give way to the burning, darker bush areas of the mountains with the extreme eastern coastline of Victoria visible beyond. Images like these are a unique contribution to our understanding of dynamic events — made possible by the human observer in orbit.
