< Back

Our Earth ~ Part II

Congratulations to 90-year old actor William Shatner for blasting off for real and returning safely. Uncle Bob and some of the NASA astronauts show what you might see when you sign up for your ride.

Panama Canal - The Panama Canal, below, is the main shipping route from the Atlantic to the Pacific Ocean.

Sedimentation in the Chepo River [upper left] is thought to be due to eroded soil from the agricultural lands near the sea. In the future, population and development pressures could threaten the canal’s supply of water from two surrounding lakes. Credit: NASA/Johnson Space Center

The Thurston Island calving off western Antarctica as seen from the window of NASA's DC-8 on Nov. 5, 2014. Credit: NASA/Jim Yungel

Uncle Bob has posed questions about this melting ice. Work it a little before looking at my solutions at the bottom of this page.

Oceans? Swell!

A. Global warming and the melting of glaciers is getting to be a big concern, especially on lands close to sea-level. What volume of ice in cubic miles has to melt in order to raise the ocean level one inch? Use 197,000,000 square miles for the Earth’s surface area, and assume it is 70% water. Allow for melting ice to shrink by 8% in volume. Assume we are raising a flat earth’s surface one inch.

B. To get a picture of this amount of ice, assume an iceberg with a square top is a fairly typical 165 feet thick (0.0313 miles) and has a very untypical square base. Give the square’s side measure and area in miles and square miles.

Amazon deforestation: Dense green vegetation gives way to pale fields in these satellite images of Brazil’s Amazon rain forest.

In an average U.S. forest, one acre contains 80 tons of carbon. This image is from NASA Terra satellite. Credit: NASA/JPL and NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Mt St Helens lost 1300 feet off its top in the 1980 eruption which killed 57 people. A mile-wide channel opened and rained rock which flew down the mountain at 150 miles per hour. Credit: Warren Hall

The Grand Canyon is one of North America's most spectacular geologic features.

Carved primarily by the Colorado River over the past six million years, the canyon sports vertical drops of 5,000 feet and spans a 445-kilometer-long stretch of Arizona desert. The strata along the steep walls of the canyon form a record of geologic time from the Paleozoic Era (250 million years ago) to the Precambrian (1.7 billion years ago), and yet it took only 5 or 6 million years for the river to carve it. Credit: NASA/JPL and NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Manicouagan crater, Quebec, Canada

This feature is one of most recognizable from our orbiters, and it’s one of the oldest impact craters on Earth. An annular lake surrounds the 40-mile inner plateau. Credit: NASA/Johnson Space Center

The Finger Lakes region is featured in this digital image photographed by an Expedition 10 crew member on the International Space Station.

Scientists believe the steep, roughly parallel valleys and hills of the Finger Lakes region were shaped by advancing and retreating ice sheets that were as much as 2 miles deep during the last ice age. The river valleys were scoured into deep troughs. The two largest lakes, Seneca and Cayuga, are so deep that the bases of their lake beds are below sea level. Credit: NASA/Johnson Space Center

The South Fork to the left and North Fork of the Shenandoah River meet in the foreground.

Front Royal, Virginia is just to the left of the combined rivers at the junction. Massanutten Mountain, covered by reddish-brown fallen leaves of the George Washington National Forest, separates the river forks. The mountains and other elements of the Appalachian Range in this scene were formed from folded sedimentary rocks that later were eroded into their present shapes; resistant rocks, such as sandstone, form the high ground while shale and limestone form the valleys. Hasselblad photograph, credit: NASA/Johnson Space Center

Check out other NASA orbiter photos.

These entries were inspired Orbit, NASA Asgtronauts Photograph the Earth, by Jay Apt, Michael Helfort, and Justin Wilkinson; National Geographic Society, 1996.


Solutions for Oceans? Swell

A. First we take 70% of the Earth's surface area and get 138 million square miles of ocean surface. One inch is about 0.00019 miles. Multiplying we get the volume of water needed: 26,220 cubic miles. This is only 92% of the volume of ice needed for the one-inch rise which comes to 28,500 cubic miles.

B. We divide the volume above by the depth 0.0313 miles to get the area of the top of the berg: 910,500 square miles, the areas of Alaska, Texas, and Utah combined. Then we take a square root to get the side of a square prism containing that much ice. We get 954 miles. Of course, with the tapering of the berg below the surface, the area at the top would have to be even bigger, but Antarctica has over 5.4 million square miles to contribute!