Archive for the ‘Earth’ Category

How Great is the Amazon River?

Friday, October 19th, 2007

The Amazon is the greatest river in the world by so many measures; the volume of water it carries to the sea (approximately 20% of all the freshwater discharge into the oceans), the area of land that drains into it, and its length and width. It is one of the longest rivers in the world and, depending upon who you talk to, is anywhere between 6,259km/3,903mi and 6,712km/4,195mi long.

At its widest point the Amazon River can be 11km/6.8 mi wide during the dry season. The area covered by the Amazon River and its tributaries more than triples over the course of a year. In an average dry season 110,000 square km of land are water-covered, while in the wet season the flooded area of the Amazon Basin rises to 350,000 square km. When the flood plains and the Amazon River Basin flood during the rainy season the Amazon River can be up to 40km/24.8 mi wide. Where the Amazon opens at its estuary the river is over 325km/202 mi wide!

Because the Amazon drains the entire Northern half of the South American continent (approx. 40% landmass), including all the torrential tropical rains that deluge the rainforests, it carries an enormous amount of water. The mouth of the Amazon River, where it meets the sea, is so wide and deep that ocean-going ships have navigated its waters and traveled as far inland as two-thirds the way up the entire length of the river.

The Amazon - Home of Extremes 

The Amazon River is not only the greatest in the world, it is home to many other “Extremes” of the natural world. Have you ever seen a catfish? They’re usually found in warm, slow moving waters of lakes and streams, and some people keep them as pets in aquariums. Catfish are pretty creepy looking fish with big flat heads and “whiskers” on either side of their heads (hence the name, catfish). Most catfish that we’re familiar with here in the U.S. are anywhere from eight inches long to about five feet, weighing in at up to 60 pounds. But the catfish that live in the world’s greatest river have all the room in the world to grow as big as nature will allow - they have been captured weighing over 200 pounds! One of the largest freshwater fish in the world is found living in the waters of the Amazon River. Arapaima, also known locally as Pirarucu, Arapaima gigas are the largest, exclusively fresh water fish in the world. They have been found to reach a length of 15 ft/4m and can weigh up to 440lbs/200kg. And yes, for you smartypants out there, sturgeon are even larger than this, but they are not exclusively freshwater fish. Sturgeon spend most of their lives at sea, or in brackish water, and only swim into freshwater rivers to spawn. (Read about the biggest freshwater fish in the world.)

Amazon River, Brazil

 

The Amazon is also home to some other extreme creatures, featured here in “Extreme Science”; the Anaconda (biggest snake), and Piranha (most ferocious). Check it out!

Amazon River Facts  

So, how did the Amazon get to be so big? The first reason has to do with its location - right at the equator. Around the “belt line” of the earth lies a warm, tropical zone where over 400 in/1016cm of rain fall every year. That averages out to more than an inch (3cm) of rain, everyday! A lot of water falls onto the land surrounding the river, what is called the “Amazon River drainage basin”. A good way to understand what a drainage basin is to think of the whole northern half of the continent of South America as a shallow dish, or saucer. Whenever rain falls and lands anywhere in the river basin it all runs into the lowest place in the pan, which happens to be the Amazon River. The sheer volume of rain in the Amazon jungle, as well as the slope of the surrounding land, combine to create the enormous river known as the Amazon.

Mount Everest

Friday, October 19th, 2007

Mount Everest with Plumes, Tibet

Mount Everest is so famous for being so high that you’ve probably heard of it before. It has been known the world over since the early 1950s when Sir Edmund Hillary and Tenzig Norgay first climbed to its awesome summit. Hillary surveyed Everest at the time and determined that it was 29,000 ft/8840m high - a figure amazingly close to the current reading of 29,035 ft/8850m, which was confirmed using radar and global positioning satellite (GPS) technology. (more…)

Diamond cutting process

Friday, October 19th, 2007

Planning

Diamond manufacturers analyse diamond rough from an economic perspective, with two objectives steering decisions made about how a faceted diamond will be cut. The first objective is that of maximum return on investment for the piece of diamond rough. The second is how quickly the finished diamond can be sold. Scanning devices are used to get 3-dimensional computer model of the rough stone. Also, inclusions are photographed and placed on the 3D model, which is then used to find an optimal way to cut the stone. (more…)

Our First Lunar Program: What did we get From Apollo?

Thursday, October 18th, 2007

American plans now call for a return of humans to the Moon by around 2020. What can we hope to gain from such a program? It will be helpful to look back at our first lunar program, Apollo, and ask what we got from it, beside some 850 pounds of rock and soil – fascinating to geologists, but perhaps not to all taxpayers. I will try to summarize highlights of the payoff from Apollo.

What was the “Apollo Program”? There was much more to it than Neil Armstrong’s “one small step,” and even more than the following five lunar landings – any one of which would have been a gigantic accomplishment. First, Apollo began with the Gemini Program, which was solely a technological warm-up for Apollo. Gemini was the first true American spaceship, with propulsion, radar, on-board computers, and extravehicular activity (“space walk”) capability. Ten manned Gemini missions were flown, developing the technological and operational capability needed for the following lunar program. However, the Gemini astronauts carried out many scientific experiments, in addition to practicing various space-flight techniques such as orbital rendezvous. (more…)

Information on our sun.

Thursday, October 11th, 2007

Our Sun is a normal main-sequence G2 star, one of more than 100 billion stars in our galaxy.

        diameter:    1,390,000 km.
        mass:        1.989e30 kg
        temperature: 5800 K (surface)
                     15,600,000 K (core)

The Sun is by far the largest object in the solar system. It contains more than 99.8% of the total mass of the Solar System (Jupiter contains most of the rest). (more…)