The 2-letter codes shown below are supplied by the ISO (International Organization for Standardization). It bases its list of country names and abbreviations on the list of names published by the United Nations. The UN also uses uses 3-letter codes, and numerical codes to identify nations, and those are shown below.
An International gathering of world leaders in science met in Geneva to discuss their latest findings. Each nation took a turn sharing its latest developments. The leader of one nation stood before the group and declared that they had devised a spacecraft which would allow their astronauts to fly directly to the sun. He was met with boisterous laughter from the audience, to which he boldly replied, “I know what you’re thinking, but we have a plan. We’re going to fly the ship at night!” About everybody knows that you can’t fly directly to the sun, for several reasons, not the least of which is that you can’t even land there because there is no there to land on. The sun is a star, which is an enormous ball of burning gases. If you remember from your science lessons in school about the three states of matter (solid, liquid, gas) you remember that gases are not solids. In order to land and stand on any celestial body, it would need to be solid because we are solid. Oh yeah, for us to fly anywhere near the sun we would have to build a spacecraft that could withstand over 1,000,000 degrees Kelvin AND keep the people inside protected from not only the extreme heat, but the intense light and solar radiation. Human beings were built to withstand the intensity of the sun from the distance of earth, not any closer. Even at this distance, too much exposure to the sun can be dangerous. Besides, we don’t really need to fly to the sun to study it, we can make observations from afar (it’s much safer).
The Source of the Sun's Tremendous Energy
You would probably think of the sun as very old, as it is estimated that the “birth” of the sun happened 4.5 billion years ago. Things that grow old usually die, but 4.5 billion years is young for our sun. It is estimated that there is enough fuel in the interior of the sun to keep that lamp burning for about another five billion years, growing twice as bright as it is now. The source of the sun’s fuel is hydrogen and helium gases. Through a special chemical reaction, called nuclear fusion, the hydrogen gas is “burned” releasing an enormous amount of energy in the form of light and heat.
Two isotopes of the element Hydrogen (tritium and deuterium) collide with each other under extreme heat in the interior of the sun. The two atoms smash into each other so hard that several things happen:
1. Like cars smashing into each other in a high speed crash, the atoms lose pieces of themselves, atomic particles
2. Unlike anything else we know of in the universe, however, an ENORMOUS amount of energy is released into the surrounding area, on the order of 450 times the amount of energy required for a fusion reaction to initiate (talk about a big return on your investment!)
3. The atomic particles from the Hydrogen atoms that were released during the collision are fused together, forming an entirely new molecule called Helium
Of course, there’s a LOT more than just two atoms smashing into each other in the center of the sun. There’s so many nuclear fusion reactions happening inside the sun at any given time that we don’t have a number big enough to count them! The light and heat energy travels from the core of the sun to its exterior (the photosphere) where we see it from earth (during the day). It takes a million years for the energy from a single nuclear fusion reaction in the center of the sun to reach the surface.
The sun is so powerful we can harness the energy from it to make our lives easier – ever heard of solar energy (using the heat from the sun to heat the water for your house)? Now that you know a little more about the sun, solar energy has a different meaning. True solar energy comes from the nuclear fusion reactions of the sun’s interior. From the knowledge we have gained about about nuclear science we have developed of the Hydrogen bomb and nuclear energy.
The word iceberg comes from the Dutch word “ijsberg” which means “ice hill”. Iceberg is the mass of ice that has become detached, or calved, from the edge of an ice sheet or glacier and is floating on the ocean. They float because of more volume which makes them less dense than water and about one ninth of the total mass of a berg projects above the water. Greenland and other N Atlantic icebergs are usually peaked and irregular in shape; Antarctic icebergs are tabular, with flat tops and steep sides. Icebergs differ from other ocean ices: sea ice is formed directly from the freezing of ocean water; pack ice is tightly packed fragments of sea ice; ice floes are small, floating ice fragments that separate from pack ice; and fast ice is ice attached to a shore. The tallest iceberg measured ever was 168m seen in 1958 off Greenland. Smaller icebergs makes a particular sound while floating and hence they are called “growlers”. Every year about 10000-15000 icebergs are formed around the world! The process of ice formation is called carving and the most enthralling of all is that the air trapped in a fully formed iceberg may be about 3000 years old!
How do icebergs form, and where do they go?
Icebergs form when chunks of ice calve, or break off, from glaciers, ice shelves, or a larger iceberg. Icebergs travel with ocean currents, sometimes smashing up against the shore or getting caught in shallow waters.
When an iceberg reaches warm waters, the new climate attacks it from all sides. On the iceberg surface, warm air melts snow and ice into pools called melt ponds that can trickle through the iceberg and widen cracks. At the same time, warm water laps at the iceberg edges, melting the ice and causing chunks of ice to break off. On the underside, warmer waters melt the iceberg from the bottom up.
Why do scientists study icebergs?
Climate scientists study icebergs as they break up for clues to the processes that cause ice shelf collapse. Scientists have noticed that the way icebergs break up when they reach warmer waters mirrors the disintegration of Antarctic ice shelves. By studying the factors that cause icebergs to break up, researchers hope to better understand the influences that lead to ice shelf breakup, and to better predict how ice shelves will respond to a warming climate.
Oceanographers follow icebergs because the cold freshwater they contribute to the sea can influence currents and ocean circulation far away from their origins. Biologists study icebergs to find out how they influence ocean life. As icebergs melt, they leak nutrients into the ocean around them. Recent studies have shown that the water surrounding icebergs teems with plankton, fish, and other sea life
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