Friday, April 20, 2007

Antartica was Warm in the past?

How can Antarctica be Warm?
On April 20, 2007 tiny fossil diatoms were discovered deep down in the ocean floor. This revealed a significant truth about Antarctica's past about 10 million years ago. Yes, it is true that it was much much hotter in the past. Let me start at the beginning so that you get it. First it was cold and there was a lot of ice in Antarctica. Then it became really hot in the middle, which the scientists very recently learned. Now, it's cold again. The scientists working on this topic were very surprised by the single-celled algae. They had never seen some of these diatoms and others they had only seen in waters with really really high temperatures. Scientists say that these diatoms are new to science and will help them understand future climate changes. Now their new goal is to recover sedimentary records close to Antarctica so that they can learn about Antarctica's history and understand how it's related to global warming. Hopefully, global warming will not occur again, but be prepared just in case
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To learn more about global warming visit:
http://news.bbc.co.uk/2/hi/science/nature/6570185.stm

Wednesday, April 18, 2007

Memory

Don't you always remember the significant details and forget the minor ones in your life?
For example, you would remember that you had a party yesterday, but you'd forget who left before Anne. Well, on April 18, 2007 Jan Born and her research group discovered that long- term memories are formed while sleeping. This process relies on the brain replaying recent events during the night. The scientists also realized that sleeping not only strengthens your memory, but it also lets you remember the order that the events occurred. They even did an experiment to see if their results were really right. For the experiment a few students were asked to learn triplets of words one after another. The next day they tested each student and only the ones that had slept were able to determine the order of the words. However, they could only remember when they recited them in a forward direction not a backwards one. In the end, every student needs at least 8-10 hours of sleep if they want to do well in school!

http://brightsurf.com/news/headlines/30003/Sleep_enforces_the_temporal_sequence_in_memory.html

Wednesday, April 11, 2007

THE SUN

There are about 100 billion stars in our galaxy and out of them our sun is the closest. With a diameter of 1,390,000 kilometers it is also the largest and therefore the hottest even though it is only a yellow star. The mass of the sun is 1.989e30 kilograms and the temperature is 5800 Kelvin on the surface, which is called the photosphere as well as the chromospere, which is a small region right above the photosphere. There is also a layer above the chromosphere called the corona layer, which has a temperature of 1,000,000 Kelvin. This layer extends millions of kilometers into space, but can only be seen during a solar eclipse. The temperature on the core is 15,600,000, which is way more than the surface. This is because each second about 700,000,000 tons of hydrogen are converted into about 695,000,000 tons of helium and 5,000,000 tons of energy in the form of gamma rays. But by the time that these gases reach the surface they would've cooled down and become only visible light. In spite of that the amount of output is still humongous and is produced by nuclear fusion reactions. The sun also emits solar winds, which are a low-density stream of charged particles, which mostly contain electrons and protons. Unlike the Earth the sun is not a solid body, instead it's a planet made up of gases. In addition, hundreds of sunspots lie on the sun. These areas are "cool" regions and only 3800 Kelvin. They can be as big as 50,000 km. in diameter. These sunspots are created by complicated interactions with the suns' magnetic field. Occasionally spectacular loops and prominences are visible along with solar flares. They can rise hundreds of kilometers high and are huge. One day the sun will become a black hole or at least die and make the world cold and dark. Unless we find a solution humans will probably become extinct just like dinosaurs. But don't worry our sun has lived for 4.5 billion years until now and will live for another 5 billion years. So we're safe for now!!!