Cosmos Computed

After we visited the Grand Canyon, we visited Meteor Crater, a ¾ mile wide impact crater in a northern Arizona desert. It is said to be the best-preserved crater in the world. In this photo, you can see the crater's bumpy rim on the horizon. Scientists believe that Meteor Crater was formed 50,000 years ago by a meteorite only 50 meters wide. It blasted such a large crater because it moved at a rate of something between 37 and 60 times the speed of sound. That's very fast. When the meteor hit the ground, it gave off energy equivalent to 10 - 20 million tons of TNT. The meteorite became extremely hot when it hit. It became so hot that most of it was vaporized, and the rest melted. The ground where it hit was no more fortunate; it vaporized and melted, too. A large quantity of material was thrown away from the site, and rained onto the ground for miles around. After the impact, fragments of the meteorite that had broken off in mid-air fell out of the sky onto the ground. Due to h...

On the second day of our road trip (see my last post here ), we visited the Grand Canyon, which is in northern Arizona. The Grand Canyon was formed by the Colorado River. The river ran over soil on the ground, and washed it away. Soon the river got to solid rock, and began to wear through that, too. As it wore through the rock, a huge gorge formed, with the river flowing through it. That gorge was the early Grand Canyon. As time went by, the canyon got deeper and deeper. The sides of the canyon fell into the river at places, and the river washed it away. When it rained, creeks and streams ran down into the canyon, eroding the sides and giving it an intricate, complicated shape. Finally, after about 40 million years of erosion, my family and I came along, and looked at the result. It's pretty impressive. Unfortunately, it was rather cold at the time, so we weren't able to stay as long as we would have liked; but it was a great experience just the same. While I was there, I took ...

I am currently on vacation in Arizona. It's really interesting here. For one, there are cool plants here that aren't where I live - like palm trees, and cacti taller than houses. For another, the weather is really nice; sunny  most of the time, and not too cold. To get to the place we're staying, my family drove for two days, from Colorado through New Mexico to Arizona. Here  are some of the photos I took along the way (just click to view): Colorado View looking up the side of a mountain Mesa Verde In these next pictures of Colorado, notice the "roots" of the mountain. They were likely carved by running rain-water. The following picture is of a butte I saw. Pardon the poor quality; the car was shaking like an earthquake for much of the trip. Arizona This picture is of some mountains far in the distance. The mountains are likely in Utah, but I'm not sure whether everything else is in Arizona or New Mexico. At first while we were in Arizona, we drove through a l...

What exactly is polarized light? You may have heard of it before, or read the name. It sounds cool, so what is it? That is what I will explain in this post. Light is like a wave, or bumpy curve, in many respects. This wave is a sine wave (see my Sine and Cosine post). The wave can oscillate (wobble) in an up-down motion, or a left-right motion; sometimes it does a mixture of both, and wobbles in a circular pattern. Look at the wall, or the floor. There are quadrillions of light waves bouncing off them. Some of the light waves oscillate in an up-down motion, others oscillate in a left-right motion, and others oscillate in a diagonal motion. The different types of waves are all jumbled together. Is it possible to have a bunch of light waves that all wobble the same way? Yes! Light like that even has a name: polarized light . You can buy filters that will polarize light; the filters are called polarizers , or polarized filters . Some sunglasses are made with polarized lense...

Trigonometry is the study of the relationship between the angles and sides of triangles. The two most essential parts of trig are the functions  sine and cosine . Both take an angle, and return a number. The way they work is really quite simple. A diagram showing sine (abbreviated sin) and cosine (cos) To find the sine of the angle θ , draw a circle with radius 1 on a graph, and put the circle's center at the origin of a graph. Find a point on the edge of the circle. The point makes an angle with the center of the circle; make sure that the angle is  θ . Sine of  θ  is the point's y-coordinate. Cosine is the point's x-coordinate. (See the picture to the right.) Sine and cosine are very useful for calculating heights and distances. For example, let's say somebody needs to know the height of a sky scraper, but isn't able to measure it physically with a tape. If he walks a certain distance away from it, and looks at the angle it subtends in the sky, he can us...

The Geminid meteor shower is coming up! At 2:00 AM, on December 14 (that's Thursday night, or Friday morning), you can see anywhere from 100 to 150 meteors per hour - depending on the sky and weather conditions. That's more than 1 meteor per minute! This particular meteor shower comes from a 5.1 km wide asteroid called 3200 Phaethon. Flecks of debris fall off this asteroid in a trail around the sun. These bits are called meteoroids . Every year, in December, Earth passes through this stream of meteoroids; when one of them enters Earth's atmosphere, it burns up and we see a meteor. If the meteor is brighter than Venus, it's called a fireball. Fireballs are much less common than meteors. This year, viewing conditions will be especially good; the peak occurs only 1 day past new moon. If you live in an area with lots of light pollution, you will definitely want to drive into the country. If you think the weather will be bad, go out a day or two before or after the peak. Kee...

You might want to check out my Blue Moon post before you read this one. It was late at night. The full moon lay high in the starry sky. Suddenly, everything started getting brighter and brighter, until the moon was as bright as the sun, and everything looked the way it does in the middle of the day - except for the glaring light pollution and the burning stars. Astounded, I pulled out a camera and snapped the photo above, and some others you can see in my Blue Moon post. About an hour later, everything went back to normal. Does that sound like a true story? Well, it isn't; that night was just like any other. To take the photos, I used a trick that I will explain in this post. When a digital camera takes a photo, this is what happens: a shutter on the front opens up, and a lens focuses light onto a tiny charge-coupled device (CCD) inside the camera. When the light hits the CCD, a small electric charge becomes present. As more and more light hits that part of the CCD, the charge ge...