Jason P.

Visualizing Earth Test 1 Form B

1. A. Describe the characteristics and major parts of the electromagnetic spectrum.

The characteristics of the electromagnetic spectrum are that it can move at the speed of light. Light moves in waves made of particles of light. Each wave has a trough, wavelength, energy, and speed. The frequency of a wave is the number of waves per unit of time. Light is called electromagnetic radiation because it can move out in all directions and not just one. Light can be reflected, refracted, and absorbed when it hits an object. The major parts of the electromagnetic spectrum are microwaves, which are long, low frequency waves that we can use for seeing quasars. Microwaves are stronger and we use them to heat our food sometimes. Infrared is not actually red, it isn't any color and we use it to see vegetation the Earth. Visible light is the light we can see, and we use it every day. UV rays are the next strongest, and we can use them to measure energy. X-rays are used to see black holes, and the strongest of them all, gamma rays are used to detect super novas, which is the death of our most powerful stars.

B. Describe two activities related to the properties of light that we did in class and explain what we learned about light from each of these.

Two activities we did in class related to the properties of light were when we gave energy to certain elements, creating light, and when we put the color filter over our spectroscopes. When we gave energy to certain elements we saw that they would give off a color. We learned that nature is lazy because it gives energy to electrons so that they move to a higher energy level because they get excited. When they lose their energy they fall back to their original spot but the energy comes out in the form of light. So we learned how light was made. When we put color filters over the spectroscope we saw that it blocked out certain colors of light. When we put a red, blue, or green color filter over the spectroscope we learned that they blocked out every color except for the color of the filter, allowing us to see only red, blue, or green light.

C. Explain what is meant by "new ways of seeing" and how the development of new tools of "vision" has created a scientific revolution of the 20th century.

"New ways of seeing," means that we are now able to see parts of the electromagnetic spectrum we never knew existed. Before the 20th century we were limited to visible light, but now we can see in all waves of the spectrum. Microscopes, telescopes, and satellites are the tools that have allowed us to see this new world. We can see things like an atom or a cheek cell now, or we can see things that are not even in this galaxy. These tools have opened us a whole new world for us. We now get different information out of things because we can tune into different waves of light, making humans unique in that aspect.

2.A. Explain what remote sensing is and how satellite imagery is transmitted and used on earth. Remote sensing is the gathering of energy from a distance. Satellites use this method to collect information for earth. Satellite imagery is transmitted and used on earth because a satellite assigns a certain number to every color value in the image. Each number is within a pixel and represents a brightness from 0-255. After that this information is sent to a computer in binary code and we have the image on earth. After that we can manipulate the images as many times as we like to extract the information we would like out of them.

B. Describe how satellite technology has transitioned from military to civilian use (historical perspective). Satellite technology was made first for the military in war. Satellites gave the military the higher ground so that they could guide their missiles to the target they desired, causing fewer deaths to innocent people. It gave the military an edge over everyone else. Now we use it for the weather and to find things out about our planet. The LandSat program used satellites to monitor the change in our environment over a certain period of time. We now have more accurate information, and for the first time we were able to predict El Nino, which saved a lot of money in damages.

C. Explain how remote sensing has provided us with an understanding of how this planet operates as an integrated system and has helped us to identify and solve global problems.

Satellite technology has allowed us to see how this planet works as an integrated system and help solve global problems because we are able to see how everything has a direct effect on everything else. We are now able to see that when we cut down the rain forests it is affecting the weather in the environment. Acid rain, global warming, and other problems are being solved now because of the satellites ability to identify a problem. Issues we didn't know needed to be solved are being solved because if they are not they will cause other problems.

3. Describe how remote sensing could provide an invaluable tool to aid in understanding growth trends in the north county, the loss of wild land areas and fire patterns, Include the following information in your essay:

A. Description of what a digital image is.

A digital image is an image made by numbers. Each number has been assigned a certain brightness value. The number is in a box called a pixel. There are 256 different brightness values, the brighter it is, the lower the value, and the darker it is, the higher its pixel value. A digital image can have both true colors and false colors depending on what you need.

B. Explanation of how visual, infrared and microwave sensing could be used in this study. Visual sensing could provide people with an image they can recognize. People would not recognize a picture in another wave of light because it would not be something hey are used to seeing.. Infrared sensing could be used to monitor how the vegetation changed as more and more people begin o move in. You could note whether it grew or if it was diminishing. Microwave sensing could be used in this study because it will tell us how the land changed as more and more people move in. Microwaves are good at showing the geography of land masses.

C. Description of how true and false color images are made and how they could be used.

True color images are made by taking an image of an object and filtering it into a gray scale of red, blue, and green. You will now have three pictures of the same object with red highlighting red, green highlighting the green, and blue highlighting the blue. Then you super impose the images on top of each other, combining the pixel values. This creates a true color image and works like a color wheel. To get a false color image you assign a color to the wavelength of light you wish to see. You then repeat the steps but instead you will get a false color image. This could be used to get different information out of the picture. You could see the affect fire has on vegetation if you use a false color image in the infrared.

D. Explanation of the role of false spectral signatures in creating false color images.

A spectral signature is the percent reflectance of an image in a certain wavelength of light. You would want to select band widths that made the information you needed stand out against everything else. You would select a different band width with each piece of information so when you made it into a false color image it would be easy to define against all of the other things. You wouldn't want to select a band width that made everything look the same because you wouldn't get any information out of the picture.