The Nature of Light itself – Robert Bateman
We are accustomed to light that we see, and use, everyday of our lives - The Nature of Light itself – Robert Bateman introduction. Light from the Sun, bounced off the Moon & Planets, the stars themselves, light bulbs, microwave ovens, heating in our homes. Most of us are familiar with visible, infrared, ultraviolet, x-rays as flavors of light. Radio uses a form of light also. But what is light, and how does it behave? Light, better known as photons, are infinitely small particles with high energy. They travel at 186,000 mph, reaching the Moon from the Earth is just over a second. Light as a particle is what we see when looking in a mirror.
It is reflected or bounced off. Light in a focused lens, however, behaves as a wave. Light over our heads at night in the city forms a dome. How can that be? Waves in the pond striking the edge and forming ripples that meet one another from crazy angles. Astronomers call it constructive and destructive interference. Even though the particles of light are very small, they travel in waves. Photographers use polarizing filters in the daytime to cut the glare, or the interfering waves of light, making anything that gets through parallel, and therefore non-interfering.
More Essay Examples on Light Rubric
The earliest photographs were done without a lens, in a process known as Camera Obscura. The dome of light over a city is due to waves, otherwise the particles, if travelling in a straight line, would simply deflect a bit on their course and keep going. They don’t do that, the light travels in waves, and the ripples go every which way, until they finally escape the Earth, thus forming a dome of light. Over time and distance, a couple of notable things happen to light. First, the waves slowly widen out, or get longer between peaks, and change frequency (or color).
Blue becomes green, green becomes red, red becomes near infrared and so on, over the course of billion of years. The very deep Hubble images taken to see near the edge of the visible universe represent light traveling 13 or so billion years, and the light from those distant galaxies are red-shifted. The color red in the Hubble Deep Field and Ultra Deep Fields were really taken with infrared filters. Second, light apparently also decays (as in a radioactive half-life). We say apparently, because this is the frontier of the physics of light.
The Pioneer 10 Spacecraft had a discrepancy of radio response round-trip time discovered after being sent out of the Solar System. Some calculated a half-life of light as 6. 5 to 8 billion years. The Astronomer Zwicky, in the 1920’s proposed that light could get tired. Others have gone over the Pioneer 10 radio response time and put forth that the spacecraft is accelerating due to some unknown force of attraction. Still others say that the discrepancy is due to distance (redshift), acceleration and half-life.
For something that you cannot hold in your hand, the nature of light has led to many discoveries and inventions no one ever intended. For Astrophysicists and Particle Physicists, the controversy will be fought with huge equations, elaborate experiments and ultra-precise measurements. For the rest of us, the knowledge of the behavior of light is sufficient. Continue reading on Examiner. com: The Nature of Light itself – San Francisco astronomy | Examiner. com http://www. examiner. com/astronomy-in-san-francisco/the-nature-of-light-itself#ixzz1DYegBvvd