[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.01,0:00:04.00,Default,,0000,0000,0000,,
Dialogue: 0,0:00:04.02,0:00:08.03,Default,,0000,0000,0000,,
Dialogue: 0,0:00:08.05,0:00:12.05,Default,,0000,0000,0000,,Something surrounds you. Bombards you
Dialogue: 0,0:00:12.07,0:00:16.09,Default,,0000,0000,0000,,some of which you can't see, touch, or even feel. Everyday.
Dialogue: 0,0:00:16.11,0:00:20.12,Default,,0000,0000,0000,,Everywhere you go. It is odorless and tasteless.
Dialogue: 0,0:00:20.14,0:00:24.15,Default,,0000,0000,0000,,Yet you use it and depend on it every hour of every day.
Dialogue: 0,0:00:24.17,0:00:28.18,Default,,0000,0000,0000,,Without it, the world you know could not exist.
Dialogue: 0,0:00:28.20,0:00:32.21,Default,,0000,0000,0000,,What is it? Electromagnetic radiation. These waves
Dialogue: 0,0:00:32.23,0:00:36.22,Default,,0000,0000,0000,,spread across a spectrum from very short gamma rays,
Dialogue: 0,0:00:36.24,0:00:40.24,Default,,0000,0000,0000,,to x-rays, ultraviolet rays,
Dialogue: 0,0:00:40.26,0:00:44.26,Default,,0000,0000,0000,,visible light waves, even longer infrared waves,
Dialogue: 0,0:00:44.28,0:00:48.28,Default,,0000,0000,0000,,microwaves, to radio waves which can measure longer
Dialogue: 0,0:00:48.30,0:00:52.31,Default,,0000,0000,0000,,than a mountain range. This spectrum is the foundation of
Dialogue: 0,0:00:52.33,0:00:56.33,Default,,0000,0000,0000,,the information age and of our modern world. Your radio,
Dialogue: 0,0:00:56.35,0:01:00.35,Default,,0000,0000,0000,,remote control, text message, television, microwave oven,
Dialogue: 0,0:01:00.37,0:01:04.37,Default,,0000,0000,0000,,even a doctor's x-ray, all depend on waves within the electromagnetic spectrum.
Dialogue: 0,0:01:04.39,0:01:08.42,Default,,0000,0000,0000,,Electromagnetic waves (or EM waves)
Dialogue: 0,0:01:08.44,0:01:12.45,Default,,0000,0000,0000,,are similar to ocean waves in that both are energy
Dialogue: 0,0:01:12.47,0:01:16.48,Default,,0000,0000,0000,,waves - they transmit energy. EM waves
Dialogue: 0,0:01:16.50,0:01:20.51,Default,,0000,0000,0000,,are produced by the vibration of charged particles and have electrical and
Dialogue: 0,0:01:20.53,0:01:24.54,Default,,0000,0000,0000,,magnetic properties. But unlike ocean waves that require water,
Dialogue: 0,0:01:24.56,0:01:28.58,Default,,0000,0000,0000,,EM waves travel through the vacuum of space
Dialogue: 0,0:01:28.60,0:01:32.60,Default,,0000,0000,0000,,at the constant speed of light. EM waves have crests
Dialogue: 0,0:01:32.62,0:01:36.62,Default,,0000,0000,0000,,and troughs like ocean waves. The distance between crests
Dialogue: 0,0:01:36.64,0:01:40.64,Default,,0000,0000,0000,,is the wavelength. While some EM wavelengths are very long
Dialogue: 0,0:01:40.66,0:01:44.65,Default,,0000,0000,0000,,and are measured in meters, many are tiny and are measured
Dialogue: 0,0:01:44.67,0:01:48.68,Default,,0000,0000,0000,,in billionths of a meter...nanometers. The number of these crests
Dialogue: 0,0:01:48.70,0:01:52.70,Default,,0000,0000,0000,,that pass a given point within one second is described as
Dialogue: 0,0:01:52.72,0:01:56.71,Default,,0000,0000,0000,,the frequency of the wave. One wave - or cycle -
Dialogue: 0,0:01:56.73,0:02:00.73,Default,,0000,0000,0000,,per second, is called a Hertz. Long EM waves,
Dialogue: 0,0:02:00.75,0:02:04.75,Default,,0000,0000,0000,,such as radio waves, have the lowest frequency
Dialogue: 0,0:02:04.77,0:02:08.79,Default,,0000,0000,0000,,and carry less energy. Adding energy increases the frequency of the wave
Dialogue: 0,0:02:08.81,0:02:12.81,Default,,0000,0000,0000,,and makes the wavelength shorter. Gamma rays are the shortest,
Dialogue: 0,0:02:12.83,0:02:16.85,Default,,0000,0000,0000,,highest energy waves in the spectrum. So, as you
Dialogue: 0,0:02:16.87,0:02:20.88,Default,,0000,0000,0000,,sit watching TV, not only are there visible light waves
Dialogue: 0,0:02:20.90,0:02:24.91,Default,,0000,0000,0000,,from the TV striking your eyes...But also radio waves transmitting from
Dialogue: 0,0:02:24.93,0:02:28.98,Default,,0000,0000,0000,,a nearby station; and microwaves carrying cell phone calls and text messages;
Dialogue: 0,0:02:29.00,0:02:33.03,Default,,0000,0000,0000,,and waves from your neighbor's WiFi; and GPS units in the cars driving by.
Dialogue: 0,0:02:33.05,0:02:37.12,Default,,0000,0000,0000,,There is a chaos of waves from all across the spectrum passing
Dialogue: 0,0:02:37.14,0:02:41.20,Default,,0000,0000,0000,,through your room right now! With all these waves
Dialogue: 0,0:02:41.22,0:02:45.25,Default,,0000,0000,0000,,around you, how can you possibly watch your TV show? Similar to
Dialogue: 0,0:02:45.27,0:02:49.31,Default,,0000,0000,0000,,tuning a radio to a specific radio station, our eyes
Dialogue: 0,0:02:49.33,0:02:53.39,Default,,0000,0000,0000,,are tuned to a specific region of the EM spectrum and can detect energy
Dialogue: 0,0:02:53.41,0:02:57.42,Default,,0000,0000,0000,,with wavelengths from 400 to 700 nanometers,
Dialogue: 0,0:02:57.44,0:03:01.46,Default,,0000,0000,0000,,the visible light region of the spectrum. Objects appear to have color
Dialogue: 0,0:03:01.48,0:03:05.50,Default,,0000,0000,0000,,because EM waves interact with their molecules.
Dialogue: 0,0:03:05.52,0:03:09.53,Default,,0000,0000,0000,,Some wavelengths in the visible spectrum are reflected and other
Dialogue: 0,0:03:09.55,0:03:13.57,Default,,0000,0000,0000,,wavelengths are absorbed. This leaf looks green because
Dialogue: 0,0:03:13.59,0:03:17.60,Default,,0000,0000,0000,,EM waves interact with the chlorophyll molecules.
Dialogue: 0,0:03:17.62,0:03:21.67,Default,,0000,0000,0000,,Waves between 492 and 577 nanometers in length
Dialogue: 0,0:03:21.69,0:03:25.69,Default,,0000,0000,0000,,are reflected and our eye interprets this as the leaf being green.
Dialogue: 0,0:03:25.71,0:03:29.70,Default,,0000,0000,0000,,Our eyes see the leaf as green,
Dialogue: 0,0:03:29.72,0:03:33.73,Default,,0000,0000,0000,,but cannot tell us anything about how the leaf reflects ultraviolet, microwave,
Dialogue: 0,0:03:33.75,0:03:37.76,Default,,0000,0000,0000,,or infrared waves. To learn more about the world around us,
Dialogue: 0,0:03:37.78,0:03:41.78,Default,,0000,0000,0000,,scientists and engineers have devised ways to enable us to 'see'
Dialogue: 0,0:03:41.80,0:03:45.82,Default,,0000,0000,0000,,beyond that sliver of the EM spectrum called visible light.
Dialogue: 0,0:03:45.84,0:03:49.85,Default,,0000,0000,0000,,Data from multiple wavelengths help scientists study
Dialogue: 0,0:03:49.87,0:03:53.90,Default,,0000,0000,0000,,all kinds of amazing phenomena on Earth,
Dialogue: 0,0:03:53.92,0:03:57.92,Default,,0000,0000,0000,,from seasonal change to specific habitats. Everything around us
Dialogue: 0,0:03:57.94,0:04:01.95,Default,,0000,0000,0000,,emits, reflects and absorbs EM radiation differently
Dialogue: 0,0:04:01.97,0:04:05.98,Default,,0000,0000,0000,,based on its composition. A graph showing these interactions across a region
Dialogue: 0,0:04:06.00,0:04:10.00,Default,,0000,0000,0000,,of the EM spectrum is called a spectral signature.
Dialogue: 0,0:04:10.02,0:04:14.03,Default,,0000,0000,0000,,Characteristic patterns, like fingerprints within the spectra allow astronomers
Dialogue: 0,0:04:14.05,0:04:18.05,Default,,0000,0000,0000,,to identify an object's chemical composition and to determine such
Dialogue: 0,0:04:18.07,0:04:22.08,Default,,0000,0000,0000,,physical properties as temperature and density.
Dialogue: 0,0:04:22.10,0:04:26.10,Default,,0000,0000,0000,,NASA's Spitzer space telescope observed the presence of water and organic molecules
Dialogue: 0,0:04:26.12,0:04:30.12,Default,,0000,0000,0000,,in a galaxy 3.2 billion light years away.
Dialogue: 0,0:04:30.14,0:04:34.16,Default,,0000,0000,0000,,Viewing our Sun in multiple wavelengths with the SOHO satellite
Dialogue: 0,0:04:34.18,0:04:38.23,Default,,0000,0000,0000,,allows scientists to study and understand sunspots that are associated
Dialogue: 0,0:04:38.25,0:04:42.24,Default,,0000,0000,0000,,with solar flares and eruptions harmful to satellites,
Dialogue: 0,0:04:42.26,0:04:46.27,Default,,0000,0000,0000,,astronauts and communications here on Earth.
Dialogue: 0,0:04:46.29,0:04:50.30,Default,,0000,0000,0000,,We are constantly learning more about our world and Universe
Dialogue: 0,0:04:50.32,0:04:54.33,Default,,0000,0000,0000,,by taking advantage of the unique information contained in the different
Dialogue: 0,0:04:54.35,0:05:02.98,Default,,0000,0000,0000,,waves across the EM spectrum