$diffraction refraction$

$diffraction refraction$

The Landsat 7 satellite image below shows the city of Atlanta as an island of heat compared to the surrounding area. Thermal radiation from the energy-absorbing asphalt and roofs in a city can raise its surface temperature by as much as 10° Celsius. This thermal energy then radiates in the form of longer wavelength infrared energy. Photons bounce around during this absorption process and lose bits of energy to numerous molecules along the way. Thus, the black pavement is hotter than the sidewalk on a hot summer day. For example, black pavement absorbs most visible and UV energy and reflects very little, while a light-colored concrete sidewalk reflects more energy than it absorbs. Some objects, such as darker colored objects, absorb more incident light energy than others. This heat is then emitted from the object as thermal energy. The more an object's molecules move and vibrate, the hotter it becomes. In this image of the Moon's southern hemisphere, low elevations are shown as purple and blue, and high elevations are shown in red and brown.Ībsorption occurs when photons from incident light hit atoms and molecules and cause them to vibrate. A shorter response time means the surface is closer or higher in elevation. The longer the response time, the farther away the surface and lower the elevation. The instrument measures the time it takes a laser pulse to hit the surface and return.

$diffraction refraction$

This reflective behavior of light is used by lasers onboard NASA's Lunar Reconnaissance Orbiter to map the surface of the Moon.

$diffraction refraction$

The physical and chemical composition of matter determines which wavelength (or color) is reflected. Color, in this case, refers to the different wavelengths of light in the visible light spectrum perceived by our eyes. The color of an object is actually the wavelengths of the light reflected while all other wavelengths are absorbed. Very smooth surfaces such as mirrors reflect almost all incident light. Reflection is when incident light (incoming light) hits an object and bounces off.

$diffraction refraction$

Diffraction refraction