The moon and Earth are examples of non-luminous objects. Non-luminous objects become visible only when they reflect light produced by a luminous object. A luminous object, such as the sun, emits its own light, because it has its own source of energy.Continue Reading
According to Penn State University's Astrology Department, the Moon has a very dark surface that only reflects about 3 percent of the sun's light. The moon's cycle is determined by the amount of light that reflects from the moon's surface in relation to its position in orbit around Earth. When only half of its surface is lit, this is called the first or third moon quarter. As Earth and the moon orbit the sun, Earth regularly blocks the moon from the sun completely; this is called a new moon. A full moon is entirely illuminated by the sun's light.
Earthshine occurs when the Earth reflects sunlight onto the moon's surface when the moon is in its crescent phase. The crescent portion is brightly lit by reflected sunlight, while the rest of the moon dimly reflects light from the Earth. As this double-reflected light travels through space, it becomes even dimmer as some of it is absorbed into Earth’s atmosphere.Learn more about Optics & Waves
Translucent materials allow light to pass through them, but they diffuse the light in a way that make objects on the opposite side appear blurred. Examples of translucent materials are frosted glass, oil paper, some plastics, ice and tissue paper.Full Answer >
Ultrasound consists of a series of extremely high-frequency waves of sound, which may be bounced off of objects to form an image in three dimensions, according to ICU Sonography. Ultrasound scanners are used to noninvasively scan the interior of many objects including the human body.Full Answer >
An echo is the reflection of sound waves off distant objects, whereas flutter echoes bounce repeatedly off multiple surfaces. An example of an echo is when someone shouts into a well, or along canyon walls, and the sound of the human voice comes back to the person's ears. A flutter echo occurs in large buildings with parallel walls, such as gymnasiums, where sounds increase to create loud environments.Full Answer >
Radar is used to detect the presence of moving or stationary objects at a distance by utilizing radio waves. It is also used to detect the speed of a moving object, to identify the type and bearing of an aircraft and to create detailed topographic maps.Full Answer >