[/caption]In the last few centuries, in which time we have had several scientific revolutions, our understanding of heat, energy and the exchange thereof has grown exponentially. In particular has been the increasing ability to gauge the amounts of energy involved in particular processes and in turn create theoretical frameworks, units, and even tools with which to measure them. One such concept is the measurement known as Emissivity. Essentially, this is the relative ability of a material’s surface (usually written ? or e) to emit energy as radiation. It is expressed as the ratio of the emissivity of the material in question to the radiation emitted by a blackbody (an idealized physical body that absorbs all incident electromagnetic radiation) at the same temperature. This means that while a true black body would have an emissivity value of 1 (? = 1), any other object, known as a “grey body”, would have an emissivity value of less than 1 (? Engineering Toolbox and Science World.
We’ve also recorded an entire episode of Astronomy Cast all about Electromagnetism. Listen here, Episode 103: Electromagnetism.
References:
http://en.wikipedia.org/wiki/Emissivity
http://en.wikipedia.org/wiki/Absorptance
http://en.wikipedia.org/wiki/Black_body
http://www.thefreedictionary.com/emissivity
http://www.monarchserver.com/TableofEmissivity.pdf
On February 15th, Intuitive Machines (IM) launched its first Nova-C class spacecraft from Kennedy Space…
We can't understand what we can't clearly see. That fact plagues scientists who study how…
Historical astronomical records from China and Japan recorded a supernova explosion in the year 1181.…
This is an image of the FS Tau multi-star system taken by the Hubble Space…
Anyone can be an underachiever, even if you're an astronomical singularity weighing over four billion…
The Solar and Heliospheric Observatory (SOHO) was designed to examine the Sun, but as a…