On this day in physics: 14 January 2005 Huygens space probe lands on Saturn's moon, Titan. The Huygen's spacecraft was named for Christian Huygens, who discovered the moon Titan. We also nod to Kurt Godel, who died on this day in 1978. His incompletness theorem proved that there are certain things that cannot be proven or disproven within a set of axioms in a system.
Word of the Day: So before we dig into what Black Body Radiation is, let's first talk about what a Black Body is. Most objects have color. This is because they reflect a specific wavelength of white light. The rest is absorbed. If a body reflects absolutely no light whatsoever, it will appear black. Now, we see black objects all the time. This isn't a true blackbody though. Most black objects do reflect at least some light. Shine a laser pointer on any black object you see. If it was a true black body, as soon as the laser pointer "touched" the object, you wouldn't see the pointer anymore. All the light would be absorbed. Black bodies are for the most part theoretical, although many objects are very very close to being true black bodies. Now, a true black body does emit electromagnetic radiation, unrelated to what it is absorbing. This is known as Blackbody Radiation. The wavelength of the electromagnetic waves are proportional to the temperature of the blackbody, and this wavelength is highly calculatable. This is what Wein, our birthday boy from yesterday's day in physics, brought to our attention.
Stars can be modelled as being very close to black bodies, i.e. nonreflective. All the energy going into the star does not come out. It is then possible to calculate the "effective" temperature of a star by using measuring the wavelength of the light that we see as starlight. This is a powerful tool for astronomers.
For a deeper dive on blackbody radiation check out this hyperphysics article or the wikipedia article.
Killer Resource: iBlackbody app Since today is a black body day, if you really want to dig deeper on blackbody radiation, and see how temperature changes the wavelength at which blackbody radation is emitted, there is a really cool app available, made by not me, called iBlackbody. It was created by a team at Georgia Tech. University, and you can read a little more about it here. At the time of this recording it's only $0.99 in the app store. I love how for a dollar you can dig so deep into something that you can keep in your pocket at any time. It's truly a great time to be alive.
Keywords: Wein, Displacement, Law, Black Body, Radiation, Huygens, Titan, Saturn
