What is blackbody radiation and why does it matter?
In: Physics
In one sentence – you know how hot objects start glowing red and yellow and white? That’s black body radiation.
Imagine an object that doesn’t emit light at all (like most objects that aren’t a lamp). For that matter, it’s black. If you put it in a dark room, you wouldn’t see it.
What turns out is that if the object eventually (formally, when it reaches equilibrium) starts radiating photons, and the frequency of photons depend on the objects temperature.
Why is it important? Well, few reasons:
First, it is an observable phenomenon we want to explain. It’s what science does.
Second, it was one of the big physical riddles that couldn’t be solved using classical methods, and led to the formulation/discovery of quantum mechanics. (You can look up what is called the UV catastrophe).
Third, it is a very useful tool. For example, we can use our understanding of blackbody radiation to calculate the background temperature of the universe, just by observing the frequency of light emitted from empty space. The results fit unbelievably well.
Latest Answers