It's cold outside today; no one would argue with that, right? Well, it turns out some scientists might.
That's because according to the laws of physics, cold doesn't exist. Instead, it's simply an absence of heat, the American Chemical Society reports. This might seem like some mind-over-matter trick to get through the polar vortex, but it has to do with thermodynamics.
Heat is, essentially, the transfer of energy between objects or systems because of a temperature difference. But the transfer only goes in one direction, from a warmer object to a cooler one, the Physics Classroom explains.
Take, for example, a bowl of ice cream in a warm room. The ice cream melts because the energy in the warm room is transfered to the ice cream. The energy moves from the warmer object (the air in the room) to the colder one (the ice cream). The same is true if you leave a cup of hot tea sitting in a cool room, but the transfer works in reverse. The tea cools off because the heat energy in the tea (the warmer object) is transferred to the air around it (the cooler object).
In reality, the idea that cold doesn't exist is a little limiting, even if true. Cold is most certainly a way to describe something. A room can be cold, for example. So can a drink. And while that may have to do with transfer of energy, the science behind it is complex.
But if it helps, you can certainly tell yourself it's not cold out today. It just isn't hot.