We live in a universe of extremes Where Space is Cold Yet The Sun is Hot.
The Sun is Hot and is about 150 million kilometers from the Earth, but every single day, we can feel its warmth. It is incredible how a burning object can cast its fire over such a large distance from afar.
Heat travels as radiation through the universe, an infrared energy wave that migrates from hotter objects to cooler ones. The waves of radiation excite molecules with which they come in contact, causing them to heat up. This is how heat flows from the sun to Earth, but the catch is that only molecules and matter that are directly in its path are heated by radiation. Everything else remains chilly.
© Photo From Nasa
Take Mercury: the temperature of the planet can be 1,000 degrees Fahrenheit lower than the radiation-exposed day-side. It can be as cold as -290 degrees Fahrenheit (-179 degrees Celsius) on Mercury at night. Compare that to Earth, where the air around you remains warm even though you’re in the shade—and even, in certain seasons, in the darkness of the night.
That’s how heat flows through our lovely blue earth by three methods instead of only one: conduction, convection, and radiation. When the sun’s light reaches and warms up the molecules in our atmosphere, the excess energy is passed to the molecules surrounding them. These molecules then bump into and heat up their own neighbors. This heat transfers from molecule to molecule and is called conduction, a chain of circumstances that warms up regions beyond the direction of the light. Conclusion? The Sun is hot AF!
The Sun is hot but space is a vacuum. So what does that mean? Gas molecules in space are too far apart to collide with one another frequently. So even though the sun heats them with infrared waves, it is not possible to transfer the heat through conduction. Similarly, convection—a type of heat transfer that occurs in the presence of gravity—is critical in dispersing heat around the Earth, but does not occur in zero-g space.
Featured Image By Bryan Goff