If the Sun is able to keep Earth warm while being millions of miles away, shouldn’t it get warmer and warmer the closer you get to it (like when you go to space)? Like how it would get warmer if you were to approach a burning house for example?
In: Planetary Science
Because there’s nothing in between the Earth and Sun to be heated. Temperature is a feature of matter, but space is empty so there is no matter to be hit by photons from the sun to be warmed.
Imagine I throw a rock. Now, if your face does not get in the way, the rock just keeps going. If you get you face in the way though, you will feel the rock.
It’s mostly empty space, so since there is nothing to hold or carry the heat, it can’t heat up.
there is nothing to heat in space it is a vacuum. there has to be something for the energy from the sun to warm
There are several types of heating: heat by conduction, convection, and radiation. The first two require a medium – such as air – to heat up and then transfer heat to something else. In space, there is no medium to heat up, so we are left with only radiated heat.
Heat transfer via radiation occurs when light ( the light can be visible or invisible to the human eye) emitted by something hits something else and causes the molecules to become excited.
When you shine a flashlight at a wall and walk closer, the beam will become more concentrated. Just like a flashlight, the closer to the sun something gets, the more intensely it is illuminated, meaning that there is more energy being absorbed and thus more heat is transfered via radiation.
This is an oversimplified explanation that neglects some other important factors like how much an object absorbs or reflects radiation, but I think it answers the basic question.
A lot of these answers don’t seem simple, so I’ll try to say it in a simpler way.
Earth has an atmosphere that can hold the heat. Imagine you are in a cold house and you boil a pot of water with the lid on. The house will still feel cold but the inside of the pot will be hot. The fire that heats the pot is like the sun, and the lid keeping the heat in is like the atmosphere.
This also explains how rain works. The steam that rises to the top of the lid is like the clouds, and the water on the lid that drips back down is like the rain.
There is nothing to impart the heat to, it’s empty space. Actually this statement is technically incorrect but technically correct. Space isn’t completely empty but it’s very close to empty. There are tenuous gases and few and far between solid particles which is why space is cold but it’s not absolute zero, and why the temperature in outer space is not consistent. But for all intents and purposes, it is empty space. So a probe flying through space will be in a very cold environment, because there is next to nothing near it to be heated up by the Sun’s radiation, but the probe itself can be heated up by it.
In space, the definition of temperature starts breaking down. That’s because when talking about temperature, you’re talking about the property of “stuff”. Air, water, rocks. Matter. Temperature is most commonly defined as kinetic energy of particles.
Vacuum of space is famously really empty. There’s not enough “stuff” to define it strictly as we do on earth. You get absolute nonsense like vacuum being 10 million degrees because the two protons per square kilometer have a lot of energy between them.
So you have to be very careful when talking about the temperature of space to define what you’re talking about.
If you put yourself between the earth and the sun, you’ll quickly find that you’re being heated as much as the earth is, because there’s sunlight shining on you. In fact, it’s quite difficult to cool down, because there’s very little to carry heat AWAY from you in the vacuum of space. And you’re not going to radiate more heat than you get until you’re, well, the temperature of the sun. As a human, I do not recommend being the temperature of the sun.
>Like how it would get warmer if you were to approach a burning house for example?
Well… That’s exactly what happens. That’s why Mercury is hotter than Earth.
The sun heats the ground, and the ground heats the air.
Space has neither, so the light just passes through.
If a photon does hit a stray gas or dust particle, it will quickly be remitted as a lower frequency photon.
The space between the Sun and the Earth *isn’t* cold because it isn’t *any* temperature at all. Space is nothing, and nothing can’t have a temperature. Stuff *in* space has a temperature. Anything i*n* space between the Sun and the Earth will actually be very hot unless it’s something is in between it and the Sun, in which case it will be very cold.
When we say space is cold, it’s kind of misleading because what we’re really taking about is the temperature of the very sparse bits of gas and dust in a given volume of space. Since there are so few molecules or bits of gas and dust in any given volume of space, it will have a low temperate, just like how it’s cold at the altitude planes fly at because the air is so thin.
Stuff *in* space can get very hot though. The sun-facing side of Mercury gets as hot as 800°F (430°C) while the side facing away from the Sun gets as cold as -290°F (-180°C). Earth is farther away from the Sun so it gets less concentrated energy, which means it doesn’t get as hot. Using the Moon as an example (since like Mercury, it has no atmosphere), the sunlit side of the Moon gets up to 250°F (121°C) in daylight and as cold as -208°F (-133°C) on the dark side.
So in summary, your instinct is mostly correct. Things *in* space are hotter the closer they are to the sun, unless something is blocking the sunlight, in which case they get very cold.
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