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How does the sun heat the Earth?
Question Date: 2014-05-14
Answer 1:

The sun gives off rays of light that travel to the earth. These light waves have energy and heat associated with them. This heat is carried through space with each ray of light, but the further away from the sun you get, the colder it gets (they lose energy). That's why Mercury and Venus are much hotter than Earth (they're closer than Earth), but mars is much colder. (It's further away than we are). When you stand outside on a sunny day, you're feeling the heat being transferred from the ray of light from the sun.

Answer 2:

There are several ways that heat can be transmitted, but in this case we're talking about light, so it's helpful to talk about radiative heat, which is transmitted through infrared radiation that is invisible to our eye.

The sun emits light of many different energies. A helpful way to classify the energy of the light is through its wavelength or frequency, which you may have heard of before. (Just like sound, where you have low frequency bass and high frequency treble, light can have many different frequencies, and these correspond to different energies.) Out of the many frequencies of light that are emitted by the sun, we can see only a small fraction, and we call this visible light. Right outside the visible spectrum of light, you've also heard of UV (ultraviolet) light, which causes sunburns, and there's also IR (infrared) light, which tend to heat things up because it makes atoms and molecules vibrate. In a toaster oven, the heater coils glow red hot, and it heats the toast through the infrared light that's emitted. In the same way, the sun emits a lot of light, and some of this light (UV, visible, IR) is absorbed when it reaches the Earth. Because no energy can be lost, the energy contained in the light is transformed into heat, which warms up the Earth. It's not just the sun that heats the Earth though. A lot of the Earth's heat comes from radioactive decay of elements in the Earth, which releases a lot of heat.

Answer 3:

Light carries energy. That energy most often becomes heat when the light shines on something. The sun heats the Earth by shining light on it.

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