Why is the earth's outside warmer?

The inside (core) is warmer. Also, WTF?

I’m going to take a guess as to what you’re getting at,

The surface of the earth is slightly warmer than the region just below the surface. This is just due to radiation from the sun and the greenhouse effect. However, in general, the temperature increases as you move towards the earth’s center.

The outside is warmer? What about the dreaded phenomenon of magma?
edit:
oh, you mean the top INCH is warmer? yep, that’s from sunshine.

The Earth lies within the space known in astronomy as the Habitable Zone, so called because the sun’s radiation output is sufficiently diffuse that water could exist in a liquid state. The location and extent of this space is determined via some mathematical hocus pocus with the star’s magnitude and the Inverse Square Law; the hotter the star, the farther out one must go to find the Zone.
Last I heard, Science™ is aware of only one extrasolar planet that resides within its star’s Habitable Zone, and that is Gliese 581d.

I think the core is hotter than the surface. But let’s say you are right and the surface is hotter.

Think about when you put something (like say, a piece of fruit, or anything else) in the sun. The heat from the sun warms it from the outside in. . . so that’s why.

Another example would be the microwave scenario. You know how when you heat something in the microwave, and you cut into it, there are times when it’s still cold in the center . . . that’s because things heat from the outside in.

@mrrich724

“You know how when you heat something in the microwave, and you cut into it, there are times when it’s still cold in the center . . . that’s because things heat from the outside in.”

Nope. Parts of your microwaved food are cold because microwaves are, well, waves. Waves interfere with each other. The cold spots are where there was destructive interference.

@ivan I’ve probably shown you this before, but you can measure the speed of light using a microwave and a stick of butter

@Rarebear

You haven’t showed me that, that’s really cool! Never thought of doing that before.