Thanks for the great question! Before you open a bottle of soda for the first time, the liquid inside of the bottle is at a higher pressure than the room you are sitting in. That is why you hear a hissing noise when you unscrew the cap, and if you squeeze the bottle you may notice that it feels tight. On the other hand, if you take the cap off of a bottle of soda and squeeze the open bottle, the bottle will easily flatten (you also may need to clean up a mess if the bottle was full!). This is an important fact to remember, because it shows that you will need to have a cap on the bottle to have it either explode or implode.

As you may have learned in school, outer space has zero pressure (you may have heard this called a vacuum) which is very different from Earth where the pressure is much, much larger than the zero pressure in outer space. Keeping this in mind, you can imagine that if you were able to take a closed, empty bottle from the surface of Earth (where compared to outer space the pressure is very high) into outer space, the pressure inside the bottle will be much higher than the pressure outside of the bottle (this is a very extreme example of an initially unopened soda bottle). Since the pressure inside the bottle is much higher, the bottle would explode!

I hope that I was able to answer your question, and please send us any other questions you may have!

PS: You may have also heard that deep under the ocean the pressure is much higher than on Earth's surface. If you were to take a closed bottle from the surface of the Earth down into the deepest parts of the ocean, then the bottle would implode.