Dr. Universe

Dear Dr. Universe: What if gravity pulled up, instead of down? Kyle, student from Cedar Lake, Ind.

Our universe would look so different, Kyle. You might not recognize it even if you could be here to see it. Unfortunately, there probably wouldn’t be a whole lot to see.

I learned about this from Washington State University professor and physicist Matthew McCluskey, who studies the material world. He explained how gravity pulls together dust, gas, and little particles floating around space to make massive clumps of matter that form stars and planets.

For example: planet Earth. Every particle in t...