gravity | Ask Dr. Universe | Washington State University

What would happen if you put a baseball-sized piece of neutron star on the Earth? Would it fall to the core of the Earth and become part of the core or pass through the Earth? – MacKenzie, 12, Louisiana

June 18, 2025 melissamayer

Dear MacKenzie,

A neutron star is what’s left after a massive star runs out of fuel and explodes as a supernova.

I asked my friend Matthew Duez about it. He’s an astrophysicist at Washington State University.

He told me that a neutron star is the densest known object in the universe. Its mass is like the sun’s mass. But a neutron star is the size of a city.

When something is dense, it has lots of stuff—or mass—crammed into a small space.

Imagine if we took all the humans on the planet and squished them together. We mash and squash them until they fit … » More …

What if gravity pulled up, instead of down? -Kyle, Cedar Lake, IN

March 9, 2015 rcwebber

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 the Earth is pulling on you at this very moment--every single one. Read More ...