A teaspoon of neutron star crushes mountains

If you managed to scoop up a teaspoon of material from a neutron star, you wouldn't be able to hold it. The spoon would immediately crash through your hand, through the floor, and plunge straight to the center of the Earth. That tiny bit of matter weighs about 1 billion tons—the same as the entire human population combined, or all the cars in the United States.

Neutron stars are what happens when a massive star runs out of fuel and collapses. The gravity is so intense that it crushes atoms until the electrons are forced into the protons, turning the whole thing into a ball of neutrons. All the empty space that usually makes up an atom is gone.

To understand this scale, imagine taking the entire Earth and crushing it down until it fits inside a marble. That marble would have the same density as a neutron star. A star with twice the mass of our sun is squeezed into a sphere only about 12 miles wide, the size of a small city.

Because they are so dense, they spin at terrifying speeds. Some neutron stars, known as pulsars, rotate hundreds of times every single second. Their magnetic fields are trillions of times stronger than Earth's, powerful enough to dissolve the atomic bonds of any matter that gets too close.

If you stood on the surface of a neutron star, the gravity would flatten you into a layer of atoms just one atom thick. Even light is bent by the gravity, allowing you to see the front and the back of the star at the same time.