White Dwarfs and the Largest Structure in the Universe

When stars exhaust their fusion fuel, they begin to collapse, blowing out their outer shells in a massive explosion. This creates planetary nebulas. At the center remains the star's core, which accounts for most of its mass. This core is about the size of Earth, but its mass is much greater. At the same time, the gravity at its surface is 350,000 times greater than that of Earth. Of course, they cannot be as dense as a neutron star. Neutron stars are also about 10 km across, but if you could extract a teaspoon of matter from them without them disintegrating into atoms and turning into neutrons, it would weigh billions of tons.

This cluster, taken by NASA's Hubble Space Telescope, consists of white dwarfs that are 12-13 billion years old.

NGC 6543 is also known as the Cat's Eye Nebula. Extinct stars explode, shedding their outer shells to form planetary nebulas like this one, and new stars begin to form. At the center remains the core of our former star, a white dwarf.

Astronomers have discovered the largest structure in the universe. It's so massive that it takes light 10 billion years to travel from one end to the other. Considering that light travels 9 billion kilometers in a year, it's incredibly massive. This object also breaks the previous record set by the Great Quasar group, which was 4 billion light-years across and comprised of 73 quasars. It's worth noting that the Great Wall, comprised of millions of galaxies, is 1.4 billion light-years larger than the Great Wall.

This object is thought to be an even larger version of the Great Wall. It consists of billions of galaxies and gas. They were able to detect this by analyzing the gamma rays from a supernova explosion that occurred there.

An artist's illustration of a Gamma Ray.