Evidence for the flatness of the universe also shows up in what's known as the critical density. At the critical density, a hypothetical universe would be flat and would eventually stop ...

Today’s universe continues to expand, even accelerating. This forces physicists to introduce dark energy to explain this unusual acceleration. Little is known about the nature of dark energy.

Feast your eyes upon the first color—not the first one in this book of course, but the first color in the universe. This bright-hot glowing peachy orange didn’t exist until approximately ...

For one, scientists observe a "cosmic fossil" called the cosmic microwave background (CMB). The first light that was free to ...

The largest known star in the universe is UY Scuti. It has an estimated radius of 1.188 billion kilometers. If UY Scuti were the center of our solar system, its photosphere , or outer shell, would ...