Cosmic Perspectives from Amid the Stars:
Astronomy Blog

According to our best estimates, the universe is 13.8 billion years old. It goes without saying that that’s extremely old. But just how long of a time is 14 billion years? The human mind has a way of underestimating massive numbers. So, to truly understand the implications of a nearly 14-billion-year-old universe, we need a scale model. Famous astronomer and science communicator Carl Sagan introduced the concept of the cosmic calendar for exactly this reason.

The true size of the universe boggles the mind. It’s so large that it is simply impossible to truly grasp its size. Even light, which travels faster than anything else, takes time to travel through space. For light, it’s eight minutes from the Sun to Earth, four years to the closest star, and a hundred thousand years to cross the Milky Way. To truly appreciate these vast distances, a scale model is necessary.