The physical universe is defined as all of space and time [a] (collectively referred to as spacetime) and their contents. [9] Such contents comprise all of energy in its various forms, including …

Dec 3, 2025 · Discover the universe: Learn about the history of the cosmos, what it's made of, and so much more. Concentrations of matter with gravity so powerful not even light can …

Nov 11, 2025 · Universe, the whole cosmic system of matter and energy of which Earth is a part.

Universe Map is your definitive guide to galaxies, stars, and cosmic structures — mapped, analyzed, and optimized for discovery and research.

Aug 31, 2025 · It tells us that the universe began nearly 13.8 billion years ago in a cataclysmic event known as the Big Bang. From a state of unimaginable density and heat, space itself …

Nov 24, 2025 · Will the universe keep existing forever? An astrophysicist explains how scientists aren’t entirely sure, but they can make predictions.

The universe is all the matter, energy, and space that exist. We can observe only a part of it - the observable universe. The entire, universe, including the part we cannot see, may be infinite. …

The universe is filled with an amazing variety of celestial objects. Find out about astronomy through history, how we understand the sky, constellations, sky maps and stars, exoplanets, …

6 days ago · Scientists have discovered one of our universe's largest spinning structures. It's a 50-million-light-year-long thread in the cosmic web.

The Center for Astophysics | Harvard & Smithsonian advances our knowledge and understanding of the universe through research and education in astronomy and astrophysics.