About 13.8 billion years ago, the Big Bang gave rise to everything, everywhere, and everywhen—the entire known Universe. What caused the Big Bang? What happened that first moment at the beginning of ...

For the first 380,000 years or so after the Big Bang, the entire universe was a hot soup of particles and photons, too dense for light to travel very far. However, as the cosmos expanded, it cooled ...

Center for Astrophysics | Harvard & Smithsonian astronomers study star clusters in a variety of ways: Looking for exotic binary systems including black holes or neutron stars. Globular clusters are ...

Our modern understanding of gravity comes from Albert Einstein’s theory of general relativity, which stands as one of the best-tested theories in science. General relativity predicted many phenomena ...

Center for Astrophysics | Harvard & Smithsonian scientists study galaxy formation and evolution in a variety ways: Looking for hidden structures and unusual stars that reveal the Milky Way’s history.

Everything you’ve ever seen or experienced on Earth was once a nebulous collection of floating gas and dust. Science is starting to understand how those particles came to take the forms you recognize ...

Matter and energy are the two basic components of the entire Universe. An enormous challenge for scientists is that most of the matter in the Universe is invisible and the source of most of the energy ...

The Milky Way is our galactic home, part of the story of how we came to be. Astronomers have learned that it’s a large spiral galaxy, similar to many others, but also different in ways that reflect ...

Center for Astrophysics | Harvard & Smithsonian scientists study planetary nebulas in several different ways: Identifying the atoms and molecules within planetary nebulas, mostly through the infrared ...

Center for Astrophysics | Harvard & Smithsonian scientists study many different aspects of white dwarfs and neutron stars: Observing the way white dwarfs interact with other astronomical objects, ...

Center for Astrophysics Harvard & Smithsonian How can we expand the limits of human knowledge further into the unknown? The Center for Astrophysics is a collaboration between the Smithsonian ...

Galaxy clusters are the largest objects in the universe that are held together by their own gravity. They contain hundreds or thousands of galaxies, lots of hot plasma, and a large amount of invisible ...