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.

The Center for Astrophysics | Harvard & Smithsonian High Energy Astrophysics division focuses on X-ray astronomy and instrumentation involved in observations of high-energy sources. This research aims ...

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 ...

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 ...

Black holes are some of the most fascinating and mind-bending objects in the cosmos. The very thing that characterizes a black hole also makes it hard to study: its intense gravity. All the mass in a ...

The Fred Lawrence Whipple Observatory (FLWO), part of the Center for Astrophysics | Harvard & Smithsonian, is a major observatory based in Mount Hopkins, Arizona. Alongside its status as an active ...

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 ...

All the atoms and light in the universe together make up less than five percent of the total contents of the cosmos. The rest is composed of dark matter and dark energy, which are invisible but ...

Interstellar space — the region between stars inside a galaxy — is home to clouds of gas and dust. This interstellar medium contains primordial leftovers from the formation of the galaxy, detritus ...

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 ...

Large galaxies like the Milky Way formed out of mergers with smaller galaxies and by stealing some of their stars. Astronomers discovered that as many as 25% of galaxies are currently merging with ...