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 ...

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 ...

The Center for Astrophysics | Harvard & Smithsonian Science Education Department (SED) is a national leader in the study of science learning, and in the research and development of evidence-based STEM ...

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 ...

Capturing the first image of a supermassive black hole using the Event Horizon Telescope (EHT). This image of the black hole at the center of the nearby galaxy M87 reveals how gravitation affects the ...

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 ...

The Center for Astrophysics | Harvard & Smithsonian Solar, Stellar & Planetary Sciences (SSP) division research is directed toward understanding star and planet formation and the physical processes in ...

Mapping the structure of galaxy clusters using the hot plasma that fills the space between galaxies. Even though this plasma’s density is low, its temperature can reach hundreds of millions of degrees ...

The Event Horizon Telescope (EHT) Collaboration has conducted test observations achieving the highest resolution ever obtained from the surface of the Earth, by detecting light from the centers of ...

Astronomers have discovered what may be a massive star exploding while trying to swallow a black hole, offering an explanation for one of the strangest supernovae ever seen. Cambridge, MA - ...

The Milky Way alone probably contains hundreds of billions of planets, based on the thousands of exoplanets we’ve already identified. These planets share a history and origin with their host stars, ...