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 ...

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 ...

Our knowledge of the events and forces that shaped the early Universe is dependent on our ability to understand the most extreme conditions. On one hand, the Universe’s origin was incomprehensibly ...

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 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 universe began 13.8 billion years ago, and in its early years, it looked completely different than it does now. For nearly 400,000 years, the entire cosmos was opaque, which means we have no ...

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 ...

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 ...

What We Know and What We Think While we can’t see dark matter, we know it’s there. And we can investigate some of dark matter’s properties using gravitational lensing. This technique measures the ...

Recipe for Stars and Planets Star formation happens in interstellar molecular clouds: opaque clumps of very cold gas and dust. The process starts when some of those clumps reach a critical mass, ...

Scientists and engineers from the Center for Astrophysics aim to achieve the following advances to enable the discovery of life on other planets: Understand the Origins of Life: We investigate the ...

Humans have studied the stars for thousands of years. To many cultures, stars were the metaphor for constancy, while everything else moved and changed. Modern stellar astronomy showed that stars do ...