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 ...

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 ...

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

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 ...

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 ...

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 ...

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 ...

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 ...

Looking for hidden structures and unusual stars that reveal the Milky Way’s history. Since our galaxy grew by merging with and eating other galaxies, traces of that violent past are visible in the ...

Most of the atoms in the universe are either hydrogen or helium, formed within the first few minutes after the Big Bang. The other elements are mostly made by nuclear fusion in stars, especially ...

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 ...