![Heart of galaxy NGC 1068](https://nsf-gov-resources.nsf.gov/styles/mobile_full_width/s3/2022-04/PF1511_artist_cropped.jpg?VersionId=zRB3bYQqrwB_9H7.6075CchE8LQW8Xyw&itok=wVDoxJAe)
Credit: NRAO/AUI/National Science Foundation; S. Dagnello
Black holes have long captured the imagination, from groundbreaking ideas in Albert Einstein’s theory of general relativity to the first image of a black hole, revealed a century later by the global Event Horizon Telescope. On this site, explore the nature of black holes, read the latest news about black hole research, and download a wide range of educational materials, images and videos of the universe’s most extreme objects.
All Sag A* multimedia — including new images, video content and a b-roll package is available for download on the EHT page.
![Black hole hidden within own exhaust](https://nsf-gov-resources.nsf.gov/styles/mobile_full_width/s3/2022-04/pf7014_nrao_h_.jpg?VersionId=UIocPT2Xrp5qX4Pg22yl_51tX.iluG9a&itok=cqogIfzx)
Credit: NRAO/AUI/NSF; D. Berry/Skyworks
What is a black hole?
Black holes are extremely dense pockets of matter, objects of such incredible mass and miniscule volume that they drastically warp the fabric of space-time. Anything that passes too close, from a wandering star to a photon of light, gets captured. Most black holes are the condensed remnants of a massive star, the collapsed core that remains following an explosive supernova. However, the black hole family tree has several branches, from tiny structures on par with a human cell to enormous giants billions of times more massive than our sun.