APOD
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
Distant Supernova, Dark Energy
Explanation: A pinpoint of light from a star that exploded over 10 billion light-years away is centered in the panel at the lower right, a cosmic snapshot of the most distant supernova . The ancient stellar detonation was detected by digitally subtracting before and after images of a faint, yellowish, elliptical galaxy included in the Hubble Space Telescope Deep Field image illustrated at the top and left. Remarkable in itself as the farthest known supernova , its measured brightness provides astounding evidence for a strange universe - one which eventually defies gravity and expands at an accelerating rate. The unseen force driving this expansion is attributed to “ dark energy ” and discovering the fundamental nature of dark energy has been called the challenge of this millennium.
| Date | April 4, 2001 |
|---|---|
| Credit | Credit: Adam Riess ( STScI ) et al., NASA |
| Authors & editors: | Robert Nemiroff (MTU) & Jerry Bonnell (UMCP) |
| A service of: |
ASD at NASA / GSFC, NASA Science Activation & Michigan Tech. U. |



