← Another date

Birthday · April 22, 1997

Historic Optical Flash Fades 
Credit and Copyright:

April 22, 1997

Every candle on your cake is a tiny imitation of the stars that made you possible.

Historic Optical Flash Fades Credit and Copyright:

A little universe, just for you

Your date.
Ready to give.

Free PNG · 1080 × 1350 · No account needed

Image rights and credit requirements apply when sharing or reusing imagery.

Change the year

APOD published April 22, 1997. Full image credits are on the original APOD entry below. A publication-date match, not a photo taken on your date. Independent of NASA.

Behind the image

Historic Optical Flash Fades Credit and Copyright:

Original APOD · April 22, 1997

The largest telescopes in the world have scrambled to point toward this faint, fading object. Why? Because it may well be the first active optical counterpart ever found for a gamma-ray burst, and could hold the clue to the distance scale to this most enigmatic class of astronomical objects. During the past two months, multiwavelength observations, claims, and counterclaims have been exchanged at a torrential pace, as astronomers wait impatiently to see what setting houses the fading transient. Above are two pictures of the optical transient (OT), one taken on February 28th, the other about a week later on March 8th. The OT arrows show the source that faded from view during this time. The OT has been examined by large telescopes including the Hubble Space Telescope and Keck, yet researchers are still scrambling to get answers to fundamental questions about its true nature. Does the OT actually move (exhibit proper motion)? Is there a faint galaxy superposed behind the OT or is this extended emission fading too? In the face of intense scrutiny with the world's most capable telescopes, the origin of gamma-ray bursts so far remains mysterious!

Explore April 22 in other years