Astronomy Picture of the Day

Explanation: No one knows for sure what caused this signal. There is a slight possibility that it just might originate from an extraterrestrial intelligence. The bright colors on the blue background indicate that an anomalous signal was received here on Earth by a radio telescope involved in a Search for Extraterrestrial Intelligence (SETI). A search for these signals is ongoing by several groups including volunteer members of the SETI League. Time labels the vertical axis of the above plot, and frequency marks the horizontal axis. Although this strong signal was never positively identified, astronomers have identified in it many attributes characteristic of a more mundane terrestrial orgin. In this case, a leading possibility is that the signal originates from an unusual modulation between a GPS satellite and an unidentified Earth-based source. Many unusual signals from space remain unidentified. No signal has yet been strong enough or run long enough to be unambiguously identified as originating from an extraterrestrial intelligence.

January February March April May June July August September October November December

<  July 2002   > Mo Tu We Th Fr Sa Su 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.

Publications with keywords: SETI
Publications with words: SETI
See also:

• The Voyagers Message in a Bottle
• A Cosmic Call to Nearby Stars
• An Anomalous SETI Signal
• A Message From Earth
• How to Search for Aliens
• Radio, The Big Ear, And The Wow! Signal
• The Voyagers' Message in a Bottle

All publications on this topic >>