Video: How Stars Destroyed Almost All the Atoms in the Universe

Video: How Stars Destroyed Almost All the Atoms in the Universe

Credit: W.M. Keck Observatory

On Thursday, May 10, 2012, Keck Observatory hosted a live webcast of an astronomy talk by Dr. Brian Siana of the University of California at Riverside. Below is the recording of that talk, which was delivered to a live audience at the Kahilu Theatre in Kamuela-Waimea, Hawaii. 

The first galaxies had an extraordinary impact on the young universe. Their ultraviolet light destroyed nearly all of the atoms in the cosmos. This process, called reionization, had severe consequences for galaxies trying to form thereafter. Unfortunately, we have no idea how it happened. In galaxies today ultraviolet light cannot escape, so the first galaxies must have been very different from those we see today. Dr. Siana will describe the quest to detect these first galaxies and their impact on the early universe.


Filter by year OR type:

View all


The sky is ready for HIRESR and NIRC2-LGS. Our observers from UCSC and UH are also ready. Sun set 06:18:00pm rise 06:04:00am
Keck 1 HIRESR is scheduled with NASA observers. Keck 2 NIRC2-LGS is scheduled for UH observers. Sun set 06:19:00pm rise 06:03:00am
We are setting up OSIRIS-LGS on Keck 1 for KECK observers, NIRC2-LGS on Keck 2 for UH observers. Sun set 06:20:00pm rise 06:03:00am
Science giant Nature recently reported on Maunakea: The mountain-top battle over the Thirty Meter Telescope
KECK/UH* observers will work with PCS+SSC/HIRESR* tonight. And NASA observers will work with NIRC2-LGS. Sun set 06:21:00pm rise 06:03:00am