As the Universe evolves in its first billion years UV radiation from
massive stars within the earliest galaxies heats the gas between
them to over 10,000 degrees Kelvin. The dark neutral hydrogen is
transformed to ionized hydrogen, shown in blue, making those regions
transparent to further ultra-violet radiation. In redshift it is about z~30 to 6.
Credits: Marcelo Alvarez, Ralf Kaehler & Tom Abel (KIPAC)
Credits: Marcelo Alvarez, Ralf Kaehler & Tom Abel (KIPAC)
