The Lyman-alpha emission in the Hubble Ultra Deep Field (HUDF) region, discovered by an international team of astronomers using the MUSE instrument on ESO’s Very Large Telescope (VLT) from distant clouds of hydrogen was a literally eye-opening surprise for the team. “This is a great discovery!” stated ESO team member Themiya Nanayakkara. This emission almost covers the entire field of view creating the theory that the sky is invisibly glowing with Lyman-alpha emission from the early Universe. The HUDF region observed by the team is an unremarkable area in the constellation of Fornax (the Furnace), which was famously mapped by the NASA/ESA Hubble Space Telescope in 2004.
This detection gave astronomers the opportunity to see faint emission from the gaseous envelopes of the earliest galaxies and revealed thousands of galaxies. The magic tool that helps the team is MUSE, a spectrograph installed on Unit Telescope 4 of the VLT at ESO’s Paranal Observatory, which sees the distribution of wavelengths in the light striking every pixel in its detector and gives new view on the diffuse gas ‘cocoons’ that surround galaxies in the early Universe. More research is expected in order to find out the cause of these distant clouds of hydrogen that emit Lyman-alpha and details of how these vast cosmic reservoirs of atomic hydrogen are distributed in space.
Just the red-shifted Lyman-alpha emission from the really far distant galaxies has a long enough wavelength to pass through Earth’s atmosphere free and be detected using ESO’s ground-based telescopes. The Microwave Window happening in the quietest part of the radio spectrum comes in addition to Lyman-alpha, as another emission phenomena of cold hydrogen line at 1420.40575 MHz), the most abundant substance in space. The hydrogen line is a frequency and is protected by the International Telecommunications Union (ITU) giving important data regarding structure of the universe and precise details for the Milky Way radio maps.
In 1959 Philip Morrison at Cornell University and Frank Drake at NRAO stated in his articles that the world’s most popular radio astronomy frequency would use as an interstellar contact for the next civilizations and over the past forty years, about three dozen other hydrogen line searches have been conducted. In 1977 the Big Ear radio telescope at the Ohio State Radio Observatory detected the so-called “Wow!” signal, the most promising SETI candidate signal to date. The “Wow!” is also the best known SETI signal, having been featured in the “X-files.”