Shortly after the big bang, the universe was an energetic mixture of particles with strong mutual interaction. The first particles that managed to free themselves from this dense primordial soup were the neutrinos, the lightest and weakest interacting particles from the standard model of elementary particles. These neutrinos are still all around us today, but are very difficult to observe immediately because their interaction is so weak. An international team of cosmologists, including Daniel Baumann and Benjamin Wallisch from the University of Amsterdam, has now succeeded in measuring the influence that this 'cosmic neutrino background' has had on the way galaxy clusters formed during the evolution of the universe. The research was published in Nature Physics.
Since time immemorial, philosophers and scholars have sought to determine how existence began. With the birth of modern astronomy, this tradition has continued and given rise to the field known as cosmology. And with the help of supercomputing, scientists are able to conduct simulations that show how the first stars and galaxies formed in our Universe and evolved over the course of billions of years.
In 2014, astronomers using the NASA/ESA Hubble Space Telescope found that this enormous galaxy cluster contains the mass of a staggering three million billion suns — so it’s little wonder that it has earned the nickname of “El Gordo” (“the Fat One” in Spanish)! Known officially as ACT-CLJ0102-4915, it is the largest, hottest, and brightest X-ray galaxy cluster ever discovered in the distant Universe.
The furthest galaxy ever observed is so far away that the starlight we now detect was emitted less than 500m years after the Big Bang. It has taken about 13 billion years to reach us. But there’s a lot of things about a galaxy that we can’t see. For example, we think galaxies are immersed within gigantic “halos” of an invisible substance dubbed dark matter. Scientists don’t actually know what dark matter is, but they know it exists because it has a gravitational pull on surrounding matter.
The events surrounding the Big Bang were so cataclysmic that they left an indelible imprint on the fabric of the cosmos. We can detect these scars today by observing the oldest light in the universe. As it was created nearly 14 billion years ago, this light — which exists now as weak microwave radiation and is thus named the cosmic microwave background (CMB) — permeates the entire cosmos, filling it with detectable photons.
Fifty years ago Captain Kirk and the crew of the starship Enterprise began their journey into space — the final frontier. Now, as the newest Star Trek film hits cinemas, the NASA/ESA Hubble space telescope is also exploring new frontiers, observing distant galaxies in the galaxy cluster Abell S1063 as part of the Frontier Fields programme.
Galaxy clusters are enormous collections of hundreds or even thousands of galaxies and vast reservoirs of hot gas embedded in massive clouds of dark matter, invisible material that does not emit or absorb light but can be detected through its gravitational effects. These cosmic giants are not merely novelties of size or girth – rather they represent pathways to understanding how our entire universe evolved in the past and where it may be heading in the future.
ESO telescopes have provided an international team of astronomers with the gift of the third dimension in a plus-sized hunt for the largest gravitationally bound structures in the Universe — galaxy clusters. Observations by the VLT and the NTT complement those from other observatories across the globe and in space as part of the XXL survey — one of the largest ever such quests for clusters.
Astronomers have discovered a giant gathering of galaxies in a very remote part of the universe, thanks to NASA's Spitzer Space Telescope and Wide-field Infrared Survey Explorer (WISE). The galaxy cluster, located 8.5 billion light-years away, is the most massive structure yet found at such great distances.