Today, the greatest mysteries facing astronomers and cosmologists are the roles gravitational attraction and cosmic expansion play in the evolution of the Universe. To resolve these mysteries, astronomers and cosmologists are taking a two-pronged approach. These consist of directly observing the cosmos to observe these forces at work while attempting to find theoretical resolutions for observed behaviors – such as Dark Matter and Dark Energy.
In between these two approaches, scientists model cosmic evolution with computer simulations to see if observations align with theoretical predictions. The latest of which is AbacusSummit, a simulation suite created by the Flatiron Institute’s Center for Computational Astrophysics (CCA) and the Harvard-Smithsonian Center for Astrophysics (CfA). Capable of processing nearly 60 trillion particles, this suite is the largest cosmological simulation ever produced.
Continue reading “A new Simulation of the Universe Contains 60 Trillion Particles, the Most Ever”
Since it was first theorized in the 1970s, astrophysicists and cosmologists have done their best to resolve the mystery that is Dark Matter. This invisible mass is believed to make up 85% of the matter in the Universe and accounts for 27% of its mass-energy density. But more than that, it also provides the large-scale skeletal structure of the Universe (the cosmic web), which dictates the motions of galaxies and material because of its gravitational influence.
Unfortunately, the mysterious nature of Dark Matter means that astronomers cannot study it directly, thus prevented them from measuring its distribution. However, it is possible to infer its distribution based on the observable influence its gravity has on local galaxies and other celestial objects. Using cutting-edge machine-learning techniques, a team of Korean-American astrophysicists was able to produce the most detailed map yet of the local Universe that shows what the “cosmic web” looks like.
Continue reading “A Dark Matter map of our Local Cosmic Neighborhood”
For astronomers, astrophysicists, and cosmologists, the ability to spot the first stars that formed in our Universe has always been just beyond reach. On the one hand, there are the limits of our current telescopes and observatories, which can only see so far. The farthest object ever observed was MACS 1149-JD, a galaxy located 13.2 billion light-years from Earth that was spotted in the Hubble eXtreme Deep Field (XDF) image.
On the other, up until about 1 billion years after the Big Bang, the Universe was experiencing what cosmologists refer to as the “Dark Ages” when the Universe was filled with gas clouds that obscured visible and infrared light. Luckily, a team of researchers from Georgia Tech’s Center for Relativistic Astrophysics recently conducted simulations that show what the formation of the first stars looked like.
Continue reading “An Extreme Simulation of the Universe’s First Stars”
In the 1960s, astronomers began theorizing that there might be black holes in the Universe that are so massive – supermassive black holes (SMBHs) – they could power the nuclei of active galaxies (aka. quasars). A decade later, astronomers discovered that an SMBH existed at the center of the Milky Way (Sagitarrius A*); and by the 1990s, it became clear that most large galaxies in the Universe are likely to have one.
Since that time, astronomers have been hunting for the largest SMBH they can find, in the hopes that can see just how massive these things get! And thanks to new research led by astronomers from the Australian National University, the latest undisputed heavy-weight contender has been found! With roughly 34 billion times the mass of our Sun, this SMBH (J2157) is the fastest-growing black hole and largest quasar observed to date.
Continue reading “There’s a Black Hole With 34 Billion Times the Mass of the Sun, Eating Roughly a Star Every Day”
One of the greatest benefits to come from space telescopes and ground-based observatories that take advantage of advanced imaging techniques is their ability to see farther into space (and hence, further back in time). In so doing, they are revealing things about the earliest galaxies, which allows astronomers to refine theories of how the cosmos formed and evolved.
For example, new research conducted by the ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) has found a “ring galaxy” that existed 11 billion years ago (about 3 billion years after the Big Bang). This extremely rare structure, which the team describes as a “cosmic ring of fire,” is likely to shake up cosmological theories of how the cosmos has changed over time.
Continue reading “Rare “Ring Galaxy” Seen in the Early Universe”
By looking deeper into space (and farther back in time), astronomers and cosmologists continue to push the boundaries of what is known about the Universe. Thanks to improvements in instrumentation and observation techniques, we are now at the point where astronomers are able to observe some of the earliest galaxies in the Universe – which in turn is providing vital clues about how our Universe evolved.
Using data obtained by the Kitt Peak National Observatory, a team of astronomers with the Cosmic Deep And Wide Narrowband (Cosmic DAWN) Survey were able to observe the farthest galaxy group to date. Known as EGS77, this galaxy existed when the Universe was just 680 million years old (less than 5% of the age of the Universe). Analysis of this galaxy is already revealing things about the period that followed shortly after the Big Bang.
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Since the mid-20th century, scientists have had a pretty good idea of how the Universe came to be. Cosmic expansion and the discovery of the Cosmic Microwave Background (CMB) lent credibility to the Big Bang Theory, and the accelerating rate of expansion led to theories about Dark Energy. Still, there is much about the early Universe that scientists still don’t know, which requires that they rely on simulations on cosmic evolution.
This has traditionally posed a bit of a problem since the limitations of computing meant that simulation could either be large scale or detailed, but not both. However, a team of scientists from Germany and the United States recently completed the most detailed large-scale simulation to date. Known as TNG50, this state-of-the-art simulation will allow researchers to study how the cosmos evolved in both detail and a large scale.
Continue reading “Watch a Simulation of a Galaxy, From the Big Bang Until the Present Day”