Gas from the intergalactic medium constantly rains down on galaxies, fueling continued star formation. New research has shown that this gas is not evenly mixed, and stars are not equal across the galaxy. This result means that solar systems are not the same within the Milky Way.Continue reading “The Milky Way Hasn’t Been Evenly Mixed”
At the heart of most galaxies is a supermassive black hole. These beasts of gravity can play a crucial role in the formation and evolution of their galaxy. But astronomers still don’t fully understand when the influence of black holes becomes significant. Did large black holes form early in the universe, causing galaxies to form around them? Or did black holes grow after its primordial galaxy had begun to form? You might call this the chicken or egg problem. But a recent study suggests that galaxies and their supermassive black holes can have a mutual interaction that allows them to co-evolve.Continue reading “Supermassive Black Hole Winds Were Already Blowing Less Than a Billion Years After the Big Bang”
Around the Milky Way, there are literally dozens of dwarf galaxies that continue to be slowly absorbed into our own. These galaxies are a major source of interest for astronomers because they can teach us a great deal about cosmic evolution, like how smaller galaxies merged over time to create larger structures. Since they are thought to be relics of the very first galaxies in the Universe, they are also akin to “galactic fossils.”
Recently, a team of astrophysicists from the Massachusetts Institute of Technology (MIT) observed one of the most ancient of these galaxies (Tucana II) and noticed something unexpected. At the edge of the galaxy, they observed stars in a configuration that suggest that Tucana II has an extended Dark Matter halo. These findings imply that the most ancient galaxies in the Universe had more Dark Matter than previously thought.Continue reading “Nearby Ancient Dwarf Galaxies Have a Surprising Amount of Dark Matter”
One of the ways we categorize stars is by their metallicity. That is the fraction of heavier elements a star has compared to hydrogen and helium. It’s a useful metric because the metallicity of a star is a good measure of its age.Continue reading “Some of the Milky Way’s oldest stars aren’t where they’re expected to be”
Galaxies build themselves up slowly over time by cannibalizing their neighbors. Using an advanced suite of computer simulations, researchers have now traced back the evolutionary history of our own Milky Way.Continue reading “The family tree of the Milky Way. The mergers that gave us the galaxy we see today”
The heart of the Milky Way can be a mysterious place. A gigantic black hole resides there, and it’s surrounded by a retinue of stars that astronomers call a Nuclear Star Cluster (NSC). The NSC is one of the densest populations of stars in the Universe. There are about 20 million stars in the innermost 26 light years of the galaxy.
New research shows that about 7% of the stars in the NSC came from a single source: a globular cluster of stars that fell into the Milky Way between 3 and 5 billion years ago.Continue reading “7% of the Stars in the Milky Way’s Center Came From a Single Globular Cluster That Got Too Close and Was Broken Up”
In the 1920s, Edwin Hubble studied hundreds of galaxies. He found that they tended to fall into a few broad types. Some contained elegant spirals of bright stars, while others were spherical or elliptical with little or no internal structure. In 1926 he developed a classification scheme for galaxies, now known as Hubble’s Tuning Fork.
When you look at Hubble’s scheme, it suggests an evolution of galaxies, beginning as an elliptical galaxy, then flattening and shifting into a spiral galaxy. While many saw this as a reasonable model, Hubble cautioned against jumping to conclusions. We now know ellipticals do not evolve into spirals, and the evolution of galaxies is complex. But Hubble’s scheme marks the beginning of the attempt to understand how galaxies grow, live, and die.Continue reading “What Shuts Down a Galaxy’s Star Formation?”
According to the most widely accepted cosmological theories, the first stars in the Universe formed a few hundred million years after the Big Bang. Unfortunately, astronomers have been unable to “see” them since their emergence coincided during the cosmological period known as the “Dark Ages.” During this period, which ended about 13 billion years ago, clouds of gas filled the Universe that obscured visible and infrared light.
However, astronomers have learned that light from this era can be detected as faint radio signals. It’s for this reason that radio telescopes like the Murchison Widefield Array (MWA) were built. Using data obtained by this array last year, an international team of researchers is scouring the most precise radio data to date from the early Universe in an attempt to see exactly when the cosmic “Dark Ages” ended.Continue reading “Searching for the End of the Universe’s “Dark Age””
For some time, astronomers have known that collisions or mergers between galaxies are an integral part of cosmic evolution. In addition to causing galaxies to grow, these mergers also trigger new rounds of star formation as fresh gas and dust are injected into the galaxy. In the future, astronomers estimate that the Milky Way Galaxy will merge with the Andromeda Galaxy, as well as the Small and Large Magellanic Clouds in the meantime.
According to new results obtained by researchers at the Flatiron Institute’s Center for Computational Astrophysics (CCA) in New York city, the results of our eventual merger with the Magellanic Clouds is already being felt. According to results presented at the 235th meeting of the American Astronomical Society this week, stars forming in the outskirts of our galaxy could be the result of these dwarf galaxies merging with our own.Continue reading “An Upcoming Impact With the Magellanic Clouds is Already Causing Star Formation in the Milky Way”
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”