It’s difficult to determine the shape of our galaxy. So difficult that only in the last century did we learn that the Milky Way is just one galaxy among billions. So it’s not surprising that despite all our modern telescopes and spacecraft we are still mapping the shape of our galaxy. And one of the more interesting discoveries is that the Milky Way is warped. One explanation for this is that our galaxy has undergone collisions, but a new study argues that it’s caused by dark matter.Continue reading “The Milky Way's Disk is Warped. Is That Because our Dark Matter Halo is Tilted?”
According to our predominant cosmological models, Dark Matter accounts for roughly 85% of the mass in the Universe. While ongoing efforts to study this mysterious, invisible mass have yielded no direct evidence, astrophysicists have been able to measure its influence by observing Dark Matter Haloes, gravitational lenses, and the effect of General Relativity on large-scale cosmic structures. And with the help of next-generation missions like the ESA’s Euclid and NASA’s Nancy Grace Roman space telescopes, Dark Matter may not be a mystery for much longer!
And then something like this comes along: a massive galaxy that appears to have little or no Dark Matter! This is precisely what a team of astronomers led by members of the Instituto Astrofisica de Canarias (IAC) noticed when observing NGC 1277. This lenticular galaxy, located 240 million light-years away in the constellation Perseus, is several times more massive than the Milky Way. This is the first time a massive galaxy has been found that doesn’t show signs of Dark Matter, which is a serious challenge to our current cosmological models.Continue reading “A Massive Galaxy With Almost No Dark Matter”
According to the most widely-accepted cosmological model, the majority of the mass in our Universe (roughly 85%) consists of “Dark Matter.” This elusive, invisible mass is theorized to interact with “normal” (or “visible”) matter through gravity alone and not electromagnetic fields, neither absorbing nor emitting light (hence the name “dark”). The search for this matter is ongoing, with candidate particles including Weakly-Interacting Massive Particles (WIMPs) or ultralight bosons (axions), which are at opposite extremes of the mass scale and behave very differently (in theory).
This matter’s existence is essential for our predominant theories of gravity (General Relativity) and particle physics (The Standard Model) to make sense. Otherwise, we may need to radically rethink our theories on how gravity behaves on the largest of scales (aka. Modified Gravity). However, according to new research led by the University of Hong Kong (HKU), the study of “Einstein Rings” could bring us a step closer to understanding Dark Matter. According to their paper, the way Dark Matter alters the curvature of spacetime leaves signatures that suggest it could be made up of axions!Continue reading “Gravitational Lensing is Helping to Nail Down Dark Matter”
Do you have a few minutes to spare and a thirst for knowledge about one of the greater mysteries of the Universe? Then head on over to ArsTechnica and check out the new series they’re releasing titled Edge of Knowledge, starring none other than Dr. Paul Sutter. In what promises to be an enlightening journey, Dr. Sutter will guide viewers through an eight-episode miniseries that explores the mysteries of the cosmos, such as black holes, the future of climate change, the origins of life, and (for their premiere episode) Dark Matter!
As far as astrophysicists and cosmologists are concerned, Dark Matter is one of the most enduring, frustrating, and confusing mysteries ever! Then, one must wonder why scientists are working so tirelessly to track it down? The short answer is: the most widely accepted theories of the Universe don’t make sense without out. The long answer is… it’s both complicated and long! Luckily, Dr. Sutter manages to sum it all up in less than 15 minutes. As an accomplished physicist, he also explains why it is so important that we track Dark Matter down!Continue reading “Missing Mass? Not on our Watch—Dr. Paul Sutter Explains Dark Matter”
We don’t quite understand how the first supermassive black holes formed so quickly in the young universe. So a team of physicists are proposing a radical idea. Instead of forming black holes through the usual death-of-a-massive-start route, instead giant dark matter halos directly collapsed, forming the seeds of the first great black holes.Continue reading “How did Supermassive Black Holes Form? Collapsing Dark Matter Halos can Explain Them”
The outer reaches of the Milky Way galaxy are a different place. Stars are much harder to come by, with most of this “galactic halo” being made up of empty space. But scientists theorize that there is an abundance of one particular thing in this desolate area – dark matter. Now, a team from Harvard and the University of Arizona (UA) spent some time studying and modeling one of the galaxy’s nearest neighbors to try to tease out more information about that dark matter, and as a result came up with an all new way to look at the halo itself.Continue reading “New All-Sky Map of the Milky Way’s Galactic Halo”
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”
Matter in the Universe is not distributed equally. It’s dominated by super-clusters and the filaments of matter that string them together, surrounded by huge voids. Galaxy super-clusters are at the top of the hierarchy. Inside those is everything else: galaxy groups and clusters, individual galaxies, and solar systems. This hierarchical structure is called the “Cosmic Web.”
But how and why did the Universe take this form?Continue reading “Slime Mold Grows the Same as the Large Scale Structure of the Universe”
It’s a difficult thing to wrap your head around sometimes. Though it might feel stationary, planet Earth is actually moving at an average velocity of 29.78 km/s (107,200 km/h; 66600 mph). And yet, our planet has nothing on the Sun itself, which travels around the center of our galaxy at a velocity of 220 km/s (792,000 km/h; 492,000 mph).
But as is so often the case with our Universe, things only get more staggering the farther you look. According to a new study by an international team of astronomers, the most massive “super spiral” galaxies in the Universe rotate twice as fast as the Milky Way. The cause, they argue, is the massive clouds (or halos) of Dark Matter that surround these galaxies.Continue reading “The Most Massive Galaxies Spin More Than Twice as Fast as the Milky Way”
The U.S. House of Representatives have passed a bill to change the name of the Large Synoptic Survey Telescope (LSST.) Instead of that explanatory yet cumbersome name, it will be named after American astronomer Vera Rubin. Rubin is well-known for her pioneering work in discovering dark matter.Continue reading “Great News! The Large Synoptic Survey Telescope Might be Named for Vera Rubin”