Supermassive black holes are just a little bit too supermassive – astronomers have difficulty explaining how they got so big so quickly in the early universe. So maybe it’s time for a new idea: perhaps giant black holes formed directly from dark matter.
Continue reading “Did Supermassive Black Holes Form Directly From Dark Matter?”An Exotic Explanation for the Most Extreme Gravitational Wave Detected so far
In May of 2019, the gravitational wave observatories LIGO and Virgo detected the merger of two black holes. One had a mass of 85 Suns, while the other was 66 solar masses. The event was named GW190521 and was the largest merger yet observed. It produced a 142 solar mass black hole, making it the first gravitational wave observation of an intermediate mass black hole. But the event also raised several questions.
Continue reading “An Exotic Explanation for the Most Extreme Gravitational Wave Detected so far”A New Technique to Find Cold Gas Streams That Might Make up the Missing (Normal) Matter in the Universe
Where is all the missing matter? That question has plagued astronomers for decades, because the Universe looks emptier than it should, given current theories about its makeup. Most of the Universe (70%) appears to be composed of Dark Energy, the mysterious force which is causing the Universe’s rate of expansion to increase. Another 25% of the Universe is Dark Matter, an unknown substance which cannot be seen, but has been theorized to explain the otherwise inexplicable gravitational forces which govern the formation of galaxies. That leaves Baryonic Matter – all the normal ‘stuff’ like you, me, the trees, the planets, and the stars – to make up just 5% of the Universe. But when astronomers look out into the sky, there doesn’t even seem to be enough normal matter to make up 5%. Some of the normal matter is missing!
Continue reading “A New Technique to Find Cold Gas Streams That Might Make up the Missing (Normal) Matter in the Universe”Nearby Ancient Dwarf Galaxies Have a Surprising Amount of Dark Matter
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”Narrowing Down the Mass of Dark Matter
Most of the matter of the universe is of a form unknown to physics. While we don’t know what the identity of the dark matter is, a new insight provided by quantum gravity is helping to drastically narrow down its mass.
Continue reading “Narrowing Down the Mass of Dark Matter”By Measuring Light From Individual Stars Between Galaxy Clusters, Astronomers Find Clues About Dark Matter
Astronomers have been able to measure an extremely faint glow of light within galaxy clusters, and that measurement came with a surprise: it traced the amount of invisible dark matter, something that scientists have been trying to pin down for decades.
Continue reading “By Measuring Light From Individual Stars Between Galaxy Clusters, Astronomers Find Clues About Dark Matter”Astronomers Hoped to see Evidence of Dark Matter Particles Inside Betelgeuse. No Luck
Axions are a hypothetical particle that might explain the existence of dark matter. But it might occasionally interact with normal matter, especially in the cores of stars. A team of physicists have searched for evidence of axions in Betelgeuse and come up with nothing. It doesn’t mean that the axion doesn’t exist, but it does mean that it will be harder to find.
Continue reading “Astronomers Hoped to see Evidence of Dark Matter Particles Inside Betelgeuse. No Luck”In Theory, Supermassive Black Holes Could get Even More Supermassive
Our universe contains some enormous black holes. The supermassive black hole in the center of our galaxy has a mass of 4 million Suns, but it’s rather small as galactic black holes go. Many galactic black holes have a billion solar masses, and the most massive known black hole is estimated to have a mass of nearly 70 billion Suns. But just how big can a black hole get?
Continue reading “In Theory, Supermassive Black Holes Could get Even More Supermassive”Weekly Space Hangout: December 9, 2020 – Casey Dreier: Are Changes Coming to NASA/US Space Policy?
We are pleased to once again welcome Casey Dreier from the Planetary Society to the WSH. Casey will update us (as much as possible) about Space Policy changes that may occur once the new American Presidential administration takes office on January 20, 2021.
Continue reading “Weekly Space Hangout: December 9, 2020 – Casey Dreier: Are Changes Coming to NASA/US Space Policy?”Neutrinos Have Played a Huge Role in the Evolution of the Universe
It’s often said that we haven’t yet detected dark matter particles. That isn’t quite true. We haven’t detected the particles that comprise cold dark matter, but we have detected neutrinos. Neutrinos have mass and don’t interact strongly with light, so they are a form of dark matter. While they don’t solve the mystery of dark matter, they do play a role in the shape and evolution of our universe.
Continue reading “Neutrinos Have Played a Huge Role in the Evolution of the Universe”