Everything dies in the end, even the brightest of stars. In fact, the brightest stars are the ones that live the shortest lives. They consume all the hydrogen they have within a few million years, then explode as brilliant supernovae. Their core remains collapse into a neutron star or black hole. These small, dark objects litter our galaxy, like a cosmic graveyard.Continue reading “The Milky Way is Surrounded by a Vast Graveyard of Dead Stars”
Sagittarius A* (Sag A) is usually a pretty quiet object, as supermassive black holes go. It’s not wildly active, like the object at the heart of M87, for example. But, every once in a while, there’s a little action in its neighborhood. Right now, there appears to be a hot blob of gas running rapidly in circles around the black hole. Astronomers detected it using the Atacama Large Millimeter Array (ALMA) in Chile. The data from that radio astronomy facility tells them more about the environment around Sag A*.Continue reading “There’s a Blob of Gas Orbiting Around the Milky Way’s Supermassive Black Hole”
Remove All Ads on Universe Today
Join our Patreon for as little as $3!
Get the ad-free experience for life
In 1916, Karl Schwarzchild theorized the existence of black holes as a resolution to Einstein’s field equations for his Theory of General Relativity. By the mid-20th century, astronomers began detecting black holes for the first time using indirect methods, which consisted of observing their effects on surrounding objects and space. Since the 1980s, scientists have studied supermassive black holes (SMBHs), which reside at the center of most massive galaxies in the Universe. And by April 2019, the Event Horizon Telescope (EHT) collaboration released the first image ever taken of an SMBH.
These observations are an opportunity to test the laws of physics under the most extreme conditions and offer insights into the forces that shaped the Universe. According to a recent study, an international research team relied on data from the ESA’s Gaia Observatory to observe a Sun-like star with strange orbital characteristics. Due to the nature of its orbit, the team concluded that it must be part of a black hole binary system. This makes it the nearest black hole to our Solar System and implies the existence of a sizable population of dormant black holes in our galaxy.Continue reading “Astronomers Find a Sun-like Star Orbiting a Nearby Black Hole”
We know the universe is expanding, and we have a pretty good idea of how fast it’s expanding, but we don’t know the rate exactly. That’s because of the different methods we have to measure the rate of cosmic expansion keep giving us slightly different results. It’s a nagging problem that bugs astronomers, so while they have worked to ensure current methods are accurate, they have also looked to new ways to measure cosmic expansion. One of these new ways involves gravitational waves.Continue reading “Colliding Black Holes Provide Another way to Measure Distance in the Universe”
In 2019 the Event Horizon Telescope gave us our first direct image of a black hole. It was a powerful image, but not one with much detail. It looks like a blurry orange donut. To be fair, the real meat of the discovery was in the data, not the image. And as a recent study shows, there’s a great deal more in the data than what we’ve seen.Continue reading “Astronomers Have Revealed a Black Hole's Photon Ring for the First Time”
The early moments of the universe were turbulent and filled with hot and dense matter. Fluctuations in the early universe could have been great enough that stellar-mass pockets of matter collapsed under their own weight to create primordial black holes. Although we’ve never detected these small black holes, they could have played a vital role in cosmic evolution, perhaps growing into the supermassive black holes we see today. A new study shows how this could work, but also finds the process is complicated.Continue reading “Primordial Black Holes Could Have Triggered the Formation of Supermassive Black Holes”
What happens when a massive star dies? Conventional wisdom (and observational evidence) say that it can collapse to form a “stellar-mass” black hole. Astronomers detect black holes by the X-ray emissions they emit.
But, what if the black hole isn’t giving off high levels of X-ray emissions? Then, it could be a very rare object indeed: a dormant black hole. Not many of these have been seen. So, it’s exciting to know that a team of astronomers has found one. It’s called VFTS 243. They detected it in Very Large Telescope observations of stars in the Tarantula Nebula, in the neighboring Large Magellanic Cloud.Continue reading “A Dormant Black Hole has Been Discovered Just Outside the Milky Way”
Way out there in space is a class of objects called blazars. Think of them as extreme particle accelerators, able to marshall energies a million times stronger than the Large Hadron Collider in Switzerland. It turns out they’re the culprits in one of the great astrophysical mysteries: what creates and propels neutrinos across the universe at blazingly fast speeds? It turns out that the answer’s been there all along: blazars pump out neutrinos and cosmic rays. That’s the conclusion a group of astronomers led by Dr. Sara Buson of Universität Wurzburg in Germany came to as they studied data from a very unique facility here on Earth: the IceCube Neutrino Observatory in Antarctica.Continue reading “We Finally Know Where the Highest Energy Cosmic Rays are Coming From: Blazars”
What happens when a star wanders too close to a supermassive black hole? The obvious story is that it gets sucked in, never to be seen again. Some of its material gets superheated on the way in and that gives off huge amounts of radiation—usually X-rays. That’s not a wrong explanation, just incomplete. There’s more to the story, thanks to a team of astronomers at the University of California at Berkeley. They used a specialized spectrograph at Lick Observatory to study a tidal disruption event. That’s where a star encountered a black hole. What they found was surprising.Continue reading “A Star Came too Close to a Black Hole and was Torn Apart. Surprisingly Little Actually Went In”
There’s a population of stars in the heart of our galaxy whipping around Sagittarius A* (the Milky Way’s central supermassive black hole). Astronomers just found the closest, fastest one (so far). It’s called S4716 and it orbits Sag A* once every four years. That makes it officially the fastest star moving at the heart of our galaxy. To give you some perspective, the Sun moves around the center of the galaxy at a much more leisurely pace once every 230 million years.Continue reading “One Star Flies Past the Milky Way’s Black Hole at 3% the Speed of Light”