Our Galaxy's Monster Black Hole Is Spinning Almost as Fast as Physics Allows
The colossal black hole lurking at the center of the Milky Way galaxy is spinning almost as fast as its maximum rotation rate.
That's just one thing astrophysicists have discovered after developing and applying a new method to tease apart the secrets still hidden in supermassive black hole observations collected by the Event Horizon Telescope (EHT).
The unprecedented global collaboration spent years working to give us the first direct images of the shadows of black holes, first with M87* in a galaxy 55 million light-years away, then with Sgr A*, the supermassive black hole at the heart of our own galaxy.
These images are incredible – but also difficult to interpret. So, to figure out what we're looking at, scientists turn to simulations. They build a bunch of virtual characteristics, and figure out which of them most resemble the observational data. This technique has been used a lot with the EHT images, but now it's been kicked up a notch.
A team led by astronomer Michael Janssen of Radboud University in the Netherlands and the Max Planck Institute for Radio Astronomy in Germany used high-throughput computing to develop millions of simulated black holes.
Then, they used that data to train a neural network to extract as much information as possible from the data, and identify the properties of the black holes.
Their results show, among other things, that Sgr A* is not only spinning at close to its maximum speed, but that its rotational axis is pointed in Earth's direction, and that the glow around it is generated by hot electrons.
Perhaps the most interesting thing is that the magnetic field in the material around Sgr A* doesn't appear to be behaving in a way that's predicted by theory.
M87*, they discovered, is also rotating rapidly, although not as fast as Sgr A*. However, it is rotating in the opposite direction to the material swirling in a disk around it – possibly because of a past merger with another supermassive black hole.
"That we are defying the prevailing theory is of course exciting," Janssen says.
"However, I see our AI and machine learning approach primarily as a first step. Next, we will improve and extend the associated models and simulations. And when the Africa Millimetre Telescope, which is under construction, joins in with data collection, we will get even better information to validate the general theory of relativity for supermassive compact objects with a high precision."
The team has detailed their methodology and findings in three papers published in Astronomy & Astrophysics. They can be found here, here, and here.
Did a Passing Star Cause Earth to Warm 56 Million Years Ago?
A Game-Changing Telescope Is About to Drop First Pics. Here's How to Watch.
Trailblazing Satellite Mission Delivers Its First Artificial Solar Eclipse
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Yahoo
2 hours ago
- Yahoo
Summer solstice 2025 is here! Today marks the longest day of the year for the Northern Hemisphere
When you buy through links on our articles, Future and its syndication partners may earn a commission. Sunlovers rejoice, for the summer solstice is upon us, bringing the longest day of 2025 while heralding the beginning of astronomical summer in the northern hemisphere. The summer solstice occurs because of a 23.5 degree tilt in Earth's rotational axis that may have arisen when an ancient Mars-sized body slammed into our planet billions of years ago, triggering the formation of our moon. The angle of this tilt is — to all intents and purposes — consistent all year round, and is currently fixed with the north celestial pole pointing close to Polaris, the current north star. Thanks to this tilt, we experience the changing seasons, equinoxes and solstices — events that have been celebrated by cultures around the world for thousands of years. Some of humanity's most iconic ancient monuments like Stonehenge and the Mayan Chichén Itzá Pyramid were purpose built to align with these seasonal markers. In the northern hemisphere the summer solstice occurs when the sun reaches its northernmost point relative to Earth's celestial equator (which is simply our planet's regular equator projected out into space). Conversely, the winter solstice takes place when the sun is in its southernmost position relative to the celestial equator. The 2025 summer solstice arrives at 10:42 p.m. EDT on June 20 (0242 GMT June 21). On this day, skywatchers across the northern hemisphere will enjoy the longest stretch of daylight all year. In New York, for example, the sun will spend more than 15 hours beating a path through the sky. At the same time, those in the southern hemisphere will mark the winter solstice, which heralds the shortest day of 2025 below the equator. You can calculate exactly how much daylight you will experience in the days around the summer and winter solstices online using daylight tracker. Naturally this amount of sunlight makes it a challenging time of year for amateur astronomers, but that doesn't mean that the summer months aren't bursting with deep space targets and beautiful asterisms. Be sure to check out our daily guide to June's night sky to discover which targets to prioritize during those short summer nights. Editor's Note: If you find a creative way to capture the Summer Solstice and want to share it with readers, then please send your photo(s), comments, and your name and location to spacephotos@
Yahoo
2 hours ago
- Yahoo
Let's celebrate: Today is the summer solstice, the longest day of the year
Editor's note: This story was first published on June 21, 2013 Welcome to the best day of the year. Today is the summer solstice, the longest day. In North Jersey, we'll get more than 15 hours of daylight. Go ahead and gloat — that's nearly an hour and a half more daylight than Key West, Florida, will get today. For those who like daylight — pretty much everyone save Dracula — today is a day to celebrate. In past eras, they actually did. "The summer solstice was a carnivalesque feast day," said Pamela H. Smith, a European history expert at Columbia University. "In England, there were bonfires, lots of beer drinking, cannons being fired off, masqueraders — people dressed up as devils and demons. "Days like the solstice were important for ancient peoples in terms of trying to find patterns in nature that were important for their livelihood, like knowing when to plant crops. All cultures had megaliths like Stonehenge," Smith said. The Earth's orbit around the sun is slightly elliptical, but not enough to cause the seasons, said Carlton Pryor, an astronomer at Rutgers University. In fact, at the summer solstice, the North Jersey region is 94.4 million miles from the sun. At the winter solstice, it's only 91.4 million miles away. The seasons are caused by the Earth's axis being tilted at a 23.5 degree angle. When the Northern Hemisphere is tilted toward the sun, the hemisphere receives sunlight more directly, for longer periods, increasing temperatures. More: Make one of these 10 books that are set in New Jersey your next beach read for summer 2025 In winter, the Northern Hemisphere is tilted away — even though it is closer to the sun in miles — so the light is less direct, more angled. The sun is lower in the sky and appears for fewer hours, causing cooler temperatures. On the summer solstice, the Earth's northern axis is tilted at its most extreme angle toward the sun. Today in North Jersey, the sun at its zenith will be at an angle of nearly 73 degrees above the horizon. On Dec. 21, it will be only 26 degrees above the horizon. The Earth's axis tilt also affects where the sun rises on the horizon. Conventional wisdom that the sun rises in the east and sets in the west is true only twice a year — at the spring and fall equinoxes. During the summer solstice, the sun rises at its northernmost point on the horizon. This morning in Hackensack, if you had faced due east, the sun would have risen about 32 degrees to the north (or to your left). At the winter solstice, it will rise 32 degrees to the south of due east (or to your right). Though the summer solstice once triggered celebrations, that's rarely the case anymore. After the Protestant Reformation in Europe, religious leaders started to call for an end to the celebrations. "A lot of Protestant pastors criticized midsummer night's eve, saying people were drinking too much, fighting," Smith said. Another reason we don't celebrate the solstice is the shift from an agrarian lifestyle. "We live in a more urban society, and we have colonized the night," said Sara Schechner, an expert on science history at Harvard University. "So we are not as bound to the cycles of nature in how we go about our lives." This article originally appeared on Summer solstice 2025 is here
Yahoo
5 hours ago
- Yahoo
Latest Starship Explosion Drastically Decreases SpaceX's Chances of Reaching Mars Without Having to Wait Years
With tech billionaire Elon Musk out of the White House after his disastrous turn as a bureaucrat, he can now focus on more pressing subjects — such as his SpaceX Starship rockets that keep on exploding into fiery columns of fire, with the latest dramatic failure this past Wednesday in Texas, when the massive spacecraft hadn't even left the ground yet. This recent setback ratchets up the pressure on Musk even further, who faces a hard deadline and steep technical challenges in his vaunted goal to reach Mars. Much of that deadline is self-imposed, as CNN points out in an excoriating new breakdown of the situation. In May, Musk said he plans to send an unmanned crew to Mars next year, but the latest blast — the latest in a string of similar explosions that have plagued Starship — seem almost certain to set him back enough to force SpaceX to miss a crucial celestial launch opportunity called a transfer window. Depending on the position of Earth and Mars from one another, the distance between the two planets can vary from 35 million to over 200 million miles. To make the journey shorter and to save cost on fuel, explorers must time their rocket launch during the transfer window, a period when Mars and Earth are in an optimal alignment that minimizes the journey's length. The next transfer window for Mars is in late 2026 and will only last for a few weeks; miss it, and the journey will be way more expensive and far longer to be practical. To still make the deadline, Musk faces the extraordinary challenge of fixing any technical challenges with Starship and present an upgraded version of the vehicle and the Super Heavy rocket booster in time before the Mars transfer window next year. In addition, SpaceX has to figure out how to fuel Starship, which needs to be topped off with propellant in orbit before making its journey to the red planet. This would involve launching numerous Starships into space and using them to fuel up the one headed to the Red Planet — a process that will pose a spectacular logistical challenge of its own. "We've never done that," Bruce Jakosky, professor emeritus of geological sciences at the University of Colorado Boulder, told CNN. "Nobody's done that — transferring fuel from one spacecraft to another in orbit autonomously." Another technical challenge SpaceX needs to solve is Starship's heat shield, which has to survive entry into Mar's atmosphere and the journey back to Earth. Back in May, Musk himself conceded that it posed "one of the toughest problems to solve." And all that is without getting into the technical feasibility of human flight to Mars, including how to shield any crew from cosmic radiation. Before any of that, of course, Starship needs to stop exploding. More on SpaceX: Elon's Explosion at Trump Appears to Have Cost Him a HUGE Deal
