Researchers announced Thursday that three years after the first image was taken of a supermassive dark hole in a galaxy 55 millions light years away, astronomers managed to "photograph” the gaping maw the smaller, but still very close black hole, which lurks at the center of the Milky Way.
Michael Johnson, a Harvard-Smithsonian Center for Astrophysics researcher, said, "We are peering in to a new environment. The curved spacetime close to a supermassive Black hole." It is alive with activity, constantly burbling with turbulent energie and sometimes erupting into bright flashes of emission.
The 2019 target was a bizarre black hole in the core of M87, a massive elliptical galaxy located in the constellation Virgo. It has a mass of 6.5 million suns. The disc's immense gravity forces surrounding material to form a disc. This accelerates it to almost the speed of light, and heats it to extreme temperatures. These results can be seen from Earth.
Sagittarius A* or Sgr A* is the black hole in the middle of the Milky Way. It is approximately 26,000 light-years from Earth. However, it is smaller. The entire solar system would be filled with the 6.5 billion solar masses that make up the M87 black hole. Mercury's orbit would accommodate the 4 million solar masses of Sgr. A*.
After years of meticulous data collection, eight radio telescopes electronically combined with atomic clocks to create a virtual dish about the size of the Earth's surface, the Event Horizon Telescope project collaborators have finally revealed the long-awaited image of Sgr. A*.
It was roughly the same feat as photographing one grain of salt in New York City with a camera in Los Angeles.
Feryal Ozel is a theoretical astrophysicist from the University of Arizona who also leads the EHT team. "Intense astronomical research has focused on Sgr. A* for decades." "Observations of stars orbiting it revealed that there was an object very large, 4,000,000 times larger than our sun. However, the object is also very faint.
She said that until now, there wasn't a direct image to confirm that Sgr. A* was indeed black holes. "Today, Event Horizon Telescope is thrilled to share with You the First Direct Image of the Gentle Giant in the Center of Our Galaxy."
Ozel stated that the image was based on multiple observations and a variety algorithms to find subtle details.
The bright ring is light that escapes from the black hole's hot gas. The black hole is too close for light to escape, so it eventually swallows any light that crosses its horizon.
Black holes can't be observed directly by definition because nothing, not even light cannot escape the crushing inward force their titanic gravity.
Their presence can be inferred by watching the impact of gravity on the trajectories and radiation emission of nearby stars.
For the past 20 years, the motions of stars within the dust-shrouded Milky Way core near Sgr A* has been closely observed. This allowed astronomers calculate the mass of the invisible object that is altering their trajectories.
Three researchers were awarded the 2020 Nobel Prize for their pioneering observations and analyses that all but confirmed the existence of a supermassive dark hole. The Event Horizon Telescope captured an image of the huge object for the first time.
This image shows Sgr A*’s dark core, the shadow of its "eventhorizon", surrounded by a lopsided circle of light created by particles racing around the hole with nearly the speed light.
The event horizon is an invisible boundary that separates a black hole from the rest of the universe. It is a zone in which nothing, not even light can escape the hole’s gravitational clutches. Anything that crosses this invisible line, including gas, dust, and wayward stars, is extinct from the known universe.
The EHT image Sgr A* looks similar to M-87's historic image. It closely matches what astronomers had expected based upon computer simulations that ran the equations of Einstein’s general theory.
Ozel stated that M-87's blackhole "is 1,500x more massive, making it 1,500x larger." It is also 2,000 miles away from us. These two images look very similar when we view them in the sky. The two black holes could not have been more different in almost every way.
The one in M87 accumulates matter at a much faster rate than that of Sgr A*. Perhaps more important, the M-87 launcher launches a powerful jet that reaches as far as the edge that galaxy. Our black hole does not. Yet, if we look closely at each black hole's heart, we see a bright ring around its shadow. She joked that black holes are like doughnuts.
Johnson stated that "only a trickle" of material was actually making it all to the black hole.
He said that if Sgr. A* was a human, it would eat one grain of rice per million years. While some black holes are capable of converting gravitational energie into light with remarkable efficiency, Sgr. A* traps almost all of it, and only one percent of that energy is converted to light.
The black hole, despite appearing so bright in the simulation images, is hungry but inefficient. Despite being four times larger than the sun, it only produces a few hundredth of the energy that the sun does. It's only possible to study it because it is in our galaxy.
M-87 is home to one of the largest black holes in the universe. However, Sgr. A* said that he was able to show us the more normal state of black holes: quiet and quiescent. M-87 was extraordinary because it was unusual. Because it's common, Sgr. A* is thrilling."
The Event Horizon Telescope team used eight radio telescopes to "see" Sgr. A*. They did this in Hawaii, North, Central, and South America.
A technique called very long baseline interferometry allows precise data from radio telescopes to be combined to create images that are comparable to what an Earth-sized dish would detect. This virtual telescope is capable of detecting a moon doughnut with the highest resolution ever created.
The data collected was approximately equal to a million TikTok videos. For supercomputer processing and analysis, thousands of hard drives were shipped physically to researchers in Europe.
"Every once in awhile, you just need to pinch yourself and think, "This is the black hole at center of our galaxy!" Katie Bouman is an assistant professor at Caltech, and an EHT team member. "It's quite amazing that we were actually capable of doing this," said Katie Bouman, an assistant professor at Caltech and EHT team member.
Stable stars exist in "hydrostatic equilibrium", which balances the inward pull of gravity and the outward push from radiation generation by fusion reactions at the core. 600 million tons of hydrogen are fused to helium every second in the sun to create the radiation pressure necessary to offset gravity and keep the stars stable.
Over billions of years, smaller stars, such as the sun, run out of nuclear fuel. Their cores then collapse to a point that quantum forces and not fusion maintain stability. These star dead and slowly cooling are called white dwarfs.
Core collapse occurs when more massive stars run out fuel. This is why the white dwarf stage continues.
A neutron star is formed when collapsing cores have up to three times as much mass as the sun. It can cram more than twice as much mass into a body that measures less than 10 miles in diameter. The densest objects visible in the universe are neutron stars. They are propped up with a different type of quantum force.
A different fate awaits stars with even greater mass. Gravity triumphs over all known nuclear forces, and core collapse continues past the point when it disappears from the visible universe. It leaves behind only an extremely concentrated "gravity well", of highly distorted space.
These remnants are called stellar mass black holes, because they were formed by the death a single star.
A few larger intermediate-mass black hole have been discovered. These could be stepping stones for the formation of supermassive black stars, which are now believed to exist in all major galaxies' cores. However, it is still unclear how these larger holes form.
The James Webb Space Telescope, which was just launched, has the primary objective to assist astronomers in charting the formation and growth such black holes after the Big Bang.
Ozel stated, "I wish that I could tell you that the second time imaging black holes is as good as it was the first." But that would be false. It's actually better. We now know it wasn’t an accident, and it wasn’t something that happened in the environment that made the ring look the way we expected.
"We now know in both cases that the heart of the dark hole, the point where there is no return, is what we see." Spacetime, which is the fabric of the universe wraps around black holes exactly in the same way regardless of their mass or the surrounding environment.
