Earth was formed four and a half billion years ago. Since then, we’ve been trapped in a cosmic dance in which the Earth revolves around the Sun and the Sun revolves around the galactic center of the Milky Way.
Sagittarius A* – A Supermassive Black Hole
Sagittarius A* is a supermassive black hole that has a mass of around 4.3 million times that of the Sun. It is located at the center of our universe. Its size and presence has been calculated due to the presence of objects around it.
The most awaited image!
The Images Of Sgr A* is simply breathing all thanks to the Event Horizon Telescope. We can also see the donut-shaped orange object with dust around and the shadow of the black hole itself.
“We were stunned by how well the size of the ring agreed with predictions from Einstein’s theory of general relativity,” said EHT Project Scientist Geoffrey Bower of Academia Sinica in Taipei.
“These unprecedented observations have greatly improved our understanding of what happens at the very center of our galaxy, and offer new insights on how these giant black holes interact with their surroundings.”
Why Did This Take So Long?
The breakthrough comes three years after the collaboration showed the first photograph of a black hole’s shadow of a supermassive black hole named M87* at the center of a galaxy 55 million light-years away, with a mass of 6.5 billion times that of the Sun.
At a distance of roughly 25,800 light-years, Sgr A* is much closer to us. However, the two black holes posed completely different problems.
Problem In Capturing The “Running” Black Holes!
Imagining a black hole is like trying to imagine the unimaginable. It’s simple, we haven’t seen one!
We cannot detect any radiation emitted by black holes. They’re so dense that not even light, the fastest known thing in the Universe, is devoured due to the enormous gravitational pull of the black hole and can’t escape beyond a point called the event horizon.
What Is This M87*?
M87* as an active galactic nucleus or simply a black hole. It’s enjoying the refueling because it is encircled by a massive disc of dust and gas which is being drawn into the black hole.
The black hole glows brightly due to the enormous friction and gravity involved. That’s what the image of M87* shows, with the black hole’s shadow in the center of the incandescent material.
Why Did We Not Try To Capture The Image Of SgrA* But Took A Picture Of A Distant Black Hole?
Scientists not being racists have a simple explanation to this question. Our galaxy’s black hole Sagittarius A* is closer to us but it is not nearly as active as M87*.
If SgrA* were a person it would only eat a grain of rice per million years, meaning it has a low appetite or it is less active though it is bigger but “it must be a picky eater”, it was a galactic joke though!
Furthermore, much of what is housed in the Milky Way galactic core is obscured by dust.
Scientists have previously discovered a cloud of gas around Sgr A*, which is an accretion disc of its own, although it is rather chilly and glows faintly.
As the black hole is smaller, the orbital period of the disc is shorter, implying that light changes on very short timescales.
“The gas in the vicinity of the black holes moves at the same speed – nearly as fast as light – around both Sgr A* and M87*,” said astronomer Chi-kwan (‘CK’) Chan of the University of Arizona.
“But where gas takes days to weeks to orbit the larger M87*, in the much smaller Sgr A* it completes an orbit in mere minutes. This means the brightness and pattern of the gas around Sgr A* was changing rapidly as the EHT Collaboration was observing it, a bit like trying to take a clear picture of a puppy quickly chasing its tail.”
Where Is That Strange Shining Coming From?
There is something that is shining brightly in radio wavelengths and it’s our Sgr A*, whom we’ve never been able to get a close look at.
How Did ETH Take The Image Of M87*?
The Event Horizon Telescope brought together eight telescopes from around the world to create an Earth-sized telescope with exceptional resolution.
During an observation campaign in 2017, a high number of photos were taken, resulting in six terabytes of data. These data had to be processed and examined, which took years and required the creation of new algorithms to account for the rapid changes.
Why Do Supermassive Black Holes Exist?
An Unsolved Mystery
To be specific, we do not know much about supermassive black holes and they still remain a cosmic mystery. We don’t know how they became so enormous. Sgr A* is actually smaller in comparison to these behemoths, the mystery extends to how they came to be at all, back at the beginning of time.
But we can’t ignore that they are an important force in the universe’s evolution. They influence star creation even outside their own galaxies, and entire galaxies swirl around them.
The supermassive black holes we generally investigate, such as M87*, are active. That’s because of the materials in the space around them emits light, and the black holes’ magnetic fields can accelerate jets into intergalactic space, both of which can reveal information about the black hole.
Significance Of SgrA*
Sgr A*’s inactiveness may have made it more difficult to imagine, but that very trait makes it a fascinating study subject. We might be able to view the surroundings around it a little more clearly because it isn’t blazing with light like a more active black hole, which could give us a clearer window into event horizon physics.
This could help us figure out how accretion works, how jets are launched, and if general relativity adequately describes the extreme space-time in the region of a black hole, among other things.
Surprisingly, the two black holes appear to be doppelgangers. According to the researchers, this means we can draw certain conclusions about black holes.
“We have two completely different types of galaxies and two very different black hole masses, but close to the edge of these black holes they look amazingly similar,” said astronomer Sera Markoff of the EHT Science Council at the University of Amsterdam in the Netherlands.
“This tells us that general relativity governs these objects up close, and any differences we see further away must be due to differences in the material that surrounds the black holes.”
The Updates Of Event Horizon Telescope Are Given Here-
All right, the time has come! We’re on the verge of bursting at the seams with excitement to share this historic moment in astronomy with you. This blog will be updated every few minutes, so keep refreshing!
For those who are just learning about the announcement, here’s what we know thus far. The EHT is responsible for the first photograph of a black hole, which was obtained approximately three years ago. We also know that the findings are about our own Milky Way,which suggests that we may be about to see the first image of Sagittarius A* (Sgr A*), the supermassive black hole at the center of our galaxy.
It will be a momentous occasion if astronomers are able to capture a direct photograph of Sgr Event *horizon… So make sure you have plenty of snacks and fluids on hand. This is something you will not want to miss.
The fact that this black hole is in our own galaxy isn’t the only thing that makes this announcement exciting. It is, in fact, a really difficult task. Sgr A* has a mass of around 4.3 million times that of the Sun, a diameter of 25.4 million kilometers, and is 25,800 light-years away. Imagining it would be like attempting to photograph a tennis ball on the Moon.
Even at their best, black holes are difficult to imagine since they are completely invisible, absorbing all electromagnetic energy. Sgr A*, on the other hand, is considerably more difficult to analyze because it is shrouded by a cloud of dust and gas.
The EHT’s observation campaign in April 2017 focused on Sgr A*. The black hole’s horizon should look like a blazing donut if astronomers have imaged it. The accretion disc of a black hole is a ring of gas and dust that emits radiation as it orbits Sgr A*.
Only 15 minutes left!
The live stream is broadcasted from the European Space Observatory’s headquarters in Germany. However, it is being broadcasted alongside announcements from Washington DC, Santiago de Chile, Mexico City, Tokyo, and Taipei are among the destinations.
The Wait Is Over!
We’re set to meet Sgr A* in person!
ESO Director General Xavier Barcons welcomes us to the event.
We’ve been so near to Sgr A* before, he says, with telescopes monitoring the movements of stars around the galactic core and measuring the supermassive black hole.
“However, direct visuals of this object have yet to be seen,” Barcons said.
Barcons is referring to the collaboration of almost 300 international scientists, a large number of support staff, and eight radio observatories throughout the world to obtain this ground-breaking conclusion. He adds that it’s a timely reminder of what can be accomplished when countries work together.
It’s finally here! With the image is Huib van Langeveld, EHT Project Director.
From the plains of Chile, where the ALMA telescope is located, we will be flying into the heart of the galaxy to meet our galactic center.
Wow, this is incredible. To be clear, we can’t see the black hole itself, but it’s there, hidden in that dark spot in the middle of a brilliant disc.
Harvard’s Sara Issaoun will be speaking. We now have direct evidence that Sgr A* is a black hole, she claims, for the first time. The black hole’s shadow is visible in the center, while hot gas spirals around it, heated by friction. We can detect radio waves emitted by this gas.
Its size in the sky is roughly 52 micro arc seconds, which is the same as imagining a doughnut on the Moon. We may use the magnitude of a black hole’s shadow to determine that its mass is roughly 4 million times that of the Sun because the size of its shadow is related to its mass. This matches Einstein’s predictions from General Relativity perfectly!
Even though the two are highly different and are in very different surroundings, Sgr A* looks remarkably similar to the first photograph of a black hole ever taken, that of M87*. This means that, regardless of the size of the environment, gravity will dominate the region around a black hole.
The technical specifics of this incredible achievement are now being shared by Thomas Krichbaum of the Max Planck Institute for Radio Astronomy in Germany.
It took 25 years to develop and perfect the procedures for combining telescopes all across the world into one massive, Earth-sized telescope capable of imaging black holes.
The result is a 3 million-fold sharper interferometer than the human eye. Six terabytes of data were gathered for the image of Sgr A*; processing of this data took several years and necessitated the creation of new instruments.
José L. Gómez of the Instituto de Astrofísica de Andalucía in Spain now explains how the Event Horizon Telescope’s eight telescopes work together to collect observations in greater detail.
He claims that Sgr A* was significantly more difficult than M87*. The region is veiled by dust, and while the gas surrounding each black hole flows at the same speed, Sgr A* is 1,500 times less massive, resulting in a substantially shorter orbit for its gas. This indicates that the gas was changing rapidly while the measurements were being performed.
Along with the image of M87*, this is the most completely vetted interferometric image ever obtained.
Christian Fromm of Würzburg University in Germany now takes the stage to explain what the image means for Sgr A*.
To model black holes, the team used supercomputers all across the world. The graphic indicates that Sgr A* is rotating and that we are staring at it face-on as compared to their models.
Mariafelicia de Laurentis of the University of Naples “Federico II” and the National Institute for Nuclear Physics (INFN) in Italy claims that the size of Sgr Ashadow, *’s like that of M87*, is consistent with relativity, despite the fact that the two black holes are accreting matter at vastly different rates still Sgr A* is a million times less than M87*.
According to de Laurentis, studying the environment around a black hole like Sgr A* or M87* will allow us to undertake fresh tests of general relativity in the hopes of discovering regions where it breaks down. This may aid our understanding of gravity and the function black holes play in our Universe. The most exciting part is still to come!
This is the next stage, according to Anton Zensus in his final remarks. “We’ve integrated the world’s most powerful radio telescopes into a single Earth-scale camera.”
Without the 300 scientists who contributed to this effort, none of this would have been possible. “How about Einstein?” Zensus inquires. “I believe he would be overjoyed.”