Astronomers snap first-ever image of supermassive black hole Sagitarrius A*
The image reveals a glowing, donut-shaped ring at the Milky Way’s heart
Written by Jennifer Chu, MIT News Office
Black holes are invisible by nature. Their pull is inescapable, forever trapping any light that falls into their gravitational abyss. But just beyond a black hole’s point of no return, light persists, and its patterns, like a photo negative, can reveal a black hole’s lurking presence.
Now an international team of astronomers, including researchers at MIT’s Haystack Observatory, has captured the light around our own supermassive black hole, revealing for the first time, an image of Sagitarrius A* (Sgr A*, pronounced ‘sadge-ay-star’), the black hole at the heart of the Milky Way galaxy.
The image was created by the Event Horizon Telescope (EHT) — a global network of radio telescopes whose movements are choreographed so they function as one virtual, planet-sized telescope. The researchers focused the EHT array on the center of our galaxy, 27,000 light years from Earth, cutting through our planet’s atmosphere and the turbulent plasma beyond our solar system.
The resulting image reveals SgrA* for the first time, in the form of a glowing, donut-shaped ring of light. This ring structure lies just outside the event horizon, or the point beyond which light cannot escape, and is the result of light being bent by the black hole’s enormous gravity. The bright ring encircles a dark center, described as the black hole’s “shadow.”
The ring’s white-hot plasma is estimated to be 10 billion Kelvin, or 18 billion degrees Fahrenheit. Judging from the ring’s dimensions, SgrA* is roughly 4 million times the mass of the sun and incredibly compact, with a size that could fit within the orbit of Venus.
The image is the first visual confirmation that a black hole indeed exists at the center of our galaxy. Astronomers previously have observed stars circling around an invisible, massive, and extremely dense object — all signs pointing to a supermassive black hole. The image revealed today provides the first visual evidence that the object is a black hole, with dimensions that agree with predictions based on Einstein’s theory of general relativity.
“It is notoriously difficult to reconstruct images from a widely dispersed array like the EHT, and both rigor and ingenuity have been required to properly understand and quantify uncertainties,” says Colin Lonsdale, director of MIT’s Haystack Observatory. “The result is a milestone in our understanding of black holes in general and the one at the center of our galaxy in particular.”
The image and accompanying analyses are presented today in a number of papers appearing in a special issue of The Astrophysical Journal Letters. The findings are the result of work by more than 300 researchers from 80 institutions, including MIT, which together make up the Event Horizon Telescope Collaboration.
Chasing a black hole’s tail
The new image of SgrA* follows the first-ever image of a black hole, which was obtained by the EHT in 2019. That groundbreaking image was of M87*, the supermassive black hole at the center of Messier 87, a galaxy located 53 million light years from Earth.
M87* is a goliath compared to SgrA*, with a mass of 6.5 billion suns (more than 1,000 times heavier than our own black hole), and a size that could easily swallow the entire solar system. And yet the image of M87* reveals a bright ring structure, much like SgrA*. The similarity between the two images confirms another prediction of general relativity: that all black holes are alike, no matter their size.
“We now have a consistent image that looks like general relativity is working on both ends of supermassive black holes,” says EHT collaboration member Kazunori Akiyama, a research scientist at MIT’s Haystack Observatory.
The images of both black holes are based on data taken by the EHT of the respective sources in 2017. However, it took far more time and effort to bring SgrA* into focus, due to its smaller size and its location within our own galaxy.
Astronomers suspect that hot gas circles both black holes at the same velocity, close to the speed of light. As SgrA* is 1,500 times smaller than M87*, its speeding light is much harder to resolve. (Similarly, it’s harder to photograph a dog chasing its tail than one running at the same speed around a large park.)
The fact that SgrA* lies in our own galaxy also presented an imaging challenge. M87* sits in a galaxy that is offset from our own, making it easier to see. In contrast, SgrA* lies at the center of our own galactic plane, which hosts pockets of heated gas, or turbulent plasma, that can distort any emissions from the black hole that reach the Earth.
“It’s like trying to see through a jet engine’s blowing warm air,” Akiyama says. “It was very complicated, and that was why this image took longer to resolve.”
To capture a clear image of SgrA*, astronomers coordinated eight radio observatories around the world to act as one virtual telescope, which they pointed at the center of the Milky Way over several days in April 2017. Each observatory recorded incoming light data using high-speed recorders developed at Haystack Observatory. These recorders were designed to process an enormous amount of data at rates of 4 gigabytes per second.
After collecting a total of 5 petabytes of data, encompassing observations of both SgrA* and M87*, hard drives full of recorded data were shipped, half to Haystack, and the other half to Max Planck Institute for Radio Astronomy in Germany. Both locations house correlators — massive supercomputers that worked to “correlate” the data, comparing the data streams between different observatories, and converting that data into signals that a planet-sized telescope would see.
They then calibrated the data — a meticulous process of weeding out noise from sources such as instrumentation effects and the Earth’s own atmosphere, to effectively focus the virtual telescope’s “mirror” on signals specific to SgrA*.
Then imaging teams took on the task of translating the signals into a representative image of the black hole — a far trickier challenge than imaging M87*, which was a larger, steadier source, changing very little over several days.
“SgrA* is changing over minutes, so the data is jumping all over the place,” says EHT collaboration member Vincent Fish, a research scientist at Haystack. “That’s the fundamental challenge in imaging this black hole.”
Akiyama, who led both the EHT’s calibration and imaging teams, developed a new algorithm to pair with those used to image M87*. The researchers fed data into each algorithm to generate thousands of images of the black hole. They averaged these images to generate one main image, which revealed SgrA* as a glowing, ring-like structure.
In coming years, the scientists expect to collect more data of SgrA* and other black holes as the EHT expands, adding more telescopes to its virtual array.
“The techniques developed for Sgr A* pave the way for spectacular EHT images and science to come, as the telescope array is expanded and refined,” Lonsdale says.
“The next step is, can we get sharper images of this ring?” Akiyama says. “Now we can only see the brightest features. We want to also capture fainter substructures. Then we expect to see something more detailed, and different from that first donut.”
Innovative Ideas and Breakthroughs from NMIMS MPSTME Civil Engineering
The department has published two patents, research papers at international conferences
The Civil Engineering department of NMIMS MPSTME has been making significant strides in the field of disaster management, flood resilience, and sustainable infrastructure. The department has published two patents, research papers at international conferences, and completed several student-led projects on topics such as renewable energy, groundwater modelling, and self-healing concrete.
The first patent, ‘Automated Flood Water Regulating Multipurpose System,’ proposes a novel approach to flood resilience by constructing multipurpose wells on the banks of rivers to discharge excess water and generate hydropower. The second patent, ‘Aqua Barrier,’ is an automated mechanism that can protect any flood-prone area, regardless of its size, from any disasters caused due to water.
The student-led projects are equally impressive, with topics ranging from low-volume rural concrete roads to oscillating tidal wave energy converters. These projects showcase the department’s focus on sustainable infrastructure, renewable energy, and innovative design.
The faculty at NMIMS MPSTME Civil Engineering department, led by Head, Dr. Meenal Mategaonkar and Research coordinator, Dr. Jigisha Vashi, played a vital role in guiding and mentoring students toward research excellence. Their expertise and guidance have enabled students to participate and win awards in prestigious competitions such as the CDRI’s ‘Imagining Disaster Resilient Structures’ and The University of Queensland’s ‘Engineering Design Challenge, and AAKAR at IIT Bombay.’
The department’s success is further evidenced by the achievements of its students in national and international conferences. Students presented their research papers in Scopus Indexed papers and conferences such as the 9th Indian Young Geotechnical Engineering Conference and the Eighth Indian Young Geotechnical Conference.
Dr. Meenal Mategaonkar, Head of the Civil Engineering Department, MPSTME, NMIMS, said, “The achievements of the NMIMS MPSTME Civil Engineering department demonstrate its commitment to developing innovative solutions for complex problems in the field of civil engineering. The department’s focus on sustainable infrastructure, disaster resilience, and renewable energy is essential for addressing the challenges faced by society today. It is a testament to the hard work and dedication of both students and faculty and their commitment to excellence.”
Embark on a Journey of Scientific Empowerment with NMIMS School of Science’s Innovative Programs!
The school is known for its strong emphasis on academic excellence, research, and innovation, and is recognized as one of the leading science schools in the country
SVKM’s NMIMS Sunandan Divatia School of Science (SDSOS) has officially announced the commencement of the admissions process for its Bachelors, Masters and Doctoral programs. The school is known for its strong emphasis on academic excellence, research, and innovation, and is recognized as one of the leading science schools in the country.
Aspiring students who are interested in pursuing a career in the field of science can now apply for various undergraduate, postgraduate, and doctoral programs offered by SDSOS. The Bachelor of Science (B.Sc.) programs are available in Applied Psychology, Biomedical Science, and Animation and VFX, while the Master of Science (M.Sc.) programs are offered in Chemistry, Biological Sciences, Applied Psychology, and Physiotherapy. The school also offers Ph.D. program in Science with various disciplines such as Chemistry, and Biological Sciences.
With a focus on creating industry-ready and research-savvy graduates, SDSOS has been at the forefront of imparting cutting-edge knowledge and practical skills through constantly evolving curriculums and state-of-the-art facilities and is situated in the heart of Mumbai.
Dr. Purvi Bhatt, I/C Dean, Sunandan Divatia School of Science, said, “The school provides a dynamic and inclusive learning environment that fosters creativity, critical thinking, and innovation. Our interdisciplinary approach to education prepares students for successful careers in science and beyond, while our emphasis on co-curricular and extracurricular activities ensures their holistic development.”
The school has a student-centric environment that supports research in niche areas of Science & Technology, state-of-the-art infrastructure, and equipment to enhance students’ hands-on skills, and a library facility that is constantly updated with the latest information. The labs at SDSOS provide modernised infrastructure and the latest equipment such as the animal tissue culture lab and the wet labs at the department of Biological Sciences offer cutting-edge technology to mould students into scientists.
School of Science offers a wide range of opportunities for students to explore their talents and interests, as well as gain valuable practical experience. The events and activities mentioned, such as Excalibur, National Science Day, Open day, Guest talks, Book Talk, Sports Day, Psych Film Fest, and club activities like photography and art, these programs provide a platform for students to demonstrate their abilities and gain insights from their peers.
The Future of Architecture Takes Center Stage at NMIMS BSSA
Leach is a co-founder of Digital FUTURES and an academician at the Academy of Europe
NMIMS Balwant Sheth School of Architecture was excited to host Open Studio 2022-23 program by the renowned architectural theorist and digital design expert, Neil Leach, on 28th March 2023 and the title was, “Tell me that AI ain’t scary”
Leach is a co-founder of Digital FUTURES and an academician at the Academy of Europe. Leach has published over 40 books on architectural theory and digital design, including “Architecture in the Age of Artificial Intelligence: An Introduction to AI for Architects” and “The AI Design Revolution: How AI Will Transform Architecture.”
In the lecture, Leach highlighted the potential threat that artificial intelligence (AI) poses to the field of architecture. With the recent launch of GPT4 and the growing capabilities of AI, there is concern among architects that their jobs may be at risk. Leach provided an informed overview of the current state of AI and its potential impact on the architecture profession.
“We are very happy and proud to host Professor Neil Leach at the school. As a leading school of architecture, we are committed to providing our students with a comprehensive education that equips them with the skills and knowledge needed to thrive in the rapidly evolving field of design. Our Open Studio program and public lectures, and talks by experts like Neil Leach, play a critical role in this mission by enabling students to learn from distinguished scholars and practitioners and engage with cutting-edge ideas and technologies. We are excited to continue providing these opportunities and look forward to seeing the impact they will have on the future of architecture and design,” said, BSSA Dean, Dr. Kaiwan Mehta. As the field of architecture continues to evolve, it is essential to stay informed about emerging technologies and their potential impact on the profession. NMIMS BSSA School enables students to learn from experts and engage with pressing issues in architecture and design. By inviting renowned scholars and practitioners like Neil Leach to share their insights and expertise, the school provides a valuable opportunity for students to expand their knowledge and deepen their understanding of the field.
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