Astrophysicists have taken the first ever photograph of a supermassive black hole at the heart of the Messier 87 galaxy, 55 million light years away from Earth.
April 10th of 2019 will be remembered as one of the most significant days for not just science, but for planet Earth. The first ever photograph of a black hole was released, and with it, proof of how far our vision can take us. In this case, to the center of neighboring galaxies. This is not just a testament to our abilities as researchers to delve deeper into problems which were previously thought unsolvable, but to us as a human race to open ourselves up to what lies beyond our Pale Blue Dot.
The image shows an intensely bright “ring of fire surrounding a perfectly circular dark hole”, as Prof. Falcke describes. The light emitted here is brighter than all the billions of other stars in the galaxy combined, which is why it can be seen at such a distance from Earth. A black hole is a region in the space-time continuum that has such a large gravitational pull, not even light can escape it. In the photograph, the edge between the dark circle and the orange ring is the point right before the gas enters the black hole.
Originally predicted by Albert Einstein’s general theory of relativity, black holes have never been observed directly. It’s curious to think how the biggest phenomenon in the natural world – by big meaning of titanic proportions – has remained invisible to us until now. We’ve known of their existence for a long time, but always through indirect measurements. In our own galaxy, the Milky Way, these indirect validations began with the detection of high intensity radio signals from the galaxy’s center. This signal was eventually pinpointed to Sagittarius A* (Sgr A*). Odd orbital behaviours of neighbouring stars, in particular of star S2, as well as the observation of massive jets of matter emanating from this point in space, later helped confirm that Sgr A* is in fact our galaxy’s supermassive black hole. Additional studies in other regions of the universe have also provided evidence for the existence of black holes via the detection of gravitational waves.
The image of M87 was generated by the Event Horizon Telescope (EHT), a global network of eight of the world’s leading radio observatories, including the Atacama Large Millimeter Array (ALMA) in Chile and the South Pole Telescope. This makes EHT, effectively and functionally, an Earth-sized telescope! Sgr A* was also included in this intensive data collection process. However, even though Sgr A* is considerably closer (26,000 light years) than M87 (500 million trillion km), Sgr A*’s signal is unsteady and difficult to interpret. Researchers therefore decided to process the M87 imaging data first.
The morning the image was released I was on my usual walk to lab. With every few steps I took I would grab my phone from my pocket and check for the much anticipated notification. Nothing. Nothing. Ugh, still nothing!… And then, finally, the long awaited BUZZ BUZZ! I stopped. Everything stopped. There it was. That asymmetric, hazy, orange circle surrounding a black center. For the first time, we could see an image of the only thing in the universe beyond which reality as we know it cannot be accounted for. We were looking at the edge. Strangely, this did not fill me with terror or despair, but quite the opposite. Awe and excitement overflowed me, as well as a deep sense of connectivity to what lies far and beyond our tiny, habitable rock.
Not many things have had such an overwhelming effect on me, although three images come to mind. The first two are related. One is the photo of planet Earth taken by the Apollo 8 mission from the lunar surface in December 24th 1968. The astronaut who took it, William Anders, said “it was the first time that people actually knew what Earth looked like”. The photograph, titled “Earthrise”, shows us our planet for what it is, a blue, life blooming sphere suspended in a dark, hostile cosmos. This photo has redefined our understanding of the word “home”, and with it, instilled a greater appreciation for it.
This mindset is highlighted further by the second photo, which was taken by Voyager 1 on February 14th 1990. When the spacecraft had flown past Neptune and was reaching a 6 billion km distance from Earth, it turned back its camera to take a photo now known as “Pale Blue Dot”. In it you see a tiny blue-white pixel of a dot (Earth) suspended in a beam of sunlight in the vast darkness of deep space. As the late Dr. Carl Sagan stated, it is on that tiny pixel of a dot that “every human being who ever lived, lived out their lives”.
The third image is slightly different in nature. It is commonly referred to as “Photo 51” and is the image of the x-ray diffraction pattern of DNA produced by Dr. Rosalind Franklin in May 1952. This was the definitive proof that researchers found to show the structure (double helix) of the molecule of life. This may not be an image of planetary proportions, but it certainly is one of planetary implications. Every living organism, from bacteria to plants to humans, requires this molecule in order to live. Our studies of the intricacies of DNA have allowed us to understand life at a level we never imagined possible. It helps define life on Earth and possibly… maybe… even help us identify life in other worlds. That remains to be seen.
The first image of a black hole joins this special mini-album with an extra twinkle that the others don’t have – I am alive now. I experienced seeing this photograph in real time, and so did everyone else who is alive now. To be able to experience this process and feel the weight of the scientific and philosophical significance of such an event is simply elating. It is in this sense of joy and wonder that I also can’t help but feel grateful. Grateful to be alive. Grateful to be alive now. Grateful for what is yet to come. And grateful to Dr. Katie Bowman, the entire EHT team, and every scientist and researcher who made this photograph possible. Thank you.