By Dr Juan Carlos Algaba
News about astronomy, and discoveries about black holes and other extraordinary celestial objects are seen in the newspapers more and more often lately. As fascinating and inspiring these discoveries may be, one could ask how this could be important for our everyday life, and why we should pay more attention to this kind of news. Well, what if I were to tell you that you are using black holes and the knowledge obtained from them every single day in your life?
In May 2019, the Event Horizon Telescope (EHT) showed to the world the first image of an astronomical super massive black hole. Malaysian institutions and Malaysian citizens were involved in the discovery. Black holes, those astrophysical objects so dense and compact that even light cannot escape from their gravitational field, had been hypothesized by John Mitchell a long time ago, back in 1784. Nonetheless, for centuries, they remained as a mathematical curiosity, until the works of Oppenheimer, Penrose, and others proved that, despite the odds, the objects where God divided by zero may exist in reality.
And thus, began a journey to discover black holes. And that journey brought us… WiFi. Back in 1970, John O’Sullivan, working in the Radio astronomy unit of the Commonwealth Scientific and Industrial Research Organization (CSIRO) in Australia, was trying to figure out how black holes could be detected. He thought that the emission of exploding tiny black holes could be detected via radio waves… but those waves would be smeared out, mixed with a lot of other waves.
He had to figure out a way to separate those signals coming from black holes from any others and sharpen them back together. His smart method involved some mathematical tools known as Fourier Transforms, and quickly proved to be very effective. Unfortunately, black holes were never detected (now we know those signals would be too faint for the detectors at the time).
Fast forward two decades, a group of researchers was wondering how they could transfer data between computers without cables. They tried with radio waves, but the signals just bounced off the walls and furniture, and mixed with the signals from radio cassettes and other devices, causing echoes, signal distortions and making a smeary useless mess of a signal. How could this be sorted out?
As lucky as they were, John O’Sullivan was around, and he had the solution. He used the method he had envisioned to detect black holes to connect computers and, in 1996, the patent for the WiFi was granted. So, if you are connecting to the network using this black hole hunting technology, let us know if you detect one of them!
But if you want to take a break from your computer and drive to your favourite mamak stall, or maybe order some food on Grab, don’t worry, because you’re able to do so thanks to black holes too! Don’t believe me? Well, have a look at your GPS, or your Waze app, and think about how it works. Like in a sonar, a signal is sent by the GPS device (in this case, a radio wave, rather than a sound wave). Since we know how fast the signal is, the distance can be obtained by timing how long it takes to reach destination. The GPS satellites and your GPS device (your smartphone, maybe?) are in contact in the same way, and since there are many GPS satellites orbiting around Earth, they can locate your position in three dimensions.
And here comes the twist: that’s how you know where you are with respect to the satellites. But, how do they know where they are themselves? For that, they look at the stars and, depending on how they look from their position, they can figure out where they are, in the same way that centuries ago navigators looked at the northern star to check where in the ocean they were.
But stars move! Very little, a tiny bit in the sky that we cannot notice by eye, but enough for the satellites to get confused about their position. Then, instead of looking at not-so-still stars, we want to look at something that appears very fixed in the sky. And the best idea for this is to look at an object that is extremely far away (so that even if it moves a bit, we cannot distinguish it), but yet luminous enough that we can see it. What are these objects? Distant galaxies that appear extremely bright because they are ignited by super massive black holes, like the one the EHT observed a few years ago.
So, without the black holes, we would not have the references for the GPS to know where they are. In turn, our GPS would be a very lousy one, maybe telling our boss that we’re enjoying in Langkawi when in reality we’re working hard in Universiti Malaya, or maybe telling our grab or Lazada driver to go to the other side of the country to deliver our goodies. Let’s thank black holes for that not happening!
On top of that, black holes are an excellent laboratory to test our current understanding of modern theories. What we learn from these may put us one step closer to consolidate the next generation computer chips (quantum or not!), and may lead us to the discovery of new compact materials, plasmas, or forms of new energy we had never thought of.
Few centuries ago, when Michael Faraday was studying magnets and how they produced some electricity when moved around, many people considered that a mere useless curiosity. In the same way nobody knew that these studies would be the basics of our current society, all based in electricity, we don’t know what kind of marvels the study of black holes can lead us to in the future. It may take decades, but we at the EHT and Universiti Malaya are working on it, so that we can bring the future to you.
Feel free to have a look at the EHT newest discoveries (including the one this December 13th) or drop by the Physics Department of Universiti Malaya to know more about this topic. Let’s embark on a journey that will take us from black holes to a brighter future!
Dr. Algaba, originally from Spain, has worked as a researcher in Ireland, Taiwan, Korea, and is currently a Senior Lecturer in Universiti Malaya. He is a member of the Event Horizon Telescope (EHT), the team who has obtained the first images of two supermassive black holes, one in the galaxy M87, and another in the centre of our own galaxy, the Milky Way.