This is the first image of Sagittarius A* (or Sgr A* for short), the supermassive black hole at the center of our galaxy. Captured by the Event Horizon Telescope array, it’s the first direct visual ev
( EHT Collaboration
Melissa Harris-Perry: Welcome back to The Takeaway. I'm Melissa Harris-Perry, and that is the sonification of a black hole released by NASA last week. Soundwaves from a black hole in the Perseus galaxy cluster resynthesized and scaled up hundreds of quadrillions of times higher than their original frequency so that they're audible to us mere humans. Maybe the most amazing thing is that it's not even the most amazing thing that we found out about black holes this week.
Female Speaker: Today, the Event Horizon Telescope is delighted to share with you the first direct image of the gentle giant in the center of our galaxy Sagittarius A*.
Melissa Harris-Perry: On Thursday, the Event Horizon Telescope team shared its image of Sagittarius A, or Sag A* as the cool astronomy kids call it. It's the Milky Way's own supermassive black hole. When I say supermassive, that's because this area in space is 4 million times the mass of our Sun, with a gravitational pull so strong that not even light can escape.
Until 2019, we had a total of zero images of black holes, we relied on a lot of math and observation of stars orbiting around something we thought might be a black hole, but we couldn't actually see anything.
Melissa Harris-Perry: You know we needed to talk to Chanda Prescod-Weinstein. She's a Professor of Physics and Astronomy at the University of New Hampshire. Suppose the author of The Disordered Cosmos: A Journey Into Dark Matter, Spacetime, and Dreams Deferred. Chanda, welcome back to The Takeaway.
Chanda Prescod-Weinstein: Hi, Melissa. Thanks for having me.
Melissa Harris-Perry: Why is this new discovery significant and not just cool?
Chanda Prescod-Weinstein: Well, I don't know if you can separate those two things. I think part of it is it's spiritually significant. Sag A* is the black hole that is at the core of our home galaxy, the Milky Way. This is our local giant as they said at the press conference yesterday. One reason that this is scientifically exciting is that it allows us to study more closely how black holes pull matter into them.
It's allowing us to gain insight into one of the big mysteries about galaxy formation, which is, did the black hole come first? Did the Galaxy come first? Are black holes and the presence of black holes and the galaxies affecting how star formation is happening and maybe actually shutting down star formation?
Melissa Harris-Perry: Do we have some initial answers to those enormous questions?
Chanda Prescod-Weinstein: Yes. Insights like this are going to be part of an analysis that happens over the next few years. In fact, the Event Horizon Telescope, which made these observations has already started to beef up its instrumentation and has added new facilities that are coming online right now. Over the next few years, we're going to get clear observations that are going to start to help theorists put the picture together. I think the other piece that's really exciting about this is that it provided yet another test of Einstein's general relativity, which passed with flying colors.
Melissa Harris-Perry: All right, why is it so hard to photograph these?
Chanda Prescod-Weinstein: First of all, dust. You know how dust really annoys you in your house. One of the first things that you might think about is, "Well, why don't we just turn the Hubble Space Telescope in the direction of the center of the galaxy and take a picture?" Right?
Melissa Harris-Perry: Right.
Chanda Prescod-Weinstein: The big problem is that an optical telescope is just going to see a lot of dust and gas that's completely obscuring it. Actually, the Event Horizon Telescope is in the millimeter. It's basically a radio wavelength, and the radio can get through all of that dust and actually get to us. Part of it is getting the frequency right and then another piece of it is that you need an instrument that can handle all of the variation and so actually Sag A*, the image changes over the course of hours. It's highly variable. It takes a lot of computational machinery to analyze the images and get the averages out.
It also requires what we call long-baseline astronomy. This really meant using telescopes from around the world that coordinated with each other so that they could capture a good image.
Melissa Harris-Perry: First of all, I'm not sure if anything could make me more excited than hearing you say that radio is the more powerful tool here. I want to ask you about this other piece that I'm completely fascinated by as a sonic and audio personnel, and that is the sound that NASA released this week. This sound of a black hole, what does it mean to say that what we're listening to is the sound of a black hole?
Chanda Prescod-Weinstein: The way that I would think about this is that it's-- with images that we take with optical telescopes, and infrared, and even with radio, we often false-color them to help people see the differences between the different regions. Similarly, here the signal has been transferred into sound and translated into sound. I think translated is really the right word, to help us have a sense of what exactly we are dealing with.
One of the things that I really appreciate with the sonification process is that it takes into account that not all of us experience the world in a visual way and some of us are hearing but not visual people. This is really a way to use all of our senses to gain some intuition for what's happening out there in the universe. It's highly inspiring. I think that's the beautiful thing about it.
Melissa Harris-Perry: Simply because I know the depth of your work and the intersections to hear you talk about the false colorization in order to see difference, and then the power of translation into sound, I feel like there's a whole another 15 minutes we need to go, but until we get a chance to do all of that, can you tell what spaghettification is.
Chanda Prescod-Weinstein: Like gravity, it's powerful. We're really talking about the trajectories of particles, whether they're light, or whether they're something more massive like an electron being stretched out by the intensity of gravity because black holes are just so massive. In the case of this one, it's like squeezing four million suns into one. That is going to cause things to get stretched out as they orbit around the center and you get spaghettification.
Melissa Harris-Perry: Such a good name. Chanda Prescod-Weinstein is Professor of Physics and Astronomy and a core faculty member in Women and Gender Studies at the University of New Hampshire. Chanda is also the author of The Disordered Cosmos: A Journey Into Dark Matter, Spacetime, and Dreams Deferred. Thank you for that out-of-this-world conversation, Chanda.
Chanda Prescod-Weinstein: Thank you so much.
Melissa Harris-Perry: If you want to see the image, check out our Instagram.
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