Welcome to brain Stuff production of iHeart Radio. Hey, brain Stuff, Lauren Vogel bomb Here. An event horizon is the point of no return, a spherical region surrounding the gaping maw of a black hole, beyond which nothing, not even light can escape. We have no idea what mysteries lie inside, but we do know that our universe ends abruptly at
this terrifying boundary into the unknown. Now, after two decades of international collaboration, some of the world's most powerful radio telescopes have captured an image of a supermassive black hole's event horizon. By doing so, they proved that the predictions arising from Einstein's theory of general relativity are valid even
in the most extreme cosmic environment possible. The black hole in the image lurks in the center of the massive elliptical galaxy Messier eighty seven, in the constellation Virgo, some fifty five million light years distant. The release of the image was highly anticipated all over the world and published in several studies appearing in the journal Astro Physical Journal Letters.
Supermassive black holes dictate the evolution of the galaxies they inhabit, so a direct look at this one's event horizon could open a new window of understanding into how these behemoths work. And this monstrous object is quite the specimen. It has a whopping mass of six point five billion sons, all crammed into an event horizon measuring nearly half a light day across. Despite its incredible size and mass, no single telescope on the planet could capture its portrait. It's simply
too far away to resolve. To remedy this, astronomers used a method known as very long baseline interferometry to combine the collective observing power of eight of the world's most powerful radio telescopes to do the job. The event Horizon Telescope is a virtual telescope as wide as our planet and powerful enough to capture the first glimpse of one of the most massive black holes known to exist. It took a team of more than two hundred researchers to
accomplish this feat. Although black holes are well black, should there be any matter close to the event horizon, extreme friction in the relativistic environment will rip electrons from atoms, creating a powerful fireworks display, and this is why the event Horizon Telescope's first image shows a dark circle surrounded
by a bright ring of emissions. These emissions are being produced just outside the black hole's event horizon, where the extremely hot gases orbiting it are heated to several billions of degrees kelvin, with the event horizon itself appearing as a silhouetted dark disc against a bright background. Features that confirm what theoretical physicists could only predict up until now.
Surely a dramatic moment for those theorists, this is possibly the most profound outcome of the event horizon telescopes observation. All of the theoretical predictions for what the event horizon telescope might see are based on the framework of Einstein's general relativity, a theory that has proven robust since its
formulation more than a hundred years ago. On seeing this first image, physicists remarked on how precisely the reality of the black hole's event horizon matches the actions of general relativity,
and this first image is just that the first. The event horizon telescope collaboration will continue observing Messier eighty seven and a second target, the supermassive black hole in the center of our galaxy, A four million solar mass object called Sagittarius A. Counterintuitively, although Sagittarius A is comparatively close only twenty light years away two thousand times close to us than Messi A eighty seven, it has a different
set of challenges. One problem is that as Sagittarius A is smaller, its emissions vary over shorter time scales than Messier eighty seven's monstrous black hole, making observations more difficult. Also, as we are embedded inside our galaxy's disc, which contains a lot of interstellar dust, the event horizon telescope signal
suffers more scattering, making it more challenging to resolve. As most of the intergalactic space between us and Messier eighty seven is pretty empty, scattering is less of a problem when we'll see Sagittarius A. Remains to be seen, But now that the technology behind the event horizon telescope has been proven, our understanding of supermassive black holes is sure to blossom. Today's episode was written by Ian O'Neill and produced by Tyler Clang. Brain Stuff is a production of
iHeart Radio's How Stuff Works. For more on this and lots of other supermassive topics, visit our home planet, how stuff works dot com and for more podcasts. For my heart Radio, visit the I Heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.