Speaker 1: Welcome to brain Stuff production of iHeart Radio. Hey, brain Stuff,
Speaker 1: Lauren Vogel bomb Here. An event horizon is the point
Speaker 1: of no return, a spherical region surrounding the gaping maw
Speaker 1: of a black hole, beyond which nothing, not even light
Speaker 1: can escape. We have no idea what mysteries lie inside,
Speaker 1: but we do know that our universe ends abruptly at
Speaker 1: this terrifying boundary into the unknown. Now, after two decades
Speaker 1: of international collaboration, some of the world's most powerful radio
Speaker 1: telescopes have captured an image of a supermassive black hole's
Speaker 1: event horizon. By doing so, they proved that the predictions
Speaker 1: arising from Einstein's theory of general relativity are valid even
Speaker 1: in the most extreme cosmic environment possible. The black hole
Speaker 1: in the image lurks in the center of the massive
Speaker 1: elliptical galaxy Messier eighty seven, in the constellation Virgo, some
Speaker 1: fifty five million light years distant. The release of the
Speaker 1: image was highly anticipated all over the world and published
Speaker 1: in several studies appearing in the journal Astro Physical Journal Letters.
Speaker 1: Supermassive black holes dictate the evolution of the galaxies they inhabit,
Speaker 1: so a direct look at this one's event horizon could
Speaker 1: open a new window of understanding into how these behemoths work.
Speaker 1: And this monstrous object is quite the specimen. It has
Speaker 1: a whopping mass of six point five billion sons, all
Speaker 1: crammed into an event horizon measuring nearly half a light
Speaker 1: day across. Despite its incredible size and mass, no single
Speaker 1: telescope on the planet could capture its portrait. It's simply
Speaker 1: too far away to resolve. To remedy this, astronomers used
Speaker 1: a method known as very long baseline interferometry to combine
Speaker 1: the collective observing power of eight of the world's most
Speaker 1: powerful radio telescopes to do the job. The event Horizon
Speaker 1: Telescope is a virtual telescope as wide as our planet
Speaker 1: and powerful enough to capture the first glimpse of one
Speaker 1: of the most massive black holes known to exist. It
Speaker 1: took a team of more than two hundred researchers to
Speaker 1: accomplish this feat. Although black holes are well black, should
Speaker 1: there be any matter close to the event horizon, extreme
Speaker 1: friction in the relativistic environment will rip electrons from atoms,
Speaker 1: creating a powerful fireworks display, and this is why the
Speaker 1: event Horizon Telescope's first image shows a dark circle surrounded
Speaker 1: by a bright ring of emissions. These emissions are being
Speaker 1: produced just outside the black hole's event horizon, where the
Speaker 1: extremely hot gases orbiting it are heated to several billions
Speaker 1: of degrees kelvin, with the event horizon itself appearing as
Speaker 1: a silhouetted dark disc against a bright background. Features that
Speaker 1: confirm what theoretical physicists could only predict up until now.
Speaker 1: Surely a dramatic moment for those theorists, this is possibly
Speaker 1: the most profound outcome of the event horizon telescopes observation.
Speaker 1: All of the theoretical predictions for what the event horizon
Speaker 1: telescope might see are based on the framework of Einstein's
Speaker 1: general relativity, a theory that has proven robust since its
Speaker 1: formulation more than a hundred years ago. On seeing this
Speaker 1: first image, physicists remarked on how precisely the reality of
Speaker 1: the black hole's event horizon matches the actions of general relativity,
Speaker 1: and this first image is just that the first. The
Speaker 1: event horizon telescope collaboration will continue observing Messier eighty seven
Speaker 1: and a second target, the supermassive black hole in the
Speaker 1: center of our galaxy, A four million solar mass object
Speaker 1: called Sagittarius A. Counterintuitively, although Sagittarius A is comparatively close
Speaker 1: only twenty light years away two thousand times close to
Speaker 1: us than Messi A eighty seven, it has a different
Speaker 1: set of challenges. One problem is that as Sagittarius A
Speaker 1: is smaller, its emissions vary over shorter time scales than
Speaker 1: Messier eighty seven's monstrous black hole, making observations more difficult. Also,
Speaker 1: as we are embedded inside our galaxy's disc, which contains
Speaker 1: a lot of interstellar dust, the event horizon telescope signal
Speaker 1: suffers more scattering, making it more challenging to resolve. As
Speaker 1: most of the intergalactic space between us and Messier eighty
Speaker 1: seven is pretty empty, scattering is less of a problem
Speaker 1: when we'll see Sagittarius A. Remains to be seen, But
Speaker 1: now that the technology behind the event horizon telescope has
Speaker 1: been proven, our understanding of supermassive black holes is sure
Speaker 1: to blossom. Today's episode was written by Ian O'Neill and
Speaker 1: produced by Tyler Clang. Brain Stuff is a production of
Speaker 1: iHeart Radio's How Stuff Works. For more on this and
Speaker 1: lots of other supermassive topics, visit our home planet, how
Speaker 1: stuff works dot com and for more podcasts. For my
Speaker 1: heart Radio, visit the I Heart Radio app, Apple Podcasts,
Speaker 1: or wherever you listen to your favorite shows.