"This is what is referred to as the black hole shadow."-Katie Bouman

https://www.youtube.com/watch?v=UGL_OL3OrCE

[Correction]. This sentence below had a number of ways to bite me in the ass. I wrote it for reasons, but they weren't good enough reasons. Let's replace it with a better link, that links to an even better link, and specify Tidal Disruption Events (TDE)s usually don't eject so long after the parent stars consumption. This TDE material was traveling unusually fast, and the implication seems to be that it was asymptoting in a tiny margin near the Event Horizon for a period of nearly three years. 

Yesterday it has been proven that something can escape a black-hole. More specifically something can escape the event-horizon if that something be a particular type of star, and this something undergo an aggressive reprocessing. One wonders what kinds of rare elements come and go in such a process.

This video can show you the last major black-hole event for context. They are deeply related, because so much of black hole observation is an extraordinary and tedious process. This video came after the first black-hole was imaged; an event that was in all the headlines for about 48 hours. But the mightiest nerds among us kept interest longer. 

Katie Bouman had just gotten credit for this discovery and tenure at Cal-Tech, so she's noticeably excited while she zooms through her slides, but good context for the spit-out black-hole is abundant here. 

• At 2:10 I love that animated slide for obvious reasons.
• Another animated slide at 4:10 shows the event horizon as it can be imaged. This would be the same black hole physics, though the scales be different when compared to yesterdays event. 
• She describes methodology for much of the remaining lecture. How they take black hole images turns out to be satisfyingly difficult. She does exactly what she should for the subject matter, meaning it gets mathy and you need physics skills to interpret much of it. But not really, it's more radio physics and you will get the idea from her nomenclature and slide images.
• 45:58 is where you can see where that image is a big deal. Because it isn't certain other specific images.
• At 50:00 she demonstrates that the black hole "evolves" over time, but intentionally does not offer a cause such as plasma, falling material, or magnetism. This is the thing the astrophysicists will be trying to relate to the spit-up black hole. 

The summary has got to be... black holes are hard to measure. Event Horizons alone take this much labor. That's why this is such a big deal. Both the first image and, even more, the event-horizon-burp-thingy.