What's special about the Event Horizon Telescope that imaged the M87* black hole?

The video discusses the imaging of the M87 black hole, comparing it to Sagittarius A* in our galaxy. It explains how black holes are measured by their event horizons and why the Event Horizon Telescope is more effective than Hubble for this purpose. The video also covers the challenges of observing black holes due to their lack of light emission and the importance of using various wavelengths. Finally, it explains why M87 star was chosen for imaging over Sagittarius A* due to its larger size and higher activity.

What challenges are faced when trying to observe black holes?

How does the size of the Event Horizon Telescope's array affect its imaging capabilities?

Why was M87 chosen for imaging instead of Sagittarius A*?