In 2019 was taken the first image of a supermassive black hole in the center of the galaxy M87 with the Event Horizon Telescope, which is a network of radio telescope located in different points of the Earth, with the purpose of making a telescope of the size of the Earth.
A radio telescope is an antenna that is capable to perceive the light in the radio part of the electromagnetic spectrum¹.
It is important to notice that in the picture what it can be seen is the effect that the black hole has in the nearby stars.
Key terms:
¹Electromagnetic spectrum: decomposition of light in its different wavelengths (from radio waves to gamma rays).
A manufacturer of printed circuit boards has a design
capacity of 1,000 boards per day. the effective capacity, however, is 700
boards per day. recently the production facility has been producing 950 boards
per day. The design capacity utilization is (950/100) *100 = 95 %