Four antennas of the Atacama Large Millimeter/submillimeter Array (ALMA)

The Event Horizon Telescope project

... of the shadow cast by the black hole at the centre of our own galaxy, as he explains to Georgia Mills... Shep - There's ... something like that? Shep - Well, in a paradox of their own immense gravity, black holes, which by definition are ... one of these black hole shadows is in the centre of our own Milky Way galaxy and radio waves are the perfect medium ...

5kg shown on the dial of a scale.

Encyclopaedia corner: black holes and kilograms

... And then from those measuring companies would make their own standards. And that's how they'd calibrate weighing ... iridium, because that doesn't rust and won't change on its own. Phil - Now scientists, I know, love to be precise. Adam ... the kilogram on eBay. Wouldn't that be fun? Adam - Yeah. I own the kilogram. Deal with it. Phil - That's fantastic. Adam ...

An artist's impression of a black hole

Quasars: Black holes and bright lights

... Chris - Are they visible light that I could see with my own eyes, or would I need a fancy telescope to see this sort ...