Roger Blanford

And he saw what he called a curious straight ray, and that was an optical photograph of a jet flying.

So I was watching my colleagues and friends learn about these jets using their wonderful radio telescopes, which have got more and more wonderful as the years have rolled by.

This was a truly extraordinary thing because an object that's no bigger than the solar system, and in many cases significantly smaller, is making enough power to outshine the surrounding galaxies by more than a thousand in some cases. That's even more impressive than a tiny little atomic nucleus in an atom producing all the power that it can produce.

there is a source of power which is the spin of the black hole, and the magnetic field is the agency for removing it, if you like. But in addition, there's all this gas that is falling inwards, swirling around the black hole. And just like a satellite in the atmosphere, it gets hot, loses energy, falls down,

The popular view is that you can't get anything out of a black hole. But if the black hole is spinning and there are magnetic field lines... like those you would associate with a picture of a magnet or the Earth, if they go through the surface of the black hole, which is called the event horizon, then it is possible to take power out of the black hole.

And that comes at the expense of the rotational energy of the black hole.

The fields are very strong and somewhat organized, as might have been expected. And also, they look like they're being created by gas swirling around the black hole, and they have the sort of distortion you might expect with it.

understanding the history of these black holes, how they started, how they grew. Like babies, they are fed and they grow. And how this happened, what their impact was on their surrounding galaxies, how they framed the evolution of the universe, that is a thing we're learning.

Of course, they can be famously destructive, but also it can be a source of power in a nuclear reactor.