The scientific community is in mourning this week with the passing of the great Professor Stephen Hawking. He has been called the greatest mind of our times.
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Remember to look up at the stars, not down at your feet
- Stephen Hawking
Aside from his iconic wheelchair, and wicked sense of humour, Stephen Hawking is most well-known for the work he has done on understanding black holes. So it seems only fitting today to write a few words about black holes, in honour of the great man.
Hawking himself once described black holes as being “stranger than anything dreamt up by science fiction writers”, and I completely agree with him. As a biologist, not a physicist, black holes are one of those concepts that my brain still struggles to process.
Black holes get their name because they appear as black voids in space. But that doesn’t mean that black holes are empty space. Far from being empty, black holes are made of a huge amount of matter,which makes them really dense. This density gives them extremely powerful gravitational fields.
Here on Earth, the gravitational field stops us from “escaping”, or from falling off the planet. The gravitational fields of black holes are so strong that they stop anything from escaping – even light. Which is why they appear as voids in space.
So where do black holes come from? It seems that they occur when large stars, much larger than our own sun, die in a supernova explosion. Sometimes these stars collapse upon themselves, and all of the mass of the star becomes concentrated in a small area – forming a black hole.
Black holes are dotted all throughout the Universe, and they come in different sizes. The biggest ones, which are millions, or even billions times larger than our sun, are called supermassive black holes. And astronomers believe that pretty much all large galaxies, including our own Milky Way, have one of these supermassive black holes at their centre.
Although I’d suggest not getting close to it. The gravitational fields of black holes are so strong that anything that gets too close will be sucked into it, and destroyed.
Aside from his understanding of space and time, one of the things I have always admired about Stephen Hawking was his ability to get people of all ages and backgrounds interested in science.
He made people want to know more about the Universe and the world we live in. He made science cool.
