Crikey. Even the title scares the life out of me.

It gets worse once the programme actually starts. One of the strengths of good science programmes - like Horizon - is that they manage to turn science into stories. Sometimes it’s a detective story, sometimes a scary story but always a story. And a story that keeps you glued to the very end. Forget tripe like EastEnders - give me something like this:

So these super-massive black holes (SMBHs from now on or my fingers will drop off) - not super, not massive but super and massive - are really very, very big indeed. In fact, they are between 1 million and 1 billion times bigger than the standard black hole.

And the standard black hole is a frightening enough thing. Caused by the ongoing contraction of its own matter the black hole - previously a star, now dead - becomes smaller and smaller and increasingly dense. Its gravitational pull becomes super-strong, pulling in gas from nearby stars, literally stripping them of all substance. Such is the intense pull of a black hole’s gravity that light itself cannot escape - hence its blackness. The more the black hole consumes the more massive - and therefore the more strong - it becomes. For me, black holes are the ultimate nightmare scenario. In my fevered imagination, one could drift by earth and simply relieve it of its atmosphere. That would be the end of us all.

You can’t see a black hole because it’s black. And it’s a hole. But you know they’re where they are by the effects they have on surrounding matter - other stars particularly. What scientists first discovered was a really big one - a SMBH - in the middle of a galaxy and it was quite a find in the world of cosmology. So they decided to look for some more.

They had a candidate too - a suspect galaxy called NGC68 which, they believed, had a whopper of a black hole at its centre. Using spectroscopy (which measures the shifts in light waves - and from which all sorts of useful information can be gleaned) they decided to compare spectroscopic photographs of NGC69 with those of a nice, quiet local galaxy called Andromeda (actually our closest galactic neighbour). What they were looking for was a spectroscopic light pattern in NGC68 that was the signature pattern of a galaxy containing a SMBH at its centre - a pattern that would hopefully contrast noticeably with the pattern emerging from the more calm Andromeda.

They got two surprises. First, they couldn’t get a clear picture of NGC68. It was too far away. But, second, they got a nice picture of Andromeda. A very nice one. One that showed that, in the middle of this, our nearest galaxy, was a super-massive black hole.

So now we find a SMBH on our own doorstep. That’s not good news. Andromeda is actually heading our way too although, in galactic terms, it’s not exactly hurrying over here but still…

Some scientists were doubtful though that the data from Andromeda absolutely suggested a SMBH so they set about looking for more. And they found them. Everywhere. So the next question, naturally enough, was: do we have one in our galaxy?

By measuring the speed at which stars move around the central core of our Milky Way galaxy scientists can detect the presence of a SMBH at its centre. They measured and, sure enough, they found themselves a nice SMBH. Not the answer I was hoping for that’s for sure.

So the next big question is: what effect does a SMBH at the centre of the galaxy have on the planets and stars that rotate at the edges? I’d like to know because that’s where I live and I’m thinking of painting the front of my house. I won’t bother if we’re facing annihilation in the near future.

Well. One thing scientists noticed was that the size of the black hole itself was directly and precisely related to the size of the galaxy. In fact, the black hole’s mass was always a half a percent of its galaxy’s mass.

Another thing: the speed at which the outer stars moved round the galaxy was also very closely related to the size of the galaxy’s SMBH. This was puzzling for one special reason; the outer stars are so far from the galactic centre that, in fact, they are totally unaffected by the SMBH that resides there. How could their speed be so well correlated to something that has absolutely no affect on them?

It seemed that if the speed of the outer stars was related to the mass of something that has no affect on them now then they relationship must have been set up earlier. Could then the SMBH have formed earlier in the galaxy’s evolution? Since every galaxy seemed to possess one were SMBHs actually a part of galactic birth?

Previous theories on galactic formation suggested gasses coalesced to form solid matter and stars. A new theory, based on the possibility that SMBHs exist at the centre of all galaxies, suggests that maybe in the early stages of development gasses became so extremely condensed that they first formed a black hole. Extreme temperatures in the region surrounding the black hole caused the rest of the gas to coalesce and to become heated - and then to form stars. The black hole, feeding off the surrounding gas and dust in a kind of feeding frenzy, sucks in all the material it possibly can growing ever larger as it does so. But at the same time it emits huge amounts of energy as the material falls into its deadly embrace and this energy starts to push the forming stars away from itself - and, eventually, out of range of its enormous gravitational pull.

Once the stars have been shoved far enough away the black hole has no more material to consume so its feeding comes to an end. The monster settles in the middle of the galaxy and, although it still possesses awesome gravitational pull, it becomes inactive in the devouring sense.

The important point - and the answer to the riddle of why the mass of the SMBH is related to the speed of outer stars that it couldn’t possibly now be influencing (and thus to the mass of the galaxy also) is that the faster the stars were moving initially, the larger the SMBH would need to be to be able to push them away. Their speed on their circular path would resist the outward push of the SMBH. A bigger SMBH would consume more material, emit more energy and thus be able to push faster moving stars away. In a galaxy of slower moving stars they will have been pushed beyond the SMBH’s range while it was smaller - so its growth would have been arrested earlier, keeping it smaller. The correlation between SMBH and star speed is set from the very beginning.

This is still theory but if it’s correct then all galaxies have, at their centres, super-massive black holes. SMBHs would be, in fact, essential ingredients in galaxy building. They would be integral to the early formation of the galaxy but then they would push their off-spring away, settling into brooding old-age while their children do their own thing.

So we can relax a little. Even though there’s some disturbing activity coming from our own, local SMBH scientists assure us that it just picked up some stray gas and that, in fact, it has more or less stopped devouring things. If their theory is correct all the Milky Way’s stars and planets - which will include us - have been pushed out of reach of its gravitational pull anyway so are quite safe from the feeding frenzy that characterised the SMBH’s earlier life. Which is a relief, actually…