The big news (for me) today is that I have acquired a copy of Mathematica. I rather hope that this can supplement my limited mathematical skills but in reality, it is going to take some considerable time to get to grips with this formidable program. I will let you know if I start making progress. For those of you who know nothing of this program, it allows one to do numerical calculations to any required precision, and also allows one to do symbolic manipulation - analytically solve partial differential equations and so on.

A new article - Neutron star takes on black holes in jet contest - reminds me of just how many unknowns there are out there. I have been thinking a lot about black hole jets but still, lack any clear explanation. However, it is probably time to get something down so I will make a start on another page for the site. The first draft is now available.

Only a few days pass and the explanation is thrown into doubt by the discovery of a supermassive black hole in the early universe. And by not being surrounded by a massive galaxy. Such upsets are normal and within a short space of time, someone will have done a simulation which shows that by tweaking a few parameters in the early universe it is all explainable. I will let you know

I have just been looking at why supermassive black holes (SMBH's) get so big. If you have looked at the rest of the site, you will realise that I have proposed that SMBH's get big by starting off as merging neutron stars with low combined spin. From then on, any accretion will make them spin up until they reach the extremal limit.

It is worthwhile looking at what others are claiming. I hope I get this correct. There are a couple of problems with the data. Some black holes are really big. Upwards of a 40 billion of our suns in mass. They all seem to have large spin rates - above half the maximal limit. Couple this with the vast outpourings of energy coming from many SMBH's, and the only known mechanism for this is for the hole to slow down (The Penrose process), there is clearly a difficult job to do in explaining these feature. The current explanation seems to be that SMBH's started off in the early universe as massive (x100 suns) suns that burnt out quickly and formed black holes. These SMBHs attracted matter around them and so seeded galaxies. Accretion over the next 13 or so billion years led the size of the SNBH we see today. Unfortunately, this fails to explain the high spin rate. To explain this, they claim it shows that most of the growth did come from absorbing gas an dust which would slow them down, but from combining with another black hole. If they were spinning with the same direction, the spin rate would increase. With no other accretion and all spinning in the same direction, this amounts to one every three years, or so for the biggest.

A new article explains the LIGO result extremely well: "The black-hole collision that reshaped physics". Well worth a read.

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