Illuminating black holes – figuratively speaking, of course
Your editorial (April 15) contains some errors. You state that the black hole in the heart of M87 has a mass of 6.5 times that of the sun. The figure should have been
6.5 billion times.
Also, the actual size of the monster is not some 40 billion kilometres in diameter – that figure refers to the size of the ‘‘event horizon’’ surrounding the beast – the region of no return, from which nothing can escape, not even light.
(Although a few theorists have speculated in recent years that some form of radiation is escaping.)
Black holes have no ‘‘size’’ in any conventional sense of that word. While they keep gobbling ever more material – even entire stars and solar systems – into their ravenous maws, and their event horizons are pushed further, the beasts themselves don’t grow larger (in diameter).
They simply add the new stuff into ‘‘singularities’’ with infinite density – a wacky concept that does not even begin to make sense, but that’s where our calculations lead to. Until, finally, the laws of mathematics break down and cannot take us any further.
The human understanding has reached its final frontier.
Aulis Alen
A poor speller writes
It has been reported that 40 per cent of Kiwi adults are unable to read at functioning levels.
This is very hard to accept if we believe other reports we get from the media, government departments, educationists and spokespeople for teachers’ groups who tell us that our education system is equal to that of anywhere in the world.
So why is this? Are so many people in this sector taking so much time chasing rainbows that they have forgotten what they trained for?
How has it taken so long to see these problems when we have so many clever clogs at the top of the learning tree?
Many of the poorer practices go back as far as I can remember.
I started school in 1935 and spent seven-plus years of agony because I could not learn to spell.
I was the poorest speller not only in the class, but the school. There was an unusual way to remedy such a shortcoming; for every misspelt word I got one stroke of the strap up to six.
A bit daunting for an 8- to 10-year-old setting out for school every morning well aware you were heading for punishment.
No wonder I left at the first chance, two terms into form 2.
I hated school except for art and excelled at maths. I have always made a study of figures, not always numerals.
I started work at 14 in which maths were an important part. I still can’t spell but slogged my way through 60 years of work in the same industry and gained respect from my peers.
I was recently taken to task for spelling mistakes but it’s a bit late to learn now.
Jim Fish