- Ken Hay
Updated: Feb 19, 2020
It didn’t happen, of course, but had I been asked to identify the subject in that now famous photograph (as above) of a black hole I would have said – “It is a colour- enhanced ultrasonography image of a perianal abscess.”
It shows an orifice which is, apparently, the black hole itself, a surrounding area of vivid, red inflammation and a collection of hot, yellow pus, (the abscess), between three and nine o’clock. It requires immediate surgery to drain the pus, relieve the pain and prevent complications.
Probably, my answer would have been wrong. But you never know - if it had been at a quiz night at a Royal Australian College of Surgeon’s social gathering I would have been beaten to the draw my many others and that answer would have been correct. (I am neither a surgeon nor a member of RACS.)
So, the photo purports to show a black hole just down the road a bit – at Galaxy M87 which is 55 million light years away! Now, the last thing I want to do is to rain on the 200 scientists jubilant parade but, I would like to have some explanations for some of my reservations.
I must emphasise that I am no stellar, (in any sense of the word), scientist and have long considered myself homozygous for the recessive maths gene but my first problem is – how does the inverse square law fit into this discovery – or vice versa? At 55 million light years away surely this law would dictate that any residual light that reaches earth would not be measurable or even detectable. But I did catch a glimpse of a diagram on a TED Talk the other night that showed the light rays emitted from the Black Hole, (or its “halo”) to be parallel. But to produce parallel light rays requires a parabolic reflector or to produce a Laser beam – as far as I know. Complicating this is the fact that the energy impacting the sensor in the Black Hole issue is not pure light as we know it. It is made up of visible light, x-rays, UV light, infra Red light, radio waves and gamma rays – all basically sit on the electromagnetic spectrum. Each has its specific range of frequencies on that spectrum. But we cop the full spectrum.
My next issue is that in the space of 55 million light year’s travel there must be a huge quantity of solid material – planets, suns, moons, asteroids, other black holes and, closer to earth, space junk. Surely this mass of solid stuff would absorb, reflect or deflect a very large quantity of light rays travelling 55 million light years.
In one light year a beam of light travels 9.46 TRILLION kilometers or 5.88 TRILLION miles – take your pick. Multiply your preference by 55 million and you get the distance travelled by the rays in question.
To produce an image incident light rays must be focussed. The lens of human eyes focuses incident light onto the fundus of the retina. The lens of a digital camera focuses light upon the sensor. These lenses are bi-convex and light passes through them to be focussed.
The Event Horizon Telescope used to capture the Black Hole rays consisted of eight radio telescopes strategically spaced upon the earth’s surface which is convex but the incident rays do not pass through this lens – they are reflected away from it or absorbed into it. This means they are dispersed. How the scientists managed to get them to focus on a single point, in real time or digitially, intigues me.
Finally, (so far), would light emitted by suns, black holes or any other light source interfere with the beams of light coming from M87? How could the telescopes and or associated software differentiate between the M87 black hole light and contaminants?
CORRECTION. In the above discussion I have talked about visible light and missed the very pertinent point that the telescopes used are RADIO telescopes NOT visible light telescopes. That puts whole new shine on the discussion. However, radiowaves are simply those on the long wavelength end of the electromagnetic spectrum amd much of what I said above would till apply but certainly NOT the bit about focussing the incident radio waves. I believe the point about the inverse square law should still apply.
One other point, my meagre education in matters related to research tells me that to attempt to prove a theory you must set out to disprove it, i.e. take the Null Hypothesis. Seems to me these scientists have taken Einstein’s Theory of Relativity, (and it remains a theory, just like the theory or theories pertinent to global warming), and set out to prove it.
I am sure others, more understanding of the technology, mathematics, the universe and computers involved in this venture could come up with answers to my questions and/or many other questions.
I very much doubt any of the scientists involved will ever stumble over this missive but I would be elated if one, or more, will and answer my questions. In the interim I welcome opinions of minds like mine.