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conumdrums, black holes and quasars

16 February 2023
Astronomy

At https://phys.org/news/2023-02-hundreds-high-redshift-quasars.html … astronomers are reporting the discovery of over 400 new high red shift quasars using the Dark Energy Spectroscopic Instrument [DESI]. The findings are on the pre-publication arXiv web site at https://doi.org/10.48550/arxiv.2302.01777 … according to mainstream astronomy thinking quasars are luminous active galactic nuclei containg central black holes with accretions disks. Their red shifts are measured from the strong spectral lines that dominate their visible and ultra violet spectra. Just as importantly, astronomers regard quasars as the most distant compact objects in the observable universe. Spectra can  be used to estimate the mass of supermassive black holes that constrain, it is thought, the evolution of quasars. Moreover, high red shift quasars that are also radio bright, are the signposts astronomers use to spot black hole activity in the early universe. Hence, it is imperative that red shift is a reality and they are looking at the furthest universe. Halton Arp, had a quite different idea of red shift, and quasars. His ideas were taken up by the recently deceased Wal Thornhill – see for example https://www.youtube.com/watch?v=t_4rO7iqxFE … which is a prediction of what the new James Webb Space Telescope may find. This, he suggests, might be the fact red shift  theory is mistaken and quasars are much nearer than astronomers allow. Only time will tell. He won’t be around for egg on the face.

Meanwhile, at https://phys.org/news/2023-02-mysteries-black-behemoths-galaxies.html … which is a related story as the black behemoths are super massive black holes. Scientists are thought to be about to unravel the birth, growth and power of black holes. Presumably they too are looking forward to the James Webb state of the art telescope. The search  is on for difficult to detect objects in the universe. Once again, a viewing of the video link above would be useful, as black holes might not be what they are cracked up to be. Thornhill also explains the doughnut like ring around the black hole that is purported to be the first picture of the supermassive black hole at the centre of our galaxy. However, the PhysOrg link notes that you can’t actually see inside the ring of material, or suffused light, at the centre of our galaxy as it is so dense. It has been consuming material for thousands of years. The gravitational pull of the black hole even prevents light from escaping. Is that a cop out? Michela Mapelli, an astrophysicist at Padue University in Italy said, everyone has heard of black holes but few people prealise how they vex astronomers. Christopher Reynolds of Cambridge University is recording the big beasts – and there are a lot of them. He says, ‘we know these black holes produce lots of jets of energy, sending shocks outward. ‘ Another problem is why the gas in the core of galaxies can bo so hot – up to 100 million C. Yet, the systems are billions of years old, it is thought, and therefore should have plenty of time to cool down’. It would seem plasma, an ionised gas, is what the problem might all be about – see the video above.

In fact, Reynolds admits he is mystified by the hot gas – in black and white text. ‘You need a heater to send out energy in the middle of the cluster and the only heater powerful enough are supermassive black holes’ he said. How the heater works is what mystifies him, and his colleagues. These black holes are not even spherical, he continues, but they spin themselves into a disk that is rife with instablilities. In spite of all the new discoveries the true nature of black holes remains obscure. Past assumptions have been shaken. It is worth adding to what he says by noting that plasma instabilities have been seen in laboratory research and are accepted when they occur on the face of the sun. Are black holes part of the same phenomena?

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