Black Holes

 

Black Holes

In describing Black holes it would be as well to first describe the structure of the universe. Our planet Earth is circling the sun along with 8 other planets. The sun is a star which may be described as a big concentration of ( mainly ) hydrogen gas which is so big that the pressure and temperature at its core enables fusion reactions to take place. These fuse hydrogen atoms together producing helium along with huge amounts of energy. This is the same process as a hydrogen bomb although happening at an immense scale and continuously.

The sun is one of many millions of stars grouped together in our home galaxy. Throughout the universe are very many millions of galaxies. The universe is very big and modern measurements suggest it is expanding. It is important to grasp the universe is not expanding into anything. There is nothing, no space, no time. The analogy often used for the expanding universe is that the universe is a bit like a balloon with galaxies on its surface. As the balloon inflates it expands and the galaxies on its surface grow further apart. This is happening in three dimensions. The effect is that we are finding other stars are becoming more distant although even at big distances the effect is still quite small.

First a largely theoretical concept Black holes became important when it was realised that a large one existed at the centre of our galaxy. Our galaxy is shaped rather like a disc with a bulged centre and spiral arms like a giant Catherine wheel. Our sun is positioned out along a spiral arm. When we look up on a clear night we see a great concentration of stars in a overhead band, the Milky Way. Indeed our galaxy is called the Milky Way and the effect arises because we are looking in from the side of the disc.

The spiral arms are rotating around the centre at high speed, so high that it became apparent that only the gravity of something very large at the centre stopped stars like the sun from flying away into space. That something is a Black hole. A Black hole is something where the gravity is so strong that even light cannot escape; it is quite literally black because nothing can escape. The Black hole has at its centre some form of matter of fantastic density, so dense that something the size of earth is only the size of a suitcase.

Before this seems impossible it is as well to know that ordinary matter, the atoms of which we are made, is almost entirely space with a small nucleus of protons and neutrons with electrons orbiting around at large distances away. This is a very simple view of an atom which is more complex but gives  the idea that an atom is mostly space. Under Black hole conditions that space disappears and a very large density is obtained. A minute bit of such matter would weigh millions of tons.

Astronomers have just seen and photographed this Black hole at the centre of the Milky Way Black holes vary in size and this has the mass of many suns. There is an immediate question- a Black hole is black, totally black, so in fact what we see is a halo of hot gas in the process of being ingested with a silhouette of nothing in the middle. In fact this halo isn’t symmetrical but rather blobby as the Black hole spins .This irregularity may be an artefact of the way the observations were made. One slight puzzle is that it was expected we would see the hole side on rather than face on as is actually observed.

The above description of a Black hole is rather limited. Einstein has shown that gravity is the result of a curvature in space-time. In a Black hole  the curvature has become so great that nothing can emerge. The above description of density of matter is a gross approximation of a phenomena which is beyond the scope of present day physics. There is a useful cop-out which says that a Black hole proceeds to a singularity; in other words to something we don’t understand. In fact what we know and can observe is that at some point in space the gravity around the Black hole is so intense that any matter will fall into the hole. This line around the hole is called the event horizon.

The observation of the Black hole was made with the Event Horizon Telescope which is several radio observatories at different places in the world working together.

It is thought that Black holes can be very large indeed. The one at the centre of our galaxy is much smaller than the only other previous visualisation which is several billions of suns in size. Very small Black holes are thought possible and there was some alarming speculation that the Large Hadron Collider could produce them. Physicists were confident this was not the case and so it proved.

For all practical purposes matter falling into a Black hole has left the universe.

Authoritarian Advance

 

Authoritarian Advance

The world is dividing into two fundamentally different governing philosophies. Broadly speaking one hand are the authoritarian mainly Russia, China plus places like Cuba, Venezuela, N Korea,Iran. On the other are the liberal democracies, most of Western Europe, UK, US plus such as Japan, S Korea.

Authoritarian countries espouse the idea of a strong leader who brooks no opposition and citizens are expectedly to do as they are told. Their citizens are subject to surveillance and their behaviours proscribed. Government propaganda replaces objective information. Authoritarian countries often pay lip service to democracy without any real attempt to obey its norms; indeed subvert it to achieve the leaders aims. Most worrying of all authoritarian countries tend to be aggressive, unhesitating to bully, threaten and even attack others who disagree. They have contempt for the rule of law in any meaningful way seeing it as another way to exert control.

In contrast liberal democracies have a free press and economy, apply democracy and have a functioning and objective legal system. In general liberal democracies have also more religious and social freedoms.

The aggression of authoritarian systems is being tragically shown in the Russian attack on Ukraine. In a steady manner Ukraine was moving from the previous Soviet control towards becoming a typical Western nation. This was an imperfect change but transitioning from the Soviet style to a Western one was always going to be slow.

There has been reporting of Russian objectives which we can dismiss as a fairy story only for the extremely gullible. There has also been a speculation about the real motives. Putin was brought up in the Soviet era. He became, as a KGB agent, into an important and prestigious role. He seeks to go back to that era.

The prime authoritarian government is in China. The secretive rulers loudly proclaim communism and maintain the most rigid control. Their aggression is shown by their imposition of tight control in Hong Kong despite solemn agreements not to do so. They maintain that Taiwan belongs to them and unhesitatingly bully all who attempt to maintain diplomatic contacts. The state control over media is absolute including internet control through a massive firewall insulating Chinese people from the cacophony of full internet use. Any information which the leadership doesn’t like is blocked.

Outside the two major counties Russia and China there are others who are authoritarian. Most often this is in an effort to maintain existing rulers. The playbook is drearily familiar; wangle power then manipulate to maintain that power whether by election rigging or by avoiding elections completely. Motivations are sometimes ideological but just as often it is a wish to enjoy wealth and power by corrupting state institutions.

One of the tragedies of democracy is that electorates can be persuaded to vote leaders into power not realising they will never have any opportunity to vote them out. Once in power the state can be manipulated. Key is to keep the armed forces or police sweet and use them to keep the population in line. Popular uprisings can occur but it takes great courage and any leader willing to be ruthless can withstand popular pressure. An example was Belarus where Lukashenko put down an uprising successfully.

In countries without any of the attributes of a modern society this is surprisingly easy. Even a country with a strong tradition of freedom such as the US can show an authoritarian streak as in denying freedom to abortion. Despite a clear majority in favour of full freedom it is possible for dedicated campaigners to use state controls to impose their views.

Religious or pseudo religious intolerance is still found in countries like Iran or Afghanistan. Purportedly Islamic rules appear more to reflect a strong cultural bias. It is a great tragedy that Afghanistan has been allowed to step back to a point where women are subject to such a misogynistic life.

Nothing lays a country open to abuse as shear incompetence of its rulers. Sri Lanka is a recent example where a “strong man” proved utterly incompetent. Sadly all to often those leaders who see themselves in strong man role find favour with authoritarian regimes. They may aspire to be a Putin themselves. Even countries with at least some semblance of a liberal society may find themselves with leaders of this type such as Bolsanario in Brazil and AMLO in Mexico.