How Black a Black Hole Is?

How Black a Black Hole is?

The black hole could be seeing orbiting Vega in a broad lane entirely clear of debris; both inner and outer rings gave it wide berth. It was hard to believe how black it was.

As Elie took short video pans of the debris ring before her, she wondered whether it would someday form its own planetary system, the particles colliding, sticking, growing, ever larger, gravitational condensations taking place until at last only a few large worlds orbited the star.

The motion of the black hole around Vega was creating a visible ripple in the bands of debris immediately adjacent. She wondered if these gravitational perturbations, these spreading rarefactions and condensations would have any long-term consequence, changing the pattern of subsequent planetary formation.

It was very like the picture astronomers had of the origin of the planets around the Sun four and a half billion years ago. Elie could now make out inhomgeneites in the rings, places with a discernible bulge where some debris had apparently accreted together.

It is hard to believe how black is a Black Hole (quotations from Megan Jorgensen). Image: © Elena

The sky was full of stars. Everywhere she looked there where stars, not the paltry scattering of a few thousand still occasionally known to naked-eye observers on Earth, but a vast multitude – many almost touching their nearest neighbors it seemed – surrounding Elie in every direction, many of them tinted yellow or blue or red, especially red. The sky was blazing with nearby suns.

She could make out an immense spiraling cloud of dust, an accretion disk apparently flowing into a black hole of staggering proportions, out of which flashes or radiation were coming like heat lightning on a summer’s night. If this was the center of the Galaxy, it would be bathed in synchrotron radiation.

The Cosmic Mystery

The Cosmic Mystery

There were only six planets known in Kepler’s time : Mercury, Venus, Earth, Mars, Jupiter and Saturn. Kepler wondered, why only six? Why not twenty or a hundred? Why did they have the spacing between their orbits that Copernicus had deduced? No one has ever asked such questions before. There were known five regular or “platonic” solids, whose sides where regular polygons, as known to the ancient Greek mathematicians after their time of Pythagoras.

Kepler thought the two numbers were connected, that the reason there were only six planets was because there was only five regular solids, and that these solids inscribed nested one within another, would specify the distances of the planets from the Sun.

In these perfect forms, he believed he had recognised the invisible supporting structures for the spheres of the six planets. He called his revelation the Cosmic Mystery. The connection between the solids of Pythagoras and the disposition of the planets could admit but one explanation : The Hand of God, Geometer.

The Hand of God, Geometer, created a Holy Geometry. Image: Mist by © Megan Jorgensen (Elena)

Kepler was amazed that he – immersed, so he thought, in sin, – should have been divinely chosen to make this great discovery. He submitted a proposal for a research grant to the Duke of Württemberg, offering to supervise the construction of his nested solids as a three-dimensional model so that others could glimpse the beauty of the holy geometry. It might, he added, be contrived of silver and precious stones and serve incidentally as a ducal chalice. The proposal was rejected with the kindly advice that he first construct a less expensive version out of paper, which he promptly attempted to do: “The intense pleasure I have received from this discovery can never be told in words… I shunned to calculation no matter how difficult. Days and nights I spent in mathematical labors, until I could see whether my hypothesis would agree with the orbits of Copernicus or whether my job was to vanish into thin air”.

But no matter how hard Kepler tried, the solids and the planetary orbits did not agree well. The elegance and grandeur of theory, however, persuaded him that the observations are unobliging by many other theorists in the history of science. There was then only one man in the world who had access to more accurate observations of apparent planetary positions, a self-exiled Danish nobleman who had accepted the post of Imperial Mathematician in the Court of the Holy Roman Emperor, Rudolf II. That man was Tycho Brahe. By chance, at Rudolf’s suggestion, he had just invited Kepler, whose mathematical fame was growing, to join him in Prague.

Johannes Kepler envisioned Tycho’s domain as a refuge from the evils of the time, as the place where his Cosmic Mystery would be confirmed.

No One May Travel Faster Than Light

No One May Travel Faster Than Light

If the world is to be understood, if we are to avoid many logical paradoxes when traveling at high speeds, there are some rules, commandments of Nature, that must be obeyed. Einstein codified these rules in the special theory of relativity. Light (reflected or emitted) from an object travels at the same velocity whether the object is moving or stationary: Thou shalt not add thy speed to the speed of light.

Also, no material object may move faster than light: Thou shalt not travel at or beyond the speed of light. Nothing in physics prevents you from traveling as close to the speed of light as you like; 99, 9% percent of the speed of light would be just fine. But no matter how hard you try, you can never gain that last decimal point. For the world to be logically consistent, there must be a cosmic speed limit. Otherwise, you could get to any speed you wanted by adding velocities on a moving platform.

Thou shalt not add thy speed to the speed of light. Image: © Meg Jorgensen (Elena)

The social and political application of the ideas of Aristarchus and Copernicus was rejected or ignored around the turn of the XIXth Century. The young Einstein rebelled against the notion of privileged frames of reference in physics as much as he did in politics. In a universe filled with stars rushing helter-skelter in all directions, there was no place that was “at rest”, no framework from which to view the universe that was superior to any other framework.

This is what the word relativity means. The idea is very simple, despite its magical trapping: in viewing the universe, every place is as good as every other place.

The laws of Nature must be identical no matter who is describing the, If this is to be true – and it would be stunning if there if there were something special about our significant location in the Cosmos – then it follows that no one may travel faster than light.

The Sky Is Important

The Sky Is Important

The sky is important. The sky covers us. It speaks to us. Before the time we found the flame, we would lie back in the dark and look up at all the points of light. Some points would come together to make a picture in the sky. One of us could see the pictures better than the rest. She taught us the star pictures and what names to call them… We would sit around late at night and make up stories about the pictures in the sky: bears, hunterfolk, lions, dogs. Other, stranger things. Could they be the pictures of the powerful beings in the sky, the ones who make the storms when angry? Mostly, the sky does not change. The same sky pictures are there year after year. The Moon grows from nothing to a thin sliver to a round ball, and then back again to nothing. When the Moon changes, the women bleed. Some tribes have rules against sex at certain times in the growing and shrinking of the Moon. Some tribes scratch the days of the Moon or the days that the women bleed on antler bones. Then they can plan ahead and obey their rules. Rules are sacred.

So what are the stars? Such question is as natural as an infant’s smile. (Quotations from Megan Jorgensen). Night Sky by © Elena

The stars are very far away. When we climb a hill or a tree they are no closer. And clouds come between us and the stars: the stars must be behind the clouds. The Moon, as it slowly moves, passes in front of stars. Later you can see that the stars are not harmed. The Moon does not east stars. The stars must be behind the Moon. The flicker. A strange, cold, white faraway light. Many of them. All over the sky. But only at night. I wonder what they are.

Speed of Light as Mystery

Speed of Light as Mystery

Something strange happens at the speed of light.

The more we think about such questions, the more troubling they become. Paradoxes seem to emerge everywhere if you could travel at the speed of light. Certain ideas had been accepted as true without sufficiently careful thought. Well, Albert Einstein posed a few simple questions that could have been asked centuries earlier. For example, what do we mean when we say that two events are simultaneous?

Imagine that I am riding a bicycle toward you. As I approach an intersection I nearly collide, so it seems to me, with a horse-drawn cart. I swerve and barely avoid being run over.

Now think of the event again, and imagine that the cart and the bicycle are both traveling close to the speed of light. You are standing down the road, the cart is traveling at right angles to your line of sight. You see me, by reflected sunlight, traveling toward you.

Royal Ontario Museum. Most people go about their daily lives as if nothing is happening. Unthinking, uncaring… (quotations from Megan Jorgensen). Source of the image: © Elena

Would not my speed be added to the speed of light, so that my image would get to you constantly before the image of the cart? Should you not see me swerve before you see the cart arrive? Can the cart and I approach the intersection simultaneously from my point of view, but not from yours? Could I experience a near collision with the cart while you perhaps see me swerve around nothing and pedal cheerfully on toward the town of Vincy? These are curious and subtle questions. They challenge the obvious. There is a reason that no one thought of them before Einstein. From such elementary questions, Einstein produced a fundament rethinking of the world, a revolution in physics.