Category: Astronomy and Physics

Astronomy and physics.

Black Holes, the Instant of Creation

The idea of an object so massive that light cannot escape from it actually goes back to the 18th century. It wasn’t until early in the 20th century that the modern concept of a black hole was put into a theoretical framework by Einstein, Schwarzschild, and Chandrasekhar (among others). (5) This has been built upon since by many notable physicists including Penrose and Hawking. A black hole has only three measurable properties, mass, electrical charge, and angular momentum or spin. (7) Black holes also have a non-zero temperature due to Hawking radiation. When an object falls into a black hole all information about these three properties becomes part of the event horizon. All other information such as size, shape, or the properties of the particles that it was composed of is supposedly lost.

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Black Holes

I’m not going to go into too much depth on what black holes are or how they come into being. The concept itself is pretty basic. It’s a region of space in our universe that has so much mass that the escape velocity is greater than the speed of light. They are defined by the event horizon, the surface that surrounds them where the gravitational pull of what is inside the black hole equals the speed of light. In other words, if you are inside a black hole and shine a flashlight towards the inside surface of that event horizon the light will never escape out into the rest of the universe. Black holes, although they can not be observed directly, can be observed by the gravitational effect that they have on their surroundings. Astronomers have “observed” these effects, weighed their masses, and have generally proven that they exist. The radius of this event horizon (called the Schwarzschild radius) is defined by a simple formula that is a function of the mass and rotation. Most of the references for this article are to Wikipedia (5) where you can find lots of fascinating details.

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The Infinite Multiverse

Let’s spend a bit of time on the concept of what a multiverse is. Most people are familiar with the concept of our universe. It consists of everything around us including all of the stars and galaxies that we can see as well as what is beyond the visible horizon, that part of space and time that has not had time for the light emitted from it to reach us.

The theory of the Big Bang says that our universe began as a very hot and dense dimensionless point some 13.7 billion years ago (2). A very small fraction of time later it went through a tremendous expansion or inflationary phase which smoothed it out. This inflation spread the tiny variations of density that were on sub atomic scales out to the size of what eventually became galactic super-cluster size. The universe literally expanded faster than the speed of light leaving most of it so far away that we can not see it. As time goes by light from an ever increasing sphere around us has time to reach us. This visible bubble is estimated to have a radius of about 46 billion light years (3). What lies beyond that can not be seen and can have no effect on us (perhaps not true – see note).

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Big Bangs and Black Holes

Philosophers have discussed and theorized for ages about the origin of our universe. It is such an important question that every culture on our planet has a story or mythology about how they and the world around them came to be. These frameworks were constructed on what they knew of their surroundings or of their recent history. The Ojibwa first nation in Canada believed the world was found by a muskrat and is carried on the back of a turtle. In the last couple of hundred years our framework has changed and is based on scientific experiment and theory. Instead of inventing our origin we build theories based on scientific experiment and then test them with new experiments. One of the most significant contributions to this framework came from Albert Einstein when he developed his theories of special and general relativity. Most of what we hold to be true about our universe is based on relativity and quantum mechanics. (As an aside, I do not understand quantum mechanics, I can grasp some of the effects, but I do not understand the fundamentals. By the same token, I don’t understand my wife, but I do comprehend how she modifies my universe.)

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Hale-Bopp

In 1996 – 1997 Hale-Bopp put on a spectacular show.

The night of March 23, 1997 there was a near total eclipse of the moon. The day started off cloudy but a cold front went through in the afternoon and the skies cleared off by dusk. My son and I drove north of town and set up my newly built barndoor camera mount on a sideroad. The night turned out to be one of those special ones with rock steady pinpoints for stars. To the north there was Hale-Bopp and to the south there was a lunar eclipse. I took a number of photos of the comet. When I picked up my pictures from the local lab I showed them to Kevin, the owner and a professional photographer. He in turn showed me the pictures he had taken of the eclipse. He got the idea that he could composite the two images into a single photo. This is one of the early attempts made by just overlaying the two negatives. He later did a composite in PhotoShop that he sold a number of copies of.

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Astronomy and Astrophysics

I enjoy the night sky and I’m lucky enough to live in an area (54N 124W) where I can see it. I bought a Coulter 8″ Dobsonian telescope 20 years ago. I still pull it out on occasion but I prefer the naked eye or a pair of binoculars. The best observing platform has to be my computer though. With it I can look at the latest images from the Hubble or check out today’s snapshots taken by the Martian rovers.