The constellation Sagittarius (from “Urania’s Mirror” a set of constellation cards published in England circa 1825)
My apologies for the blogging break last week. Usually I try to write a new post every weekday, but last week was a blogging holiday. To reinvigorate things after the lost week, let’s turn to a big subject—in fact a super-massive subject! Long ago, Ferrebeekeeper featured a post about Eta Carinae, a blue hypergiant with a hundred times the mass of the sun (which is itself a million times more massive than Earth). Stars like Eta Carinae are rarely formed and short lived—there are probably less than a dozen in our galaxy. However compared to the most massive object in the galaxy, Eta Carinae is puny and common. Twenty six thousand light years away from the solar system there exists a truly monstrous space object!
In 1974, Astronomers discovered an astronomical feature which was emitting exotic radio waves in the Sagittarius constellation. The scientists named the feature “Sagittarius A” and set out to determine what it was. Part of the feature seems to be the remnants of a star which had gone supernova. A second part of the feature is a cloud of ionized gas surrounded by an even larger torus of molecular gas. In the middle of Sagittarius A is something which is emitting most of the high energy electromagnetic radiation visible to radio telescopes. The cloud of ionized gas seems to be emptying into it and nearby stars orbit it with greater velocity than stars move anywhere else in the galaxy (in fact the object affects the proper motion of thousands of nearby stars). And yet the space object at the center of Sagittarius A has a diameter of only 44 million kilometers–a bit less than the distance between the middle of the sun and Mercury at its perihelion (when the rocky planet is closest to the sun). By calculating the proper motion of thousands of nearby stars, scientists determined that the mysterious object at the center of Sagittarius A (which they took to calling Sagitarrius A*) has mass of 4.31 million suns (i.e. solar masses). Whatever lies at the center of Sagittarius A–which I probably should have mentioned, is also the center of the Milky Way Galaxy–is smaller in volume than a large star, but has a mass which exceeds by many orders of magnitude even exotic hypergiants like Eta Carina.
Of course the only kinds of discrete objects which we know (or even hypothesize) to be capable of attaining such mass are black holes. It is believed that most (indeed probably all) galaxies have super-massive black hole at their centers. Smaller galaxies have small super massive black holes (forgive the oxymoron) but large galaxies have immense central black holes which can equal billions of solar masses. Radio astronomers have observed plumes of exotic electromagnetic radiation coming from the center of other galaxies, and they wondered where the Milky Way’s galactic center was located. It seems that a supernova near the galactic center blew away a great deal of the dust and gas on which the black hole would otherwise “feed” thereby making the galactic center of the Milky Way less energetic than the active center of farther (e.g. older) galaxies.
Artist’s Conception of Galactic Center
The super massive black holes which lie at the center of galaxies may be a result of the accretion of matter around stellar-sized black holes (which could grow quickly in matter-rich galactic cores) but most astrophysicists believe they are instead a primordial feature of the Big Bang around which galaxies themselves coalesced. The ultimate nature of super massive black holes remains unknown and seems to be tied to the nature and shape of our universe.
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May 29, 2012 at 7:57 PM
Val
I believe that the Big Bang was the result of the explosion of the ultimate black hole, and all these smaller black holes are just clumps of the original that were too dense to be expressed as normal matter. One day, all the galaxies will collapse into their respective black holes and then perhaps, if the universe has not expanded too far, those black holes will draw together, collapsing into another ultimate black hole, which in time with produce another Big Bang.
May 30, 2012 at 11:27 AM
Wayne
That’s a spiritually satisfying hypothesis! I wish I were more deft at astrophysics so that I could assess the idea further, but alas, I am not a physical scientist and can’t poke holes in your model universe (anyway that might contribute to the soundness of the concept). I do have to say that ending with a giant black hole and another big bang sounds more appealing than “the big freeze” model of the end of the universe which strikes me as horribly depressing.
May 30, 2012 at 12:48 PM
Val
Thanks! I’m not a scientist either — I just like to theorize. It’s really just an ultra macro oscillation between on and off. I’ve always been fascinated in the way that the microcosm and the macrocosm mirror each other, for example veins and nerves with the same form as rivers, etc. I do like the idea of an oscillating universe, and yes, I find it infinitely preferable to the gradual fizzling out of the “big freeze”.
Just curious, if you were to poke holes – would they be black ones??
May 30, 2012 at 11:07 PM
Wayne
Based on your answer, I guess they would be recursive fractal holes….
June 22, 2012 at 1:28 AM
Michaela Jayne
Perhaps the ‘shape’ is not a shape. . .with it’s ‘edges’ only touching it’s self and therefore not really being a definable ‘shape’ like. . .say, a cube.
If everything is touching everything else, and there is nothing which is not a part of the ‘thing’, then there is no need for anything beyond the universe.
If it is a proper shape, then there also must be more to it all then what is included in your idea. . . which makes me wonder if how that stuff which is beyond would affect and interact with your model.
Any thoughts?
June 22, 2012 at 1:47 PM
Wayne
I don’t know. I’m neither an astrophysicist or a topographer, but I find the torus to be incredibly satisfying (and it seems to meet at least some of your criteria). Yum…donut!