THE DAILY ASTRONOMER March 24, 2014 Up And, then the Emperor of Astronomy entered into a dispute with the Chancellor of the Universe. It started with a simple question: Chancellor: Who decides what is up relative to the Universe? And then the Emperor replied Chancellor, Up is a term specific to a given object or system. It has to be this way as up and down are two dimensional constructs applied to three dimensional objects. Set a ball on a shelf and the top is defined by whatever point happens to be highest on it. Roll the ball and this point changes. On Earth, we define up as North, aligned with the North Pole. Weve adopted this convention through inculcation: the repeated exposures to maps that place the northernmost regions along the top and the southern regions at the bottom. So, we have an intuitive sense that up corresponds to north. Weve applied this directional word to North as a consequence of this association. Conversely, an Australian cartographer would most certainly dispute our hemisphere-specific definition. She would have likely inverted the directions so that the South Pole occupied the pinnacle, with the North Pole at the nadir. Ive inferred from the question your assertion that up cannot be objectively defined. And, I gladly concede the point. The situation becomes increasingly more complicated when we extend our view beyond the planet, for Earths North Pole does not correspond to that of the galaxy. The Galactic North Pole is within the constellation Coma Berenices, which is not aligned at all with the North Celestial Pole. In fact, our solar system describes a 60 degree angle relative to the Galactic Equator. Our Galactic Up is well away from true North. Beyond this level we encounter the Local Group of Galaxies: the assortment of proximate galaxies. Here, the notion of up cannot be truly defined as there is no consistent orientation of all the component galaxies. We determined the Galactic Equators location through analysis of neutral hydrogen, emissions from which indicate the region of highest concentration. This maximum concentration would presumably correspond to the galaxys plane. The Local Group of Galaxies offers no such standard by which to gauge equivalents in longitude and latitude. The adage, There is neither up nor down in space is correct. These terms must be specific to a given location. The word up is little more than a psychological comfort to humans accustomed to a two dimensional civil life in a higher dimensional reality. And, as Chancellor of the Universe, you would be more familiar with human psychology than I. Perhaps comfort is irrelevant to the issue at all. I defer this issue to you.
Posted on: Tue, 25 Mar 2014 12:00:17 +0000
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