Posts

Three Websites

This is one of three websites containing short essays I have written about astronomy. The present site describes and explains various astronomical phenomena and events. The two others are: Philosophical Astronomy , which takes a more theoretical look at the subject, and SkyMarks , a compilation of stargazing columns that appeared monthly for a couple of years in the New Haven Register . And here is a list of all of my publications on astronomy. Enjoy, and clear skies! -- Joel

Comet Day, Anyone?

  By Joel Marks Published in the Institute for Ethics and Emerging Technologies blog, July 1, 2015 On this day 245 years ago – July 1, 1770 – humanity had its closest known encounter with extinction (with the possible exception of the Cuban Missile Crisis). Two weeks before that date the French astronomer Charles Messier had discovered a faint comet in the constellation Sagittarius, which thereafter rapidly brightened and began moving swiftly across the sky. At its peak it was naked-eye, and its coma, according to various observers, the apparent size of from 5 to 16 full moons across. Lexell’s Comet, so named after another astronomer who subsequently calculated its orbit, was then under one-and-a-half million miles from Earth, or less than six times the distance of the Moon, and thus the nearest a comet has ever approached us in recorded history. (Kronk n.d.) It was also larger than any asteroid known to have come that close, and in fact large enough to have wrought global consequences

Dueling Designations

Copyright © 2007 by Joel Marks Look, up in the sky! It's a planet! No, it's a pluton! No, it's a ... kenning! On August 24, 2006, the International Astronomical Union voted to demote Pluto from a planet to a dwarf planet. This has not sat well with many in and out of the astronomical community. For one thing, the term “dwarf planet” is bizarre since it is intended to remove Pluto from the ranks of the planets. But if something is a dwarf x, isn’t it still an x? For example, a dwarf star is a kind of star; indeed, our own sun is one. This means that the term “dwarf planet” is a kenning, a term to which I was led by rhetorician extraordinaire Prof. Kip Wheeler and defined in Wikipedia as “a figure of speech, substituted for the usual name of a person or thing. … compris[ing] two terms, one of which (the 'base word') is made to relate to the other to convey a meaning neither has alone.” Allison Griswold, a former student of mine, suggested the apt example of “starfish,

Going Lightly

The designation "dark energy" for the something that constitutes the bulk of the known universe is clearly a placeholder. A permanent name for this fifth force of nature may await the determination of what exactly it is. All that seems to be known about it thus far is that it has a repulsive effect that is in some sense "the opposite of gravity." Whether this will prove to be its most distinctive feature once its full nature becomes known is anybody's guess (and certainly not mine, since I'm not a physicist). Should it turn out to be so, however, I propose that it be named "levity." Not only would this be suitable in its literal meaning (as the opposite of gravity), but it would also serve to lighten things up a little in a universe which heretofore has been dominated by gravity. So ... let there be levity! (I've been promoting this idea for many years, as witness a letter to the editor in Natural History magazine, which you can see by clicki

Apophis

Copyright © 2006 by Joel Marks Revision of “Reckoning Might Come from Sky,” New Haven Register, April 13, 2006, page A6 Twenty-three years from today, on April 13, 2029, the residents of this planet will witness an unprecedented harbinger of their doom. An asteroid the size of the Empire State Building will be visible to the naked eye as it hurtles by at a distance of less than the earth’s circumference. The asteroid's scientific name is 99942 Apophis. Its proper name comes from the Greek rendering of Apep, the ancient Egyptian spirit of destruction. This name fits. If Apophis were to strike the earth, it would wreak untold havoc. And given certain as-yet unknown contingencies of the asteroid's orbit, it might do just that. It is especially meet to reflect on this today, which commemorates the ancient Passover, when people in Egypt took steps to assure God’s slaughterous spirit would pass over or spare them. Apophis was discovered on June 19, 2004, when it was given the

And Then There Were Eight

Copyright © 2005 by Joel Marks Originally published with the title “Discovery of 10th planet may mean there really are only eight” in the New Haven Register on August 3, 2005 (page A6) At first I was excited to learn that a tenth planet has just been discovered in our solar system. But a moment's reflection made me realize that this probably means there are only eight planets. How could that be? The status of the ninth planet, Pluto, has been in question ever since a new category of solar system object was discovered, which are now collectively known as the Kuiper Belt. Analogous to the ring of asteroids that orbit the Sun between Mars and Jupiter, these are tens of thousands of planetoids that orbit the Sun beyond the orbit of Neptune. That is also where Pluto spends most of its time (although Pluto's eccentric orbit sometimes brings it closer to the Sun than Neptune). So there has been the surmise that Pluto may not be a planet but simply the largest member of the Kuiper Bel

Golden Age of Astronomy

Copyright © 2004 by Joel Marks Originally published in the Evening Division Student Newsletter of the University of New Haven, vol. 1, no. 5, June 2004 We live in the golden age of astronomy. The discoveries that are being made on a daily basis dwarf anything before in human history. Perhaps the only rival would be the prehistoric discovery of the starry sky itself, when our ancestors first looked up at night (or in the daytime too) and took note that what was above them was something wonderful. Sad to say, the current explosion of human understanding of the cosmos is matched only by the unprecedented indifference to it by contemporary humanity. And that is likely due to the simple fact that what was plainly visible to our distant, and even recent, ancestors, is no longer so to most of us urban and suburban dwellers. The starry sky has been all but eliminated by light pollution. There is ignorance of even the most basic phenomena that were known for thousands of years, such as the phas