18 January 2016, 11.45 AM
Asteroid Earth Hits and Cluster Concentrations – Beware of ECAs
Asteroid Earth Hits and Cluster Concentrations Defy Probability Rational – Beware
Asteroids are both a mystical area of research, and also a scary thing to study. Mystical for now, because we don’t know much about them, they seem to have so many different attributes, and because we can only guess the rest. And, scary because if a rather large one hits the Earth, well we could end up like our friends the dinosaurs – extinct!
The most scary of all asteroids are ECAs or Earth Crossing Asteroids, that is to say crossing Earth’s predictable path and projected orbit, which is a lot different than NEOs or Near Earth Objects, although an NEO could be an ECA, we are very concerned with ECAs, or at least we are at our Think Tank which operates online. Look up definition on Google of ECA to get a better understanding, as there are some decent papers written on them, and some nice Wikipedia entries as well.
Now then, ECAs often come in streams, such a meteor showers, or travel in clusters or bands. Not only should we be concerned with ECAs but also ECCs or Earth Crossing Comets, yes, a comet can hit a planet, we recently saw what happened when one hit Jupiter. Ancient Earth civilizations talk about near misses of comets and how fragmentations hit the Earth, lit up the sky etc, it’s definitely in the human recorded written record.
Those ECAs which travel together make it easier for us to predict as they are periodic, still, when they come around there is always a chance one big one in the group could hit us. Then there are the less-than-predictable deadly rouge asteroids which we might sometimes see, and sometimes not. Often one comes really close to Earth, even within our Moon’s orbit distance, but we don’t see it until it has already passed; meaning we dodged another bullet and didn’t even know it, which is both good and bad.
Bad because it means we are incompetent at finding NEOs which come dangerously close, and good, because a medium or large sized NEO near Earth Object which is an ECA could scare the holy heck out of human populations. Please consider all this.
1.-The Association of Earth-Crossing Asteroids with Meteoroid Streams,” Steel, D. I. – Published in the Journal: Earth, Moon, and Planets, Volume 68, Issue 1-3, pp. 13-30 (1995EM&P…68…13S).
2.-Book Review: “The origin of comets / Pergamon, 1990” by SV Clube, and SS Genuth, published in the Journal for the history of astronomy vol. 23, pt. 3, p. 215 (1992); (BC: 1992JHA….23..215C).