Looking up to the skies has only gotten more exciting in the wake of the recent asteroid disintegration over Chelyabinsk, Russia, and the near-miss only hours later by the asteroid 2012 DA14 that passed between the Earth and our geosynchronous satellites on Feb. 15. 
But asteroids are not the only thing making life interesting for planet-bound inquisitors this year as 2013 is likely to be one of the richest years for comet sightings in recent history. 
Right now Comet Lemmon is making a tour around the Sun, visible to the naked eye from the southern hemisphere, which should last for a few more weeks. 
According to the NASA Astronomy Picture of the Day for Feb. 16 the comet is unnaturally green due to its chemistry. NASA said the greenish tint comes from the coma’s diatomic C2 gas fluorescing in sunlight. 
Although spotting the comet can be difficult, it is visible to the naked eye which I can confirm as I have actually gotten a chance to see it myself and photograph it.
This was pretty astonishing considering that under normal circumstances nothing in the night sky is normally green (for the same reason that radiating things like hot coals or molten metals aren’t ever green).
These encounters with asteroids near Earth and comet Lemmon are only the beginning of this potentially spectacular year of comets. 
According to Donna Pierce, assistant professor of astronomy in the Mississippi State University Department of Physics and Astronomy, who is an expert in the field of comet research, another comet labeled PANSTARRS is due to pass through the inner solar system in March. 
PANSTARRS is special because it is a long period comet that has probably never come through the inner solar system before, only recently nudged out of the Oort cloud of comets on the edge of our solar system. 
Later this year an even more spectacular comet, called ISON, will be making its tour through the inner solar system. 
Pierce said if all goes right, in the middle of November ISON could easily be as bright as the full moon and be visible during the daytime.
These comets are probably going to be bright, but, “every comet presents a new challenge; they can do anything,” Pierce noted. 
This is corroborated by the strange characteristics of the green Comet Lemmon as it passes by us nearly invisible to the eye right now. 
NASA warns that many variables could change and present a sub-spectacular show, “One hazard is the sun. Tidal forces and solar radiation have been known to destroy comets. A recent example is Comet Elenin, which broke apart and dissipated in 2011 as it approached the sun. Elenin, however, was a much smaller comet.” 
On the bright side, if comet ISON does break apart early or disintegrate when it passes the sun, astronomers will be given a valuable source of information by being able to see the revealed interior of such a large comet. 
As Pierce remarks, understanding the interiors of comets plays a key role in understanding the early formation of the outer solar system, “Comets would have formed in the area of the giant planets, where there is more ice. They are the bricks and mortar of the outer solar system, which is an unknown field.”
Remarkably, all of these nearby solar system events are unrelated. They are just all happening astonishingly close to each other when compared to the normal frequency of every few decades. 
Really it is astonishing that two asteroids would graze Earth in the same day and that after nearly seven years of no Great Comet sightings all of a sudden we get several in the same year. 
Be sure to take advantage of this spectacular year and watch these comets closely as they may very well be the brightest that some of us ever get to see in our lifetimes.
I would say it is a happy coincidence we get upwards of five spectacular solar system events in one year, and perhaps it is nature’s way of reminding us to look up every now and then and pay attention to what we have so little control over. 
Ironically, the same things that brought so much fear into the minds of the ancients should rightly bring fear into ours. 
We have very little control over what is visible to our telescopes, and even less control over what the gravitational interactions of the solar system throw at us. 
When you look up at night and watch our temporary visitors streaming overhead enjoy the sights, but remember what these things are capable of so we can try to avoid any unpleasant collisions in the future.