Starry Night: Late March 2012

Posted Wednesday, March 14, 2012 in Features

Starry Night: Late March 2012

Messier 99, Photo by Hunter Wilson.

by Tristan Radtke

Potential asteroid impacts create a stir

With the dawning of 2012, it seems, potential sources for end-of-the-world scenarios are being scouted out by scientists and laymen alike. While some of the focus has remained terrestrial with issues like global warming and attributed natural disasters, many of the doomsayers have their eyes focused on the heavens – particularly on our nearest celestial neighbors, the rocks, dust and asteroids that travel the empty distances between our planets.

So, perhaps, there could have been a better time for scientists at the Near Earth Object Program to mention to the general public that the asteroid 2011 AG5 might strike the Earth in February of 2040 – with the widely reported chances of 1 in 625, as was reported in this ABC news story on February 28.

Since then, a number of highly qualified members of the scientific community have weighed in with suggestions on how to deal with the problem, such as a call for future plans to deal with the asteroid, as well as more data to be gathered on the object by former Apollo astronaut Russell Schweickart amongst others.

The problem with getting a full set of data regarding 2011 AG5 appears to be that its position in the Solar System precludes gathering data on it for at least the next few months, due to its proximity to the Sun, and without that data the current estimates are being made using extrapolations of the asteroid’s orbit based on what amounts to about half a full solar orbit worth of data.

If the asteroid were to strike the Earth, it would be likely to produce energy within the atmosphere equivalent to about a 105 MT thermonuclear device. This would be larger than any man-made explosion to date, and certainly catastrophic for the region it struck, but likely well within the survivable range for most humans on the planet.

And while a 1 in 625 chance (or even the more current prediction – 1 in 500) sounds a bit close for comfort, it should be noted that even at the higher 1 in 500 chance, there remains a 99.8% chance that the object misses the Earth completely. Furthermore, the Near Earth Object Program expects the odds to change “in Earth’s favor” as more data becomes available later in the year, according to this press release on February 28.

**The Stars**

If the weather stays favorable, late March will be a very good time to go looking for some deep space objects in the Constellation Virgo.

Virgo has some exceptional deep sky objects, not the least of which is the Virgo galaxy cluster, to which the Milky Way belongs.  Within this cluster are 11 Messier objects, more than any constellation except Sagittarius (which has 15).  One of the most exceptional members of the Virgo cluster is actually within Coma Berenices, and is known as Messier 99.  It is an unbarred spiral galaxy, and with a reasonably good amateur telescope can be seen face on.  So dust off your scope, put on a jacket, and get out there while the Moon is new. 

** The Planets **

• Mercury: Mercury will be just barely visible just after sunset on March 15, and by the end of the month Mercury will have become the “Morning Star”, rising and visible just before sunrise around 5:35 a.m.

• Venus: Venus will remain in conjunction with Jupiter at mid-month, setting around 10:30 p.m., and by the end of March, Venus will set around 11 p.m.

• Mars: On March 15, Mars will set at just about sunrise, around 6:05 a.m. On March 31, Mars will have moved a bit further into the night sky, setting around 5 a.m.

• Jupiter: Jupiter will continue its “dance” with Venus in mid-March, setting just before Venus at around 10 p.m.  By the end of the month, the pair will have broken away from one another, with Jupiter moving earlier into the evening sky and Venus moving further into the night sky. Jupiter will set on March 31 around 9:15 p.m.

• Saturn: Saturn will rise at around 9:20 p.m. on March 15, and will move slightly over the month, ending March rising around 8:15 p.m.

• Uranus: Uranus is lost in the glare of the Sun to begin mid-March, and remains there through the end of the month.

• Neptune: Neptune is lost in the glare of the Sun at mid-month. By the end of March, it will rise around 5 a.m., with surrounding light conditions dark enough to spot it just ahead of the morning twilight.

• Pluto: Pluto will rise at around 3 a.m. on March 15, just ahead of the Moon. By March 31, it will rise around 1:50 a.m.

** The Moon **

The Moon will be waning to third quarter on March 15 and new by March 22. It will begin waxing into April, reaching first quarter before the end of March, around March 30.

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