7 May 2012

Supermoon May 2012

Yesterday (6 May) was one of those evenings that sky gazers have been anticipating for a long time.  A rare lunar phenomenon happened.  You may not even notice it yourself if you are simply a casual observer but last night the moon will appeared larger and brighter than normal. Take a look at these amazing pictures to get an idea what all the fuss was about.

Some astrologists refer to this as a supermoon but there are even those who are calling last nights moon an extreme supermoon because the moon was also at the fullest part of its sequence.  The real name for the term is rather different – astrological purists refer to it as a lunar perigree.

As the moon’s orbit around the earth is elliptical the difference between its furthest and nearest points would, at first glance, be cause for concern (and if the distance between the two happened overnight it would most certainly be a time to, well, panic).  254,000 miles is the furthest the moon is ever away from the earth.  At is closest it is still 220,000 miles away but that means that it is closer to us by 34,000 miles.

While it is true that tidal forces increase by about fifteen percent during a lunar perigree that does not mean that tides will be higher by the same percentage.  The average perigree tidal rise is around an inch – nothing much to throw your arms up in horror there, then!  In fact the dire effects that the moon is said to have on the weather during its perigree are largely a creation of the blogosphere.  Here at Kuriositas we are happy to stand up and be counted when it comes to debunking what amounts to lunatic lunar conspiracy theory!


First Image Credit Bill Collinson

2 October 2010

Double Lasers Shoot the Moon

Some guys have all the luck.  September 18 marked the first ever International Observe the Moon Night (which is referred to as InOMN) which is set to become an annual event.  Visitors at the NASA Goddard Visitor Center in Maryland were in for a treat.

They were able to watch as not one but two green lines pierced the sky above the Space Center. These lasers were aimed at the moon not to repel an alien invasion or to detect a battle fleet but the aim of the procedure was detection.  The lasers were tracking our own spacecraft.

The object they were seeking was the Lunar Reconnaissance Orbiter.   The lasers fire twenty eight times a second and travels a quarter of a million miles.  The LRO is itself moving at 3,600 miles per hour as it proceeds on its orbit around the moon and it is only the size of a minivan. This is an artist's impression of what they were after.

This is the first attempt to track a space ship through laser ranging and it produces – amazingly – measurements of distance that are accurate to about four inches.  A telescope on the Goodard Campus is used to direct the laser pulses towards the Lunar Reconnaissance Orbiter.  Knowing the speed of the laser is paramount as the distance from earth to the LRO is determined by measuring the length of time it took the lasers to reach it.

You may have noticed that the beams in some of the pictures seem to be coming from above.  This is an illusion - they are in fact coming from a secondary ground system at the facility.