Sunday, February 22, 2015

Time Of The Season

Venus, Mars, & Moon in alignment - photo by Junie Quiroga
There was a rare coincidence in the sky the other night with the planets Venus, goddess of Love, and her boyfriend Mars, conveniently appearing on Valentine's Day and aligning with the first crescent moon of the new lunar year.  A nice way to start the new year with symbols of love and romance but not very practical in terms of celestial timekeeping. More than anything it highlights the irreconcilable nature of the solar and lunar calendars that still persists in the world and, for a variety of reasons, we can't seem to choose between.

Relationship between Moon, Earth & Sun
The trouble of course is that in a solar year it takes planet earth nearly 365 1/4 days to go around the sun while at the same time the moon is taking a little less than 28 days to orbit the earth. (27 days,7 hours, 43 minutes, 11.6 seconds to be precise) No matter how you divide these numbers you will never get anything other than approximately 13 lunar months in an average solar year which makes for a very inaccurate calendar that will keep changing every year as the lunar months keeps moving into different parts of the solar year.

The main reason we started keeping track of time was so we knew when each season would begin and end and we could plant and harvest our crops accordingly. Now of course it's for planning holidays. As the earth moves around the sun it ends up in precisely the same place each year moving thorough the seasons from spring equinox to summer solstice, fall equinox, winter solstice, and back again to spring. For this reason a solar calendar is much more practical than a lunar one yet the lunar one still exists.  Why?

The answer of course is religion. While the solar calendar is a practical one, religious people still use the lunar calendar for their important festivals and have what is called a lunisolar calendar.  Jewish and Islamic people have a calendar that is 354 days but Jews have made adjustments that allow certain festivals like Passover, a spring festival, to occur after the spring equinox but the Muslim calendar makes no adjustment for Ramadan which must occur in the 9th lunar month and, as a result, is 11 days earlier every year. For Christians, Easter is determined to be the first Sunday after the full moon on or after March 21st, the spring equinox.  

Chinese Zodiac
It was Pope Gregory XIII who reformed the calendar in 1582 to make up for the difference in accumulated time between the Egyptian solar calendar which, at 365 1/2 days, was actually 11 minutes and 14 seconds too long, and determined January 1st to be the start of the New Year,  Still, it took more than 500 years for the rest of the world to agree to this common calendar. Zoroastrians, and many people in the Balkans, Iran, and Central Asia still celebrate New Year's day on March 21st, the spring equinox, and many East Asian countries of course use the Chinese calendar which is also lunisolar and has been adjusted to allow the New Year to fall on the second new moon after the winter solstice, a date somewhere between January 21 and February 20th.

Astrological Zodiac
While the Chinese zodiac has its 12 year cycle of various animals there's also the astrological zodiac with its 12 monthly signs representing the path of the sun across the celestial sphere over the course of a year.  Though also solar in terms of marking time, by dividing up the sun's path into 12 equal parts of 30 degrees of longitude, early astrologers also thought the position of the planets and their associated constellations could influence a person's life and people to this day continue to check their horoscopes to see what's been predicted for them.

It takes 24 hours for earth to complete a rotation on its axis and on clear days we see the sun and on clear nights the moon.  Regardless of the calendar people choose to follow, the sun rises and sets every day, as do the ocean tides which are controlled by the gravitational pull of the moon. It's all part of an incredible celestial clockworks that never ceases to amaze and, when the planets line up like they did this week, it's another way of marking the time of the season.

Sunday, February 8, 2015

Radar Love

English Bay with the fog rolling in - photo by Junie Quiroga
Contrary to popular belief it doesn't rain all winter long in Vancouver but, on those clear sunny days a different form of condensation can occur and, that is something called fog. Sunny days mean starry nights and starry nights are much cooler than cloudy ones so when the sun goes down and the land and ocean starts to cool off the rising warm air meets the cool air above and forms fog. Normally this only lasts for the night but, being hemmed in with mountains, the cold air can remain stationary for days acting as a lid over the waterways and keeping the fog in place until the next round of rain appears to clear the air.

View of Vancouver fog from the local mountains
While the view from the local mountains can be spectacular, it makes visibility difficult for city dwellers and non-existent for anyone on the ocean.  There really isn't anything more terrifying than unexpectedly encountering fog and having to cruise blindfolded, particularly if a freighter suddenly appears in front of you. If you were trying to fly an airplane through fog or cloud you would need to have a license with an instrument rating but for boaters there aren't any legal requirements.

Typical GPS device for recreational boaters
It was only recently the government brought in licensing requirements to operate a recreational boat but there are no rules around required instrumentation or how to use any of these devices. Until not so long ago most recreational boaters got along with just a compass and paper charts but, more recently, there have been a large number of marine GPS chartplotter navigation devices for boaters to choose from that integrate ocean charts and satellite tracking (something every new car owner is now getting to experience along with anyone in possession of a smartphone). While a GPS is great for knowing where you are and helping you plot a course to where you want to go, it doesn't help you see anything if you are in fog, and for that you need radar.

Radar is the acronym for "radio detection and ranging" and, while the various components of a marine radar system are quite complicated in their design, the concept and process is actually as simple as understanding how a flashlight operates. Walking in the dark and using a flashlight you're actually sending out light waves that reflect off any object in front of you and bounce back to your eyes with your brain telling you what you're seeing and how far away it is. In the case of radar, radio waves are used instead of light waves to do the same thing.

A piece of equipment called a magnetron produces the radio waves, and an antenna, working as both a transmitter and a receiver, sends them into the air in front and then listens to the reflection to see if anything was picked up. Anything picked up is then processed by another piece of equipment and displayed on a screen that lets the operator know where any nearby ships are and how fast they are travelling. It all happens very quickly with radio waves travelling outward and bouncing back at the speed of light which is 186,000 miles per second or 7 times around the world in one second.

Ship radar display

While the safest way to navigate is in clear daylight, a mariner in the Pacific Northwest can easily get caught out and having radar can be a life saver.  It's mandatory of course for commercial vessels but more and more recreational boaters are having it installed as well.  When you're trying to get home to loved ones it isn't the message you send them that's important but rather the message your radar sends to you.

Freighter appearing out of the fog - photo by Junie Quiroga