See an extremely rare Pi Day Total Lunar Eclipse this week
A blood moon on Pi Day only comes along every 300-400 years. Here's how to see it from anywhere.
This Friday, March 14, is Pi Day and what better way could there be to celebrate this essential mathematical constant, than with a phenomenon Pi can help predict decades or even centuries in advance — a Total Lunar Eclipse.
This week we will be treated to a rare sight in our skies. Overnight from Thursday into Friday, the Full Worm Moon will align with the Sun and Earth to pass directly through Earth's shadow.
The result will be the first total lunar eclipse visible from across Canada in over 2 years.
This 'blood moon' total lunar eclipse will occur at the same time for all observers across the country.
It begins at just before midnight, Eastern Daylight Time (EDT), as the Moon begins to enter the penumbra, the diffuse outer part of Earth's shadow. It will be challenging to notice this part of the eclipse, as the penumbra only causes the Moon's brightness to dim slightly.
It becomes much more noticeable when the partial eclipse starts about an hour later. This is when the Moon starts to cross the inner, darker part of the shadow (the umbra), and it appears as though a bigger and bigger "bite" is being taken out of the Moon. The partial eclipse lasts for nearly an hour and a half, afterwhich the Moon will turn completely red as the total phase of the eclipse begins. A little over an hour later, the Moon will start to exit the umbra, with the second partial eclipse phase persisting for around an hour and 15 minutes. Afterwards, the Moon will gradually brighten as it exits the penumbra, and it will complete its transit across Earth's shadow about six hours after the event began.
Consult the chart below for the exact timing in your time zone, to ensure you don't miss out.
Will we see it?
Whether you can see this total lunar eclipse or not will depend on the sky conditions in your area. Consult your local forecast beforehand, to see if your weather is cooperating.
However, the updated national forecast map, below, gives a basic idea of what the sky conditions will be like, late Thursday night into early Friday morning.
The best places to see the eclipse from appears to be through parts of Atlantic Canada, southern Quebec, and southern Ontario. However, some clouds moving through southern Ontario earlier in the event may block the view to start.
What if it's cloudy?
If you're trapped under overcast skies on Thursday night through Friday morning, there's still a way to see the lunar eclipse!
Griffith Observatory, in Los Angeles, California, is livestreaming the event for all to see!
Their stream will also be available after the event, if you missed out due to conflicting schedules.
What is Pi and why is it important?
Simply put, pi is the number you get when you divide the distance around a circle's edge (its circumference) by the distance across the circle (its diameter).
The circumference of a circle rolled out flat plots the value of pi. Credit: Wikimedia Commons
Thus, if you draw a circle exactly 1 metre across, its circumference will be pi metres. A circle 1 centimetre across will be pi centimetres around.
As the above circle unrolls and its circumference is compared to a ruler laid on the ground, the end of the circle will not fall exactly on one of the ruler's marks.
In fact, no matter how close together those marks are, or how small of a space they measure, or how closely we zoom in on the ruler, the end of the circle will never, ever fall exactly on one of the lines.
For this reason, pi is called an irrational number. No matter what you do, you can't divide one whole number by another whole number and arrive at pi. There are examples that come close (such as 22 ÷ 7 = 3.14285714286), but they only give a rough approximation.
As far as we can tell, given our current level of technology and knowledge of the universe, the decimal places of pi apparently go on forever and produce no pattern of any kind that we can recognize! Currently, supercomputers have calculated π to over 202 trillion decimal places, and have found no end to it or any repeating patterns.
Fortunately, the cosmos is forgiving enough that we don't need to know pi to the last digit to produce practical results.
Due to the importance of pi to our understanding of the universe, March 14 — 3-14 — was chosen as "Pi Day", to celebrate this mathematical constant. And how do you celebrate such a thing? Typically, with pie!
Pi pie, courtesy koka_sexton/Flickr
The significance of a Pi Day Eclipse?
Pi is used in computing a lot of things in science. Anything that involves circles, ellipses, or curves will have Pi somewhere in the equation.
This applies to weather, with the coriolis effects of the atmosphere's motion on our rotating planet.
It also factors heavily in the calculations of the orbits in the solar system. In this case, we couldn't properly calculate the orbit of the Moon around Earth, and the Earth around the Sun, without knowing the value of pi.
The shape of the Moon's orbit around Earth, the angle of the sunlight, and the size and shape of Earth's shadow are all computed using pi. (NASA's Scientific Visualization Studio)
The fact that we do know pi means that we can use the equations of planetary motion to predict lunar eclipses and solar eclipses, years, decades, or even centuries out. We know the size and shape of Earth's shadow due to pi, as well, which is crucial in figuring out the exact timing of a total lunar eclipse.
Pi Day eclipses are exceptionally rare, as well.
The last time there was a total lunar eclipse on March 14 was 372 years ago, in 1653! The next one? In the year 2351, 326 years from now! So, don't miss out!
(The thumbnail image for this article depicts a simulation of the peak of the March 14 Total Lunar Eclipse from NASA's Scientific Visualization Studio, along with the orbital path of the Moon (diagonal line) and the relative size and shape of the umbra and penumbra of Earth's shadow (concentric circles), all of which we know due to our knowledge of the mathematical constant, Pi (shown in the greek alphabet).)