Crimson Moon – A Total Lunar Eclipse

A meme showing Lance Corporal Jack Jones, from the fictional Home Guard platoon portrayed in popular British sitcom 'Dad's Army' uttering his familiar catchphrase: "Don't Panic!" with a total eclipse of the Moon appearing crimson red in the background.The Motion of Celestial Spheres

The Universe never sleeps.  Every now and then, the night sky presents us mere mortals with some heavenly spectacle.  A Bonnie Tyler moment.  This Friday, the Moon will enter the catwalk dressed in red to accomplish its otherwise normal nightly travel around the Earth.  For one night only.  A strange and rare celestial sight at dusk – a total lunar eclipse.   

Once in a blue moon, you get a lunar eclipse.

Mind you…  This is not just any eclipse, it’s an M&S….  Ahem!!  I meant, a total lunar eclipse.

Hhmmm…  Mainstream media always make it sound like a such scoop but… this is the 2nd total lunar eclipse this year.

Except this one will be visible from Europe, as well as from Africa, Asia, Australia and South America.  I guess that’s worth pointing out.

 

A pseudo-photograph showing a golfer, dressed in white and donning a red cap, (looking suspiciously like American President and property magnate Donald Trump) putting a shot on the Moon surface, with the Earth rising in the background.The Geometry of a Lunar Eclipse

The Moon is our planet’s natural satellite and…  It’s all the rage at the moment, since President Trump has views on its annexation.  His idea or his friend’s in the East?  Well, I suppose it’s prime “real estate”.

But seriously…

“Astronomers say it will be the longest-lasting lunar eclipse of the 21st century.”

What?!!  The longest eclipse of the Moon EVER this century?  Or the longest TOTAL eclipse of this century SO FAR?

Sigh…  Lazy and sensationalist reporting of a lunar eclipse.

Give it time, okay.  After all, it’s only 2018.  For goodness’s sake…

 

The Orbit of the Moon

A diagram describing the complete path of the Moon's orbit around the Earth.
The path of Moon’s orbit around the Earth. The orbit is elliptic. And no matter what its phase is, the Moon always shows us the same side, illuminated by the Sun.

It takes the Moon about 27.3 days to complete its orbit around the Earth.

Here comes a diagram.

With the months being 28 to 31 days long, it makes the Full Moon and the New Moon fall on a different day of the month every year.  It can be rather difficult to keep track.

 

A diagram showing the different phases of the Moon's total eclipse.
The Full Moon is eclipsed as it passes behind the Earth (relative to the Sun) and into its shadow.

Behind the Earth and into its shadow

Lunar eclipses occurs when the Moon passes directly behind Earth and into its shadow, which takes place only when the Sun, Earth and Moon are aligned, on the night of the Full Moon.

During a total lunar eclipse though, Earth completely blocks direct sunlight from reaching the Moon.

A diagram showing the angular diameter of the Earth obscuring the visible side of the Moon.When the Moon appears red, the only light reflected from the surface of the Moon, has been refracted by the Earth’s atmosphere

As sunlight penetrates the atmosphere, the gaseous layer filters the radiation.  The rays are refracted in such a way that the green to violet wavelengths on the visible spectrum scatter more strongly than the red wavelengths.

 

An excerpt from comic book series "The Adventures of Tintin", showing the surprise and terror caused by an eclipse to ancient Incas.

Reddish Moon, Reddish Moon

“Blood moons” have only recently been welcomed on Earth.  In past centuries, the deep red cast of the Moon’s eclipse was usually seen as an omen of terrible events.

Egyptians saw the eclipse as a sow swallowing the moon for a short time.  Incas believed that lunar eclipses occurred when a jaguar ate the Moon.  They also feared the Moon could come down and devour all the animals on Earth, and would wave their spears and shout at the Moon to dissuade it.

In China, people would ring bells to prevent a dragon from biting the Moon.  For the Zhou Dynasty, the sight of a red moon engulfed in darkness was believed to foreshadow famine or disease.

Biblical texts warn that “The Sun will turn into darkness, and the Moon into blood, before the great and terrible day of the Lord comes.”

But…

Don’t panic!

 

Fortunately, we’re a bit more relaxed about the whole phenomenon nowadays…

Astronomers have a prosaic explanation for the Moon’s crimson colour: the Moon passes through the shadow of the Earth.

However, its disc does not go completely dark because some sunlight – mainly the longer-wavelength, redder end of the spectrum – passes through Earth’s atmosphere and bends around the edge of the planet, so that it falls onto the Moon’s surface.

It is in fact / The light of the sunrise and sunset on Earth that will provide the Moon its red glow on Friday evening.

 

Weather permitting, A Leisurely Affair…

Weather permitting, the lunar eclipse will begin after the Moon rises in the south-east, at around 20.50 BST (GMT +1) on Friday.  The eclipse of the Moon will continue in the early hours of Saturday.

If the sky is a bit cloudy where you are, don’t panic!

 

You can still get a chance to see it provided you are patient.

The eclipse will last several hours.

 

Compared to solar eclipses, which occur when the Moon passes in front of the Sun and completely blots out sunlight for a matter of minutes, a blood moon is a fairly leisurely affair.

Remember to breathe slowly!  In and out.  In and out.

 

It is safe to watch with the naked eye.  But a good pair of binoculars won’t go amiss…

Safe to watch.

 

Nevertheless, if you own a telescope, then it is safe to say that it’s always another-worldly experience to feel as if you were flying over the Moon.  The most seasoned sky-watchers out there will know exactly what I am talking about.

It makes me go all lyrical…

♫ A total eclipse of the MOO-OOON! ♫