That’s not its official name, of course.
Neither is it a peri-Cheez Whiz moon, another moniker bandied about the household in recent weeks. When a massy-looking full moon last appeared — just last month, on the night of July 12 — it bore the fake-cheese colour.
Sunday night, anybody who steps outside and looks moonward will see a similarly bloated orb. It is the second in a sequence of three oversized full moons we will be treated to this year, and is the biggest-looking of them all.
The official name of the moon that we can view Sunday night describes the event much more ploddingly than our alternatives. Because the Earth sits off centre within the moon’s egg-shaped path around our planet, once every month the moon approaches Earth about 50,000 kilometres closer than when it swings out on the other, long side of its orbit.
That closer encounter is called the moon’s perigee.
When the timing of the perigee coincides with either the full or new phase of the moon, pointy-headedness truly comes into ascension. No doubt only after considering all the possibilities within the classical languages that science usually draws on and pondering innumerable likely references to laws of nature, wonders of the universe and marvels of artificial cheese and other foodstuffs, astronomy chose to label the phenomenon a “perigee moon.”
Because a perigee moon is up to 50,000 kilometres closer to us, when it is in the full-moon phase, it looms bigger and more dramatically than the moon usually does.
A perigee moon can appear up to 14 per cent larger and 30 per cent brighter than the everyday, unassuming, mild-mannered Clark Kent full moon.
Of course, no matter how big or small it might appear to us mere mortals here on Earth, the moon always remains the same size. No, seriously, it doesn’t pack on a few billion tonnes of cheese spread overnight.
Modern-day superlativism does try to save the day — er, night — in the name department. Much of the western world has recently started calling the super-big perigee moon a “supermoon” because, well, it looks super-big.
Although the nickname lacks about as much as the scientific term does, it at least casts a certain Marvel Comics light on the matter.
“Up in the sky, look! It’s a street light. It’s a communications satellite. It’s Supermoon!
“Higher than the tallest skyscraper, faster than the International Space Station, it appears when you least expect it, exposes dark secrets and brings crime to light, then disappears just as quickly under a flick of cloud cover.”
Supermoons appear regularly. Four to six supermoons — including both full and those dark, mysterious new moons — occur each year.
In 2013, however, as during this summer, three full supermoons occurred during three consecutive months, although only one received much press.
This year, the moon’s public-relations department came out swinging. Building on the momentum of last year’s threesome suite, we started 2014 with a double-hitter of two new supermoons in January. Our summer supermoon hat trick began on July 12 and ends Sept. 9.
Sunday night’s supermoon, however, will outshine both of the others. It will pass within 357,092 kilometres of Earth, more than 2,000 kilometres closer than either July’s or September’s supermoons. That distance — the equivalent of a long two-day drive from the coast to, say, Brandon, Man., for us humans, but a pittance for the moon — will make the moon loom and us swoon.
To get maximum effect, begin your moonwatching at moonrise. Lucky for us, the full moon always rises as the sun sets, and always rises opposite the sunset. So look toward Bellingham beginning about 8:20 p.m. As the moon rises, the angle of viewing along the horizon will create an illusion, making the moon seem even bigger and even more super.
Which means that Sunday night’s full moon should be called a super-duper moon.