Space and Physics
Good news for lunar lovers, as the first Supermoon of the year is fast approaching on August 19 at 6:26 pm UTC. It’s also a double whammy of celestial phenomena: as well as being “super”, the Moon will be “blue” – here’s what that all means.
The Moon’s orbit is not quite a perfect circle, so as it travels around the Earth it passes through its closest point (we call it perigee) and its most distant (known as apogee). A Supermoon occurs when the Moon is full and at perigee – and because it is at its closest to us, it appears bigger and brighter, hence the term Supermoon. The difference is difficult to notice with the naked eye, however.
Monday’s Supermoon will be the first of four this year, with the others occurring on September 18, October 17, and November 15. Of these, the one in October is tipped to be the closest at 357,364 kilometers (222,055 miles). Next week's approach will be 361,970 kilometers (224,917 miles) – compared to the average Earth-Moon distance of 384,400 kilometers (238,900 miles), that’s pretty close.
If you weren’t excited enough at the prospect of a bigger, bolder Moon, the coming Supermoon will also be a Blue Moon – but unfortunately, it won’t be turning a stunning shade of sapphire.
There are two definitions of Blue Moon, which have nothing to do with color. The first is a seasonal Blue Moon, the third Full Moon in a season that has four Full Moons. This is the traditional definition and the type we will be seeing on Monday. The other definition refers to the second Full Moon in a single month.
Despite what the phrase “once in a Blue Moon” might have you believe, they’re not that uncommon: Blue Moons tend to occur every two to three years.
August’s Full Moon is also known as a Sturgeon Moon – the Algonquin tribes in what is now the northeastern USA named it as such after the fish, which are caught more easily this time of year.
The upcoming Supermoon Blue Moon extravaganza will be best viewed on Monday evening, but the Moon will appear full for three days, from Sunday morning through early Wednesday. Check out these tips on how to capture it with your smartphone.
4![An artist’s concept looks down into the core of the galaxy M87, which is just left of centre and appears as a large blue dot. A bright blue-white, narrow and linear jet of plasma transects the illustration from centre left to upper right. It begins at the source of the jet, the galaxy’s black hole, which is surrounded by a blue spiral of material. At lower right is a red giant star that is far from the black hole and close to the viewer. A bridge of glowing gas links the star to a smaller white dwarf star companion immediately to its left. Engorged with infalling hydrogen from the red giant star, the smaller star exploded in a blue-white flash, which looks like numerous diffraction spikes emitted in all directions. Thousands of stars are in the background.]](https://assets.iflscience.com/assets/articleNo/76155/aImg/79193/jet-m.jpg)
