You won't have to wait long for the first of three chances in 2019 to see our satellite at its biggest and best.
The rise of a full moon is one of the most underappreciated natural sights of all. Once each month while the sun is setting in the west, our fully illuminated satellite pokes above the eastern horizon as a delicately colored orange-yellow disc. For many stargazers, it's the highlight of the month. However, a few times each year the full moon can look as much as 14% larger and can be 30% brighter than usual, and when that happens it's called a supermoon. Luckily, in 2019 there are three,
What is a Supermoon?
There is actually no hard definition and, unless you watch a supermoon as it rises, you're unlikely to notice much difference. First coined in the 1970s by astrologer Richard Nolle, the term supermoon refers to a new or full moon within 90% of its closest approach to Earth, something astronomers call perigee. That happens three times in 2019. It's caused by the moon's elliptical orbit, which means it gets to around 19,000 miles (30,000km) closer once each month. Only when that coincides with a full moon or a new moon is it called a supermoon. The best way by far to observe a supermoon is to watch it rise behind buildings or mountains so you can more easily appreciate the size difference.
The Two Types of Supermoons
There are two types of supermoon: a full moon supermoon and a new moon supermoon. The latter happens during the day, so can't be observed, and is therefore of little interest to moongazers. There is a new moon supermoon on Sept. 28, 2019. However, there are three full moon supermoons in 2019, on Jan. 21, Feb. 19, and March 21.
The Super Blood Wolf Moon on Jan. 21, 2019
January's full moon is popularly called the Wolf Moon, though also the Ice Moon and the Old Moon. On Jan. 21 the moon will be 222,043 miles (357,344km) from Earth, which is further away than normal, so it's also a supermoon. Lastly, but most impressively, it's also a total lunar eclipse. Popularly known as a “blood moon,” these are relatively rare events, though this is the third of three in the last year. It will be a spectacular sight visible from all of North America. As it moves through Earth's shadow, the only light it receives will be sunlight that has traveled through Earth's atmosphere. That light turns the moon a delicate orange, copper and/or pink color. The event will peak when the disc of the moon is completely colored, which is called totality. Although it being a supermoon makes it appear slightly larger in the sky, it does mean that totality lasts for less time. At the last total lunar eclipse, a micromoon — when the Moon is furthest away, so smaller in the sky — meant that totality lasted for 1 hour and 38 minutes. The Super Blood Wolf Moon will be the last total lunar eclipse visible from North America until May 26, 2021.
Totality begins at 9:12 p.m. PST, January 20 and 12:12 a.m. EST on Jan. 21 from North America, and will last for 62 minutes.
The Super Snow Moon on Feb. 19, 2019
On Feb. 19 our satellite will be 221,681 miles (356,761km) from Earth — the closest it gets — to create the biggest supermoon of the year. Also called the Storm Moon and Hunger Moon because of it being at the coldest time of year, the Super Snow Moon may be a good time to get used to going out at dusk. Wait for a few days until the Super Snow Moon is rising a few hours after twilight, and you may be able to see what astronomers call "zodiacal light," when it's possible to see sunlight reflecting on dust in the solar system. It will be easiest to see during the two weeks after 2019's Super Snow Moon. Look to the west after dusk from a (very) dark sky site.
The Super Worm Moon on March 21, 2019
The third and final supermoon of 2019 occurs in March. Known by Native Americans as the Worm Moon because of the seasonal appearance of earthworm trails, March's Full Moon has also been called the Full Sap Moon and Full Crow Moon. This Super Moon will be 224,173 miles (360,772km) from Earth. It will occur just a day after the vernal equinox, the beginning of spring in the northern hemisphere.
When Are the Next Supermoons?
There are only a handful of supermoons each year, always in quick succession. Those dates are it for 2019, with the next full moon supermoons not until March 9 and April 8, 2020, and the next new moon supermoon on Oct. 16 and Nov. 15, 2020.