Stargazers will soon have the chance to witness a "double" meteor shower as both the Alpha Capricornids and the Southern Delta Aquariids reach their peak this week, CNN reported.
The twin-skywatching event is "just an amazing coincidence," Nicholas Moskovitz, a planetary astronomer at Lowell Observatory in Arizona, told Live Science.
Having two meteor showers peak within 24 hours of each other is "a little bit unusual," Moskovitz said. "But the idea of multiple showers being visible in a single night? Certainly not too uncommon."
There are over 900 meteor showers throughout the year, meaning an average of two to three meteor showers occur per night, Moskovitz noted. However, not all of these are "major" meteor showers like the Perseids or Geminids, which feature over 100 meteors per hour. Most meteor showers are minor, and astronomers are just beginning to systematically study and measure these showers thanks to newly developed instruments, Moskovitz said.
Meteor showers occur at regular intervals due to their predictable orbits around the sun. The small annual variation in their intensity is determined by when comets release debris and how long the debris has been floating in space. Predicting meteor showers is important for the safety of spacecraft and humans travelling in space, said Moskovitz, who leads the Lowell Observatory Cameras for All-Sky Meteor Surveillance (LO-CAMS), a network of cameras that monitor meteors.
At its peak, the Southern Delta Aquariids will display around 20 to 25 meteors per hour, compared to "background" meteor showers, which typically show around five meteors per hour. The Southern Delta Aquariids will appear "pretty faint," Moskovitz said. "You really need to get to a dark site, away from lights and traffic, stay off your cell phones, let your eyes acclimate to the dark, and you may have a chance of seeing some of those faint objects."
The Alpha Capricornids are less frequent but often associated with "bright fireballs with bigger meteor chunks coming in, burning up, and getting brighter, making for a more spectacular show," Moskovitz said. These bright meteors are made of marble-sized particles, while fainter meteors are usually grain-sized.
When And Where To Watch It
Meteor showers occur when Earth's orbit intersects a comet's path, causing the rocky debris left behind by the comet to burn up as it enters Earth's atmosphere. During this double meteor shower, Earth will cross the orbits of comet 96P/Machholz, which causes the Southern Delta Aquariids to peak from July 29 to July 30, and comet 169P/NEAT, which creates the Alpha Capricornids peaking from July 30 to July 31.
Wednesday night is the best time to view both showers, Robert Lunsford of the American Meteor Society said, as the moon wanes and loses about 8% illumination each night. (The moon's illumination can hinder the visibility of the fainter meteors.) On Monday, the moon will be about 34% full, and on Wednesday the orb will be 16% full, according to NASA's Daily Moon Guide.
The double meteor shower will be best viewed in the Southern Hemisphere, where the radiant, or the apparent point from which the shower originates, will be almost overhead. People in the Northern Hemisphere can also see the meteor shower if they have a clear view of the southern horizon.
Both meteor showers will continue until mid-August.
"Almost all meteor showers peak in the early morning hours between 2 and 4 a.m.," Moskovitz said. "So if you want to catch either one of these, your best chances of seeing meteors are to get to a dark site and do so after midnight."
Both showers are best viewed with the naked eye. For other skywatching events this year, a new pair of binoculars or a good backyard telescope might be useful.
