Some 100 meteors an hour will blaze across the sky tomorrow night—the Perseids are back for their annual visit. While they've been visible since late July and will continue to be through late August, the annual peak of the show begins late tomorrow night, August 12, and will be at its most spectacular in the early morning hours of August 13.
Named after the constellation Perseus, where the meteors appear to originate, the Perseids are actually the tail of dust, ice, gas, and gravel—much of it more than 1000 years old—following the Swift-Tuttle comet, which orbits the Sun every 133 years. As the Earth moves through Swift-Tuttle's vast debris field on its own orbit, bits of this debris smash into the Earth's atmosphere at 140,000 mph, disintegrating in dramatic streaks of light.
The constellation Perseus—named after the mythological Greek warrior who beheaded Medusa, among other legendary exploits—rises in the northeastern sky around 10 p.m. local time. The show begins on August 12 soon after and continues through the early morning of August 13, peaking around 4 a.m. The American Meteor Society has a nice guide to watching this year's show. (Pro tip: bring a reclining lawn chair.)
It should be a fantastic display this year thanks to dark skies. In 2014 the shower peaked during a so-called Super Moon, whose reflected sunlight flooded the sky, limiting how many meteors could be seen. But this year the peak of the shower—when the Earth moves through the densest band of debris—arrives right before the new moon, meaning the skies will be optimally dark. If you're in a city, light pollution will interfere with the show. In a rural area you'll be able to see three to ten times as many meteors—and perhaps spot the Milky Way in an edge-on view of our galaxy, witnessed from our location in the lonely boondocks of a spiral arm far from the galactic center:
To create this image, three cameras took continuous time-lapse pictures on the platform of the European Southern Observatory's Very Large Telescope, located in Chile, during the nights of 12–13 and 13–14 August 2010. Image credit: European Southern Observatory, Flickr // CC BY 2.0
NASA’s Marshall Space Flight Center in Huntsville, Alabama will host a live Ustream broadcast from 10 p.m. EDT to 2 a.m. EDT highlighting the science behind the meteor shower and NASA research related to meteors and comets. During the broadcast, you can tweet questions to @NASA_Marshall using #askNASA.
And if you're anywhere near the NASA Wallops Flight Facility Visitor Center on Wallops Island, VA, watch the show with NASA educators on nearby Assateague Island. After an astronomy 101 presentation, everyone will decamp for the great outdoors for night sky observations through telescopes and binoculars beginning at 8:45 p.m. EST.
There are countless other viewing events going on across the country. Find a local astronomy group or observatory near you—or simply grab some binoculars.
NASA created a composite image five years ago—the last time we had dark skies for the Perseids—of the skies above the Marshall Space Flight Center in Huntsville, AL.:
A composite of more than 100 individual meteor images. The linear streaks are meteors, most of them Perseids; the dotted arcs are stars; and the brightest arc on the left side is the moon. Image credit: NASA/MSFC/MEO
By the way, Swift-Tuttle will make its next closest approach to Earth on August 5, 2126. While in the past there had been some fear that the comet could smash into Earth at some point, recalculations have put us in the clear—at least until the fifth millennium CE. People alive then should keep an eye on the skies around September 15, 4479.