The Mental Floss Field Guide to Viewing the Solar Eclipse

A total solar eclipse will cross the United States on August 21, 2017, and if you want to catch it, you'll probably want to start making preparations now. To see the total eclipse (which you really want to do!), you will need to travel to the path of totality. Mental Floss spoke to Mitzi Adams, a heliophysicist at NASA Marshall Space Flight Center, about everything you need to know to see the Sun disappear, photograph the process, why it's important to scientists, and how cultures around the world have interpreted the celestial phenomenon.

WHAT AM I LOOKING FOR DURING THE ECLIPSE?

The total solar eclipse is made up of phases. First, there's first contact, when the Sun and Moon first "touch." This leads into the partial phase, when it looks like someone is taking increasingly large bites from the Sun. Next is the actual eclipse itself, when the Sun is totally covered by the Moon. It lasts a very brief time, from a few seconds to just over two minutes, depending on where along the path you view it. The Sun passes through partial phases again as the Moon continues on its way. During the total phase, remove your eclipse eyewear and behold the corona of the Sun, wispy, revenant limbs of light reaching from a black hole in the sky. Stars and planets will be visible as day has turned to an eerie, ethereal night.

Down on the Earth's surface, says Adams, you'll notice that nature has no idea what's going on. "During the total phase when the light from the Sun's photosphere is completely blocked, some animals react," she tells Mental Floss. "The cows may start walking toward the barn. Horses may do the same. Crickets start chirping. You'll hear frogs. Birds will go to roost. Chickens will react the same way they do at sunset. All animals, including the human ones, react to eclipses in some way. The human reaction is typically, 'Wow! Look at that!'"

WHAT TOOLS CAN I USE TO VIEW AN ECLIPSE (WITHOUT GOING BLIND)?

During the partial phase of a total eclipse, you need to wear special eclipse glasses that protect your eyes from the Sun. This isn't some overly cautious government recommendation that only the squares follow. If you don't wear the glasses, you won't be able to see anything that's happening because you are staring at the Sun. Eclipse glasses can be found online, at public libraries and museums, and, along the path of totality, science advocacy and public education initiatives should have glasses freely available in large quantities. By the time the eclipse gets here, if you can't find glasses, it's because you didn't want to find them.

If you want to up your game, though, the Bill Nye Solar Eclipse Glasses might soon be the It-item of Milan's runways. Described as featuring a "stylish frame that is fashionable for both men and women" (complete with a silhouette of Nye's face on one of the arms), these glasses are "built to last"—and they would have to be. It will be seven years before the next total solar eclipse over North America.

Eclipse glasses will not magnify the eclipse. You can, however, use a telescope or pair of binoculars if you want to get a closer look. You really need to know what you're doing, though, and if this is your first eclipse, ask yourself if it is worth fiddling with knobs during what might be a once-in-a-lifetime event. If you're going to use a telescope, though, here's some advice from the heliophysicist:

"The safest way is to have a special filter that will fit over the front of the telescope," says Adams. "The telescope could be a refractor or a reflector. Binoculars would also work, though you want either two filters, or one filter while you block the light over one side of the binocular pair. Any of these filters will fit over the front."

The filters will be made of mylar or glass, she says, and warns that they must be specifically certified as safe for viewing the Sun. "You do not want to use any kind of filter that will screw into an eyepiece because they will crack, and it doesn't take very long—just a couple of seconds—to build up the heat to crack the filter."

If you want to view the Sun up close during the partial phase of the eclipse, be on the lookout for sunspots, the darker areas seen on the surface of the Sun. The current phase of the Sunspot cycles suggests that there won't be any Sunspots large enough to see with the naked eye. With a telescope, though, you might have better luck.

WHEN NASA LOOKS AT THE SUN, WHAT ARE THEY LOOKING FOR?

"We want to learn as much about Sun as possible," says Adams. "We're trying to study from the core of Sun all the way out to the corona, which is the outer layer of the Sun's atmosphere. The eclipse will enable us to study the inner corona. We can actually build pictures of events on Sun from the photosphere, through the chromosphere, and into the corona."

Scientists will combine the visible light images that they get from the eclipse with images from sources such as NASA's Solar Dynamics Observatory in orbit around the Earth. The observatory views the Sun in multiple wavelengths—mostly extreme ultraviolet—continuously, but it is unable to get the inner corona in visible light. "We can't really study the full spectrum unless we're using images from a solar eclipse," says Adams.

HOW DO I PHOTOGRAPH THE ECLIPSE?

Nikon has provided a comprehensive guide to photographing the Sun both conventionally, on a tripod, and with a special telescope mount. Eclipse2017 also has a useful set of pointers for how to preserve the moment. But the big thing to remember is, DO NOT USE A FLASH—not for reasons related to photography (though seriously, do you think your Galaxy S6 flash is strong enough illuminate the entire sky?) but because part of the wonder of the event is the day turning to night! Light pollution is already a problem for skywatching. Don't turn the eclipse into a light toxic waste dump. (Do not use a flashlight, either.) The best photography advice might be to keep your camera at home and enjoy the total eclipse with your eyes—not through a glass screen.

CAN I HELP DO SCIENCE?

Yes, and the American Astronomical Society has you covered. There's Citizen CATE, in which amateur astronomers across the country will use identical cameras and telescope equipment to take pictures of the Sun's inner corona; the Do-It-Yourself Relativity Test, in which, during the eclipse, you can "measure the gravitational deflection of starlight and prove for yourself that Einstein really was right" with no special equipment; the Eclipse Megamovie Project, which will use images and footage taken of the eclipse by citizen scientists across the country, and, from that, stitch together a high-definition video of the eclipse; and there are many, many others.

WILL TRAVEL BE A PROBLEM?

Yep! Finding a hotel room will be a problem. Entrepreneurial members of Airbnb who live along the path of totality are renting out square footage in their yards for people to set up tents, and they're charging hundreds of dollars for the favor. Your best bet for finding a reasonably priced room is Nashville, which is the largest city on the path and a major tourist destination year-round. Traffic will be a problem, though nobody knows how bad, exactly, because it's been 38 years since an eclipse path of totality passed over the continental United States, and nearly 100 since the last coast-to-coast eclipse. What you need to know is that 200 million people live within a day's drive (about 500 miles) of the path. It doesn't take a civil engineer to imagine how that might go. Parking will be a problem. Make sure your gas tank is full, you have food and water in the car, and for the love of all that is good and holy, insist that the kids try to use the bathroom before you get on the highway. It might be a very long, very slow drive even for short distances.

I HAVE KIDS—WHAT DO I DO WITH THEM?

Bring them! Most of the communities along the path of totality are pulling out all the stops. While you wait for the (very brief) show, there will be plenty of entertainment, and NASA will have beachhead presence across the country with science demonstrations for kids and adults alike. Just make sure everyone has their own pair of eclipse glasses.

THE ECLIPSE WILL NOT CHANGE THE SUN'S RAYS AND GIVE YOU CANCER.

There are a lot of mistaken beliefs about eclipses that should be put to rest. "One large misconception is that somehow going outside during the eclipse is dangerous—that there are somehow 'eclipse rays' that happen, and that the Sun is more dangerous during an eclipse," says Adams. "That's just not true. The light from the Sun is exactly the same from an eclipse as when it's not eclipsed."

Likewise, staring at an eclipse when it is at totality will not make you go blind. Indeed, during totality, that's when you take off your eclipse glasses and specifically stare at the Moon-concealed Sun.

WHAT GROUPS ARE CELEBRATING THE EVENT?

The entire U.S. will see at least 70 percent coverage of the Sun, which is pretty good when compared with the 0 percent coverage we get every day. As such, the whole country will evolve into one massive solar celebration, with literally thousands of parties and viewing events being held at schools, libraries, museums, parks, amateur astronomy groups, university astronomy departments—you name it, they're doing it. There are multi-day music festivals in Oregon and Illinois, the latter of which is called Moonstock, with Ozzy Osbourne headlining.

Even if you live outside the path of totality, NASA will help you host an eclipse party. They've even built an international map of experts that you can reach out to for party entertainment. (Ozzy Osbourne will not have useful astronomy advice, I can assure you. But Brian May, on the other hand … )

WHERE WILL HAVE THE BEST WEATHER FOR THE ECLIPSE?

The entire path of totality has a reasonable chance of good weather. For the very best weather in the country on eclipse day, Great American Eclipse says that Oregon is the place to be. "While the Oregon coast is at risk of marine clouds," they report, "the interior of this state actually enjoys the nation's best weather prospects." Snake River Valley, Idaho, and western Nebraska are also recommended for their extensive network of highways and farm roads. If clouds roll in, you can easily relocate to some place more favorable.

HOW HAVE CULTURES INTERPRETED ECLIPSES OVER THE CENTURIES?

Our friends at the Lunar and Planetary Institute have commissioned an extraordinary collection of multicultural eclipse folktales, performed by professional storytellers Cassandra Wye and Fran Stallings. The stories reveal how people around the world going back centuries have explained and interpreted eclipses, from the Batammaliba people of Africa, whose eclipse origin story sees the Moon taking revenge on the Sun, to the Anishabe people of North America, for whom the Sun was briefly imprisoned.

The Leonid Meteor Shower Peaks This Weekend—Here's the Best Way to Watch It

mdesigner125/iStock via Getty Images
mdesigner125/iStock via Getty Images

We're nearing the end of 2019, but there are still a few astronomical events to catch before the year is s out. This Sunday—November 17—the Leonid meteor shower is expected to peak. Here's everything you need to know before viewing the spectacle.

What is the Leonid meteor shower?

Like all meteor showers, the Leonids are caused by meteoroids from outer space burning up on their descent toward Earth. These particular shooting stars come from the rocky tail of Comet 55P/Tempel-Tuttle. Each November, debris from the comet pummels the Earth's atmosphere, causing meteors to light up the sky at rates that can exceed 1000 per hour.

The Leonids won't reach that frequency this year. According to EarthSky, the meteors would peak at a rate of around 10 to 15 per hour in a dark, moonless sky. But because the moon will be bright this weekend, sky-gazers will likely see less of them, with only the brightest shooting stars shining through.

How to See the Leonids

For your best chance of spotting the Leonids, look up the night of Sunday, November 17 and early in the morning of Monday, November 18. The shower reaches its peak after midnight. The moon will be in its waning gibbous phase at that time, so even with clear skies, viewing conditions won't be ideal. But there are ways to increase your chances of seeing as many meteors as possible. Try finding a large object to stand under—such as a tree or building—that will block your view of the moon. If you don't see anything right away, be patient: The more time you give your eyes to adjust to the darkness, the more likely you are to spot a shooting star.

What is Mercury in Retrograde, and Why Do We Blame Things On It?

NASA
NASA

Crashed computers, missed flights, tensions in your workplace—a person who subscribes to astrology would tell you to expect all this chaos and more when Mercury starts retrograding. For the remainder of 2019, that means October 31-November 20. But according to an astronomer, this common celestial phenomenon is no reason to stay cooped up at home for weeks at a time.

"We don't know of any physical mechanism that would cause things like power outages or personality changes in people," Dr. Mark Hammergren, an astronomer at Chicago's Adler Planetarium, tells Mental Floss. So if Mercury doesn’t throw business dealings and relationships out of whack when it appears to change direction in the sky, why are so many people convinced that it does?

The History of "Mercury in Retrograde"

Mercury retrograde—as it's technically called—was being written about in astrology circles as far back as the mid-18th century. The event was noted in British agricultural almanacs of the time, which farmers would read to sync their planting schedules to the patterns of the stars. During the spiritualism craze of the Victorian era, interest in astrology boomed, with many believing that the stars affected the Earth in a variety of (often inconvenient) ways. Late 19th-century publications like The Astrologer’s Magazine and The Science of the Stars connected Mercury retrograde with heavy rainfall. Characterizations of the happening as an "ill omen" also appeared in a handful of articles during that period, but its association with outright disaster wasn’t as prevalent then as it is today.

While other spiritualist hobbies like séances and crystal gazing gradually faded, astrology grew even more popular. By the 1970s, horoscopes were a newspaper mainstay and Mercury retrograde was a recurring player. Because the Roman god Mercury was said to govern travel, commerce, financial wealth, and communication, in astrological circles, Mercury the planet became linked to those matters as well.

"Don’t start anything when Mercury is retrograde," an April 1979 issue of The Baltimore Sun instructed its readers. "A large communications organization notes that magnetic storms, disrupting messages, are prolonged when Mercury appears to be going backwards. Mercury, of course, is the planet associated with communication." The power attributed to the event has become so overblown that today it's blamed for everything from digestive problems to broken washing machines.

What is Mercury in Retrograde?

Though hysteria around Mercury retrograde is stronger than ever, there's still zero evidence that it's something we should worry about. Even the flimsiest explanations, like the idea that the gravitational pull from Mercury influences the water in our bodies in the same way that the moon controls the tides, are easily deflated by science. "A car 20 feet away from you will exert a stronger pull of gravity than the planet Mercury does," Dr. Hammergren says.

To understand how little Mercury retrograde impacts life on Earth, it helps to learn the physical process behind the phenomenon. When the planet nearest to the sun is retrograde, it appears to move "backwards" (east to west rather than west to east) across the sky. This apparent reversal in Mercury's orbit is actually just an illusion to the people viewing it from Earth. Picture Mercury and Earth circling the sun like cars on a racetrack. A year on Mercury is shorter than a year on Earth (88 Earth days compared to 365), which means Mercury experiences four years in the time it takes us to finish one solar loop.

When the planets are next to one another on the same side of the sun, Mercury looks like it's moving east to those of us on Earth. But when Mercury overtakes Earth and continues its orbit, its straight trajectory seems to change course. According to Dr. Hammergren, it's just a trick of perspective. "Same thing if you were passing a car on a highway, maybe going a little bit faster than they are," he says. "They're not really going backwards, they just appear to be going backwards relative to your motion."

Embedded from GIFY

Earth's orbit isn't identical to that of any other planet in the solar system, which means that all the planets appear to move backwards at varying points in time. Planets farther from the sun than Earth have even more noticeable retrograde patterns because they're visible at night. But thanks to astrology, it's Mercury's retrograde motion that incites dread every few months.

Dr. Hammergren blames the superstition attached to Mercury, and astrology as a whole, on confirmation bias: "[Believers] will say, 'Aha! See, there's a shake-up in my workplace because Mercury's retrograde.'" He urges people to review the past year and see if the periods of their lives when Mercury was retrograde were especially catastrophic. They'll likely find that misinterpreted messages and technical problems are fairly common throughout the year. But as Dr. Hammergren says, when things go wrong and Mercury isn't retrograde, "we don't get that hashtag. It's called Monday."

This piece originally ran in 2018.

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