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Few People Die From Lightning Strikes These Days. Why?

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This decade will go down in weather history as one of the wildest in modern times. Since 2010, we’ve seen both the widest and strongest tornado on record touch down in Oklahoma. Mexico felt the wrath of the strongest hurricane ever recorded in terms of wind speed. The American West is enduring a years-long drought with no end in sight. But it’s not all bad news. This decade is also on track to see the lowest number of lightning deaths we’ve ever recorded in the United States, and that’s quite the accomplishment.

Lightning is an underestimated killer. We’re so used to thunderstorms that their presence is almost second nature unless they’re unusually strong. Scientists estimate that we see about 16,000,000 thunderstorms around the world every year, and the United States alone averages about 22.5 million flashes of cloud-to-ground lightning in a typical year. That’s a little nerve-wracking when you consider that a single bolt of lightning is hotter than the surface of the sun and packs enough electricity that a direct strike to your body can stop your heart before you have time to react.

Most people who are struck by lightning survive the frightening encounter, though with some serious lingering effects. Lightning is usually only deadly when the electrical charge crosses a victim’s heart and causes it to stop beating, and even then they can be revived if a fast-acting bystander performs CPR. Given the amount of lightning that crashes around us on a regular basis, you’d expect the number of lightning deaths in the United States to be sky high, right? Surprisingly, no: Since 2010, we’ve only seen an average of 26 people die each year due to lightning strikes.

Just over two dozen lightning deaths every year sounds like a big number, sure, but the overall downward trend of lightning fatalities over the past 75 years is one of the most incredible weather statistics out there.

A chart showing the number of reported lightning deaths each year between 1940 and 2015. Chart: Dennis Mersereau

We’ve seen a steady decline in the number of lightning fatalities almost every year since recordkeeping began back in 1940. During the 1940s, you could expect an average of 329 people to die as a result of a lightning strike every year. By the 1960s, the average number of fatalities had dropped by more than half to just 133 deaths per year. The new millennium brought about an average of just 41 lightning deaths per year, and the number continued to slowly tick down with time.

Why are we seeing fewer lightning deaths in the United States than ever before? It’s more complicated than any one cause, but there are at least three major factors at play. The first is the most obvious—you’re probably reading this article indoors at your computer or on your phone. If you were around in the middle of the 20th century and didn’t live in a city, you spent significantly more time outdoors for both work and play than we do today. The simple act of more people spending more time indoors is a significant factor in the rapid drop-off in lightning fatalities.

Another major factor was the invention of weather radar after World War II. Before radar came into widespread use, threatening clouds on the horizon or distant rumbles of thunder were your only clues that a thunderstorm was on its way. If a storm is close enough that you can hear thunder, you’re close enough to be struck by lightning. Weather radar took the surprise out of approaching storms, and now we can watch bad weather roll toward us before you can even see the clouds out your window.

The third factor likely has to do with education. We know so much more about the weather today than we did a few decades ago, let alone in the middle of the 1900s. Weather safety education in school, on the Internet, and through efforts by organizations like the National Weather Service—“when thunder roars, go indoors!”—have helped tremendously in raising public awareness about the dangers of lightning and how to find safe shelter when a storm bubbles up. 

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More Details Emerge About 'Oumuamua, Earth's First-Recorded Interstellar Visitor
 NASA/JPL-Caltech
NASA/JPL-Caltech

In October, scientists using the University of Hawaii's Pan-STARRS 1 telescope sighted something extraordinary: Earth's first confirmed interstellar visitor. Originally called A/2017 U1, the once-mysterious object has a new name—'Oumuamua, according to Scientific American—and researchers continue to learn more about its physical properties. Now, a team from the University of Hawaii's Institute of Astronomy has published a detailed report of what they know so far in Nature.

Fittingly, "'Oumuamua" is Hawaiian for "a messenger from afar arriving first." 'Oumuamua's astronomical designation is 1I/2017 U1. The "I" in 1I/2017 stands for "interstellar." Until now, objects similar to 'Oumuamua were always given "C" and "A" names, which stand for either comet or asteroid. New observations have researchers concluding that 'Oumuamua is unusual for more than its far-flung origins.

It's a cigar-shaped object 10 times longer than it is wide, stretching to a half-mile long. It's also reddish in color, and is similar in some ways to some asteroids in our solar system, the BBC reports. But it's much faster, zipping through our system, and has a totally different orbit from any of those objects.

After initial indecision about whether the object was a comet or an asteroid, the researchers now believe it's an asteroid. Long ago, it might have hurtled from an unknown star system into our own.

'Oumuamua may provide astronomers with new insights into how stars and planets form. The 750,000 asteroids we know of are leftovers from the formation of our solar system, trapped by the Sun's gravity. But what if, billions of years ago, other objects escaped? 'Oumuamua shows us that it's possible; perhaps there are bits and pieces from the early years of our solar system currently visiting other stars.

The researchers say it's surprising that 'Oumuamua is an asteroid instead of a comet, given that in the Oort Cloud—an icy bubble of debris thought to surround our solar system—comets are predicted to outnumber asteroids 200 to 1 and perhaps even as high as 10,000 to 1. If our own solar system is any indication, it's more likely that a comet would take off before an asteroid would.

So where did 'Oumuamua come from? That's still unknown. It's possible it could've been bumped into our realm by a close encounter with a planet—either a smaller, nearby one, or a larger, farther one. If that's the case, the planet remains to be discovered. They believe it's more likely that 'Oumuamua was ejected from a young stellar system, location unknown. And yet, they write, "the possibility that 'Oumuamua has been orbiting the galaxy for billions of years cannot be ruled out."

As for where it's headed, The Atlantic's Marina Koren notes, "It will pass the orbit of Jupiter next May, then Neptune in 2022, and Pluto in 2024. By 2025, it will coast beyond the outer edge of the Kuiper Belt, a field of icy and rocky objects."

Last month, University of Wisconsin–Madison astronomer Ralf Kotulla and scientists from UCLA and the National Optical Astronomy Observatory (NOAO) used the WIYN Telescope on Kitt Peak, Arizona, to take some of the first pictures of 'Oumuamua. You can check them out below.

Images of an interloper from beyond the solar system — an asteroid or a comet — were captured on Oct. 27 by the 3.5-meter WIYN Telescope on Kitt Peak, Ariz.
Images of 'Oumuamua—an asteroid or a comet—were captured on October 27.
WIYN OBSERVATORY/RALF KOTULLA

U1 spotted whizzing through the Solar System in images taken with the WIYN telescope. The faint streaks are background stars. The green circles highlight the position of U1 in each image. In these images U1 is about 10 million times fainter than the faint
The green circles highlight the position of U1 in each image against faint streaks of background stars. In these images, U1 is about 10 million times fainter than the faintest visible stars.
R. Kotulla (University of Wisconsin) & WIYN/NOAO/AURA/NSF

Color image of U1, compiled from observations taken through filters centered at 4750A, 6250A, and 7500A.
Color image of U1.
R. Kotulla (University of Wisconsin) & WIYN/NOAO/AURA/NSF

Editor's note: This story has been updated.

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Scientists Analyze the Moods of 90,000 Songs Based on Music and Lyrics
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Based on the first few seconds of a song, the part before the vocalist starts singing, you can judge whether the lyrics are more likely to detail a night of partying or a devastating breakup. The fact that musical structures can evoke certain emotions just as strongly as words can isn't a secret. But scientists now have a better idea of which language gets paired with which chords, according to their paper published in Royal Society Open Science.

For their study, researchers from Indiana University downloaded 90,000 songs from Ultimate Guitar, a site that allows users to upload the lyrics and chords from popular songs for musicians to reference. Next, they pulled data from labMT, which crowd-sources the emotional valence (positive and negative connotations) of words. They referred to the music recognition site Gracenote to determine where and when each song was produced.

Their new method for analyzing the relationship between music and lyrics confirmed long-held knowledge: that minor chords are associated with sad feelings and major chords with happy ones. Words with a negative valence, like "pain," "die," and "lost," are all more likely to fall on the minor side of the spectrum.

But outside of major chords, the researchers found that high-valence words tend to show up in a surprising place: seventh chords. These chords contain four notes at a time and can be played in both the major and minor keys. The lyrics associated with these chords are positive all around, but their mood varies slightly depending on the type of seventh. Dominant seventh chords, for example, are often paired with terms of endearment, like "baby", or "sweet." With minor seventh chords, the words "life" and "god" are overrepresented.

Using their data, the researchers also looked at how lyric and chord valence differs between genres, regions, and eras. Sixties rock ranks highest in terms of positivity while punk and metal occupy the bottom slots. As for geography, Scandinavia (think Norwegian death metal) produces the dreariest music while songs from Asia (like K-Pop) are the happiest. So if you're looking for a song to boost your mood, we suggest digging up some Asian rock music from the 1960s, and make sure it's heavy on the seventh chords.

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