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Astrophysicists Detect Gravitational Waves Once Again

The hat-shaped Sombrero galaxy was not involved in the gravitational wave research, but it is lovely. Seen edge-on, it features an unusually large and extended central bulge composed of billions of old stars, while its dust rings harbor many younger and brighter stars. Its center is thought to house a large black hole. Image credit: NASA/Hubble Heritage Team

Just four months after the announcement of the first detection of gravitational waves, physicists say they’ve recorded another burst of these elusive ripples in space-time, again coming from a merging pair of black holes, far beyond our galaxy.

The first gravitation wave detection, announced with great fanfare in February, was sparked by a signal recorded at the twin LIGO detectors on September 14 of last year; this latest signal tripped the detectors on December 26. (The acronym stands for Laser Interferometer Gravitational-wave Observatory.)

“We now know that the first detection wasn’t just luck,” LIGO team member Duncan Brown, of Syracuse University, tells mental_floss. The odds of the earlier signal being a false alarm were on the order of a million to one—but, notes Brown, “people do win the lottery sometimes.” This second detection clinches it, he says. “This tells us that we will be making regular detections of binary black holes” in the coming years.

The LIGO team announced the discovery today at a meeting of the American Astronomical Society in San Diego. Their paper will be published in the journal Physical Review Letters

The paper, which examines data collected by LIGO from September 2015 to January 2016, also hints at a third gravitational wave event, recorded last October, although that event is less certain (and is being described only as a “candidate signal,” and not necessarily a “detection”).

Black holes form when massive stars collapse in the final stage of their evolution. Occasionally black holes end up orbiting other black holes, their orbits gradually shrinking as the system loses energy. Eventually they accelerate and merge, sending a blast of gravitational waves out across the universe.

Until this year, gravitational waves were purely theoretical, a prediction of Einstein’s general theory of relativity, published 100 years ago.

NASA created this visualization of two black holes merging when the discovery of gravitational waves was announced earlier this year.

The black holes that caused the December signal are smaller than those responsible for the earlier event; in this case their masses are believed to have been about 14 and about 17.5 times the mass of the Sun (in the earlier case, they were 29 and 36 times as massive as the Sun). Because of their smaller size, they took longer to execute their final orbits, Brown says. As a result, while the earlier signal was a mere blip, lasting about one-tenth of a second, this event lasted for a relatively leisurely 1.5 seconds. During that time, the two ultra-dense stars, having orbited each other for perhaps 100,000,000 years, performed their final loops. “This time we saw about 30 orbits, before they finally crashed into each other and merged,” Brown says.

The result is an even bigger black hole—though not quite as large as you’d expect by just adding up the masses of the two black holes that gave rise to it. That’s because roughly one solar mass was converted into energy, via Einstein’s famous equation, E = mc2. The magnitude of the explosion boggles the imagination. “When a nuclear bomb explodes, you’re converting about a gram of matter—about the weight of a thumbtack—into energy,” Brown explains. “Here, you’re converting the equivalent of the mass of the Sun into energy, in a tiny fraction of a second.”

As powerful as the blast was—for an instant, it would have produced more energy than all the stars in the universe—the ripples it unleashed were almost vanishingly small by the time they reached the Earth, having traveled across some 1.4 billion light years of space.            

For now, scientists can only estimate what direction these signals have come from; however, their ability to “triangulate” locations will greatly improve when another gravitational wave detector, Italy’s Virgo facility, is incorporated into the network of detectors, possibly as early as this autumn. India and Japan are also set to bring gravitational wave detectors online in the years ahead.

LIGO began operation in 2002, but with only a fraction of its current sensitivity. The detectors, located in Louisiana and in Washington state, were upgraded last fall in an effort known as “Advanced LIGO.” The facility is still operating at just one-third of its potential maximum sensitivity, Brown says.

As gravitational wave observations become routine, physicists will be able to tackle some of the outstanding problems in astrophysics and cosmology—many of which involve the puzzling properties of black holes, as University of Florida physicist Clifford Will tells mental_floss: “Where do black holes come from? Were they born small, and then grow? Or are there mechanisms that can produce 30 or 40 stellar mass black holes from the get-go? Did they form within binary systems? Or did one black hole capture another, later in life? These are the questions that astronomers and astrophysicists will be thinking about.”

Adds Brown: “The field of 'gravitational wave astronomy' is now open for business.”

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What Pop Culture Gets Wrong About Dissociative Identity Disorder
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From the characters in Fight Club to Dr. Jekyll and Mr. Hyde, popular culture is filled with "split" personalities. These dramatic figures might be entertaining, but they're rarely (if ever) scientifically accurate, SciShow Psych's Hank Green explains in the channel's latest video. Most representations contribute to a collective misunderstanding of dissociative identity disorder, or DID, which was once known as multiple personality disorder.

Experts often disagree about DID's diagnostic criteria, what causes it, and in some cases, whether it exists at all. Many, however, agree that people with DID don't have multiple figures living inside their heads, all clamoring to take over their body at a moment's notice. Those with DID do have fragmented personalities, which can cause lapses of memory, psychological distress, and impaired daily function, among other side effects.

Learn more about DID (and what the media gets wrong about mental illness) by watching the video below.

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25 Dapper Outfit Choices for Fashionable Pets
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Lavishing your furry friends with adorable attire is a benefit of pet ownership that they don't mention on the adoption forms. Whether you prefer practical clothing like sweaters and jackets or statement pieces like bow ties and tutus, these dapper duds are perfect for a howl-iday or "gotcha day" gift, or simply for saying, "Who's the cutest little pupper in pajamas? You are!"

1. CASHMERE DOG SWEATER; FROM $165

dog in sweater
Canine Styles

This classic cable-knit cashmere sweater is a sophisticated look for Fido or Finn. Get it from Canine Styles, a luxury dog emporium in New York City that has plenty of posh and preppy outfits.

Find It: Canine Styles

2. TOGGLE DOG COAT; $85

dog in coat
Canine Styles

This toggle coat (available in orange, navy, and tan) is as fashionable as it is warm. Made of Melton wool, it has Velcro closures to make getting dressed easy. It's great for long walks in the country.

Find It: Canine Styles

3. DOG TUXEDO; FROM $90

Dog in tuxedo
Etsy

This satin tuxedo is perfect for the canine members of your wedding party, though it will brighten up any other occasion as well. The custom, handmade outfit comes complete with a snappy bow tie.

Find It: Etsy

4. DOG BELLE DRESS; FROM $45

Dog Belle Dress
Etsy

The queen of your castle can feel like a Disney princess in her very own version of Belle's iconic yellow dress from Beauty and the Beast. This ball gown is made from yellow crepe satin with chiffon overlay on the bodice and features hand-painted gold detailing on the skirt. Enchanted rose not included.

Find It: Etsy

5. POODLE SKIRT OUTFIT FOR DOGS; $26

Rubies Pink Fifties Girl Pet Costume
Amazon

What if you could buy a 1950s poodle skirt for your poodle? This retro dress is comprised of a pink poodle skirt, striped bodice, and sequined belt, and comes with a bow headband.

Find It: Amazon

6. RIBBED CROCHET BUNNY SWEATER; $25

bunny in a sweater
Etsy

Your snuggle-bunny will look like a little fancy-pants in this ribbed crochet sweater. Choose from seven colors, including this dashing deep red.

Find It: Etsy

7. BESPOKE MONOGRAM DOG SWEATER; FROM $155

Dog in sweater
Ruby Rufus

Bespoke clothing isn't just for humans: British luxury dog clothing brand Ruby Rufus will make your pooch a custom monogram sweater made with 100 percent Italian cashmere. You can even order it in your dog's favorite color.

Find It: Ruby Rufus

8. HOT PINK DOG TUTU; $17

Dog in hot pink tutu
Etsy

Tutus look absolutely adorable on tiny humans and animals alike. If your pooch wants to get in touch with its inner ballerina, then grab this hot pink number from Etsy. Rave reviews are a sure thing.

Find It: Etsy

9. PINK DOG POLO SHIRT; $35

Dog Pink Polo Shirt
Canine Styles

This pink polo shirt is perfect for your preppy fur baby. It features not one but a veritable multitude of crocodiles. They'll be the most dapper dog at the country club.

Find It: Canine Styles

10. DOG BARN COAT WITH BROWN CORDUROY COLLAR; $85

Dog in barn coat
Canine Styles

When it's time for a walk, your dog will look effortlessly chic in this fancy barn coat. It comes in navy, cranberry, orange, hot pink, and loden and features convenient pockets for anyone with opposable thumbs.

Find It: Canine Styles

11. WHITE PET NECK RUFF; $26

Pet Neck Ruff
Etsy

Your canine or kitty will look like their painting belongs in London's National Portrait Gallery with this Elizabethan neck ruff.

Find It: Etsy

12. CHICKEN SWEATER; $25

chicken wearing sweater
Etsy

Chickens can get cold when they're strutting around outside. A sweater (well, more like sweater vest) for your bird can also help prevent feather picking during molting season. Or, it can simply keep them warm while they stare pensively across a snowy landscape.

Find It: Etsy

13. PET CIRCLE SCARF; $15

dog in scarf
Etsy

An infinity scarf is a perfect burst of color on a dreary early morning walk. The proprietor of Mitten Made on Etsy originally designed this wool snood for her miniature Dachshund to help keep her warm during the long, cold winters in Michigan.

Find It: Etsy

14. FAB DOG TRAVEL RAINCOAT; FROM $18

Fab Dog Travel Raincoat
Chewy

This timeless yellow rain slicker will look great on any puppy when it's raining cats and dogs. It's made of 100 percent waterproof nylon shell that keeps fur dry. Bonus: It's perfect for an It Halloween costume.

Find It: Chewy

15. LACE CAT OR DOG COLLAR; FROM $10

cat in lace collar
Etsy

This handmade, white lace collar is a must-have for fancy felines. It's also embellished with a large rhinestone.

Find It: Etsy

16. FITWARM PENGUIN PAJAMAS FOR DOGS; FROM $10

Fitwarm Cute Penguin Xmas Dog Pajamas
Amazon

Keep your pupper warm on cold winter nights with these penguin PJs. They're great for doggie sleepovers or lazy weekends on the couch watching Netflix.

Find It: Amazon

17. PLAID CASHMERE DOG COAT; FROM $225

dog in plaid coat
Canine Styles

Your dog will look like a proper gentleman in this smart plaid peacoat. This fine garment is made of cashmere with a faux fur lining and leather buttons, and is a perfect shield against chill and fog.

Find It: Canine Styles

18. SATIN PET BOW TIE; FROM $8

Satin Bow Tie for Dog
Etsy

This satin doggie bow tie is perfect for any occasion. It comes in several colors and features a Velcro fastener that makes it easy to attach to a collar. Plus, 10 percent of every sale goes to charity: specifically to SPCA (Society for the Prevention of Cruelty to Animals) and Feeding Pets of the Homeless.

Find It: Etsy

19. RED DOG DRESS; FROM $34

dog in dress
Etsy

Your good boy or girl will look red carpet-ready in this elegant gown. The voluminous tulle skirt is to die for, and each bow is embellished with beads. Custom orders are also available.

Find It: Etsy

20. DOG TIE; FROM $13

Dog tie
Etsy

Your pooch will be ready to stun at any black tie event. This tie is designed like a collar, making it easy to dress your four-legged friend. This Etsy store gives back: 10 perfect of all sales are donated to an animal protection association.

Find It: Etsy

21. NAUTICAL DOG DRESS WITH MATCHING LEASH; $20

Dog sailor dress
BaxterBoo

Perfect for a day on the town or setting sail in a schooner, this is the sailor outfit you never knew your best furry friend needed. This vintage throwback also comes with a matching leash.

Find It: BaxterBoo

22. TARTAN FLANNEL PET BOW TIE; $5.50

tartan pet bow tie
Etsy

Your dog or cat will turn heads in this flannel tartan bow tie. It has a convenient elastic loop that slides over your pup's collar.

Find It: Etsy

23. PUCCI DOG SHIRT; $23

dog in Pucci dog shirt
Etsy

Only the fanciest dogs wear, err, Pucci. Grab this punny "designer" t-shirt for your pup. This high-quality cotton statement piece is perfect for small breeds.

Find It: Etsy

24. PINK POLKA DOT AND LACE DOG HARNESS DRESS; $20

Pink Polka Dot and Lace Designer Dog Harness Dress
BaxterBoo

This feminine pink polka dot dress is simply adorable. It features a convenient built-in harness and comes with a matching leash.

Find It: BaxterBoo

25. PET SWEATER VEST; $6

pet sweater vest
Amazon

Your dog or cat will look like an erudite Oxford professor in this sweater vest. Note that the button on the pocket is shaped like a bone.

Find It: Amazon

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