Month: January 2017

In the fall of 1979, a group of unknown actors, a director desperate for a hit, and a special effects visionary got together in the woods of New Jersey to create the stuff of legend. Friday the 13th was supposed to be a simple exercise in good movie business, a film that would make money thanks to clever manipulation of the horror genre and some gory scares. Instead, it became a watershed moment in horror filmmaking, a landmark that has inspired countless imitators and nearly a dozen sequels.

Today, Friday the 13th is an essential slasher classic, but the road to success wasn’t exactly easy. To celebrate the film, and its often tumultuous production, here are 17 facts about the birth of the legend of Jason Voorhees.

1. THE ORIGINAL INSPIRATION WAS HALLOWEEN.

In 1978, producer and director Sean Cunningham was looking for a model on which to build a commercially successful film, and he found one in John Carpenter’s horror classic Halloween. The two films ultimately don’t share much other than very broad slasher tropes, but Cunningham says he “was very influenced by the structure of Carpenter’s film.”

2. THE FILM WAS BEING ADVERTISED BEFORE IT EVEN HAD FINANCING.

Hoping to drum up publicity for his project, Cunningham took out an ad in the July 4, 1979 edition of Variety, featuring the film’s now-iconic logo bursting through glass. At the time, the general structure of the film was in place, but Georgetown Productions had not yet fully agreed to finance it, and the advertised November 1979 release date was a pipe dream. Still, Cunningham did get a response from the ad.

“Everybody wanted this film,” he later said.

3. THE SCREENWRITER HAD A DIFFERENT TITLE IN MIND.

Though Cunningham very quickly latched on to the idea of Friday the 13th as a title, well before the film got made, screenwriter Victor Miller originally came up with something else. In the spring of 1979, he was calling the film Long Night at Camp Blood.

4. MANY OF THE SPECIAL EFFECTS WERE “BAKED” IN THE CAMP’S KITCHEN.

Tom Savini is now a makeup effects legend thanks, in part, to his work on Friday the 13th. And in making the film, he and assistant Taso Stavrakis actually ended up using the camp to finalize the special makeup effects. According to Savini, many of the latex appliances ultimately used to create the film’s gruesome murders were baked in the pizza ovens at the camp where the movie was filmed.

5. THE CAMP USED FOR FILMING IS STILL OPERATIONAL.

Camp Crystal Lake is actually Camp No-Be-Bo-Sco, a fully operational camp that the cast and crew were granted access to after campers left for the summer in 1979. It is still in use today.

6. KEVIN BACON WAS NOT THE FILM’S BIGGEST STAR AT THE TIME OF SHOOTING.

Though he’s without question the biggest name in the movie now, Kevin Bacon hadn’t done much prior to Friday the 13^th, apart from things like a small role in Animal House. At the time, the film’s biggest name was Harry Crosby, son of then-recently-deceased legendary singer Bing Crosby, who played Bill.

7. SHELLEY WINTERS WAS THE FIRST CHOICE FOR MRS. VOORHEES.

For the now-iconic role of Mrs. Pamela Voorhees, Cunningham and company went in search of an actress with a recognizable name whose career was nevertheless on the decline, so she could be paid relatively little and the budget could stay low. Cunningham eventually made a list of actresses he was considering, and two-time Oscar winner Shelley Winters was his top priority. Winters wasn’t interested, and while fellow candidate and Oscar-winner Estelle Parsons actually negotiated to be in the film, she ultimately backed out. Cunningham also considered actresses Louise Lasser and Dorothy Malone right up until filming began, but ultimately the production wound up with Betsy Palmer in the role.

8. BETSY PALMER TOOK THE PART SO SHE COULD BUY A NEW CAR.

When Cunningham finally got around to offering Palmer the part of Mrs. Voorhees, she suddenly found herself in need of cash. After more than a year on Broadway, her car broke down as she drove back to her home in Connecticut. She might never have taken the movie if she hadn’t needed the money for a new car.

“I got home at five in the morning, and it was a situation where I desperately needed a new car,” Palmer said. “If I hadn’t needed a car, I don’t think I would’ve done Friday the 13th.”

9. SEVERAL CREW MEMBERS PLAYED THE KILLER BEFORE PALMER WAS CAST.

Even as filming got underway, Cunningham was still looking for an actress to play Mrs. Voorhees, so many of the early murder scenes were actually shot without Betsy Palmer, with members of the crew standing in for the hands of the murderer. For example, when Annie’s (Robbi Morgan) throat is cut early in the film, special effects assistant Taso Stavrakis is the one wielding the knife.

10. BETSY PALMER GAVE MRS. VOORHEES A DETAILED BACKSTORY.

When she was finally cast, Palmer dove deep into her character. As a Method actor, she wanted to know more about the character than the audience, and came up with a backstory that built on the killer’s hatred of sexual transgression. In her mind, Pamela had Jason out of wedlock with a high school boyfriend, and her parents ultimately disowned her for her sins because that “isn’t something that good girls do.”

11. JASON WAS JUST A REGULAR KID IN THE FIRST DRAFT.

In Victor Miller’s original script, the character of Jason Voorhees was, basically, just a kid who accidentally drowned in Crystal Lake. But financier Philip Scuderi wanted something more, and brought in screenwriter Ron Kurz for some rewrites. One of Kurz’s most important contributions to the film was to transform the tragic boy into the deformed child we see in the final movie.

12. DURING FILMING, THE CREW WAS ENTERTAINED BY LOU REED.

Because the camp was closed during filming, and situated in the deep New Jersey woods, the cast and crew didn’t see much outside interference, but it turned out they had a very famous neighbor: Rock star Lou Reed, who owned a farm nearby.

“We got to watch Lou Reed play for free, right in front of us, while we were making the film,” soundman Richard Murphy said. “He came by the set and we hung around with each other and he was just a really great guy.”

13. ONE ACTOR WAS TEMPORARILY BLINDED BY FAKE BLOOD.

For the scene in which Bill (Harry Crosby) is killed by multiple arrows, one of which lands in his eye, Tom Savini used a fake blood formula that included a wetting agent called PhotoFlo, which was supposed to make the fake blood soak into clothing and look more realistic. Unfortunately, PhotoFlo is not an ingredient used for “safe blood,” meaning blood that’s going to be encountering the face of an actor. For the arrow-in-the-eye moment, a latex appliance was applied to Crosby’s face, along with the blood. As the scene was shot, the blood welled up into Crosby’s eyes, causing intense pain when the appliance was removed.

“So our unsafe blood had an opportunity to fill up Harry’s eyes under the appliance used to keep the arrow looking like it was in his eye and it surface-burned poor Harry,” Savini said. “Not a proud moment.”

Crosby had to be taken to the hospital for treatment, but was ultimately fine.

14. KEVIN BACON’S ICONIC DEATH TOOK HOURS TO FILM (AND ALMOST DIDN’T WORK).

Perhaps the most iconic death in the film occurs when Jack (Kevin Bacon) is killed with an arrow shoved through his throat from underneath the bed he’s lying on. It’s a brilliant special effects moment, and was also the most complex death scene in the film. To make it work, Bacon had to crouch under the bed and insert his head through a hole in the mattress. Then, a latex neck and chest appliance were attached to give the appearance that he was actually lying down. Getting the setup right took hours, and Bacon had to stay in that uncomfortable position the entire time. For the bloody final moment, Savini—also under the bed—would plunge the arrow up and through the fake neck, while his assistant—also under the bed—operated a pump that would make the fake blood flow up through the appliance. To further complicate things, the crew needed someone to stand in for the killer’s hand as it held Bacon’s head down, and they settled on still photographer Richard Feury.

So, after hours of setup and latex building and planning, it was finally time to shoot the scene, and when the moment of truth came, the hose for the blood pump disconnected. Knowing that he basically only had one take (otherwise they’d have to build a new latex appliance and set everything up again), Stavrakis grabbed the hose and blew into it until blood flowed out, saving the scene.

“I had to think quick, so I just grabbed the hose and blew like crazy which, thankfully, caused a serendipitous arterial blood spray,” Stavrakis said. “The blood didn’t taste that bad either.”

15. THE FINAL SCARE WAS SUPPOSEDLY NOT IN THE ORIGINAL SCRIPT.

The story of who invented the final scare in the film, in which a deformed Jason bursts out of the lake and grabs Alice (Adrienne King) from her canoe, is disputed. Victor Miller, Tom Savini, and uncredited screenwriter Ron Kurz all claim credit for it, Kurz because he claims to be the one who made Jason into a “creature,” and Savini because he claims the moment was inspired by a similar final scare in Carrie. Whatever the case, it left a lasting impression.

16. THE MAIN THEME MUSIC CAME FROM A LINE OF DIALOGUE.

When composing the score for the film, composer Harry Manfredini was looking for a distinctive sound to identify any point when the killer appeared in a scene. When he first saw a print of the film, he heard Mrs. Voorhees, imitating Jason, saying “Kill her, Mommy!” and decided that was the key. So, he took two syllables from that line of dialogue, spoke them himself, and made the iconic sound.

“So I got the idea of taking the ‘ki’ from ‘kill’ and the ‘ma’ from ‘mommy,’ but spoke them very harshly, distinctly, and rhythmically into a microphone and run them through this ’70s echo thing. It came up as you hear it today! So every time there was the perspective of the stalker, I put that into the score,” Manfredini said.

17. THE SCREENWRITER HATES THE SEQUELS.

One of the key twists of the original film, particularly in light of its many sequels (counting a crossover with A Nightmare on Elm Street and a reboot, there are 11 now), is that Jason is not actually the central figure. He provides a haunting mythology, but the real villain is his mother. For screenwriter Victor Miller, this was very important, and he framed Pamela Voorhees as the mother he never had, a woman who tirelessly professed love in her own crazy way. When the film became a hit, and the inevitable sequel featured Jason as the new killer, Miller was disappointed.

“To be honest, I have not seen any of the sequels, but I have a major problem with all of them because they made Jason the villain,” Miller said. “I still believe that the best part of my screenplay was the fact that a mother figure was the serial killer—working from a horribly twisted desire to avenge the senseless death of her son, Jason. Jason was dead from the very beginning. He was a victim, not a villain. But I took motherhood and turned it on its head and I think that was great fun. Mrs. Voorhees was the mother I’d always wanted—a mother who would have killed for her kids.”

Additional Sources: On Location In Blairstown: The Making of Friday the 13^th by David Grove (2013)

 
While the United States deals with its usual conga line of snow and ice storms that are a frequent visitor in the middle of winter, our closest ally across the pond found itself in the midst of an unusual situation: not only did parts of typically temperate Great Britain see a decent amount of snow this week, but the snow was accompanied by thunder. Parts of the United Kingdom experienced thundersnow as a potent winter storm brought heavy precipitation, blustery winds, and the threat of significant coastal flooding to Scotland and England.

A strong ripple in the jet stream allowed a low-pressure system to develop near Scotland and work its way down the eastern English coast late this week, bringing more than half a foot of snow to higher elevations of Scotland and coating areas as far south as London with a light dusting of snow. That doesn’t sound like much, but just like bigger cities in the United States, even a small amount of snow can cause mass chaos if it hits at the wrong time. The storm led to mass flight cancellations, snarled highway traffic, and even caused thousands of evacuations along the coast, where authorities worried that a storm surge—sea water pushed inland by strong winds—would inundate coastal communities.

But the adverse impacts of the snowstorm were overshadowed in news coverage by that unusual buzzword: thundersnow. Thundersnow occurs during a thunderstorm that produces snow instead of rain. The mechanisms that produce rainy thunderstorms and snowy thunderstorms are largely the same, even if the air temperature is below freezing.

A band of snow can become strong enough to produce lightning through two processes known as convection and forcing. Convection occurs when an area of warm air quickly rises through cooler air above it. Convective snow is most common during lake effect snow events like those you’d find on Lake Ontario or Lake Erie, since the process requires extreme vertical temperature gradients that can result from bitterly cold air flowing over a warm body of water.

The other process, known as forcing, is what caused the thundersnow in the United Kingdom this week. A strengthening low-pressure system involves fast, dynamic changes in the atmosphere, especially when one of these storm systems quickly gains strength. Such a fast-developing storm can cause large amounts of lift in the atmosphere, a process that forces air to swiftly rise like you’d see during convection. This creates intense bands of snow that can grow so strong that they produce thunder and lightning. This process is responsible for the thundersnow that occurs during blizzards and nor’easters, those powerful storms that regularly hit the U.S. East Coast during the winter. Thundersnow can be pretty exciting—just ask The Weather Channel’s Jim Cantore:

The name “thundersnow” can be a bit misleading. One of the most enjoyable things about a snowfall is how silent it is outside when there’s a thick blanket of snow on the ground. Snow absorbs sound waves so efficiently that you can usually only hear ambient noises immediately around where you’re standing. Snow muffles the sound of thunder for the same reason. Thunder that might be audible for many miles during a rainy thunderstorm might only be audible for a few thousand feet away from where the lightning struck. Unless the lightning strikes very close to where you are, you might only see a bright flash during thundersnow without ever hearing the thunder.

While thundersnow is a fascinating phenomenon to encounter, it does involve lightning, after all, and it’s just as dangerous as any other lightning bolt you’d see in a rainy thunderstorm. If you’re ever lucky enough to experience thundersnow, the event is best enjoyed indoors and out of harm’s way.

The giraffe’s closest living relative is a striped, long-tongued beast called the okapi. These forest-dwelling creatures are elusive—so much so that the species wasn’t discovered by western scientists for centuries. Here’s what every animal enthusiast should know about okapis.

1. OKAPIS WERE UNKNOWN TO SCIENCE UNTIL FAIRLY RECENTLY.

While traveling through central Africa in the 1800s, European explorers would sometimes hear reports of a shy, hoofed, forest-dwelling mammal with distinctive striped hindquarters. During the late 1870s/’80s, a Russian adventurer named Wilhelm Junker managed to obtain a sample of the animal’s hide. Noting its stripes, he misidentified its owner as some new species of zebra, antelope, or chevrotain.

Rumors about the mystery creature eventually reached Sir Harry Hamilton Johnston, a British colonial administrator with a passion for biology. In 1899, he was appointed Special Commissioner of Uganda, and the following year, Johnston was given two shoulder belts made with the skins of an animal the locals called “o’api.” Then, in 1901, he received three more specimens: an entire hide and two isolated skulls. Their anatomy demonstrated that the species was in fact a close cousin of the giraffe. By the end of the year, a correspondent of Johnston’s had announced the existence of this animal—which we now know as the okapi—in a scientific paper, with the scientific name Okapia johnstoni.

2. OKAPIS AREN’T SOCIABLE.

How did the okapi, which stands over 5 feet tall and can weigh between 440 and 770 pounds, go undiscovered by scientists until 1901? The species’s preferred habitat played a big role in keeping it off the radar. Even today, scientists have a hard time locating or monitoring okapis because they live in dense, inhospitable forests. Since the striped herbivores are so difficult to observe in the wild, we know very little about their social habits. But with this said, it would appear that okapis lead a solitary existence. According to data collected from radio collars, adults spend most of their lives inside of a territory that might overlap with those of other individuals, but okapis seldom cross paths. While newborn calves will hang around their mothers until they mature, the evidence suggests that full-grown okapis—unlike giraffes—don’t travel together (although other researchers have noted that okapis might travel in pairs on rare occasions).

3. PROPORTIONATELY, OKAPIS HAVE LONGER TONGUES THAN GIRAFFES DO.

Both of these herbivores have long, prehensile tongues that help them pull leaves off of tree limbs. The tongues are bluish or grayish in color over the first several inches, which scientists believe prevents them from getting sunburned. A giraffe can be up to 19 feet tall—so relative to its smaller body size, the okapi’s 14- to 18-inch tongue is more impressive than the giraffe’s 20-inch tongue.

4. THE SPECIES’S RANGE IS NOW CONFINED TO ONE COUNTRY.

We know from a range of evidence that okapis once lived in Uganda. Unfortunately, they seem to have gone extinct there. Currently, wild okapis can only be found within the neighboring Democratic Republic of the Congo, where they live in the dense forests of the northern and central recesses. Population estimates vary, but most scientists think that just 10,000 to 50,000 non-captive okapis are left in the world. They’ve recently been classed as endangered across their entire range.

5. ONLY MALES HAVE HORNS.

Okapis are sexually dimorphic, which means there are visible differences between the sexes that have nothing to do with their reproductive organs. For example, male okapis have a horn structure called an ossicone (like a giraffe), but females don’t have real horns, and instead have bumps. When mating season arrives, rival bucks will often use the horns to flank one another.

6. OKAPIS SOMETIMES EAT CHARCOAL.

These browsers subsist on a varied diet that includes the seeds, fruits, and leaves of more than 100 different types of plants, and the occasional fungi. To obtain important minerals, okapis will also lick clays that they find at riverbanks and eat charcoal off of scorched trees.

7. BABIES CAN GO OVER A MONTH WITHOUT POOPING.

Nobody knows why, but newborn okapis usually don’t defecate for the first time until they’re four to 10 weeks old. (But it’s still unknown how much the peculiar situation of zoos affects this timeframe. Until the late 1970s, many baby okapis were suffering from rectal prolapse because of bored mothers overlicking their young’s rectal area.) This could be a survival strategy: Fecal material can attract predators, so maybe the absence of bowel movements early on helps to conceal the calves’ scent from leopards and other carnivores.

8. THEIR FEET RELEASE A FOUL-SMELLING SUBSTANCE.

On each foot, an okapi has a peculiar gland that sits between the toes and secretes a pungent, waxy material often described as tar-like—and during forest excursions, they sometimes leave that material behind. It’s been speculated that this helps okapis mark their territories, which they’ll also do by spraying urine over shrubs. While an adult female will generally ignore other individuals who wander onto her home range, males apparently behave aggressively towards each another and try to ward off intruders of their own sex. (In the process, those horns are put to good use.)

9. OKAPIS HAVE AN UNUSUAL GAIT.

Giraffes and okapis differ from the majority of quadrupedal animals in the way that they walk. To get from Point A to Point B, most quadrupeds—including dogs and cats—will simultaneously move one leg on their right side and another leg on the left side. In contrast, okapis and giraffes swing both right limbs forward at the same time, then they’ll do likewise with both left limbs. (For a visual aid, check out the above video.) However, when there’s a need for speed, the two species will gallop in a horse-like manner.

10. THEY EMIT NOISES THAT ARE TOO LOW FOR THE HUMAN EAR TO DETECT.

Okapis may not be the most vocal of animals, but they aren’t mutes either. “We hear coughs, bleats, and whistles quite often,” Dr. Matt Anderson, a behavioral ecologist who’s studied the okapis at the San Diego Zoo, notes in a blog post. Mothers will also communicate with their calves by releasing infrasounds—noises that fall below the normal limits of human hearing. Bioacoustics expert Elizabeth von Muggenthaler recently discussed this phenomenon in a 2013 paper. By keeping close tabs on okapi behavior, she’s found that you may be able to tell when an okapi is making infrasounds by watching the creature’s body language. As they generate ultra-low-frequency calls, the animals are known to rapidly jerk their heads upward and point their noses to the sky [PDF].

11. NOT ALL OKAPIS HAVE THE SAME NUMBER OF CHROMOSOMES.

Human cells generally contain 23 pairs of chromosomes, or 46 in total. Dog cells have 78 overall while 38 can be found in those of cats. But okapis are different. Although most have 46 per cell, a few specimens feature 44 or 45. What’s truly baffling about this is that okapis with an atypical chromosome count appear perfectly normal and healthy. The individuals who have 45 per cell are especially perplexing. Animals with an odd number of chromosomes usually exhibit physical abnormalities. Yet in a bizarre twist, the 45-chromosomed okapis look ordinary, as do their offspring. Geneticists are still trying to figure out what’s going on here.

The data collected by wearable devices may be able to tell you much more than how many steps you’ve taken or hours you’ve slept. A new long-term study from researchers at the Stanford University School of Medicine suggests that fitness monitors, smart watches, and other wearable biosensors may be able to detect initial signs of illness before the wearer has noted any symptoms, according to a New Scientist report.

The results were published on January 12 in PLOS Biology. More than 40 individuals participated in the study and used wearable devices for up to two years. Researchers used the gadgets to track subjects’ pulse rates, skin temperature, and other measurements, and monitored when they deviated from normal baseline measurements. Sure enough, the researchers noticed that subjects exhibited an elevated heart rate up to three days before exhibiting signs of a cold or infection. Their skin temperature was sometimes higher, too.

“We think that if your heart rate and skin temperature are elevated for about two hours, there’s a strong chance you’re getting sick,” the study’s lead author, Michael Snyder, told New Scientist. (Snyder experienced the phenomenon first-hand when he received an early warning from a wearable that he had contracted Lyme disease during an excursion to rural New England.) Researchers also noticed that variations in heart rate patterns could distinguish between participants with insulin resistance (a risk factor for Type 2 diabetes) and healthy subjects, CBS News reports.

The research at this stage is still experimental, but Snyder and his colleagues are hoping to use what they’ve learned to build algorithms that let smart devices notify their wearers when they may be falling ill. Though the inevitable is still likely to occur, that way smart device owners will have been given fair warning—which means they can rest up and take care of themselves.

[h/t New Scientist]

Among the many upsides to being British royalty, there is this: You never have to use a last name. For one thing, everyone already knows who you are. There’s only one Queen, for instance, so it’s not like Elizabeth has to specify which one she is.

However, the British royal family does have a last name, as Business Insider reminds us. The British royal family’s last name is technically Windsor, but that’s a relatively new development.

Before 1917, royals were usually known by the territory they ruled or the Royal House of which they were a member, as the Royal Family’s website explains. For example: The full name of Queen Victoria’s eldest son, King Edward VII, was Albert Edward Saxe-Coburg-Gotha—a mouthful he inherited from his father, Prince Albert of Saxe-Coburg and Gotha.

In 1917, though, Edward’s son, George V, was presented with a conundrum: His surname sounded somewhat German, which was an unwelcome association during World War I, so he named his family after Windsor Castle. Since then, any descendants of Queen Victoria (aside from married women) bear the last name Windsor.

In 1960, to make things more confusing, Queen Elizabeth II and her husband, Prince Philip, decided to add their own spin to the Windsor name, distinguishing their descendants from the rest of the royal family. So her children and their children can use Mountbatten-Windsor as their surname on official documents such as marriage and birth certificates. (Fans of Netflix’s The Crown caught a glimpse of the discussions that went into the surname decision, though the series didn’t tell the full story.)

Kings and queens are welcome to change the last names of their family at will, since it’s a matter of precedent rather than an official decree. And royals sometimes adopt other names when it’s convenient. Princes Harry and William used Wales as their last name while serving in the military, adopting their father’s designation as the Prince of Wales.

With such a complicated naming protocol, it’s no wonder most Royal Family members go by their titles instead.

[h/t Business Insider]

Have you got a Big Question you’d like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

It’s a traveler’s worst nightmare: You arrive at the airport looking forward to a much-needed vacation only to learn your seat has been bumped. Unfortunately for frequent fliers, this is an unavoidable risk of traveling, and the video below from TED-Ed illustrates why.

In this animated lesson, Nina Klietsch explains that an airline’s decision to overbook flights is based on probability. For the same reason that doctors keep patients waiting past their appointment time and hotels turn away guests with reservations, airlines sell more seats than they have under the assumption that a certain number of fliers won’t show up.

This assumption is built on carefully calculated statistics. Factors like traffic, weather, and time of day are all plugged into algorithms that determine how many extra seats an airline should sell for a certain flight. Chances are that enough people will miss the flight to make overbooking the profitable choice, but there’s a small chance that more people will check in than expected and leave some unlucky passengers feeling cheated.

Though there’s no way to guarantee your seat is secure when you book it, there are a few steps you can take to increase your chances of getting on the plane. Check in early and board the plane as soon as you’re able to do so. Paying more money for a higher class ticket also lowers the likelihood of getting bumped from a flight (though getting downgraded to a cheaper seat with an unfair refund is also a possibility). Lastly, if you do find yourself on an overbooked flight, never volunteer to take one for the team. Passengers who are bumped involuntarily receive more compensation than if they had elected to miss the flight.

[h/t TIME Money]

by Jeva Lange

Readers with triskaidekaphobia, avert your eyes now:

✈️️ Finnair flight 666, at 13 o’clock on Friday the 13th with a 13 year old aircraft, has landed safely in HELhttps://t.co/0kWfkcARmO pic.twitter.com/OPvpyyq4F4

— Flightradar24 (@flightradar24) January 13, 2017

All the omens were seemingly against Finnair flight 666 making it from Copenhagen to Helsinki without a layover in The Twilight Zone, but flight tracker FlightRadar24 reports the plane has landed safe and sound.

@flightradar24 Who the heck would get on this flight?

— High Altitudes (@highaltitudes) January 13, 2017

The number of rabbits feet, horseshoes, and lucky pennies that were on board is unknown.