It is a cruel irony that the fun of a night of drinking tends to be directly correlated to the level of misery we experience the morning after. And as we get older, it doesn’t get any easier. “At some point,” Dan Brooks wrote in The New York Times Magazine, “we discover that innocent behaviors, like drinking 10 beers and yelling about the Hold Steady until the lights come on, now result in terrible consequences.”

Science has figured out a lot of things — the birth of the universe; cures for diseases; and, magic devices that allow us to communicate with friends, read about hangovers, and argue with strangers on Twitter from just about anywhere. Surely there must be some way to enjoy the revelry of a boozy evening without all the head-throbbing hell of a hangover the next day.

But, until recently, there had been distressingly little serious scientific effort put towards the study of hangovers.The science of why we get hangovers has been mostly an educated guess. Happily, things are starting to change. Over the past few years, researchers have begun to put a dent in the fog surrounding our post-drinking foggy-headedness.

We should all know by now that heavy boozing can have lots of terrible consequences beyond just hangovers. It can cause health problems and prompt bad decisions with life-changing consequences too.

The upside of drinking is that alcohol triggers a release of dopamine and urges to dance on tables and hug your friends while slurring something about “I love you man!” The effect is particularly pronounced in the nucleus accumbens, one of the brain’s pleasure centers and the amygdala, a part of the brain that stores memories of the bad things that happened last time you got drunk and thought it was a neat idea to jump off a hotel balcony into a swimming pool. But, drinking also has effects on the brain and the rest of the body that makes the next day a living hell.

Dehydration is Only Part of It

Dehydration has long been among the more popular explanations for hangovers. But, it turns out that may be wrong — or at least not completely right. Dehydration probably does play some role. Alcohol suppresses vasopressin, an anti-diuretic hormone produced by the pituitary gland that promotes reabsorption of water by the kidneys. A dearth of vasopressin causes the kidneys to allow more water to pass into the bladder rather than being returned to the body, an effect easily observed in the long late-night bathroom lines at bars. In short, and this should come as a surprise to no one, you pee more when you’re drunk. For every refreshing Hendricks’ gin and tonic you drink, you’ll lose anywhere from two to four times as much water.

Dehydration tends to cause headaches, dizziness and other unpleasantries. Still, dehydration alone does not account for the singular agony of a raging hangover. Drinking water or sports drinks will make a hangover a bit less brutal, but it won’t cure it. There must be more too it.

Hangovers and the Brain

You rarely get a hangover while you’re drinking. The hangover starts only after your blood alcohol concentration begins to fall. In fact, hangover severity reaches its peak when blood alcohol levels fall to zero. This provides an important clue.

A typical hangover may just be a milder version of the alcohol withdrawal syndrome suffered by alcoholics who give up the bottle. Which is why the “readministration of alcohol” — science-speak for a morning after Bloody Mary — tends to temporarily make things better. The exact mechanisms for how this happens are just beginning to be understood.

Ethanol in booze binds to nerve receptors normally occupied by gamma-aminobutyric acid (GABA), an important neurochemical messenger that calms brain activity. Awash in GABA-like ethanol molecules after that last round of beer pong, to keep everything in balance, the brain cuts back on GABA and kicks production of an excitatory neurotransmitter called glutamate into high gear.

Meanwhile, down in the liver, your body is furiously filtering out the alcohol you’ve filled it with over the course of the evening. As the alcohol departs, your brain is left with a deficit of GABA and a surplus of high-octane glutamate. The imbalance sends the nervous system into an overexcited state, which is why you wake up suddenly in the night after drinking.

Richard Olsen, a neuro­scientist at UCLA has been studying these neurophysiological effects with an eye towards developing a hangover cure. Olsen thinks a compound that blocks alcohol from acting on certain GABA receptors could mitigate its unpleasant after-effects — and he’s found a promising lead.

Jing Liang, one of Olsen’s graduate students, began testing Chinese herbs traditionally associated with moderating the effects of alcohol. Liang discovered that one herb, called Hovenia, contains a molecule called dihydromyricetin that acts on the right GABA receptor. Controlled experiments with dihydromyricetin in rats and not-so-controlled experiments conducted by Liang, Olsen and their colleagues at local bars following scientific conferences have shown promise.

“Jing [Liang] gave a talk at a meeting about our results, and we invited our friends to the bar afterward to try it out,” Olsen told Wired. “Now, this is not publishable, and you can’t use it for evidence for the FDA, but it’s good for us to know what kind of dose we should be using in our clinical trial—and that it doesn’t hurt anybody and does something to us that we want.”

The scientists who took dihydromyricetin before drinking reported feeling less drunk, and less hangover the next day, according to Wired.

Several anti-hangover supplements are now on the market boasting dihydromyricetin as an active ingredient.

Another group of researchers led by Dutch scientist Joris Verster, have styled themselves as the Alcohol Hangover Research Group, or AHRG for short. AHRG has been developing some important new science on the topic. They even made a logo — a beer and an empty wine glass lying on its side.

Verster and his AHRG colleagues favor a theory that actually an inflammatory response is a likely culprit. Studies have found elevated levels of cytokines, which are signaling molecules released in response to trauma and inflammation, after drinking. It turns out, that injecting cytokines in otherwise healthy people creates symptoms that closely resemble a hangover. As Adam Rogers wrote for Wired:

A team in Korea noticed that hangovers are accompanied by elevated levels of molecules called cytokines, which are used as communication signals by the immune system. If you inject those into a healthy subject, that person will start to have all kinds of familiar-sounding symptoms, including nausea, gastrointestinal distress, headache, chills, and fatigue. Potentially even more interesting, higher-than-normal cytokine levels also interfere with memory formation—which might account for ethanol-­related lapses in recall as well.

This explains why Nonsteroidal Antiinflammatory Drugs (NSAIDs) such as Ibuprofen work reasonably well at moderating the effects of hangovers. Perhaps more sophisticated anti-inflammatory drugs could be developed that work even better.

Another contributing factor might be acetaldehyde, which is produced as alcohol is metabolized in the body. Most people break it down before it becomes much of a problem. But, acetaldehyde is toxic and if you drink enough, you’ll probably be hugging the toilet as your body tries to expel it.

Trace chemicals and impurities called congeners may also contribute to hangovers too. Joris Vester studied these effects and created this useful chart:

Methanol, a byproduct of fermentation found in higher levels in whiskey and red wine, might be part of the reason these drinks cause worse hangovers than high-quality vodkas, which have almost no congeners at all. Sugary drinks could also trigger blood sugar effects that compound the consequences.

Let’s be clear, getting blitzed is not a great idea. But, if you must, science is here to help:

• Drink High-Quality Vodkas — Higher-end vodkas with fewer congeners are less likely to produce hangovers. If you’re going to drink a lot, splurging on the top-shelf stuff may be worth it. Avoid bourbons, which contain the most congeners. Also, binge drinking red wine, which also contains a lot of congeners, isn’t the brightest move either.
• Drink Lots of Water — Dehydration isn’t the only cause of a hangover, but every little bit helps. Drinks with lots of electrolytes like Pedialyte and Gatorade are good too.
• Take NSAIDS — Taking a couple ibuprofen or aspirin before bed after drinking can work wonders. Just don’t take Tylenol. It inhibits liver function and can theoretically kill you if you take it while drinking.
• Hair of the Dog May Work…Temporarily — It’s merely delaying the inevitable, but if you want to fend off your hangover for a bit longer, and you haven’t had too much, a few mimosas might help.
• Dihydromyricetin Supplements — Although there are as yet no conclusive studies, they seem to work in rats and, at least anecdotally, seem to help with people too.

Much of what you think you know about Christmas is wrong: Christmas is the day Jesus was born (it’s not); it’s a timeless tradition of family togetherness (nope); and, by the way, your Christmas tree? It’s totally a pagan symbol.

1. Christmas Was Once a Rowdy Street Party

The time of family togetherness — and shopping — that we now associate with Christmas is a relatively recent invention. Up, until the 19th century, Christmas was a wholly different affair. What was it like? The words to “We Wish You a Merry Christmas” provide a hint: “bring us some figgy pudding” “and a glass of good cheer,” and by the way, “we won’t leave until we get some.” What’s all this about demanding pudding and booze and refusing to leave until it’s provided? Seems kind of pushy.

Now bring us some figgy pudding
Now bring us some figgy pudding
And a glass of good cheer.

Good tidings we bring to you and your kin
We wish you a Merry Christmas and a Happy new Year

We won’t go until we get some
We won’t go until we get some
We won’t go until we get some, so bring some out here

That’s because, until the 19th Century, most working-class people spent Christmas at the pub getting sloshed before stumbling out into the street and going from house to house demanding food and drink. In a way, it was like drunken adult Halloween, minus the trouble of having to find a costume. As The Economist explained in this years Christmas Double Issue, “Mostly this was tolerated in good humour—a kind of ritualised disorder, when the social hierarchy was temporarily inverted.”

Early Puritan colonists in Massachusetts actually canceled Christmas altogether. (Leave it to the Puritans to spoil all the fun.) By the mid-nineteenth century, as the industrial revolution moved more people into cities, things started to get out of control. Christmas celebrations often were hard to distinguish from street riots. Newspapers started to encourage people to stay home with their families, and soon, new Christmas traditions were born.

2. The Star of Bethlehem Might Not Be a Star at All

There are a number of theories to explain just what it was the Wise Men saw, but among the most promising is that it wasn’t a star at all, rather it was a rare triple conjunction of Saturn and Jupiter. When this happens, the earth, sun and Saturn and Jupiter line up three times in a short period of time. This would create a remarkable sight in the sky sure to catch the attention of the Wise Men, who are thought to be astrologers from Babylon — present-day Iraq.

One of the unusual aspects of the biblical story is that the Wise Men saw the star in their home country, then saw it again after meeting King Herod in Jerusalem and followed it to Bethlehem. The appearance and disappearance of a triple conjunction would explain this.

There was a triple conjunction in 7 BC, on May 29, Sept. 29, and Dec. 4. Jesus birth came in the time of King Herod, according to the Bible. Herod is thought to have died in 4 BC. So, it would have been three years before Herod’s death, which would have fit the biblical timing.

There are other theories too, including a comet noted by Chinese astronomers in 5 BC in the constellation Capricorn, a Nova (the bright birth of a new star), and other planetary alignments. Dr. David Hughes, a physicist at the University of Sheffield in England published an exhaustive study of all the competing theories in the scientific journal Nature in 1976 and included an interesting chart illustrating how well they track with the timing in the biblical account.

But, the triple conjunction theory fits all the facts of the biblical account well, says Tim O’Brien, who is associate director of Jodrell Bank Observatory in Cheshire, England. “You would [only] get a triple conjunction like this about every 900 years,” he says. So, it would clearly portent something important. “A triple conjunction of this kind ticks all the boxes.”

3. Jesus Wasn’t Born on Dec. 25

There’s nothing in the Bible to suggest Dec. 25 as the day of Jesus birth. Early Christians chose various days to celebrate the Messiah’s birth before eventually settling on Dec. 25. The Roman emperor Constantine proclaimed Jesus was born on November 18th. A third century Christin document thought to have originated in North Africa pegs it as March 28. Either are more likely candidates than December 25th.

In Luke’s gospel (Luke 2:7-8) shepherds are said to have been watching over there flocks at night.

7 and she gave birth to her firstborn, a son. She wrapped him in cloths and placed him in a manger, because there was no guest room available for them. 8 And there were shepherds living out in the fields nearby, keeping watch over their flocks at night.

December would have been cold and rainy in ancient Judea, so shepherds would be unlikely to be tending their flocks outdoors. In December, they would bring their flocks into a shelter at night. Shepherds would only have their flocks outside at night in the spring or early fall. Further, the biblical account in Luke (Luke 2:1-4) also tells us that Jesus was born around the time of a Roman census.

2 In those days Caesar Augustus issued a decree that a census should be taken of the entire Roman world. 2 (This was the first census that took place while[a]Quirinius was governor of Syria.) 3 And everyone went to their own town to register. 4 So Joseph also went up from the town of Nazareth in Galilee to Judea, to Bethlehem the town of David, because he belonged to the house and line of David.

These didn’t occur in the winter when rain and rutted roads would have made travel arduous. Generally, a census would take place in the spring or summer when the weather was better. In fact, there’s actually no real evidence at all that Jesus was born on December 25th. That date was chosen for other reasons (more on that later).

4. Christmas is Probably a Repurposed Pagan Holiday

The reason we celebrate Christmas on December 25th goes back to Ancient Rome. The first time we hear of Jesus birth date as December 25th is centuries later in a fourth-century Roman almanac.

The most popular theory for how we settled on December 25th is that it coincided with the Roman pagan festival of Saturnalia, which took place in late December to coincide with the winter solstice. The Roman Emporer Aurelian set the date of the feast of Sol Invictus, the pagan sun god, as December 25th in 274 AD. It’s very plausible that early Christians simply repurposed the feast of Sol Invictus for the celebration of Jesus’ birth.

Recruiting pagans to Christianity, was a priority of early Christians. Fixing the celebration of Christ’s birth to an already established pagan holiday may have made it more attractive to potential converts says historian William Walsh. “[T]he important fact then … to get clearly into your head is that the fixing of the date as December 25th was a compromise with paganism” (William Walsh, The Story of Santa Klaus, 1970, p. 62).

However, Christian writings from around this time make no reference to this. Instead, they see the coincidence of Christ’s birth with the solstice as an auspicious sign. Early Christians weren’t known to adopt other pagan customs, that came later. It wasn’t until the reign of Emperor Constantine a century later that Christians began to adopt some aspects of pagan culture, such as turning pagan temples into churches.

Another theory is that the timing of Jesus’ birth was set to the timing of Jesus Crucifixion. The Biblical account tells us the crucifixion took place during Passover, so early Christians had a more precise idea about its date. Third century Christians thought that Jesus’ death and conception, later celebrated as the Feast of the Annunciation, occurred on the same day. C.E. Tertullian of Carthage calculated that the date for both was March 25. Add nine months, and you get December 25th.

5. The Christmas Tree Began as a Pagan Custom

Our contemporary celebration of Christmas includes many pagan trappings. But, most came later. Many pagan cultures had traditions of bringing greenery into the home around the winter solstice to represent new life and renewal amid the bleak mid-winter gloom. The Christmas tree first emerged in 16th and 17th century Germany. But, Christmas trees were not widely seen in England and the United States until the mid-nineteenth century when Queen Victoria, borrowing a tradition from the childhood of her German mother, displayed a Christmas tree at Windsor Castle. An illustration of Victoria and Albert’s Christmas tree was published in the London News in 1848 and was republished in America two years later. From then on, Christmas trees were a hit.

The true meaning of Christmas has little to do with what date you celebrate it or how. There’s nothing in the Bible that tells us how we should celebrate it, or even that we must celebrate it at all. Over the centuries, ideas and traditions have been borrowed from different cultures to create the festive joyous season that we celebrate now as “the most wonderful time of the year.”