Even if you live alone, it’s easy to believe that a tiny man with a hammer takes up residence in your radiator all winter long, happily banging away. What else could explain those sudden, low-pitched clangs, which are as unpredictable as they are annoying? But as SciShow’s latest video explains, tiny drops of water are to blame for the phenomenon.
“You have a central boiler that boils water, and the steam that the boiler makes takes up way more space than it did as a liquid,” host Stefan Chin explains. “As it expands, it pushes itself through a series of pipes. Now, assuming you've opened the intake valve to let the steam into the radiator, it will rush in and push the air out through a small air vent on the opposite end. And when there's enough steam inside the radiator, the pressure causes the vent to close, trapping the steam inside.”
As this steam cools, the radiator’s metal grows warmer. Some of the vapor converts back into water and drips down the pipes, but the steam can also fling droplets of condensed water against the radiator’s inner walls—and that's what causes those startling sounds.
Watch SciShow’s full video below to learn more about why your radiator becomes louder than a mechanic’s garage during the winter.
Along with Mercury in retrograde, the full moon is a pretty popular scapegoat for bad luck and bizarre behavior. Encounter someone acting strangely? Blame it on the lunar phases! It's said that crime rates increase and emergency rooms are much busier during the full moon (though a 2004 study debunked this claim). Plus, there's that whole werewolf thing. Why would this be? The reasoning is that the Moon, which affects the ocean's tides, probably exerts a similar effect on us, because the human body is made mostly of water.
This belief that the Moon influences behavior is so widely held—reportedly, even 80 percent of nurses and 64 percent of doctors think it's true, according to a 1987 paper published in the Journal of Emergency Medicine [PDF]—that in 2012 a team of researchers at Université Laval's School of Psychology in Canada decided to find out if mental illness and the phases of the Moon are linked [PDF].
To test the theory, the researchers evaluated 771 patients who visited emergency rooms at two hospitals in Montreal between March 2005 and April 2008. The patients chosen complained of chest pains, which doctors could not determine a medical cause for the pains. Many of the patients suffered from panic attacks, anxiety and mood disorders, or suicidal thoughts.
When the researchers compared the time of the visits to the phases of the Moon, they found that there was no link between the incidence of psychological problems and the four lunar phases, with one exception—in the last lunar quarter, anxiety disorders were 32 percent less frequent. "This may be coincidental or due to factors we did not take into account," Dr. Geneviève Belleville, who directed the team of researchers, said. "But one thing is certain: we observed no full-moon or new-moon effect on psychological problems."
So rest easy (or maybe not): If people seem to act crazy during the full Moon, their behavior is likely pretty similar during the rest of the lunar cycle as well.
When you agree to be part of a yearlong space study, you forfeit some right to privacy. In astronaut Scott Kelly’s case, the changes his body endured while spending a year at the International Space Station (ISS) were carefully analyzed by NASA, then published in a scientific journal for all to see. Kelly submitted blood samples, saliva samples, and cheek swabs. Even his poop was subjected to scrutiny.
As PBS reports, Scott Kelly’s fecal samples revealed that his gut microbiome underwent significant but reversible changes during his time in orbit. In what was surely good news for both Kelly and NASA, his gut bacteria didn’t contain anything “alarming or scary,” according to geneticist Martha Hotz Vitaterna, and it returned to normal within six months of landing on Earth.
Even after being subjected to the challenging conditions of space, “Scott’s microbiome still looked like Scott’s microbiome, just with a space twist on it,” said Vitaterna, who was one of the study’s authors.
The fecal probe was one small part of a sweeping NASA study that was just published in the journal Science, more than three years after Kelly’s return. Dubbed the Twins Study, it hinged on the results of Kelly’s tests being compared with those of his identical twin, retired astronaut Mark Kelly, who remained on Earth as the control subject.
NASA’s goal was to gain insight into the hazards that astronauts could face on proposed long-term missions to the Moon and Mars. The agency has gone to great lengths to get this information, including offering to pay people $18,500 to stay in bed for two months in order to replicate the conditions of anti-gravity.
It also explains why NASA was willing to launch unmanned rockets into space to collect samples of Kelly’s poop. On four different occasions at the ISS, Kelly used cotton swabs to pick up poo particles. When the rockets arrived to drop off lab supplies, they returned to Earth with little tubes containing the swabs, which had to be frozen until all of the samples were collected. The process was tedious, and on one occasion, one of the SpaceX rockets exploded shortly after it launched in 2015.
The study also found that his telomeres, the caps at the ends of chromosomes, had lengthened in space, likely due to regular exercise and a proper diet, according to NASA. But when Kelly returned to Earth, they began to shorten and return to their pre-spaceflight length. Shorter telomeres have a correlation with aging and age-related diseases. “Although average telomere length, global gene expression, and microbiome changes returned to near preflight levels within six months after return to Earth, increased numbers of short telomeres were observed and expression of some genes was still disrupted,” researchers wrote.
Researchers say more studies will be needed before they send the first human to Mars. Check out NASA's video below to learn more about what they discovered.