Scientists have confirmed the existence of lonsdaleite, a rare hexagonal form of diamond named after British crystallographer Kathleen Lonsdale, in ureilite meteorites from the mantle of a planet in our solar system.

According to the new findings, a large asteroid probably collided with the planet collided about 4.5 billion years ago, and the hexagonal structure of lonsdaleite’s atoms, making it harder than the cubic structure of terrestrial diamonds.

In 460 BC, Hippocrates described the earliest documented premenstrual syndrome, but it wasn't until 1931 that Dr. Robert Frank gave it a modern look with his paper on "premenstrual tension." In 1953 it was re-branded "premenstrual syndrome" because it covered so many symptoms. About 150.

By the early 1990s, women, and then men, were ridiculing the idea because no two women described the same thing. When a syndrome covers everything, it covers nothing, the clinical guidance notes.

Sleep apnea is a condition where people experience partial or complete obstruction of their airways during sleep and stop breathing several times a night. It can can manifest as loud snoring, gasping, choking and daytime sleepiness and is believed to affect at least 7 percent of the population.

There is correlation between that and obesity, diabetes, cigarettes, and alcohol. There is no plausible biological mechanism for why those would cause sleep apnea, it is just correlation - epidemiologists look at rows of inputs and columns of effects - and that is the problem with a new paper claiming a link to cancer. 

Quantum magnetism exploration is getting a boost from atoms about 3 billion times colder than interstellar space.

Space is cold, of course, but is warmed by the afterglow from the Big Bang. A Kyoto team instead used lasers to cool its fermions, atoms of ytterbium, within about one-billionth of a degree of absolute zero, the unattainable temperature where all motion stops, far colder than interstellar space.

The teen years are a challenging time for people transitioning from adolescence to adulthood, especially if they have mental health issues.

The online posting, sending or sharing of hurtful content is like being trapped in a small town, except possibly the whole world sees it. So why would someone do it to themselves?

That's the puzzle of digital self-harm. Like older forms of self-harm (cutting, burning, hitting oneself), there is worry it will lead suicidal ideation and attempts, but since peers assume a third-party is the culprit, the dysphoric or abnormal reasons to post cruel, embarrassing or threatening content about themselves is compounded.

It is common today to have food, or even a feast, to memorialize the dead. It is a legacy from ancient times.

Across the Roman Empire, funerary rituals were conducted to ensure the protection of deities and the memory of the deceased.  They were required by law.