If you went back in time and accidentally killed one of your ancestors, what would happen to you?When it comes to hypotheticals about time travel, this is one of the most popular and compelling questions of all, well, time. And it isn’t just a plot device that science fiction writers and filmmakers use to drive a story. The so-called Grandfather Paradox has been weighed by physicists and philosophers alike for nearly a century.What Is the Grandfather Paradox?(Credit: Drawlab19/Shutterstock)Bro ...read more

“Look in a mirror,” begins You Are All Sanpaku, a health book from 1965 written by macrobiotic advocate and anti-war protestor George Ohsawa. There you see the whites of your eyes and, if you have sanpaku, a space between the iris and lower lid. This white crescent indicates “a grave state of physical and spiritual illness […] and an extraordinary susceptibility to disease, accidents and tragic death.”Having stared in their eyes (or pictures) he diagnoses many celebrities of the day, i ...read more

In the early morning hours of Sept. 19, 1910, Mary Hiller awoke inside the Chicago home she shared with her husband and four children. The gas light at the head of their stairway, which she always left running overnight, was out — so she sent her husband to investigate.Upon inspection, Clarence Hiller found an intruder: a recently paroled man named Thomas Jennings. The two struggled briefly before several gunshots rang out, leaving Hiller dead. Prior to this fatal encounter, Jennings had sexua ...read more

I frequently toss and turn at night. If a breeze whispers through the curtains, I’m up; if a car backfires, I’m wide awake. And, apparently, I’m not alone.According to a 2022 survey conducted by Gallup and the mattress retailer Casper, a third of U.S. adults reported their sleep the previous night as either fair or poor — versus good, very good or excellent. This suggests that around 85 million of us, based on 2020 Census data, aren’t getting enough shuteye.Across the internet, noise a ...read more

Everything in the fire station parking lot was bathed in a red glow. Although this is Hawaii, the air felt especially steamy and warm. Nearby, lava fountains up to 150 feet (60 meters) tall were blasting from fissures. The scene was vaguely apocalyptic, beautiful but terrifying. Kīlauea had started to erupt from the lower East Rift Zone for the first time in over 50 years, right in the middle of the Leilani Estates subdivision, pouring lava into people’s backyards. For U.S. Geological Survey ...read more

In the late 1950s, dentist and US Navy Capt. Kirk C. Hoerman, then a young man in his 30s, attempted to answer a bold question: Might the saliva of prostate cancer patients have different characteristics from that of healthy people? Could it contain traces of a disease that’s so far away from the mouth?Without wasting more of their own saliva on elaborate discussion, Hoerman and his colleagues from the department of dental research at the Naval Training Center in Great Lakes, Illinois, got d ...read more

The average person in the U.S. uses an enormous amount of plastic — much more so than in other countries. And this number has surged in recent decades.Back in 1980, annual plastic use in the U.S. was around 60 pounds per person. By 2018, this figure had risen to 218 pounds. A paper from 2020 estimated that 46 million tons of plastic waste was created in the U.S. in 2016.“We estimated that in the U.S., our population produces more plastic waste than in any other country on the planet. That's ...read more

In late 2019 and early 2020, bushfires in Australia destroyed the habitat for millions of animals as well as homes for thousands of people. UNICEF estimated that the fires somehow impacted 40 percent of Australian children. Many children felt traumatized by the fires, and because teddy bears have the power to calm and comfort, UNICEF organized therapy sessions with handmade teddy bears that children could keep and cuddle.Researchers are learning more about the emotions people attach to teddy ...read more

As heavy snows have closed parts of Yosemite National Park in California, it's a good reminder that when visiting one of the 63 national parks in the U.S., always have a backup plan. The national parks are a wonder to behold. They help preserve pristine natural areas and the organisms that live there. However, they are also subject to extreme and unpredictable weather and are home to wildlife you won't often encounter anywhere else, which can hinder your visit. The best way to have a fun and sa ...read more

For better or worse, humans have sent an ark's worth of other animals into space. This veritable zoo of space travelers includes dogs, mice, fish, tortoises, frogs, spiders and non-human primates.But let's start with some little guys — fruit flies. First Animals in Space: Fruit Flies(Credit:Tomasz Klejdysz/Shutterstock)Fruit flies were the first animals of any kind to leave the planet. Fruit flies make good experimental subjects because they're remarkably similar to humans at the genetic and ...read more