Earthquakes are a natural disaster that occurs because of the sudden release of energy in the Earth’s crust. Seismic waves are created and the tremors that are felt can be measured by seismometers. Earthquakes are measured based on their magnitude (the Richter scale). There have only been a couple that registered over a magnitude of 9.0 on the seismometer. An earthquake with a magnitude greater than 9.0 is an extreme natural disaster and are very rare.

How to pass a lie detector test - Photo credit: Lwp Kommunikáció - Flickr The polygraph is no ordinary psychometric test. Although widely used by government agencies, especially in law enforcement and intelligence, polygraph techniques have been repeatedly discredited as pseudoscience by the scientific community. Polygraphs are based on the simple notion that most people become physiologically ‘aroused’ in response to their own lies. The typical arousal response includes increased heart rate, respiration, blood pressure, and skin conductivity.

**Snipers have always held a place of esteem and fascination in popular culture, perhaps because of the amazing level of precision and patience involved with long-distance kills. ** While sniping has a long and illustrious history, the range and precision of weapons has improved with advancing technology in recent years, enabling longer shots. Handheld computers, devices that gather information about the weather and quality of the atmosphere, and laser rangefinders have all improved shooter accuracy.

Black holes are undoubtedly one of the most bizarre and intriguing phenomena in the universe. We’ve only known about them for about a hundred years, though their existence has been postulated since the 18th century. What is a black hole, anyway? What really happens when you fall into one? Astronomers and physicists have been wrestling with black hole mysteries for years, but a growing consensus has emerged on a number of points.

On the whole, American cities have become much safer. After years of declining rates of violent crime, they are now about as safe as they were in the 1960s. But violent crime is still a problem in lots of cities. And while the gap between urban and suburban crime rates has narrowed, suburban spaces still tend to be safer than urban places. Echoing that trend, it seems the safest cities in America are predominantly suburbanized middle-tier cities with moderate population density.

Does déjà vu hint at parallel universes? Is it evidence of reincarnation from a past life? Or is it simply a curious mental error, a telltale glitch in our brain that hints at the architecture of the mind? It depends on who you ask. Déjà vu invokes a sudden sensation of familiarity, most commonly in response to a scene, but the stimulus could also be a person, place, or even just a passing thought.

Like a monster trash compactor stretching from the ground to the heavens, tornadoes descend with little warning from the planet’s scariest storms, taking just a few minutes to ruin thousands of lives. F5 tornado Elie Manitoba 2007 (Photo credit : Justin-Hobson - Wikipedia) Like any natural disaster worth its salt, tornadoes remind us of how puny we humans and our built structures really are. Here are 12 cool facts about tornadoes to keep you from getting bored as you crouch in a dank, dark cellar hiding from the most violent storm on the planet.

Photo credit: Rodrigo Gianesi/Flickr Racism is like an invasive species. As a mindset and expression of larger cultural attitudes, it tries to overwhelm its competitors wherever it sets seed. Defining victory as someone else’s oppression, racism causes imbalance and conflict in societies in which multiple races or ethnicities of people live and work. It promotes hostility within a culture, and ultimately leads to hatred and violence. Why are people racist?

Credit: Ars Electronica/Flickr Everyone forgets things some of the time. You walk into a room and entirely forget why you decided to enter. You are mid-conversation and suddenly space-out what was just said. Although odd and sometimes embarassing, short-term memory loss below a certain threshold doesn’t mean anything at all. However, if you are having significant, unexpected and unexplained trouble remembering things that just happened, it could be a symptom of a greater problem.

Gluten allergy symptoms. Credit: Shannonlee/Pixabay These days, it’s not uncommon to encounter a person with a gluten allergy or celiac disease. According to the Statistic Brain website, about 1 in every 133 people in the U.S. have celiac disease. Restaurants and food manufacturers are becoming more aware of this and adjusting their menus and product offerings accordingly. However, there are hidden sources of gluten in many foods. Also, some people may experience gluten allergy symptoms and not know that the reactions are related to diet.