1. Human. 2. Getty Images It doesn't. While it's true that parts of Scotland are some of the wettest places in Europe, with annual rainfall up to 4,577 mm, it doesn't rain constantly. More to the point, precipitation is governed by geophysical laws, not human behaviour. 3. Getty Images The best estimate of the age of the universe, as of 22 March 2013, is 13.798 billion years, plus or minus 0.037 billion years within the Lambda-CDM concordance model, otherwise known as the standard model of Big Bang cosmology. 4. Getty Images Mountain erosion takes place over geologic timescales and can be influenced by a number of factors. However, assuming a steady erosion rate of 1mm/year, it would take Mount Everest — which currently stands a 8,848m — 88.5 million years to erode away to nothing. 5. Getty Images DiagnosisPro lists more than 440 possible causes for chest pain, ranging from acute coronary syndrome to myocarditis. Even if determined to be non-cardiac in origin, chest pain is generally considered a medical emergency. 6. Getty Images Quite apart from the road safety risk, sex on a public highway would fall under the common law offence of outraging public decency. It is punishable by unlimited imprisonment and/or an unlimited fine. 7. Getty Images We still don't know for sure, but it's looking increasingly likely that some form of microbial life did once exist on Mars. Conditions in the planet's distant past were certainly conducive to it. Drilling samples recovered by NASA's Curiosity rover earlier this year were found to contain traces of sulphur, nitrogen, hydrogen, oxygen, phosphorus and carbon, all key chemical ingredients of microbial life. 8. Getty Images There are three major philosophical schools of thought concerning the so-called "mind-body problem": dualism, materialism, and idealism. Dualism holds that the mind exists independently of the brain; materialism holds that mental phenomena are identical to neuronal phenomena; and idealism holds that only mental phenomena exist. Speaking in purely scientific terms, studies in functional neuroimaging have shown that three brain regions — the insular cortex, anterior cingulate cortex, and medial prefrontal cortex — are critical for self-awareness. 9. Getty Images Technically, no one has ever seen rain. Water molecules absorb certain wavelengths in the electromagnetic spectrum and scatter others. What we "see", or perceive as light, are the scattered photons hitting photoreptor cells in our retinas, not the water itself. 10. The doctrine of immortality is essential to many of the world's religions, and recent breakthroughs in cellular chemistry suggest that radical life extension, delaying and stopping aging, may soon be achievable. Active pursuit of physical immortality can either be based on scientific trends, such as cryonics, digital immortality, breakthroughs in rejuvenation, or predictions of an impending technological singularity. 11. Getty Images No two people's DNA blueprints are ever exactly alike. Not even "identical" twins are identical in the genetic sense. And even if by some fluke they started out that way at conception, they wouldn't stay the same for long. According to molecular geneticist Shiva Singh: "Cells are dividing as we develop and differentiate. More importantly, these cells may lose or acquire additional DNA. The genome is not static." 12. Getty Images It doesn't "go" anywhere. Physics tells us that all moments exist equally, at once — it's only our consciousness that distinguishes the present from the past or future. According to Max Tegmark, a cosmologist at the Massachusetts Institute of Technology: "If life were a movie, physical reality would be the entire DVD: Future and past frames exist just as much as the present one." 13. nnm.ru Love can be understood, in evolutionary terms, as part of the survival instinct. Strong emotional bonds between organisms increase their chances of surviving long enough to procreate, thereby facilitating the continuation of the species. It's easy to see how natural selection favours individuals who form such attachments. 14. Getty Images Mostly in the brain. Studies in neuroscience have identified a number of chemicals that appear to be associated with feelings of love. These can be broken down into two distinct phases. Dopamine, norepinephrine, and serotonin are more commonly found during the early, intense attraction stage of a relationship. Oxytocin and vasopressin seem to be more closely linked to long-term bonding. However, these neurotransmitter chemicals do generate physical sensations elsewhere in the body, similar to the fight-or-flight responses caused by fear or stress: decreased appetite, goosebumps, butterflies in the stomach, etc. 15. Via wfuv.org The number of working cowboys in America started to decline in the 1890s with the invention of barbed wire, which enabled farmers to keep cattle within designated zones and made long cattle drives unnecessary. However, the job is not completely obsolete. According to the United States Bureau of Labor Statistics, 9,730 people currently work as livestock handlers. Of these, 3,290 are listed in the subcategory of spectator sports, which includes rodeos and circuses. 16. Getty Images Impossible to say. Scientists and philosophers alike have tried and failed to come up with a watertight definition of "now", since direct experience of "the present moment" is ultimately subjective. To complicate matters, "now" as we perceive it is actually 70 milliseconds in the past due to the time it takes our brains to process sensory stimuli. 17. Getty Images It's real life.