과학 이야기

Did you know that the transparent 'glass' we commonly use is actually in a chemical state that is neither fully solid nor liquid? Chemically, glass is composed of silicon dioxide (atomic molecular bonds) and is classified as an 'Amorphous solid' because it lacks an ordered crystalline structure. When a liquid is rapidly cooled, its atoms don't have time to arrange themselves into a regular crystal form, causing it to solidify while retaining the disordered atomic arrangement of the liquid. For this reason, the chemical community sometimes views glass not as a simple solid, but as a substance with the characteristics of a 'supercooled liquid that is extremely viscous and has stopped moving.' It's an interesting behind-the-scenes fact that the glass we look through every day might actually be a frozen liquid with time stopped.

Did you know that a single-celled organism with no brain or nervous system has perfectly replicated Tokyo's subway map? 'Slime mold,' a type of organism, has the characteristic of finding and connecting the most efficient shortest paths when searching for food. When researchers placed food at various city locations around Tokyo and cultivated slime mold, it created a network that almost perfectly matched the Tokyo subway system designed by humans over decades. This demonstrates the remarkable optimization ability of a simple mass of cells to solve complex urban engineering problems. It's an interesting fact showing that life forms possess perfect efficiency algorithms even without a centralized brain.

- Cities That Have Entered Autumn The criteria for autumn, calculated via Excel: Cities where the 9-day moving average of the average temperature has dropped below 20 degrees Celsius are: Chuncheon North, Inje, Daegwallyeong, Yeongwol, Hongcheon, Taebaek, Jeongseon, Chupungnyeong, Jecheon, and Cheongsong (Gyeongbuk). These are all cities with high altitudes. The entry period was around early September for all of them. Even when it warmed up again mid-month, they didn't recover, so it's judged that they've entered autumn. And Taebaek, which is the coolest in Korea and has no tropical nights, actually entered autumn on August 30th, wow ㄷㄷㄷ In the case of northern Gyeonggi and Gangwon areas like Paju, Dongducheon, and Cheorwon, it seemed like they were entering autumn like the cities above in early September, dropping below 20 degrees, but then recovered to above 20 degrees as it warmed up mid-month, reversing the trend once. Since the average temperature has been dropping again after the 25th, it seems they will announce that autumn began in late September around early October when the 9-day moving average calculation finishes. Well, Seoul is still a ways off. But seeing the pattern of the northern cities, it feels like we're one step closer to autumn.

The place where the fiercest winds in the solar system blow is Neptune, the blue planet farthest from the Sun. Neptune's wind speeds reach an astonishing 2,100 km/h, which is 7 times faster than Earth's strongest typhoons and surpasses the speed of sound. What's remarkable is that Neptune is an extremely cold outer planet, receiving only about 1/900th the amount of sunlight Earth does. While atmospheric movement is typically driven by solar thermal energy, Neptune has very little solar heat, which instead maintains an extremely cooled state that reduces atmospheric friction. Thanks to this, even the slightest internal heat source on the planet is enough to prevent power loss and accumulate, allowing it to continuously maintain the most destructive and fastest Superwind (supersonic storm) in the entire solar system.

- Pacific Ocean 1. Monitoring Area: Nino 3.4 2. Longitude and Latitude: 5 degrees North/South, 170-120 degrees West longitude (Eastern Pacific) 3. Phenomenon Monitored: El Niño/La Niña 4. Judgment Criteria: Sustained change of 0.5 degrees Celsius or more compared to the average for 5 months This is a representative indicator of global climate change, and all equatorial waters are monitored by dividing them into Nino 1.2.3.4. - Atlantic Ocean 1. Monitoring Area: ATL3 2. Longitude and Latitude: 3 degrees North/South, 0-20 degrees West longitude (Eastern Atlantic) 3. Phenomenon Monitored: Atlantic El Niño/La Niña 4. Judgment Criteria: Immediately upon a change of 0.5 degrees Celsius or more compared to the average Compared to the Pacific, the influence is indirect, with different timing of occurrence and shorter duration. - Indian Ocean 1. Monitoring Area: Near Indonesia (East), Near Africa (West) 2. Longitude/Latitude omitted (due to character count) 3. Phenomenon Monitored: Indian Ocean Dipole Mode (West minus East deviation), positive and negative phases 4. Judgment Criteria: Sustained change of (+/-) 0.4 degrees Celsius or more for over 3 months Eastern and Western Indian Oceans are connected by waterways, so temperature deviations tend to synchronize directly.

To predict global climate change, we are monitoring the water temperature at specific locations in the ocean. Basically, ocean currents, due to the Coriolis effect from Earth's rotation, result in warm currents on the western side of the sea and cold currents on the eastern side. In the equatorial Pacific, the west is on average 5 degrees warmer. However, due to some global cause or periodically, temperature changes occur, and If a phenomenon where the temperature is 0.5 degrees higher than the average (average of the last 30 years) lasts for more than 5 months, it's called El Niño. If it's 2 degrees or more, it's a Super El Niño. Conversely, if the temperature is 0.5 degrees lower and this is maintained for over 5 months, it's La Niña, and if it's 2 degrees or more lower, it's a Super La Niña. When these significant temperature changes occur, a large-scale movement of water vapor takes place, leading to changes in atmospheric pressure. This can cause floods in dry climates and droughts in previously humid regions. It not only affects low-latitude regions but also influences the atmospheric pressure at high latitudes in the Arctic and Antarctic, consequently causing phenomena like extreme cold and heavy snowfall. Due to character limits, the representative sea surface temperature measurement points for each ocean will be covered in the next post...

Did you know that a massive interstellar cloud called 'Sagittarius B2', located at the center of our Milky Way galaxy, has been found to contain large amounts of chemicals that give off a raspberry flavor and the aroma of rum? Astronomers analyzed the composition of this dust cloud using space telescopes and confirmed the widespread presence of 'ethyl formate', an organic compound responsible for the distinct flavor of raspberries and the scent of rum. So, a cloud carrying the sweet scent of fruit and the aroma of alcohol drifts in the middle of space, hundreds of light-years away. The pitch-black universe isn't just a desolate inorganic space; it holds far richer and more surprising scents than we imagine.

Have you ever seen a stream of liquid, like shampoo or thick detergent, splash onto the floor and then unexpectedly spring back up into the air instead of just falling? This peculiar phenomenon is known in fluid dynamics as the 'Kaye effect'. It occurs when a viscoelastic liquid, like the ones mentioned, falls and creates a thin layer of air beneath the stream. The liquid then glides over this air layer as if it were a lubricant. When the stream hits the pool of liquid on the ground, it bounces off frictionlessly, momentarily jumping into the air like a spring. Although it disappears in just a few seconds and is hard to notice, this phenomenon of liquid spontaneously leaping upwards is one of the most fascinating and beautiful physical occurrences demonstrated by everyday fluid dynamics.

6. Mole (Number of Molecules) Original Definition: The actual number of atoms in 12g of Carbon. Current Definition: Redefined using Avogadro's constant. Reason for Change: Varies depending on isotope ratio. 7. Candela (Luminosity) Original Definition: The brightness of a candle as a standard. Secondary Definition: The brightness of a black body of a reference area at the melting point of platinum. Current Definition: Redefined using frequency and radiant intensity (light is green light with a wavelength of 555nm). Reason for Change: A candle's brightness varies with combustion conditions. Difficulty in implementing a high-temperature black body.

2. Meter Original Definition: One ten-millionth of the distance from the North Pole to the Equator along the meridian passing through Paris. Current Definition: The distance light travels in a vacuum in 1/299,792,458 of a second. Reason for Change: Errors in measurement results, minute changes in the standard prototype. 3. Kilogram Original Definition: The weight of one liter of water at 4 degrees Celsius. Current Definition: Redefined based on the Planck constant. Reason for Change: Can vary depending on pressure conditions. Minute changes in the standard prototype. 4. Ampere Original Definition: Defined based on the force applied between two conductors separated by one meter in a vacuum. Current Definition: Redefined based on the elementary charge of an electron. Reason for Change: Difficulty in implementation. 5. Kelvin (Celsius temperature + 273.15) Absolute zero became -273.15 degrees Celsius by calculating the point where molecular motion ceases according to Charles's Law. Original Definition: 1/100th based on the melting point (0) and boiling point (100) of water. Second Definition: Based on the triple point of water. Current Definition: Redefined based on the Boltzmann constant. Reason for Change: Varies depending on isotopic composition.