- 2946 - TEMPERATURE - a race to the bottom? - Scientists are probing the extreme ends of the spectrum of what’s called “absolute temperature“. At the upper limit, absolute hot is a theoretical furnace where the laws of physics melt away. On the flip side, absolute zero is cold, so cold there’s nowhere to go but up. This absolute zero is almost within scientists’ grasp.
- Rodney Dangerfield , tells his side of hardship:
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- “When I was born, I was so ugly that the doctor slapped my mother."
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- "When I started in show business, I played one club that was so far out, my act was reviewed in Field and Stream." ( That is a fishing magazine if you did not get it )
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- "Every time I get in an elevator, the operator says the same thing to me: “Basement?'"
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- "When my parents got divorced, there was a custody fight over me. ... and no one showed up."
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- "I never got girls when I was a kid. One girl told me, `Come on over, there's nobody home.' I went over. There was nobody home."
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- "When I was 3 years old, my parents got a dog. I was jealous of the dog, so they got rid of me."
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- "When we got married, the first thing my wife did was put everything under both names — hers and her mother's."
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- "With my wife, I don't get no respect. The other night there was a knock on the front door. My wife told me to hide in the closet."
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- "With my wife, I get no respect. I fell asleep with a cigarette in my hand. She lit it."
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------------------ 2946 - TEMPERATURE - a race to the bottom?
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- Temperature tends to be relative. It is a difference measurement to some standard like the point at which water freezes could be zero Centigrade. Or, her fever is above normal, 98.6 Fahrenheit.
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- To understand absolute zero temperature, you first need some Physics 101. The atoms that make up matter are always moving. Temperature measures those atoms’ kinetic energy, or energy of motion. The faster they move, the higher their temperature. Absolute zero, though, is almost perfect stillness.
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- Nothing in the universe has ever reached absolute zero as far as we know. Even space has a background temperature of 2.7 Kelvin.
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- We do now have a precise number for space: -459.67 Fahrenheit, or -273.15 degrees Celsius, both of which equal 0 Kelvin.
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- Different materials vary in how cold they can get, and theory suggests we’ll never get to absolute zero. But with an arsenal of new tools and techniques, scientists inch ever closer to reaching that rock bottom temperature.
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- In 1995, University of Colorado Boulder physicists observed “Bose-Einstein-Condensation” , a fifth state of matter that only exists within a sliver of absolute zero. At such a low temperature, individual atoms overlap so much that they collapse into a single quantum state where they collectively act as a single entity.
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- The discovery of Bose-Einstein Condensation opened a new field of science in which physicists can probe quantum behaviors.
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- Quantum computing, instead of relying on bits, the 1;s and 0’s that regular computers use, quantum computers use “qubits” to make calculations. In theory, these machines can conquer problems much faster than today’s computers.
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- But to work, their atoms or molecules must be cooled to a couple hundredths of a degree above absolute zero, a realm where quantum features aren’t lost in the electrical noise that heat can create.
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- When helium gets cold, it gets weird. It can glide friction-free through narrow tubes, sustain currents for long periods of time and flow up and over a container’s sides. Scientists describe it, and some ultracold gases, like Bose-Einstein Condensation, as a superfluid.
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- Superfluids might exist in neutron stars, the small, dense relics of supernovas not massive enough to form a black hole. Superfluids have also led to the discovery of supersolids, which have the odd property of being able to flow through themselves. These materials let scientists probe fundamental mysteries of nature.
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- What is the coldest natural place in the Universe? Although temperatures plummet on the dark side of the moon and the shadowy craters of Pluto, those locales look balmy compared with the Boomerang Nebula. About 5,000 light-years away, this star system is just 1 degree Kelvin above absolute zero.
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- To sneak up on absolute zero, scientists have used vacuums and lasers in elaborate experiments to cool atoms of a gas. A vacuum can cool a gas without condensing it into a liquid or solid but its atoms still move. That’s where lasers come in.
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- In order to chill an atom, a series of lasers intersect to slow its momentum. When an atom absorbs a light particle, or photon, from a laser, it emits another photon. When physicists tune the lasers in just the right way, an atom traveling in one direction absorbs one photon and then emits another in a different direction and at a higher energy. The atom will then slow down, photon by photon.
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- By catching an atom in the crosshairs of multiple lasers, researchers can decrease its momentum from every direction. This technique, first used in the 1970s, is called laser cooling.
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- But there’s a way to go even lower. A technique called “evaporative cooling” siphons off a gas’ highest-energy atoms like soup cooling by releasing heat as steam. By combining lasers and evaporative cooling in new ways, scientists have chilled gases to about 50 trillionths above 0 Kelvin.
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- Scientists employ elaborate laser setups like this to study superchilled atoms. The frigid matter gives insights into quantum behaviors.
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----------------- Here is how low temperatures have been in a race to the bottom:
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- 2564 - TEMPERATURE - calculating global Warming? How to measure the temperature of stars? Knowing the temperature of the Earth how to calculate the total energy being radiated? We live on the surface of a 2,000,000,000,000,000 one hundred light bulbs. And, the Sun that is warming us has a surface temperature of 6,000 degrees Kelvin. How do we know these things?-
- 2563 TEMPERATURE - Getting Temperature from Light? If we measure the frequency emitted we know the energy gap between orbits for that particular atom. And , if we know the energy gaps for each element we can measure the frequency of radiation and identify the element that created. it. That is how astronomers know the makeup of stars and gas nebulae that are billions of light years away.
- Review 505 How small is the Atom”
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- Review 983 - “How an Atom Works”
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- Review 985 - “Measuring How an Atom Works“.
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- Review 986 - “How a Molecule Works“.
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- Review 924 - “Rutherford’s Atom”
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- Review 1740 - “Temperature of the Earth”
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- Review 2377 - “Defining the Atom”
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- Review 2333 - “Rainbows can Tell Us What the Universe is Made Of.”
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- Review 2555 - History of the Atom to 1925
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- Review 2555 - History of the atom after 1925
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- 1926: Chemists first describe a method, called “adiabatic demagnetization“, that uses magnetic fields to cool materials below 1 kelvin.
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- In 1933, scientists employ it to chill a salt to 0.25 Kelvin. That’s low, but not as low as laser cooling can go.
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- 1978: First demonstration of laser cooling takes materials to 40 Kelvins; 10 years later, physicists use laser cooling to achieve 43 millionths of a Kelvin.
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- 1997: Three physicists share the Nobel Prize for inventing laser cooling.
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- 2015: Stanford University researchers chill a gas made of rubidium, a soft metal used to make solar cells, to 50 trillionths of a degree above absolute zero, setting a new record.
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- 2017: Physicists at the National Institute of Standards and Technology in Boulder, Colorado, chill an aluminum membrane to 0.00036 kelvin, lower than theory predicted possible for the material. The experiment suggests a way to see quantum effects, like a single object coexisting in two places at once.
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December 21, 2020 TEMPERATURE - a race to the bottom? 2946
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