physics
American astronomers Edwin Hubble and Milton Humason used the 100-inch telescope outside Los Angeles to observe that the farther away galaxies are from the earth, the faster they are from us. This discovery paved the way for what we now call the big bang model. BIGBANG model is an idea that all the matter and energy we saw around us were once concentrated in a small space. This means that the universe-and perhaps time itself-has a beginning.
1954
biology
German zoologist Gustav Kramer believes that many animals and plants have a biological clock to control their biological rhythm. He thinks it has something to do with the "sun compass" that birds and bees seem to use to navigate. Further experiments by his compatriot Klaus Hoffmann showed that these "circadian rhythms" lasted about 24 hours and actually helped birds fly.
1964
physics
Two American scientists, physicist arno penzias and radio astronomer robert wilson, discovered the mysterious all-sky glow with a radio antenna at Bell Laboratories in Homedale, New Jersey. This radiation was quickly called "cosmic microwave background" and sometimes described as the echo of the Big Bang. Whether the "big bang" should be considered is a preliminary debate. Some cosmologists believe that the universe will go through a cycle of expansion and contraction.
1967
Physics? Calculated by time
For centuries, seconds have been defined as 1/86400 of a day. But the atomic clock is very accurate, which reveals the irregularity of the earth's rotation. Now it is obvious that the time of day is slightly different due to climate and geological processes and tidal friction. In other words, the discovery of atoms can make timepieces better than planets. The official redefined the second as the duration of 9 19263 1770 vibrations of a specific isotope of cesium.
197 1 year
physics
When a commercial airliner with the same atomic clock flies around the earth twice-first to the east and then to the west-the theory of relativity is tested and the results are compared with the same clock on the ground. The resulting difference is called time dilation, which is very small (less than one millionth of a second), but it can be easily measured by a clock, and the results are consistent with Einstein's special relativity and general relativity.
1972
biology
Two groups of scientists, led by robert moore and Victor Eichler in Chicago and Friedrich Stephen and Owen Zucker in Berkeley, discovered the brain regions that control the circadian rhythm. The key structure is suprachiasmatic nucleus or SCN, which processes light and dark information from retina. Later studies on mice found that the destruction of SCN would destroy the rhythm of animals-SCN transplantation could restore them.
1988
Physics? culture
Stephen Hawking, a British physicist, published A Brief History of Time, a popular book about time and space and the universe, which became a best seller. Hawking identified three different "time arrows": psychological arrow (which supports our memory of the past and how we imagine the future), thermodynamic arrow (the direction of entropy increase) and cosmological arrow (the direction of the universe).
1989
biology
An Italian woman named Stefania Follini came out of a cave in New Mexico and spent 130 days there, with no contact with the outside world and no clocks. Shortly after the experiment began, her awakening cycle changed from 24 hours to 25 hours. Finally, it lasted for 36 hours. 130 days later, she estimated that 60 days had passed. There is still a lot to know about how our bodies track time, but these experiments show that our biological clock is more than just a biological equivalent of a mechanical clock.
In 2009
physics
Noah Linden, Sandu popescu, Tony Short and Andreas Winter pointed out in an influential paper that the arrow of time can be explained by entanglement in quantum mechanics. When a physical system is intertwined with the surrounding environment, it will get closer and closer to balance, and this one-way evolution determines the arrow head of time. The work of this group is based on the idea put forward by Seth Lloyd in his doctoral thesis 1988.
20 13
physics
Researchers studying possible gravitational quantum theory have begun to suspect that space and time are not the basic characteristics of the universe. Physicists juan maldacena and Leonard Susskind put forward a key idea in 20 13, and put forward the equivalence between quantum entanglement and wormhole. After Einstein and his co-authors published two papers in 1935, this idea is sometimes called ER = EPR. If it is true, it means that quantum interaction sews up the space-time structure.
20 15
Physics? Calculated by time
The team led by physicist Jun Ye has developed the most accurate atomic clock to date. It is called strontium lattice clock, which records the vibration of strontium 87 atoms and "ticks" at the frequency measured in femtosecond (one billionth of a second). If such a clock has been running since BIGBANG, its gain and loss will not exceed one second. Strontium lattice clock is now used to detect basic physics and can be used as a dark matter detector.
20 18
biology
A group of Norwegian scientists led by Cao Tao found that the cellular network in the brain seems to play a vital role in linking the consciousness of time lapse with the formation of memory. This study on rats shows that some cell groups in the brain area adjacent to the hippocampus are called the lateral olfactory cortex, which encodes situational memory by "allowing the hippocampus to store a unified representation of what, where and when". . "
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