It has been happening for over 4.5 billion years but only recently has it dawned on me that the best, most colourful and inspiring sunrises seem to be between November and February. Meteorologist Stephen Corfidi agrees and says it has to do with the confluence of a few meteorological factors. The reds, organges and yellow colours of sunset and sunrise are created by a phenomenon called Rayleigh scattering. The same phenomenon makes the sky appear blue during the day. Sunlight contains all the colours of the rainbow. But not all the colours reach the ground in the same concentration. Nitrogen and oxygen molecules in our atmosphere act as little mirrors for blue and violet light, in particular. That means not as much blue or violet light reaches the ground. Instead, it bounces around in our atmosphere, creating the blue dome of sky we’re all so familiar with
At sunrise and sunset, light has to travel through a greater distance of atmosphere to reach our eyes — so even more blue light, and even some green and yellow light, gets filtered out. That leaves us with the warmer hues of the visible light, the reds and oranges, and it’s why sunrises and sunsets look like the sky is on fire.
The air is typically filled with these tiny particles called aerosols, which are produced by things like trees but also by industrial activities. Aerosols attract water vapor and enlarge, essentially filtering the light we see in the sky and scattering it. But in the winter when the air is colder and dryer, there are less of these colour-filtering aerosols in the air, meaning we see colours in all their intensity.
So how many sunrises has the Earth witnessed? If we assume a 24 hour day thats 1642500000000
sunrises but this is a massive underestimate. Takanori Sasaki presents a graph relating the development of life ("though not an expert on the issue") with the length of the day through time. According to it, the first evidence of life, 3.5 billion years ago, happened when the day lasted 12 hours. The emergence of photosynthesis, 2.5 billion years ago, happened when the day lasted 18 hours. 1.7 billion years ago the day was 21 hours long and the eukaryotic cells emerged. The multicellular life began when the day lasted 23 hours, 1.2 billion years ago. The first human ancestors arose 4 million years ago, when the day was already very close to 24 hours long.
Being philosphical, the Earth (and universe for that matter), have taken a lot of trouble over billions of sunrises to form me so that I can admire, experience wonder and feel uplifted at its spectacle.
The air is typically filled with these tiny particles called aerosols, which are produced by things like trees but also by industrial activities. Aerosols attract water vapor and enlarge, essentially filtering the light we see in the sky and scattering it. But in the winter when the air is colder and dryer, there are less of these colour-filtering aerosols in the air, meaning we see colours in all their intensity.
So how many sunrises has the Earth witnessed? If we assume a 24 hour day thats 1642500000000
sunrises but this is a massive underestimate. Takanori Sasaki presents a graph relating the development of life ("though not an expert on the issue") with the length of the day through time. According to it, the first evidence of life, 3.5 billion years ago, happened when the day lasted 12 hours. The emergence of photosynthesis, 2.5 billion years ago, happened when the day lasted 18 hours. 1.7 billion years ago the day was 21 hours long and the eukaryotic cells emerged. The multicellular life began when the day lasted 23 hours, 1.2 billion years ago. The first human ancestors arose 4 million years ago, when the day was already very close to 24 hours long.
Being philosphical, the Earth (and universe for that matter), have taken a lot of trouble over billions of sunrises to form me so that I can admire, experience wonder and feel uplifted at its spectacle.
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