Nousulaskuajat
Nousulaskuajat refers to the times of day when the sun begins to rise and set, marking the transition between day and night. These periods are characterized by gradually increasing or decreasing light levels. The exact timing of nousulaskuajat varies significantly depending on geographical location, time of year, and latitude. At the equator, the duration of daylight and darkness remains relatively constant throughout the year, leading to less pronounced changes in sunrise and sunset times. Conversely, higher latitudes experience much greater variations in nousulaskuajat, with long daylight hours in summer and short daylight hours in winter. The astronomical phenomenon responsible for these changes is the Earth's axial tilt as it orbits the sun. During summer in the Northern Hemisphere, the northern half of the Earth is tilted towards the sun, resulting in earlier sunrises and later sunsets. The opposite occurs during winter. The precise moment of sunrise is typically defined as when the upper edge of the sun's disk appears on the horizon, while sunset is when the upper edge disappears below the horizon. These transitions are often accompanied by beautiful atmospheric phenomena such as twilight, where the sky is illuminated by indirect sunlight.