![]() ![]() Secondly, the Earth’s atmosphere refracts (bends) sunlight. Because the Sun is not a point, and has upper and lower edges, this means that the equinox has a slightly longer day than night. Technically, sunrise starts when the upper edge of the Sun meets the eastern horizon, and sunset ends when the upper edge of the Sun sinks below the western horizon. This seems obvious, but it affects how scientists measure sunrise and sunset. Shutterstock/Dimitrios Karamitrosįirstly, the Sun has a size – it’s not just a point in the sky. The lengths of the day and night aren’t quite the same, and there are two reasons for this.Įarth’s tilt. As it turns out, this is only approximately true. You might think that the lengths of the day and night would be equal during the equinox. This happens twice a year, once in late March and once in late September. When the centre of the Sun’s disc perfectly crosses the equator, astronomers define this as the equinox. READ MORE: 13 fall books that will make you thinkĮarth’s axial tilt also means that our planet’s equator is tilted relative to the plane of its orbit around the Sun – what astronomers call the “plane of the ecliptic”. This is why we have seasons here on Earth. As the Earth spins on its axis and orbits the Sun, the intensity of the sunlight reaching different parts of the Earth’s surface changes. Instead, Earth’s axis is knocked somewhere on its side – the technical name for this is “axial tilt”, and this tilt is responsible for both the seasons and the equinox. Shutterstock/ArtreefĮarth is not like Venus. To see how well younger children understand the passing of the seasons, we have a KS1 Science quiz all about autumn, winter, spring and summer.The Sun throughout the year. They have some great places for you to visit across the country and closer to you. ![]() If you want to find out for yourself then take a look at the Woodland Trust website. The sights, sounds and even smells make our woodland a magical place at this time of year. I think that there is no better place than a forest in the autumn. Autumn is a time of beauty in nature as well as rest. Leaves on trees are changing colour and starting to fall to the ground.īare trees, departing birds, short days, cold weather and hibernating animals – it’s easy to see why our ancestors regarded the autumn and winter as times associated with death. Many animals will prepare for the winter by migrating or growing thicker coats. The shorter days mean not only more darkness but also more cold weather. It also was a time to mourn the Sun as he departed until the spring.īut what does the autumnal equinox mean for the natural world? The first sign of autumn is the later dawn and the earlier dusk. Mabon marked the end of the harvest and was a time of rest. ![]() This was a place where people would gather to celebrate Mabon, the pagan autumn festival. Stonehenge in Wiltshire is perhaps the most famous. They even built primitive observatories to mark the passage of the Sun through the heavens. One of these two marks the beginning of spring and the other the start of autumn. When we point towards the Sun it’s spring and summer, when we point away it’s autumn and winter, and on the two days a year when we point neither away from nor towards the Sun we get an equinox. It’s an astronomical event caused by the Earth’s tilt. The word equinox means equal night and that’s because on this day, day and night both last for 12 hours. Today is the autumnal equinox – the first day of autumn from an astronomer’s point of view. ![]()
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