٢٠ سبتمبر ٢٠٢٦
كيش من المدار
بالألوان الحقيقية، من مقياس MODIS على القمر الصناعي Terra التابع لناسا.
NASA Worldview / GIBS
الخليج الفارسي نهاراً
الخليج كله في مرور واحد، مع رسم الخطوط الساحلية.
NASA Worldview / GIBS
الخليج الفارسي ليلاً
مقياس VIIRS حساس بما يكفي لتصوير أضواء المدن: هذه صورة للمنطقة مرسومة بمواضع الناس.
NASA Worldview / GIBS
Analemma over the Callanish Stones
صورة اليوم الفلكية من ناسا.
If you went outside at the same time every day and took a picture that included the Sun, how would the Sun's position change? A visual answer to that question is an analemma, a composite image taken from the same spot at the same time over the course of a year. The featured analemma was composed from images taken every few days at noon near the village of Callanish in the Outer Hebrides in Scotland, UK. In the foreground are the Callanish Stones, a stone circle built around 2700 BC during humanity's Bronze Age. It is not known if the placement of the Callanish Stones has or had astronomical significance. The ultimate causes for the figure-8 shape of this and all analemmas are the tilt of the Earth axis and the ellipticity of the Earth's orbit around the Sun. At the solstices, the Sun will appear at the top or bottom of an analemma. The featured image was taken near the December solstice and so the Sun appears near the bottom. Equinoxes, however, correspond to analemma middle points -- not the intersection point. In two days there will be an equinox ("equal night"), when day and night are equal over all of planet Earth. Many cultures celebrate a change of season at an equinox. APOD's main NASA site is moving: From apod.nasa.gov to science.nasa.gov/apod
هذا الشرح بالإنجليزية ولم يُترجم.
Giuseppe Petricca