polytropos' photos with the keyword: Astronomie

Have a guess! (brain teaser) Imagine pulling a rope around the globe (which is a perfect sphere) and tensing the rope tight. Now you add 10 meters to the rope and distribute the rope around the globe so that it is equidistant from the globe (see sketch above). ➽ What is the distance x between the globe and the rope? ➽ Do you think it is enough height for a fly to crawl down through? Answer: In the calculation above you can see that the distance is 1,59 m!! And the astonishing point is: You can do the same with an orange (fruit) and it will give the same result!! Well, mathematically not really remarkable, but imaginatively it's astonishing! :-) ... and there is an additional point that you may have noticed: on the globe above GB is missing. So the Brexit also is solved! ;-)) Due to several complaints I have reinserted the British Isles. ;-)) By the way: , have you also noticed that longer texts are no longer completely translated by the translator? According to ➽ Sami Serola's riddle. ...

It's a little bit more accurate than => my sketch. Taken from the moon on a wonderful spring evening. See also PIP. :-)

waxing half moon Foto mit einer Nikon, montiert an ein Reflektor-Teleskop Ø 85 mm. Ich habe das Bild noch in alten Beständen gefunden, und gedacht, das dürfe ich der Öffentlichkeit nicht vorenthalten ;-) Anziehungskraft Erde / Mond: Gravitationskonstante G: 6,67430 * 10^-11 m³/kg*s² Gewicht des Mondes (m1): 73’490’000’000’000’000’000’000 kg (7,349 * 10^22 kg) Gewicht der Erde (m2): 5,972 * 10^24 kg Abstand – Mond (r): 384'400 km (384'000'000 m) Anziehungskraft F = G * ((m1 * m2) / r) = [(6,6743 * 10^-11) * (5,972 * 10^24) * (7,349 * 10^22)] / 384'000'000² = 1,985 * 10^20 Newton. 1 N = 0,102 kg F = 2,02486 * 10^19 kg (20'248'600'000 t) (46.7394, 07.3783) [170/200]

hot spots on the moon, visible from the earth. One day in the far past the moon stopped rotating because of the force of gravity of the earth. That's why we see now always the same side of the moon. In the above picture we can see the half of the waxing moon. Taken with a Nikon, mounted on a reflector telescope Ø 85 mm. 01 – 06: Vallis Alpes and mares ("oceans") on the moon. 11 – 17: Apollo landing points on the moon, 1969, 1971 and 1972. 21 – 27: biggest craters. ➽ See also PIP ;-) ➽ enlargement Ko Hummel (46.7392, 07.3868)

the earth's faitful companion in total eclipse See also PIP ;-) ► Havana Moon: · ♯ ♪ ♫ ♪ ♫ ♪ · :-) (46.73162, 07.44620)

Sonnenfinsternis vom 12.08.2026, 20:16 MEZ. Aufgenommen mit dem Handy direkt durch das Okular eines Teleskops Celestron Regal M2 100ED mit Solar-Filter. An der oberen Seite der Sonnensichel sind noch Sonnenprotuberanzen zu erkennen. (46.9512, 07.4389)

Sonnenfinsternis vom 12.08.2026, 20:01 MEZ Aufgenommen mit dem Handy direkt durch das Okular eines Teleskops Celestron Regal M2 100ED mit Solar-Filter. Sehr amateurhaft, aber das Resultat war trotzdem unerwartet gut. ;-) (46.9512, 07.4389)