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Schmu
Anmeldungsdatum: 23.06.2021
Beiträge: 112
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 Schmu Verfasst am: 10. Aug 2021 00:46 Titel: Neptun und Uranus |
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Ich schaue mir gerade diese beiden Planeten an, die Zusammensetzung ist ja ähnlich 80% wasserstoff, helium, bissle Methan. Der Neptun ist ein wenig grösser aber unwesentlich. Was mich nun erstaunt ist die Temperatur, Neptun ist deutlich weiter von der Sonne entfernt als Uranus aber die Temperatur ist nur ganz bissl geringer. Wie kann das sein? Hat Neptun eine zusätzliche Energiequelle, ist es radioaktiver Zerfall? Wo kommt das her? |
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Füsik-Gast
Gast
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| Füsik-Gast Verfasst am: 10. Aug 2021 11:41 Titel: internal heat |
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Es gibt bei Planeten verschiedene Quellen für die Erwärmung ohne Sonneneinstrahlung.Diese innere Erwärmung(internal heat) kann radiokativer Natur sein,aber bei den Gasriesen wird u.a. eine gravitative Erwärmung vermutet.Bei Neptun,ähnlich Jupiter,ist diese innere Erwärmung recht hoch,
da fällt Uranus etwas aus dem Rahmen.
Füsik-Gast. |
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willyengland
Anmeldungsdatum: 01.05.2016
Beiträge: 677
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| willyengland Verfasst am: 10. Aug 2021 12:48 Titel: |
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siehe:
https://en.wikipedia.org/wiki/Uranus#Upper_atmosphere
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Why Uranus's internal temperature is so low is still not understood. Neptune, which is Uranus's near twin in size and composition, radiates 2.61 times as much energy into space as it receives from the Sun,[23] but Uranus radiates hardly any excess heat at all. The total power radiated by Uranus in the far infrared (i.e. heat) part of the spectrum is 1.06±0.08 times the solar energy absorbed in its atmosphere.[16][85] Uranus's heat flux is only 0.042±0.047 W/m2, which is lower than the internal heat flux of Earth of about 0.075 W/m2.[85] The lowest temperature recorded in Uranus's tropopause is 49 K (−224.2 °C; −371.5 °F), making Uranus the coldest planet in the Solar System.[16][85]
One of the hypotheses for this discrepancy suggests that when Uranus was hit by a supermassive impactor, which caused it to expel most of its primordial heat, it was left with a depleted core temperature.[86] This impact hypothesis is also used in some attempts to explain the planet's axial tilt. Another hypothesis is that some form of barrier exists in Uranus's upper layers that prevents the core's heat from reaching the surface.[15] For example, convection may take place in a set of compositionally different layers, which may inhibit the upward heat transport;[16][85] perhaps double diffusive convection is a limiting factor.[15]
In a recent study, the ice giants' interior conditions were mimicked by compressing water containing minerals like olivine and ferropericlase. It showed that much magnesium could be dissolved in the liquid interiors of Uranus and Neptune. A thermal insulation layer made of dissolved magnesium in Uranus due to a larger quantity in Uranus than Neptune was proposed as a possible explanation of Uranus's low temperature.[87] |
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Gruß Willy |
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