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DB
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Do planets have actual lumosity or are they just lit up by stars? Might be a stupid question but I am just wondering.
Thnx
Thnx
Personally I do not know but I assume they might have because of some of the chemical reactions that happen on some of them (like the Great Spot on Jupiter). I don't know, to be honest, but I would say yes.DB said:Do planets have actual lumosity or are they just lit up by stars? Might be a stupid question but I am just wondering.
Thnx
Well THIS particular planet is certainly luminous! It's a big pain in the butt, and I'm glad I live in a thinly populated place.The Bob said:Personally I do not know but I assume they might have because of some of the chemical reactions that happen on some of them (like the Great Spot on Jupiter). I don't know, to be honest, but I would say yes.
Sorry.
The Bob (2004 ©)
Jupiter radiates twice as much heat as it receives from the Sun. No other planet comes even close to doing this. This fact is the key to understanding Jupiter's complex and beautiful cloud circulation pattern. There must be some internal energy source, perhaps the energy remaining from Jupiter's collapse from a primordial gas cloud 20 Mkm across to a protoplanet 700,000 km across, 5 times the present size of Jupiter. This catastrophic phase of collapse theoretically started, when the temperature grew sufficiently high to break up hydrogen atoms. The rapid phase may have taken only 3 months to occur, following the 70,000 years it had previously taken to shrink from a more diffuse cloud. Jupiter is undoubtedly still contracting.
The heat emanating from the interior of Jupiter produces huge convention currents. The bright zones are rising currents of gas driven by this convection. The belts are falling gas; the tops of these dark belts are somewhat lower (about 20 km) than the tops of the zones and are about 10 K cooler.
Earth-based infrared observations measure temperatures only 100 K to 200 K in the uppermost atmosphere far above Jupiter's clouds. Yet Pioneer's data at other infrared wavelengths reveal that at a pressure of one-half that of the Earth at sea level, the temperature of supposedly frigid Jupiter reaches a boiling 400 K.
Infrared radiation refveals Jupiter's temperature in the upper atmosphere to be very cold because of the planet's great distance from the Sun, about 133 K (-220 F), on both the sunlit and nighttime sides. At a lower level, the poisonous clouds are warmer. Gaps in the clouds have revealed still lower haze layers with even higher temperatures of around 250 K (-9 F).
Jupiter's infrared thermal radiation is generated by the heat of the planet itself. This figure turns out to be about twice as much energy as Jupiter absorbs from the Sun!. Theorists believe Jupiter is slowly contracting, releasing gravitational energy as heat and radiation. This radiation was most intense when Jupiter formed and has declined ever since to the low level observed today. According to some theoretical models, the core may be over twice the size of Earth and have a temperature around 30,000 K.
Nereid said:We can do this - from Earth - for Mercury and Venus, but not for the others. Do you know why DB?
Also, even if the Earth had no cities, fishing fleets, etc, it would still be quite visible 'at night' from out in space ... at least some of the time. Do you know why?
No, the luminosity of a planet depends on several factors such as its size, distance from its star, composition, and atmospheric conditions. For example, a smaller planet with a highly reflective atmosphere may have a higher luminosity than a larger, darker planet.
A planet's luminosity is calculated by measuring the amount of light it reflects and emits. This can be done using telescopes and special instruments that can detect different wavelengths of light.
No, not all planets emit light. Planets do not have their own light source like stars do. However, they can reflect light from their star or other sources, which gives them a luminous appearance.
Yes, a planet's luminosity can change over time. Factors such as changes in atmospheric conditions or the amount of light it receives from its star can affect a planet's luminosity. Additionally, some planets may have active processes such as volcanic eruptions that can also impact their luminosity.
A planet's luminosity can have a significant impact on its habitability. If a planet receives too much or too little light from its star, it can affect the temperature and conditions on the planet's surface. This can ultimately determine if the planet is suitable for life to exist.