Which planet radiates more energy

The earth-atmosphere energy balance is achieved as the energy received from the Sun balances the energy lost by the Earth back into space. In this way, the Earth maintains a stable average temperature and therefore a stable climate.

Using units of energy from the sun as a baseline the energy balance is as follows:. The absorption of infrared radiation trying to escape from the Earth back to space is particularly important to the global energy balance. Energy absorption by the atmosphere stores more energy near its surface than it would if there was no atmosphere. An appropriate temperature is one requirement for life as we know it.

The factors responsible for the great differences and our good fortune are the topic of this module. All objects, including stars and planets, radiate energy to their surroundings.

The wavelengths of the emitted radiation depend on the temperature of the object. Although you cannot see the radiation from a warm radiator, you can feel the warming infrared emission absorbed by your skin. If you raise the temperature of an object high enough, some of the emitted wavelengths are in the visible region of the spectrum and you see the object glowing, first red-hot and then, as its temperature increases, white-hot like the filament of an incandescent light bulb.

The emission energies as a function of wavelength from such objects can be approximated by the Planck equation for emission from a black body. A black body is an object that absorbs all wavelengths of light that fall on it. Emission from a black body is closely approximated by the emission from a tiny hole in a hollow object held at a constant temperature and was measured in the 19th century. This module of the ACS Climate Science Toolkit is based on the black-body emission properties of the sun and planets of our solar system.

The Planck equation is complex and most easily interpreted graphically as in this figure. Note that the emission scales differ by a factor of a million for the hot object that represents the sun and cool object that represents the Earth. Small helium droplets form where it is cool enough, precipitate or rain down, and then dissolve at hotter deeper levels. As the helium at a higher level drizzles down through the surrounding hydrogen, the helium converts some of its energy to heat.

Interior heat and helium rain Precise measurements from the Voyager 1 and 2 spacecraft indicate that Saturn is radiating 1. Lang, Tufts University. The temperatures and pressures are so high in the cores of Jupiter and Saturn that hydrogen exists in a metallic state. Temperatures in the outer reaches of the solar system are cold. The surface temperature of Jupiter is minus degrees Celsius minus degrees Fahrenheit and that of Neptune is minus degrees Celsius minus degrees Fahrenheit.

As a result, the outer planets are cooling off, and part of the energy they radiate is left over from their formation. In the case of Jupiter, which is larger in volume than all the other planets put together, this leftover energy allows it to radiate with an energy that is about 1. Saturn is smaller than Jupiter and farther from the sun, so it should be dimmer, but in fact it shines with an energy that is 2.

Scientists believe this extra energy results from a phenomenon called helium rain. Saturn's more rapid cooling allowed helium droplets to form in its atmosphere, and because they are heavier than hydrogen, they fall toward the center of the planet. The friction they generate as they fall through the atmosphere accounts for the extra heat.

This explanation also accounts for the lack of helium in Saturn's upper atmosphere.