Strange changes in Neptune's brightness may mean the Sun is warming it up

May 21, 2007 12:06 GMT  ·  By

Neptune is the eighth and farthest known planet from the Sun in the Solar System. Named after the Roman god of the sea, it is the fourth largest planet by diameter and the third largest by mass, having 17 times the mass of Earth.

One of the coldest planets in the solar system, with an atmospheric temperature close to −218 ?C (−360 ?F), a complete revolution around the Sun takes 164.88 Earth years.

A couple of astronomers wrote a book on Neptune, with an intriguing name: Suggestive correlations between the brightness of Neptune, solar variability, and Earth's temperature. In it, H. B. Hammel and G. W. Lockwood propose a theory after having examined the planet between 1950 and 2006.

The authors claim that Neptune got brighter over the last 50 years, which could mean the Sun may actually play a part in the global warming of a planet, including Earth's. Even though the observations were made during a less than a third of Neptune's year, changes in the sun must also be considered, as space influences add to the already grim forecast.

Hammel and Lockwood said that "[...] components of the solar output might have an impact on the atmospheres of both Neptune and Earth (e.g., ultraviolet flux, magnetic field strength, cosmic ray shielding)."

They don't deny mankind's negative influence in global warming, as pollution is responsible for the majority of the warming processes, but claim the Sun could be working against us.

"?(E)ven for the well-studied Earth temperature variability, the steady rise in temperature since the mid 1970s is not fully understood but has an anthropogenic component due in part or entirely to rising greenhouse gases, in combination with changes induced by sulfate and volcanic aerosols, and/or other forcing factors. Total solar irradiance seems to be ruled out as a driving factor in temperature variations, although other components of solar output may still play a role," the scientists wrote.

We obviously can't make the Sun change its behavior, but we must definitely change ours, and Neptune may be sending us a warning message.