[대한민국청소년의회 뉴스 / 박소현 인턴 기자] The two planets at the far end of the solar system, Uranus and Neptune, have similar features and are often compared to twin planets.
Uranus is regarding 15 times the mass of Earth, and Neptune is regarding 17 times the mass of the Earth, and its size is similar at first glance. Although the atmosphere is made up of hydrogen, helium, and methane, the color is distinctly different: Uranus is light blue and Neptune is dark blue. A recent study has revealed the reason for the difference in color between the two planets.
The color difference between Uranus and Neptune is believed to be due to the difference in the thickness of the atmospheric haze layer. The research team led by Dr. Patrick Irwin, a professor of planetary physics at Oxford University in the UK, recently published their findings in the Journal of Geophysical Research: Planets to explain the difference in color between the two planets.
In the past, scientists have speculated that Neptune’s dark blue color is due to methane, which absorbs red light and reflects blue light. Methane makes up regarding 1.9% of Neptune’s atmospheric mass. However, it is not known why Uranus, which is known to contain more methane at a rate of 2.3%, has a lighter color than Neptune.
For the new investigation, astronomers mobilized near-infrared spectrometers from the Gemini Northern Observatory and the Hubble Space Telescope. By analyzing the results of observations at various wavelengths, a new model including haze particles in the atmospheres of the two planets was created. As a result of observation, the atmospheres of each of the two planets had three layers of haze for each altitude, and the thickness of the middle layer showed a clear difference.
Neptune’s haze layer is thinner than Uranus’s because Neptune’s dynamic atmosphere moves, producing methane snow, which removes haze particles in the process. On the other hand, in the case of Uranus, which has a slow atmosphere, the haze layer is much thicker. Additionally, the team speculates that this intermediate layer may have caused the black dots on each planet.
However, so far, Voyager 2 is the only spacecraft that has explored these two planets, and there is not much information available regarding these planets at this point in the absence of any future exploration plans. More in-depth studies of Uranus and Neptune are expected with NASA’s Neptune Orbital and Atmospheric Orbiter or the James Webb Space Telescope, scheduled to launch in the 2030s.
