This fall was followed by significant warming at the South Pole, an equally shocking discovery.
These observations were made by a team of international astronomers who studied nearly 100 thermal infrared images of Neptune in an attempt to unify common trends in the eighth planet’s temperature from the Sun.
- The planet is 49,244 km in diameter, four times larger than Earth.
- Its temperature varies from -218 to -200 C.
- The planet is 4.5 billion kilometers from the Sun (on average).
- It has 14 moons.
- Like Uranus, it is an ice giant. It is mainly made up of water, ammonia and methane.
- It is mostly composed of silicate and a strong core of iron.
- Its atmosphere, 8000 km thick, is mainly composed of dihydrogen (85%), helium (13%) and methane (2%).
- The blue color of Neptune comes primarily from methane, which absorbs light at red wavelengths.
- Neptune’s winds are very fast in the solar system, reaching 2000 km / h.
- The planet has a system of very fine and fuzzy rings.
Summer has been in the southern hemisphere of Neptune since 2005. Therefore, scientists have the opportunity to study the evolution of temperature after the Australian summer solstice.
You should know that Neptune, like Earth, has seasons that revolve around the Sun. However, a Neptune season lasts about 40 years, and a Neptune year lasts 165 Earth years.
Researchers have measured Neptune’s temperature from all images taken by space and ground telescopes’ thermal cameras over the past two decades. They analyzed the infrared light emitted by the planet’s stratosphere, which helped them draw a table of Neptune’s temperatures and its variations as part of its Australian summer.
The data collected show that despite the arrival of the Australian summer, much of the planet has gradually cooled over the past two decades. Thus, between 2003 and 2018, Neptune’s global average temperature dropped by 8 C.
This change is unexpectedMichael Roman, a graduate of the University of Leicester in the United Kingdom, explains.
When we observed Neptune at the beginning of its southern summer, we expected the temperature to warm slowly and not be cold.
In addition, astronomers have been surprised by the dramatic warming of Neptune’s South Pole over the past two years. Between 2018 and 2020 the temperature rose rapidly to 11 C.
Although Neptune’s hot polar vortex has been known for many years, no such rapid polar warming has been observed on the planet before.Note the researchers who published the details of the work The Planetary Science Journal (New window) (In English).
Hard to explain
Astronomers still do not know how to explain Neptune’s temperature variations.
They may be due to chemical changes in Neptune’s stratosphere, random weather events, or the solar cycle.They say.
Additional data will be collected over the next few years to help explain these fluctuations.
Future telescopes, the European giant telescope and the James Webb Space Telescope, It will allow us to observe temperature changes in more detail, but also to better understand the chemistry and temperature of Neptune’s atmosphere.
” I think Neptune is very mysterious to many of us because we still know very little about it. ⁇
All of this represents a very complex picture of Neptune’s atmosphere and how it changes over time.He explains.