and is unfortunately no longer among us to comment on the discoveries made on of the solar system, but their colleagues continue to explore these worlds. If the gases that are and is much better known to us now after the missions and Cassini, the Frozen – Discovered by Herschel ( ) and Le Verrier ( ) – still holds many mysteries.
Only the Voyager 2 probe approached Uranus and Neptune and discovered in the latter case amuch more active than expected for a planet so far away (therefore receives much less sound than Saturn), like it possesses a spot, black this time, suggesting a huge planetary anticyclone.
NASA’s Hubble Space Telescope has taken time-lapse images of a large dark storm on the vanishing Neptune. A recent Hubble program called Inheritance from the atmosphere of the outer planet, or OPAL, provides annual global maps of our gas giant planets, allowing planetary scientists to see changes in formations such as Neptune’s dark storms. To get a fairly accurate French translation, click on the white rectangle at the bottom right. The English subtitles were then to appear. Then click on the nut to the right of the rectangle, then on “Subtitles” and finally on “Automatically translate”. Select “French”. © NASA Goddard Space Flight Center, Katrina Jackson
have therefore been content since the 1980s to continue their study of Uranus and Neptune using telescopes on Earth or with Hubble in . We see a new illustration of this with an article published in Journal of Geophysical Research: Planetsbut also in free access on showing the work of an international team led by professor i planetary at Oxford University.
This work is based on analyzes of archival data covering several years, first collected with Hubble, which was obtained with its spectro-imager (STIS) and ranges frominfrared, as well as the many images that Hubble has taken of Uranus and Neptune with the mythical Wide angle camera 3 (WFC3). Data collected with the telescope Twin north andInfrared telescopic system (IRTF) off also proved valuable.
These observations have provided scientific models for radiation transferof the two giants (and of these atmospheres themselves) largely consist of ice and which now allow better understand why with and very similar rays, and equally similar compositions and structures, Uranus and Neptune still have different colors.
Layers of aerosol mists and various turbulent atmospheres
Initially, planetary scientists were just looking to develop a model that would help them understandand in the atmosphere of the ice giants. But as Mike Wong, an astronomer at the University of California at Berkeley and a member of the team behind the discovery of Uranus and Neptune’s colors, specifies in a press release, ” Explaining the color difference between Uranus and Neptune was an unexpected bonus! “.
Irwin explains that ” it is the first model that also takes into account the observations ofreflected sun ultraviolet to near infrared. It is also the first to explain the visible color difference between Uranus and Neptune. “.
As explained in more detail in the diagrams below, the researchers’ new model involves three layers of aerosol nebula (remember that ais a suspension of fine droplets or particles in a for example in the form of smoke or ) at different altitudes in the atmosphere of each planet. That haze particles, just above the level of methane, turns out to be thicker on Uranus than on Neptune and this is what affects the visible color of the two planets.
As in the case of the explanation of the blue color of the sky and the white color of the clouds on Earth, planetary scientists in their models have taken into account .named after involved in explaining these effects more than a century ago
Jet currents only affect Neptune and Uranus on the surface
Article bypublished on 23/05/2013
Thaton Neptune and Uranus would be limited to their surface, according to a group of planetary scientists. This is the conclusion reached by the researchers who indirectly studied the gravitational field generated by the two . The method they used should be able to be applied to Jupiter in a few years.
The conquest of space has enabled the birth of a comparative planetology, using the tools of internal and external geophysics, tested on Earth, to try to understandand from other planets . In this way, it is possible to learn more about our planet itself.
You can not vary, its composition or its temperature, as one would do in the laboratory to better understand a physical system. But’ is responsible for performing these experiments with the various of the solar system. We can thus transpose the models of on earth at and to see if they make it possible to predict, via simulations, the meteorology of the planets.
Scientists likefrom Department of Environmental Science from Weizmann Institute of Science (Israel), is also trying to understand the climate of gas giants like Jupiter and Saturn. The Geophysicist has just been co-published, in an article in which he provides a new assessment of the thickness of the layers where (Where jet streamsin English) about Neptune and .
Winds blow at 1,000 km / h on Neptune and Uranus
Since the observations of the missionwe know these violent are found on the surface of the two planets and that they even blow there by one over 1,000 km / h. A kind of whose size exceeds that of the Earth also occurs there.
It was also a surprise toowho did not expect to see so much activity on icy planets with low energy from the light of , as they are located at distances of several billion kilometers from it. Though has a strongly inclined axis of rotation so that it is almost parallel to the planet’s orbital plane and that one of its poles is almost opposite to the Sun in we see that the atmospheric phenomena on Uranus and are very much alike.
To decipher what is happening inof these giants it is necessary to specify the models for their internal structure. We can use the laws of physics to build them, but it is necessary to limit them by observations and measurements. It is possible to use, for example where is planets for this purpose. This is how the measurements are of the mission gave us information about the interior of .
A method of exploring Jupiter and exoplanets
It turns out, however, that the gravitational field affects the properties of the fluid flow on a rotating planet. On Earth, this is a fact well known to external geophysicists. Sowinds show that they enclose areas of low and high pressure. Via the estimates of these pressures, we can go back to the planet’s inhomogeneous gravitational field and finally to the characteristics of the distribution of in the inner layers. This is exactly what the scientists realized, based on data on the jet streams from Neptune and Uranus.
Planetologists conclude that jet streams should not extend to a depth of more than 1,000 km. Remember that the radii of Neptune and Uranus are approximately 24,600 and 25,400 km, respectively.
When the missionsand will arrive near Jupiter, the data they will collect should make it possible to use the same method as the scientists, to limit the inner structure of the largest planet in the Solar System. We should be able to do the same in the future .