Carl Sagan And the Andre Braich Unfortunately, you are no longer with us to comment on the discoveries that have been made on the giant planets in solar system But their colleagues continue to explore these worlds. If the gases Jupiter And Saturn is better known to us now after the missions Juno The Frozen Cassini – Discovered by Herschel (Uranus) and Le Verrier (Neptune) – still holds many mysteries.
just the probe Voyager 2 Get close to Uranus and Neptune, and discover in the latter case A meteorology More active than expected for a planet so far away Sun (Therefore receiving much less sound energy from Saturn), which has a black spot this time, indicating a massive presence Storm Anticyclone planets.
NASA’s Hubble Space Telescope has captured time-lapse images of a large dark storm on the waning planet Neptune. Hubble’s latest program is called Legacy of the atmosphere of the outer planets, or OPAL, annual global maps of our gas giant planets, allowing planetary scientists to see changes in formations like Neptune’s dark storms. For a fairly accurate French translation, click the white rectangle at the bottom right. The English translation should then appear. Then click on the nut to the right of the rectangle, then click on “Subtitles” and finally on “Translate automatically”. Choose “French”. © NASA Goddard Space Flight Center, Katrina Jackson
planetary scientists So they have been content since the 1980s to continue their study of Uranus and Neptune using telescopes on Earth or with Hubble at orbiting. We see a new clarification of this in an article on Journal of Geophysical Research: Planetsbut also in free access on arXivPresentation of the work of an international team led by Patrick IrwinMr physical Planets at Oxford University.
This work is based on analyzes of archival data covering several years first collected with Hubble, acquired using the Spectrophotometer Imaging System (STIS) and ranging from ultraviolet to ultraviolet.InfraredIn addition to many pictures taken by Hubble of Uranus and Neptune with the mythical 3 . wide field camera (WFC3). Data collected using the telescope North Gemini and theInfrared telescope attachment (IRTF) from NASA has also proven its worth.
These observations have fueled scientific models of radioactive transport in ambiance Of the two giants (and from these two atmospheres themselves) made up largely of ice which now allow Astronomy scientists Better understand why with masses and very similar rays, and similar compositions and structures, Uranus and Neptune still have Colors Different.
Aerosol fog layers and different turbulent atmospheres
Initially, planetary scientists were only looking to develop a model that would help understand Clouds and the fog In the atmosphere of ice giants. But, as Mike Wong, an astronomer at the University of California at Berkeley and a member of the team responsible for discovering the colors of Uranus and Neptune, outlined in a press release, Explaining the color difference between Uranus and Neptune was an unexpected bonus! “.
Erwin explains that It is the first model that takes into account the feedback light solar reflected wavelengths Ultraviolet to near infrared. He was also the first to explain the visible color difference between Uranus and Neptune. “.
As shown in more detail in the graphs below, the researchers’ new model includes three layers of aerosol mist (remember that aerosol It is a suspension of droplets or fine particles in a Gasfor example in the form of smoke or fog) at different altitudes in the atmosphere of each planet. The Middle class Fog particles, above the level Concentration Methane, it turns out to be thicker on Uranus than on Neptune and this affects the visible color of two planets.
As in the case of explaining the blue color of the sky and the white color of clouds on Earth, planetary scientists have taken into account in their models Rayleigh and Mie . light scattering effectson the name Physicists He explained these influences over a century ago.
Jet currents only affect Neptune and Uranus at the surface
Article from Laurent Sacco Posted on 05/23/2013
The jet streams According to a group of planetary scientists, Neptune and Uranus will be limited to their surface. This is the conclusion reached by researchers, indirectly studying a field gravity Created by both gas giants. The method they used should be applicable to Jupiter within a few years.
The conquest of space allowed the birth of comparative planetary science, in which instruments of internal and external geophysics, tested on Earth, are used to try to understand geology and the climatology from other planets solar system. In this way it is possible to learn more about our planet itself.
You can’t change Earth massor its composition or temperature as one would do in a laboratory to better understand a physical system. But’Universe He is responsible for conducting these experiments with the manifold stars for the solar system. Thus we can switch models climate on the ground in Mars And the Venusto see if they make it possible, through simulations, to predict the meteorological forecasts of the planets.
Researchers like Yohay CaspiThe Department of Environmental Sciences The Weizmann Institute of Science (Israel), is also trying to understand the climate of gas giants such as Jupiter and Saturn. The geophysicist just shared a post in temper naturewhich is an article providing a new assessment of the thickness of the layers where jet streams (where jet streamsin English) on Neptune and Uranus.
Winds blowing at a speed of 1000 km / h on Neptune and Uranus
Since the mission notes Voyager 2we know that these winds Violent planets exist on the surface of planets, and they even explode there at a Speed above 1,000 km / h. types of Tornadoes Those larger than Earth’s occur there, too.
It was also a surprise for astrophysicistswho didn’t expect to see much activity on icy planets with low energy of light Sun, because they are located at distances of up to several billion kilometers from it. although Planet Uranus It has a strongly tilted axis of rotation, so that it is parallel to the orbital plane of the planet, and one of its poles is approximately opposite the Sun at winterwe see that the atmospheric phenomenon on Uranus and Neptune very similar.
To decipher what is happening in ambiance Of these giants, it is necessary to determine the models of their internal structure. We can use the laws of physics in their construction, but it is necessary to limit them to observations and measurements. For example, it is possible to use a file magnetic field where is the gravitational field planets for this. This is how the measurements are gravity of the task grill He gave us information about the interior of the moon.
A way to explore Jupiter and the outer planets
However, it has been shown that the gravitational field affects the fluid flow properties on a rotating planet. On Earth, this is a fact that is well known to outside geophysicists. So field speed Winds appear to wrap around areas of low and high pressure. By estimating these pressures, we can return to the inhomogeneous gravitational field of the planet and finally to the characteristics of the distribution issue in the inner layers. This is exactly what the researchers realized, based on data on the jet streams of Neptune and Uranus.
Planetary scientists have concluded that the jet streams should not extend to a depth of more than 1,000 km. Remember that the radii of Neptune and Uranus are about 24,600 and 25,400 km, respectively.
When missions Juno And the juice They will arrive near Jupiter, and the data they will collect should allow the researchers to use the same method, in order to constrain the internal structure of the largest planet in the solar system. We should be able in the future to do the same with Hot Jupiters.
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