» solarsystem
solarsystem
Rotation of Neptune
Lawrence Sromovsky (University of Wisconsin-Madison), NASA/Space Telescope Science Institute
A time-lapse animation of the rotation of Neptune has been assembled from images taken by NASA's Hubble Space Telescope and the Infrared Telescope Facility on Mauna Kea, Hawaii. By observing the planet at different wavelengths, astronomers see different levels of the atmosphere. These images show Neptune's storms, dark spots, and its powerful equatorial jet stream.
Video: 480 kB, MPEG
Neptune's atmosphere
Neptune's atmosphere was first revealed to us when Voyager flew by the planet in 1989. Since then, the Hubble Space Telescope has provided scientists with more detailed views of the cloud structure and dynamics. Some features of the atmosphere include dark spots, methane cloud tops, and a complex circulatory system. The northern dark spot, discovered using the Hubble in 1995, may be a hole in the methane cloud tops, allowing one to see deeper into the atmosphere. As the air in the atmosphere flows over the spot, the particles condense to form methane ice crystal clouds. Neptune's equatorial jet stream is not driven by the Sun as it is on Earth, but is driven by an internal energy source. Neptune radiates about twice as much energy as it receives from the Sun. This energy may warm the clouds triggering the atmospheric circulation we observe.
Ellen Cohen
Tags:
Comet Impact with a Gaseous Planet: The Atmosphere
Kevin Zahnle (NASA Ames Research Center) and Mordecai-Mark Mac Low (American Museum of Natural History)
Video: 438 kB, MPEG
Motivated by the Comet P/Shoemaker-Levy 9 impact with Jupiter in the summer of 1994, scientists began to calculate the effects of such an impact on the comet as well as on Jupiter. Once the comet had traveled deep into the atmosphere, it was ultimately destroyed in a powerful explosion. This explosion sent a plume of material shooting hundreds, even thousands, of kilometers above the cloud tops. The material eventually fell back into the Jovian atmosphere where it produced the scars
or spots seen on Jupiter after the collision.
The simulation
Using a complex computer code to calculate the structure and density of the gas, scientists are able to predict what would happen to the gas in the Jovian atmosphere during the collision. In this movie, the comet explodes sending material ballooning out into the atmosphere. After exploding from the upper cloud deck, the material will soon fall back to the atmosphere and come to equilibrium with the surrounding gas in the atmosphere.
Brian Abbott
The Topography of Venus
Grant L. Hutchison, NASA
Video: 605 kB, MPEG
Venus has one of the thickest atmospheres in the Solar System. Seeing the surface is hopeless using conventional telescopes. However, by using radar, we are able to get an idea of the topography of the surface. In this animation, the surface features of Venus are seen as the planet rotates on its axis. Because this is not an image, we do not have information about the color and other aspects of the surface. The false color here is correlated with elevation, black and purple being the lowest elevations and red and white being the highest elevations.
The Venusian surface
The surface of Venus is quite different from that of Earth or Mars. On Venus only about 10 percent of the surface is considered to be highlands, compared to 45 and 50 percent on Earth and Mars, respectively. Venus is mostly low-lying plains with rolling hills. In fact, 60 percent of the surface is covered by rolling hills that are flat to within plus or minus 1 kilometer (0.6 miles). Only 16 percent of the surface lies below this plain. There are two Earth-continent-sized highland regions which extend several kilometers above the mean elevation. The highest point on the planet, Maxwell Montes, is 11 kilometers high (2 kilometers above Mt. Everest) and is part of the Ishtar Terra continent. This continent is the second largest on the planet, about the size of the continental United States. Aphrodite is the largest highland region and is about the size of Africa.
Ellen Cohen
Tags:
