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This page shows what I think are the 8 best images of 2000 of Io. Some have been taken this year some were taken last year. What ever the year they were taken in, they were released this year and are the best for one reason or the other. I will be counting down to the new year with this page starting on Christmas Day, 2000. The best image, the creme de la creme, will be published here on December 31, 2000, the last day of the 21st Century and the 2nd millennium.
Jason's Comments: This is the best image of Io released in 2000. This image shows close ups of the interior of the Chaac caldera. You can see individual lava flows and the cliff bordering the caldera. The exterior of the caldera appears bumpy, like near Camaxtli and Prometheus. The bottom closeup shows a deep pit where lava in the caldera drained.
To see this image up close, go to its Planetary Photojournal Catalog Page or its University of Arizona page.
Jason's Comments: This image shows a close up mosaic of the Prometheus lava flow and the surrounding terrain. I chose this version of the mosaic because this is clearer and the contrast is better. Some of the bumps in the surrounding terrain appear like rounded hills, especially in the eastern or right part of the mosaic. Other bumps appear like linear ridges, almost like a Spanish tile roof. This can be seen in the middile part of the mosaic. The darker areas are lava flows. The darker the area, the younger the lava flow. The brighter the surrounding terrain, the more fresh SO2 frost exists. The multiple frost streams show that the plume that emanates from the western part of the mosaic, comes from many sources at the edges of active lava flows.
To see this image up close, go to its Planetary Photojournal Catalog Page or its University of Arizona page.
Jason's Comments: What an amazing splash of color! Greens, reds, oranges, blacks, and yellows. All of these colors are caused by sulfur impurities like iron and selenium and sulfur allotropes. The actual volcano is only 19 km across and is covered in green material (indicating iron impurities). From this volcano, lava has spilled on to the surrounding landscape. Some of the lava comes from a lava tube going toward the northwest. From here, dark lava spews forth.
To see the original caption, go to this image's Planetary Photojournal catalog page.
Jason's Comments: In light of the recent news of a possible new eruption at Tvashtar (see news article), I thought I would put this image in here. Now true, the one taken in I25 had higher resolution. However, this shows more detail on the many lava flows here at Tvashtar. Which one of these areas erupted? If it was the same as in November 1999, then the dark, L-shaped lava flow was the culprit. Maybe Galileo can find out next year when it flys over Tvashtar at only 200 km distance in August 2001.
Check out this image's Planetary Photojournal page.
Jason's Comments: This image shows the Amirani-Maui lava flow. It shows the evolution of the lava flow from a crack, bursting with hot lava and bubbling sulfur, to a massive flow field with multiple breakouts marked by black spots in this image. They are dark because they are too hot or too young to have been sufficiently covered by sulfur dioxide frost to brighten. The purple spot just below center is where the Amirani plume, seen since 1979, erupts.
To see this image up close, go to its Planetary Photojournal page or its University of Arizona page where a larger copy can be found.
Jason's comments: I think this image represents all manner of terrain types you would see on Io. In this image you see frost hills, long lava flows, calderas, pyroclastic deposits, and active volcanic activity. Also note one of my favorite features on Io, "The Arrow," which is just left of center. The six calderas on the right part of the image form a volcanic chain. Unlike the Hawaiian chain, which is caused by movement of the Pacific plate over a hot spot in the mantle, this is caused by outbreaks of lava and caldera collapses along a bent fracture in Io's crust. Lava from Io's mushy magma ocean (also called the mantle) travels up fractures such as this one and onto the surface. Don't bother looking for the fracture. Its too thin to see and is likely covered in 1 to 2 km of frost when not bordering a volcano. Another note: the caldera at the far left is called Chaac Patera and the large caldera at the bend in the chain is called Camaxtli Patera. Try saying that 3 times fast.
See the original caption at its Planetary Photojournal site or its University of Arizona site (a nice, large copy of this image can be found there ;)
Jason's Comments: You don't get much of a closer look than this. This image has a resolution of 5.5 m/pixel, meaning that you could easily see a house, if one existed here. In this image you see a cliff that has been degrading for some time. Surrounding the cliff is a ring of forst and beyond that some darker material. Now here it gets really intesting. Within this dark material are streams maybe 10-20 meters wide and 150 meters long. What created these? Liquid Sulfur dioxide, perhaps? What ever created these we don't know for sure, more than likely some kind of sulfur compound. However, these streams represent evidence of natural springs on Io. BTW, note the degraded appearance of some of the terrain. Some of it looks like a layered terrain, other parts, a very jaged terrain. This may represent sublimation erosion on Io. Sublimation erosion may also be what is degrading the promenence.
See the orginal caption at its Planetary Photojournal site
Jason's Comments: This has be my favorite region of Io, the Hi'iaka Region. Two mountains border a large lava flow. The tallest part of this complex is in the north part of the northern mountain. This peak reaches 11,000 m into space. I have always imagined what I might be like to stand on the one of those mountains and look out over the large lava flow.
See the orginal caption at its Planetary Photojournal site.
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