Wallpaper: Comet Halley

When comet Halley last swung into the vecinity of the inner solar system, it was one of the lesser impressive apparitions in probably hundreds of years. In previous visits, the Halley either fascinated or horrified people everywhere. It was, as I would imagine, an object one could not ignore hanging in the sky above. Instead of a glorious vision in the sky, 4 independent probes were launched for the historic event to see what Halley was really all about. The one that returned the best images was the European Giotto probe which got in pretty close and returned the above image.

IMAGE NOTE: The image above is one rarely posted and may be a more recent “clean-up” version of the one more commonly seen when doing a google search for comet halley (seen at left here). The only alterations I made to this was to extend the slight haze beyond the tail so that it runs off the upper left hand side of the cropping. Color is ever so slightly enhanced from the original. Now whether or not the original was enhanced… that I don’t know.

Wallpaper: Triton Portrait

Another big surprise of the Voyager mission was the discovery that the coldest place in the solar system is also home to a considerable amount of geological activity. The moon appears to be widely populated by a large amount of cryovolcanos which were observed directly by Voyager in 1989. These volcanos can be seen in this image as small black smudges mostly located running across the center of the disk. It also has a tenuous atmosphere almost entirely composed of nitrogen.

One of the most interesting bits of information about Triton to me is that the orbit runs in the opposite direction of Neptune’s rotation. This suggests that at one time, Triton may have been a dwarf planet captured by Neptune’s pull. This would also explain the lack of numerous moons which we see at many of the other gas giant planets. Triton would have swept through the Neptune system and probably either collided with or ejected whatever moons may have existed in the system. Triton also has a very slowly decaying orbit and will likely collide with Neptune or shatter into pieces to form a new ring system in 3.6 billion years.

Image Note: This is the orignal Triton portrait image that was posted to this site. The newer and improved main top image was recently generated by Ted Stryk and posted to unmannedspaceflight.com.

Wallpaper: Titan Portrait

Titan is without a doubt, not only one of the most interesting moons, but it is easily one of the most interesting places in all the solar system. It has been determined that Titan is host to the only other lakes ever to be discovered off Earth! Data also supports the idea that Titan has rain and other kinds of weather as well as cryovolcanism (a type of cold volcano). Even with all this, it is near impossible to eek out an interesting image of the place as its thick atmosphere hides everything taking place on the surface. Additionally, similar to Venus and Uranus, the clouds fail to show much in the way of structure or detail as well.

Wallpaper: Titan Eclipse

Titan passed in between Cassini and the sun giving us this opportunity to see the haze of the atmosphere lit from behind.

WALLPAPER NOTE: The original image only revealed half the disc. To complete the full image the top half was taken, flipped and overlapped with another lesser impressive eclipse image to avoid obvious repeat. So, in reality, the lower half of the image is “faked” but it is composed entirely of real references.

Wallpaper: Enceladus Portrait

During my run through posting images of the major moons of the solar system, I felt compelled to include this tiny 600km moon in the mix as it has suprised most scientists to be quite an active little place. Usually any body as small as Enceladus would fail to have any geological activity, but in 2006 the Cassini spacecraft discovered that there are several active geysers spewing water and ice into the space around it. These geysers have even established a tenuous atmosphere of mostly water vapor at the southern poles where the geysers are located.

WALLPAPER NOTE: I have to be honest… those stripes in the southern region with the geysers… they aren’t really blue. They would be bright gray like all the rest. Its just irresistable to use the blueish tones because they outline where all this geological activity is going on. I usually don’t use false-color.

Wallpaper: Callisto

With 3 other facinating large moons in orbit around Jupiter, asking for yet another in Callisto would have been expecting too much. This body is one of the most heavily cratered bodies we have yet seen. The heavy cratering record tells us that little has changed here on Callisto since early in the solar system’s history. So, not unlike our moon, not very much happens here… ever.

Although there are some theories being floated that Europa may not be alone in its candidacy for an internal ocean of water. Some think that Ganymede and even Callisto may also host such environments but to a lesser degree.

Wallpaper: Ganymede Portrait

The largest of all the moons in the solar system is actually larger than the planet Mercury. The moon also shows evidence to tectonic plates (the same process that causes earthquakes on Earth) and there may even be some underground ocean as on Europa though it is less likely to be nearly as extensive. Recent observations from the Hubble Space Telescope suggest that there may be a tenuously thin atmosphere of pure oxygen at Ganymede due to the radiating of water ice into oxygen and hydrogen. In this scenario the hydrogen is lost to space while the oxygen (being a heavier element) is retained at the surface.

Wallpapers: Ganymede at Half Phase

Ganymede in the best “disk” detail I have ever seen. There are some great close up images of Ganymede, but for some reason most of the images that show the moon from a distance are usually blurry and lack the detail you see here. This composite is by Ted Stryk but the trick is that his original was only in black and white, so I ham-handedly used other images of Ganymede to colorize it. So… the color here is interpretive and not based upon actual data.

Wallpaper: Europa Portrait

Europa has become a focal point of interest in our solar system. Subject to the same tidal forces that tear Io apart, Europa is less severely effected by this and here the stress takes the form of internal heating which keeps the moon from being frozen throughout. It has more-or-less been confirmed that below its icy crust lies an almost global ocean of 100% water. Considering that the center of the moon is quite warm and the icy shell is of course frozen rock-solid, somewhere in between must lie a zone with temperatures similar to that of earth deep within this watery underground ocean. As any marine biologist will tell you, the Earth's oceans are riddled with life. Even in places of extreme heat and cold, life still somehow has survived the ages and has adapted to such extreme environments. Leading to conjecture that no-matter the obstacles to life ever developing on the surface of such a place… the mere presence of earth-like conditions deep within Europa's dark underground water ocean may have been just enough for some if not many forms of life to evolve and survive to this day. There are many missions on the drawing board right now to find out more answers including a Europa orbiter, various landers and one truly aggressive mission that would involve melting through the crust and “injecting” a submersible probe into the watery core. For a new and improved portrait image of Europa see here.

Wallpaper: Europa at Half Phase

Awesome detail of Europa on this half phase image by Ted Stryk. The cracks and ridges which suggest the internal watery ocean are clearly evident and are Europa’s most notable features.

Wallpaper: Io Portrait

Io is the first large moon of Jupiter and is the most geologically active body in the solar system. Its close proximity to Jupiter and tidal forces from the giant and its 3 other giant moons push and pull the moon apart internally. This causes Io to turn itself inside out and fuels its many active volcanos. Due to this constant volcanic activity the surface of Io is quite young, continually being reshaped with not a crater to be found.

Image Note: The image itself is largely original and complete. I added the "dark side" details and completed disk. The the two plumes showing at the edges of the dark side of the disk are also additions. The plumes are taken from other real images and they do appear in true scale, however some brightening of these plumes were likely applied to these original images to show detail, so I darkend them a bit and reduced the color saturation that usually results from these manipulations.

Wallpaper: Luna Portrait

Galileo, on its way to the Jupiter system, looked back at the moon (Luna) and returned this image which largely shows the side of the moon we never see from Earth. The far side of the moon was first photographed by the Soviets in 1959 with the Zond-3 spacecraft.

Wallpaper: Pluto/Charon Family Portrait

Just for old times sake, I made the effort to post some kind of imagery of Pluto to complete the “classic” planetary set most of us have grown up with. For years scientists have pressed NASA to prioritize a mission to the only planet left in the solar system that has yet to be visited by any kind spacecraft and finally one was approved. Lucky for Pluto (and us) that the New Horizons mission was launched in January and is on its way to a rendezvous with Pluto in 2015. In a strange turn of events (only a few short months after launch) Pluto was demoted from planetary status to dwarf planet status… which politically may have nixed the entire mission as I am sure some of the budget hawks that make these kinds of decisions were convinced of the mission's importance by others stressing that it was the sole unvisited planet in the solar system. However, now scientists are excited that a new mission is already on its way to visit a whole new class of planetary bodies for the first time. This mission also expects to be able to re-route New Horizons to rendezvous with additional kuiper-belt objects after its initial Pluto mission. These targets have yet to be announced as scientists expect that some of these targets may not have even been discovered as of this time. Imagine how exciting it will be for the discoverer of a new planetary body to find out that there is already a mission on its way to explore the newly discovered object.

Wallpaper: Neptune Portrait

Neptune is the newly designated last “planet” in the solar system. It is the fourth gas giant and like Jupiter, it has its own “Great Red Spot” only in the case of Neptune it has been referred to as the “Great Dark Spot”. Like the other giants it also has a tenuous ring system and a system of moons. Only one of those moons, Triton, stands apart in size and characteristics and is one of the more interesting places to see in the solar system.

Wallpaper: Uranus Portrait

Second only to Mercury, Uranus tends to get the “boring” award from most due to its lack of almost any kind of cloud details. Among its five moons, there also isn’t really that much going on beyond what one might expect from such medium to small sized moons (with the possible exception of Miranda). However, there are a few things about Uranus that strike interest in it like the ring system, its axis is turned to about 98 degrees and more recently Hubble observations suggest that Uranus does have periodic cloud details not seen when Voyager flew past. As fate would have it, Uranus was in an unusually quiet mood in 1986.

Wallpaper: Saturn Portrait

Usually the favorite of most due to its fabulous ring system which easily makes Saturn the most picturesque bodies in the solar system. It also has an extensive system of moons which makes Saturn, like Jupiter, almost a mini system within our Solar System. One of its moons, Titan, is more of a planet than some planets are in that it has a thick atmosphere, is large in size, has weather and recent radar images suggest an extensive system of methane/ethane rivers and lakes.

Wallpaper: Jupiter Portrait

Jupiter is a mini system within our solar system. Had it become considerably more massive during the formation of the solar system, it may have ignited and given us a binary star system. It is quite large in comparison to the other planets and its mass is 2.5 greater than the combined mass of all the other planets in our system. The best feature of all is Jupiter’s system of four large moons, Io, Europa, Ganymede and Callisto. These moons are in their own right, more fascinating than many planets happen to be. For example, one of its moons (Europa) has become what many scientists are calling our Solar System’s “most likely place to currently harbor life”, other than Earth.

Wallpaper: Io Against Jupiter

Io was observed against Jupiter here in this partial family portrait. Its close proximity to Jupiter is what tears the tiny moon apart internally and causes the large amount volcanism discovered by Voyager and monitored by Galileo. Oddly enough, this image was taken by Cassini on its way to Saturn during its gravity assist pass through the Jupiter system.

Wallpaper: Mars Portrait

Mars is historically the most popular planet in our system. It has been the subject of many science-fiction stories as well as legitimate scientific investigation in the search for life outside of our own home. Recent missions to Mars have all but confirmed the idea that Mars was at one time a wet Earthlike place, covered rivers, seas and even oceans. Where all that water has gone is the subject of great interest and many have not given up the idea that we may one day still find some kind of life there if not the remains of life that had at one time thrived on the surface.The below wallpaper was the previous “portrait” image of Mars, but I have decided that the new Rosetta image of Mars captured during its gravity assist in 2007 is a better full globe image of the red planet. Notice the color variation… which is true? Well, the newer one from 2007 looks closer to Hubble views as seen from Earth orbit and unless they are manipulating colors from Hubble it would lead me to think that the Rosetta image is more honest.

Wallpaper: Venus Portrait

Venus may be the most inhospitable place in our solar system to be or consider going. Its atmospheric pressure at the surface is 90x that of Earth and the temperature hovers around 400ºC. The extreme temperature on Venus is due to a greenhouse effect which is generated by its unusually dense atmosphere of CO2 which makes it actually hotter than Mercury. It seems to me more likely that astronauts might one day visit Pluto before they ever attemp any kind of mission to the hell that is Venus.

The image itself is Venus in true color. Rarely are images shown of Venus as it actually appears due to the small amount of details available. Very minor manipulations were applied to this image including some brightening of the full disk and contrast which helped bring out a bit more of the natural color. Also the image has been scaled up which would normally result in some blurring, but with venus… who can tell?