In a bit of sisterly silliness, Rhea appears to have photojacked an otherwise lovely portrait of her big sister Titan in this image from Cassini! An honest mistake, I’m sure….the smaller moon quickly realized her transgression and exited the scene shortly after: 🙂 In all seriousness though, these photos illustrate the amazing differences in Saturn’s…
Tag: science
From a Distance
The MESSENGER spacecraft took this photo of Mercury on October 10, 2009, from a distance of almost 2 million miles. Just days earlier, MESSENGER flew over the surface of the innermost planet at an altitude of only 140 miles. With no atmosphere to disperse heat, the day side of Mercury can reach nearly 800º F…
LITD Highlight: What The Hex?
I originally posted this article on February 20, 2009. I like the image a lot, and there’s a link to a cool animation of the hexagonal feature around Saturn’s north pole. As Saturn’s spring approaches, its north pole comes into view and reveals the curious six-sided geometric shape rotating in its uppermost latitudes. This image…
Send your message to Venus!
The AKATSUKI Message Campaign Next year, the Japan Aerospace Exploration Agency (JAXA) will launch its Planet-C Venus Climate Orbiter, which will explore the atmosphere of Venus and investigate wind dynamics, cloud formation and other meteorological mechanics of Earth’s neighboring planet. And from now until December 25, you can register online to add your name and…
A Passing of Spheres
Rhea overlaps sister moon Dione in this image, taken by Cassini on October 22. One of a series of raw images showing the moons approach and then pass each other. Even at their closest passing the two moons are separated by more than 90,000 miles. Image: NASA/JPL/SSI
Methane Skies
In this raw image from Cassini, giant scallop-edged cloud patterns become visible in Saturn’s atmosphere with camera filters specially designed to detect methane. Light and dark banding of the clouds at various latitudes are also extremely distinctive through this filter. Although mostly hydrogen and helium, Saturn’s atmosphere does contain elements like methane and ammonia. Saturn’s…
It’s a Marvelous Night for a Moondance
In another animation made from raw images taken by Cassini, Mimas passes in front of Rhea (?), whose face is partially covered by Saturn’s rings…which in turn are darkened by the shadow of the planet itself. I removed distracting background stars, as well as dust and streaks often seen in raw photos. Rhea is 950…
Finding Relief
On September 29, 2009 the MESSENGER spacecraft, soaring 10,000 miles above the northern hemisphere of Mercury, captured this image of the rugged terrain of our solar system’s smallest planet. Sharp hills, undulating ridges and craters of all sizes gouge the surface of Mercury, not only the smallest planet but also the densest and least explored,…
Sister Moons
Little Tethys is getting a lot of face time in front of Cassini’s lens. In this photo, from a raw image taken on October 17, Tethys passes across the hazy face of her much larger sister, Titan. 662-mile-wide Tethys is dwarfed by the 3,200-mile-wide Titan, although the distance that separates them in this image reduces…
Just Passing By
Tethys, shown in my previous post, orbits Saturn outside the rings in this animation made from 17 raw images taken by Cassini. After passing the dark side of Saturn Tethys follows the curve of the rings, and is passed on the “inside track” by the smaller Mimas (top). Meanwhile another moon, perhaps Atlas or Pandora,…
Full Moon
Here’s an amazing portrait of Tethys, a 662-mile-wide, airless and  heavily-cratered moon of Saturn. The photo was taken by Cassini on October 14, 2009, with the moon fully lit by the sun. Its high reflectivity (albedo) indicate a large amount of ice in its composition. I adjusted the image to bring out the details in…
A Rhea View
Here’s an amazingly detailed view of the extensively cratered surface of Rhea, Saturn’s second-largest moon, taken during a particularly close encounter by Cassini on October 13, 2009. About 950 miles wide Rhea is less than a third the size of Titan, Saturn’s largest moon. Unlike Titan, Rhea has no atmosphere at all to speak of…
Lights in the Dark 