July’s been busy with fresh takes on familiar faces. NASA recently released some of the clearest, most detailed views of Titan, Saturn’s largest moon. With a diameter of 3,200 miles (5,150 km), Titan is the solar system’s second largest moon after Jupiter’s Ganymede and the only one with a dense atmosphere. NASA employed the Cassini spacecraft to peer beneath Titan’s veil of haze by photographing it in infrared light. Infrared lies just beyond the red end of the rainbow. Although humans can’t see it, we can feel it as the sensation of heat. Infrared blasts right through Titan’s haze.
These six images of the moon represent some of the clearest global views produced so far and show the surface the way it would look to a casual observer. They were created using 13 years of data acquired by the Visual and Infrared Mapping Spectrometer (VIMS) instrument on board NASA’s Cassini spacecraft. Although taken under a wide variety of lighting and viewing conditions, the photos were smoothly combined to create these seamless views.
Vast, windswept equatorial dune fields composed of complex organic compounds look like chocolate milk in the photos. Scientists describe their appearance as “100-meter (328 feet) high mountains of coffee grounds.” The bright terrain is icy material, while the bluish and purplish areas have different compositions that may be enriched in water ice. With a surface temperature of –290° F (–179° C), water ice is as hard as granite on the moon. Cutting across this chill landscape are rivers of liquid natural gas, including methane and ethane.
Telescope technology has truly come a long way in recent years. Not only are ground-based telescopes huge but they employ adaptive optics to still the turbulence caused by Earth’s ever-churning atmosphere. This photo of Neptune was made with the European Southern Observatory’s VLT (Very Large Telescope), an instrument that consists of four separate 8.2 meter (27 foot) mirrors. Astronomers create an artificial star high in the atmosphere above the telescope by pointing a powerful laser into the sky. As the “star” shifts and blurs with variable air currents and changing temperatures, that information is fed to a computer which deforms the mirror to negate the effects. Instead of a blob (right image) Neptune snaps into view with more detail than even the Hubble Space Telescope can show. The bright cloud streaks are driven by powerful winds in the planet’s methane-rich atmosphere.
The Japanese asteroid sample return mission Hayabusa 2, which launched in December 2014, has been busy since it arrived at Ryugu last month. This small asteroid or floating space mountain (take your pick) is only about a half-mile (900 meters) across and circles the sun in the main asteroid belt. For a time, the probe hovered about 12.5 miles (20 km) above its surface, but during the week of July 16, mission control took it down to less than 3.7 miles (6 km) or just 19,500 feet high. That’s only half the altitude of a commercial jet liner! A largish, shallow crater is seen near the center of the photo but otherwise what jumps out are the thousands of giant boulders. Lots of awesome places to sit down and take in the view … of more boulders.
NASA’s Juno spacecraft completed its 14th close flyby of the planet Jupiter on July 15. As it zipped some 3,900 miles (6,200 km) above the cloud tops, it captured this image of a swirly band of high clouds in the planet’s North North Temperate Belt. Viewed in amateur telescope from Earth, this belt looks like a thin, gray pencil line near Jupiter’s north polar region. For decades, scientists have wondered how deep these bands extend down into the atmosphere. Juno discovered that these bands of flowing atmosphere actually penetrate deeply – down to a depth of about 1,900 miles (3,000 kilometers).