by Kim Malville
August 2: Look to the south about 9pm for Scorpius and Sagittarius. Scorpius is one of the most visually satisfactory constellations, with a head to the right and a long tail ending with pinchers. You will find Jupiter near Antares the bright red heart of the scorpion. Sagittarius looks like a teapot, and you will find Saturn above the handle of the “teapot”.
August 8-9: The moon comes within 2° of Jupiter August 11: Jupiter stops its retrograde (westward) movement and begins moving eastward.
August 11-12: The famous Perseid meteor shower peaks on this night. However, there will be a moon just a few days from full, which will drown the fainter meteors with its brightness. The shower occurs over a period of several weeks, from July 17 to August 24, so you can enjoy Perseid meteors on many warm summer nights before and after the peak when the moon is not in the way.
Dragonfly & Titan
In July, NASA announced the plans for a new style of exploration of the outer solar system, using a drone name Dragonfly to visit Titan, the largest moon of Saturn. Dragonfly will launch in 2026 and arrive in 2034, having covered a distance of 886 million miles. Titan’s dense air and low gravity will allow the 300-kilogram, sedan-size quad-copter, which will be powered by a radioactive generator, to hover with 38 times less power is than needed on Earth. Unlike the slow-moving Martian rovers, Dragonfly can flit effortlessly from one intriguing spot of Titan to another. It is a wonderful concept. Ultimately, the quadcopter’s explorations may be able to last up to 8 years after landing before its nuclear power source peters out. Eventually, I can imagine the residents of various outposts on Titan may get their books delivered by Amazon using these efficient quad-copters.
Saturn has a whopping 62 moons. I’m sure there are still more out there, waiting to be discovered. But, Jupiter remains the King with 79 known moons Saturn has its own boasting rights with its magnificent rings and an extraordinary moon known as Titan. Among all the moons of the solar system, Titan is the only one with a substantial atmosphere. In fact, it has a surface atmospheric pressure 50% larger than that of Earth. Furthermore, Titan is the only place besides Earth known to have liquids in the form of flowing rivers, lakes and oceans. There are no flowing rivers of liquids in Antarctica. But Titan has them because it is so very cold: 290°F below zero (-179°C). Titan’s “water” is liquid methane and ethane. Surprisingly, the landscape of rivers and shorelines looks very much like the earth.
Its largest oceans of liquid hydrocarbons are substantial, hundreds of feet deep and hundreds of miles wide. Beneath Titan’s thick crust of water ice there may be more liquid—an ocean primarily of water rather than methane. Here’s a factoid for you: Titan’s dense atmosphere and its low gravity mean that a raindrop of liquid methane would fall slowly, roughly 5.2’ per second, the speed at which snowflakes fall on Earth compared to rates of terrestrial rainfall at up to 30 ft/s. They would be about a centimeter across, compared to about half that size on the earth. The slower speed and larger drops would make it easier to see that raindrops are flattened by the atmosphere as they fall. Future astronauts are to be advised to stay inside—it would not be fun to be hit by one! Titan orbits Saturn once every 15 days and 22 hours, always keeping one side toward Saturn, like our moon keeps one side always toward the earth.
Its atmosphere is 94% nitrogen and about 5% methane. Therein lies an interesting puzzle. Energy from the Sun, weak that it is at that distance, still should convert all traces of methane in Titan’s atmosphere into more complex hydrocarbons within 50 million years. This is, of course, a short time compared to the age of the Solar System. Methane must therefore be replenished by some means, which probably would be eruptions from ice volcanoes on its surface, which have not yet been detected by our satellites.
Cassini spacecraft studied Titan during its exploration of Saturn and its moons. The most exciting part of the Cassini spacecraft’s 12 1/2 years orbiting Saturn was back in December 2004, when the mothership began orbiting Titan, and dropped the European Space Agency’s Huygens probe in January 2005. The probe was named after the Dutch 17th-century astronomer Christiaan Huygens, who discovered Titan in 1655. Huygens became the first spacecraft to land on an object in the outer solar system. To this day, the Huygens probe’s touchdown on Saturn’s moon Titan remains the most distant landing ever achieved by humankind. It transmitted data to the Cassini mother ship for 72 minutes. The surface it saw had many geologic features similar to those found on Earth, including plateaus, dune-filled deserts, and, at its poles, liquid seas and rivers. Titan’s subsurface water could be a place to harbor life as we know it, while its surface lakes and seas of liquid hydrocarbons could conceivably harbor life that uses a different chemistry than terrestrial life. It would be truly alien life on the surface, built out of hydrocarbons. Evolution in such a cold ocean probably would have been much slower than on earth and, of course, it would have to be extremely adaptable and hardy to survive under such conditions. Its gazpacho-like broth of organic molecules and water could have resulted in reactions that created amino acids like those making up our DNA’s double helix.
There are oceans of water beneath an extraordinary number of dwarf planets, moons, and asteroids in our solar system. Life may exist in abundance in our neighborhood. We haven’t found it yet because it is hiding beneath underground oceans.