For many years man has been inquisitive about life and the conditions on other planets. The latest discovery was of Saturn and its moons by a robotic spacecraft called Cassini-Huygens, commonly known as Cassini. It was named in honour of the astronomers Giovanni Cassini and Christiaan Huygens. It was a joint effort between NASA, the European Space Agency (ESA) and the Italian Space Agency (ASI). It was a robotic spacecraft made up of NASA’s Cassini probe and ESA’s Huygens lander. Teams from fifteen countries contributed to the designing, building, flying and collecting data from the spacecraft. The function of the probe was to study Saturn and its system while the lander was used to land the probe on Titan, Saturn’s largest moon.
Cassini was launched on the 15th October 1997 , after almost two decades of intensive study, was commanded on the 15th September 2017 to be burned up in Saturn’s upper atmosphere. Before being destroyed, it made some risky passes between Saturn’s rings for maximum scientific study. The discoveries made by Cassini were:
- Landing on Titan in the outer solar system: The conditions on Titan, Saturn’s largest moon, are similar to those on prehistoric earth, before life evolved. There’s evidence of methane rain, erosion, drainage channels. There are also lakes and seas of liquid methane and ethane. For the first time there was an onsite measurement of atmospheric temperature.
- Icy structures on Enceladus: On this moon was discovered a subsurface ocean making it a place for further scientific discoveries.
- Saturn’s rings seen in a different light: The rings of Saturn were observed as being active, especially the F ring and the possible birth of a new moon.
- The great northern storm of 2010 – 2011: Saturn has been observed to have a storm every thirty years. However, in late 2010 a storm arrived ten years earlier which was captured by Cassini. The storm existed for almost a year, which took the shape of a swirling band and ended when its tail collided with its head. During this period the highest temperatures were recorded, and unknown molecules were detected.
- Saturn’s length of day still remains unknown: Saturn’s radio waves, known as Saturn Kilometric Radiation, have been used to calculate the length of its day. Similar radio waves are emitted by Jupiter to determine its length of day. However, the radio wave pattern controlled by Saturn’s rotation is different in the northern and southern hemispheres. The contributing factors are rotational variations of both hemispheres which appear to change with the planet’s seasons and the hemispheres also swap rates.
- Vertical structures found on the rings: The sun shines on the edge of the rings once every 15 years. However, the northern and southern parts of the rings receive little sunlight. The lengths of the shadows on the rings were measured for the first time in this rare moment.
- Prebiotic chemistry on Titan: This has the most chemically complex atmosphere in the solar system. From methane and sunlight, more complex molecules are formed which creates a smog and then fall to the surface of the moon.
- Mystery of the dual bright-dark surface of the moon Lepetus solved: This moon has a two-faced surface. Cassini showed that this is the result of some dark, reddish dust found in the moon’s orbital path which lands on the leading face of the moon. The dark areas absorb the energy and become warmer while the uncontaminated areas remain cooler.
- The polar regions of Saturn: The polar regions seem to be one of the most fascinating parts of the planet. There’s the presence of a long-lived hexagonal-shaped jet stream in the north and two hurricane-like storms at both poles.
Other discoveries were made of the planets Jupiter and Venus and also of a few other moons of Saturn such as Phoebe, Rhea, Hyperion and Dione.
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