Yesterday we wrote about the end of the Cassini mission. We mentioned that an early highlight of that mission was landing the Huygens probe on Titan in January of 2005. Titan is a moon of Saturn and the largest moon in our solar system. Scientists were very interested in studying Titan thinking they might find evidence of life. Instead, the Titan studies verify Earth’s uniqueness.
It took seven years for the Huygens lander to make the 2.2-billion-mile (3.5 billion km) journey to Saturn on board the Cassini spacecraft. Cassini arrived at Saturn in June 2004, but it was not until Christmas Day that the Titan probe separated from the Cassini spaceship. On January 14, the probe entered the upper atmosphere of Titan at 12,400 miles (almost 20,000 km) per hour. After opening three parachutes, Huygens eventually completed a 150-minute descent to land on the surface of Titan.
As Huygens descended to the surface, it made measurements of all kinds and turned on a spotlight to photograph its soft landing. It then sent pictures and data from the surface of Titan to the Cassini spacecraft for about an hour-and-a-half. The Cassini spacecraft relayed the data and pictures to Earth. This expedition was an incredible success and told us much about conditions in another area of the solar system.
Some experts predicted that they would find life, or at least the precursors of life, on Titan. Spectrographic analysis of the atmosphere had shown a huge amount of nitrogen and some methane (natural gas) in the atmosphere. The presence of methane was of special interest to scientists because methane, with a carbon atom and four hydrogen atoms, is the building block of more complicated organic molecules. Some biochemists predicted massive numbers of complex organic molecules in oceans of hydrocarbons on Titan–perhaps even some basic life-forms.
As the Huygens probe sent back pictures from Titan, scientists were amazed to see carved river channels, old shorelines, and clouds. With a temperature of minus 300 degrees Fahrenheit (-184 C) these obviously could not be water-carved channels. As Huygens landed, it broke through a crusty surface and sank several inches into the ground. The chemical studies of the spongy surface showed that it was not rock, but frozen gaseous material. Titan’s atmosphere could not sustain life. The clouds turned out to be methane,and scientists could find no oxygen or oxygen compounds on Titan. Titan has a spongy surface saturated with organic compounds. The density of Titan tells us that deep down under all of this organic ice there must be very dense rock.
It is becoming apparent that the other planets in our solar system have very little in common with Earth. Titan studies verify Earth’s uniqueness once again. Jonathon Lunine, a planetary scientist who worked on this project, described the findings in this way, “This is a planetary scene like no other, vaguely disturbing and nightmarish to me and certainly not Mars or Venus.”
Our point is that all the discoveries science has made about the solar system have shown how special and unique the Earth is. It is wonderful that humans can build a machine to probe such strange and exotic places. As we learn more about the universe, we see the truthfulness of the Psalmist’s words, “The heavens declare the glory of God; the skies proclaim the work of his hands. Day after day they pour forth speech; night after night they reveal knowledge” (Psalms 19:1-2, NIV).
–John N. Clayton © 2017