Oil is probably the most important - and controversial - form of energy used on our planet. Its uneven distribution in different countries and the ever-shrinking stores of this vital resource do not help matters for our fossil-fuel-dependent society.
According to an article in the January issue of the Geophysical Research Letters, a research team led by Ralph Lorenz from the Hopkins Applied Physics Laboratory in Laurel, Md., has discovered significant amounts of oil-like substances on Saturn's largest moon, Titan.
The Hopkins scientists used the radar instruments on NASA's Cassini spacecraft, which is a cooperative mission by NASA, the European Space Agency (ESA) and the Italian Space Agency (ASI). Cassini has been in orbit around Saturn and its moons since 2004, sending back tremendous amounts of valuable data to Earth-bound scientists.
A large part of the mission involves studies of Titan. Several hundred lakes and seas have been observed on the surface. Unlike on Earth, however, the seas are not full of water - they contain hydrocarbons, the same organic compounds that make up oil and natural gas.
A dozen of the seas are so big that they each exceed Earth's known oil and coal reserves. All of the natural gas reserves on Earth would be enough to satisfy the United States' hunger for energy for about 300 years. (Of course, oil supplies will run out much sooner since other countries also need oil and the demand continues to increase.)
By comparison, just one of these lakes on Titan carries the same amount of energy-providing organic substances, and there are quite a few lakes scattered across Titan's surface. The researchers caution that these are just estimates, since they have only mapped about 20 percent of the surface.
The conditions on Titan are rather harsh compared to our Earth. An average temperature of negative 290 degrees Fahrenheit makes the environment inhospitable to life. In addition, the lakes are filled with either methane or ethane rather than water.
The regions between the lakes and seas cover 20 percent of the surface and carry molecules called "tholins." All life known at this point is based on hydrocarbons, which are long carbon chains surrounded by hydrogen atoms. They played the most important role in the chemical processes before life on Earth.
Tholins are rudimentary assemblies of multiple hydrocarbons. The term goes back to the great astrophysicist Carl Sagan who pioneered the search for extraterrestrial life. The presence of tholins is a precursor to the eventual development of life as we know it.
Methane is one of the most abundant hydrocarbons on Titan. It is a strong greenhouse gas which can affect the climate of the moon by trapping sunlight and warming the atmosphere. If all of the methane were found on the surface, it would soon evaporate.
Since there is no evidence of massive evaporation, Lorenz and his team have concluded that there are likely even larger stores of methane deep inside Titan that periodically release gas to the surface through volcanic activity.
Of course, we are probably decades, if not centuries, away from being able to reach the outer planets and return materials from them. We won't be getting oil from Titan anytime soon.
For the time being, the presence of hydrocarbons on Titan is much more interesting to scientists than politicians. Where did they come from? The fossil fuels we use on Earth today are the crushed remains of plants and animals that lived over a hundred million years ago.
Since there is no life on Titan, one has to wonder how all of these organic molecules were formed in the first place ... and whether they might one day form the basis for life on another world.
