Rock Doc: Seas on Titan and your heating bill

By E. Kirsten Peters, College of Agricultural, Human & Natural Resource Sciences

peters-e-k-2010-80PULLMAN, Wash. – Like most regions of the country, the area where I live suffered through colder than average temperatures in mid-November. If you pay your heating bill month by month, you are now facing the sticker shock that results from those bitter times. Happy holidays.

I heat my home with a natural gas furnace supplemented by a woodstove in the living room. It’s a small stove, really designed only for emergencies and for fires built for fun on a Sunday afternoon. In other words, it doesn’t heat the whole house, and it works only with constant tending.

But during our cold snap, I built some fires in the woodstove to try to take the edge off the natural gas bill I was incurring. The woodstove is in the same room as the thermostat for the house, though, so heating with it caused the temperatures in the rest of the house to crash. Still, I was doing what I could to lessen what I would later owe the power company.

Sea of frigid methane

The main ingredient in natural gas is methane. It’s colorless and odorless, so utility companies add a “rotten egg” smell to it. That way, if there is a leak, your nose becomes aware of it and you can evacuate your home, then call 911.

Methane occurs elsewhere in the solar system besides the Earth. It’s abundant on Titan, one of the moons of Saturn. On Titan, methane is a liquid because the temperature there is almost 300 degrees below zero Fahrenheit.

Scientists have now plumbed the depths of three frigid seas of methane on Titan. An article online at sciencenews.org told me that the second largest of the seas, called Ligeia Mare, holds enough methane to fill Lake Michigan three times.

NASA’s Cassini probe reached the neighborhood of Saturn in 2004 and it’s still sending back data. The spacecraft was told to send radar pulses directed toward Titan’s seas.

Exploration continues

Results in some places included two sets of reflected energy. The first waves were from radar bouncing off the surface of the methane sea. The second, weaker, waves were from radar bouncing off the floor of the methane sea, under the surface. Together, these indicate the depth of liquid methane.

The shallow parts of the sea are some 20-40 yards deep. In other parts of the Ligeia Mare, however, the methane is so deep that no reflections from the bottom were detected, indicating places that are more than 200 yards deep.

It’s amazing to me what we are continuing to learn about our solar system – information ranging from data beamed back from a spacecraft landing on a comet to this information about Titan’s methane seas. I’m also amazed by what I owe the power company for methane I used in November – but I’m trying to keep some perspective about it.

 

Dr. E. Kirsten Peters, a native of the rural Northwest, was trained as a geologist at Princeton and Harvard. This column is a service of the College of Agricultural, Human and Natural Resource Sciences at Washington State University.