Europa Diary III
On Polar Bear Time
|Jupiter's moon Europa.Credit: NASA
The Europa Focus Group is a collaboration of scientists who study Jupiter's moon, Europa. This ice-covered world may be one of the few places in our solar system other than Earth that has a water ocean, and liquid water is believed to be one of the key factors in the development of life. Astrobiologists and other scientists eager to learn more about Europa recently headed to Alaska's North Slope.
The scientists studied the region's unique terrain, providing insight for future missions to the icy landscape of Europa. Flying in small aircraft to study geographical features, driving snowmobiles over glacial terrain, digging bore holes to get a glimpse of ice history -- all the activities pursued by these hardy adventurers may someday be duplicated on the surface of Europa by robotic spacecraft.
Matt Pruis, a support scientist with NorthWest Research Associates in Seattle, Washington, attended the North Slope conference and kept a journal of the events.
Friday, 25 April 2003
What a day! I arose to a brilliant morning sun still low on the horizon. The brightness of the morning made me appreciate my glacier glasses - they protect my eyes from the intense light reflecting off the Arctic tundra. After a quick breakfast, we prepared the snowmobiles for a daylong excursion onto the ice. Since we planned to travel greater distances today, we used nine snowmobiles, with sleds trailing behind to carry passengers and equipment.
We paused briefly before heading out onto the ice so that we could discuss some of the ice features we had seen during yesterday's overflight. We also were waiting for an honored guest. An elder of the community, Arnold Brower Sr., had agreed to accompany us onto the ice.
|Arnold Brower, Sr. teaching Europa Focus Group members about ice.. Credit: M. Pruis
Arnold has an extraordinary personal history. He is the son of Charles Brower, one of the first Westerners to settle in Barrow back in the 1880s. As a young boy of 14 or 15, Arnold's father told him to choose between schooling in San Francisco or reindeer herding with his older brother, Tom. It was a difficult decision; he could earn a dog sled team if he went herding, but he would have more opportunities if he went to school. He chose to go reindeer herding.
Reindeer herding turned out to be an education in itself. Arnold listened to the stories of the elders, and they taught him about the region's natural resources. He spent years herding reindeer around the country, and this gave him an intimate knowledge of the land.
Following this traditional lifestyle, he lived with his wife and young children in a small sod house away from the village. He left to serve in World War II, and when he returned he came to work in Barrow. He has been working with visiting scientists ever since. Arnold also was president of the Barrow Whaling Captains Association for many years, and he has held several important positions in Alaska's government.
Arnold knows the science of sea ice better than many "schooled" scientists ever will. I am amazed how a man with such incredible intelligence and wisdom can remain so humble and well-grounded.
After Arnold arrived we stayed around the camp for longer than we'd planned, because a polar bear had been spotted moving through the compound. In such cases we were advised to go onto "polar bear time" and wait until it decided to move on. Although we were all eager to get to work, I recalled what Fridtjof Nansen had said in his book "Farthest North":
"Patience [is] a medicament of which every polar expedition ought to lay in a large supply."
Once the polar bear moved a safe distance away, we boarded our snowmobiles and headed out onto the ice. I was probably not the only person who was comforted by having Matt Irinaga accompany us to keep an eye out for polar bears. Matt is a logistics coordinator for the Barrow Arctic Science Consortium (BASC). That basically means he helps us get everything done. He arranged for our use of BASC facilities, supplying us with everything from snowmobiles to arctic gear. Matt accompanied us on today's daylong excursion to ensure that all us "new-bee" arctic explorers didn't injure ourselves, do excessive damage to the BASC equipment, or accidentally surprise a polar bear!
|Matt Irinaga on the look-out for polar bears. Credit: M. Pruis
At our first stop, we examined some pressure ridges that formed when two ice floes collided. Arnold Brower Sr. described the process of their formation for us, and pointed out a small crack in the ice about 15 to 20 meters from the ridge. He said this crack forms because the ridge is too heavy for the ice to support. The cracks remain open because they do not extend all the way down to the seawater; they are just surface cracks caused by bending of the ice sheet. The amazing thing is, Max Coon and I had proposed that some of the features on Europa may be similar to the cracks Arnold described.
As I looked up at the nearby ridge, with its multitude of broken ice blocks, I saw Matt Irinaga perched on the top, scanning the horizon for polar bears. Polar bears obtain a yellowish tint to their fur coats as they age, making them easier to see against the white ice, but they can still be difficult to spot. The bear is so much better suited to this terrain than we are. A polar bear merely needs to stand up to peak over 2 or 3-meter high pressure ridges, but we have to climb all the way to the top to look over.
In the afternoon, we drove over to the Beaufort Sea, and saw incredible ice deformation occurring there. Easterly winds along this coast grind the pack ice against the near-shore grounded ice, forming spectacular shear ridges in the winter. In the spring, ice blocks move freely in the open water, rotating when they collide with the pack ice or shore-fast ice.
|Snowmobiles assembled for exploration and adventure. Credit: M. Pruis
Hajo Eicken drilled an ice core, and showed us the sediment that had been caught up in the ice as it formed. This sediment provides a habitat for organisms. Hajo and his colleges recently discovered that bacteria growing on these sediments remain active down to -20 degrees C (-4 F)!
The ice in this region is only rarely that cold, so the bacteria can remain active throughout most of the dark polar winter. This insight is of obvious interest to scientists who study icy worlds like Europa, since it demonstrates how life can function in extreme cold. It also shows that we might not have approached the true temperature limits for life yet, even here on our own planet.
Even though bacteria can function at extremely cold temperatures, that doesn't mean humans should. Throughout the day we received a mixture of cloud and sun and steadily rising temperatures, and by the end of the day we were removing layers of clothing instead of adding more on. Still, we decided we would make only one more stop, so we headed for Point Barrow, the northern-most point in the United States. There is no good reason to be within one-eighth of a mile of a geographic curiosity and not stop to take a group picture!
Support for the conference was provided by the NASA Astrobiology Institute. Dr. Ronald Greeley (Arizona State University) organized the meeting; Dr. Hajo Eicken (University of Alaska) organized and led the field excursions. The Ukpeagvik Inupiat Corporation allowed the use of their meeting facilities and provided access to key field areas.
Matthew Pruis is a third-year graduate student in Marine Geology and Geophysics at the University of Washington's School of Oceanography. He received his Bachelor of Science in Applied Geophysics from the Michigan Technological University. His graduate advisor is H. Paul Johnson . In addition to his graduate work, Matt also works at NorthWest Research Associates, Inc. as a research scientist. In this multi-part Europa Diary series, Matt Pruis chronicled his impressions for the Astrobiology Magazine, as part of his participation in the Europa Focus Group's recent journey to Alaska's North Slope.
Related Web Pages
Europa Diary I: Landing on Alien Terrain
Europa Diary II: Life on Ice
Europa Diary III: On Polar Bear Time
Europa Diary IV: Walking on Thin Ice
Alaska Europan Photo Gallery (Credit: Matt Pruis/ Jere Lipps )
Ice on Europa
Iñupiat native people
Barrow Arctic Science Consortium
Ukpeagvik Inupiat Corporation
Interpreting Europa's Features
Infrared Spectroscopy: An Overview
Galileo Project Home