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Ancient Caves Dives Deep But Shares Local Connection

Friday, March 6, 2020

Dr. Larry Edwards has developed a technique that gives us information about climatic changes hundreds of thousands of years in the past. 

This spring, visitors to the Science Museum of Minnesota will experience the thrill of scientific discovery in places few will ever venture in Ancient Caves, a new IMAX film in the William L. McKnight-3M Omnitheater. 

While the movie showcases adventures in caves across the world, viewers will also find local connections. In addition to featuring an extensive network of caves right here in Minnesota, viewers will meet Dr. Larry Edwards, an isotope geochemist at the University of Minnesota. Dr. Edwards is known for his role in the development of modern uranium-thorium (or Th-230) dating methods, which identify the age of an object by the amount of radioactive thorium it contains. This dating technique played a large part in springboarding the science—and the adventure—in Ancient Caves!

I was drawn to the earth sciences because I like being out of doors,” Dr. Edwards says. “From there it was really a matter of ‘What can I do in terms of laboratory capabilities that are new that would also be able to answer questions about how the earth works?’ That got me into learning new things about climate using new laboratory techniques.” 

In addition to being one of the most cited earth scientists in the world, his Th-230 dating methods are what’s used to “read” the information found in the cave deposits studied in Ancient Caves. With samples collected by paleoclimatologist Dr. Gina Moseley, Dr. Edwards can obtain previously inaccessible information about historic and prehistoric climate and ocean chemistry that informs patterns of climate change.  

We asked Dr. Edwards to tell us more about what this research shows us about our planet’s past and future:

The dating technique seen in the film can give us information from hundreds of thousands of years in the past...decade by decade. 

In terms of human time scales it’s long, but in terms of geologic time scales we’re just touching the surface, and we’re doing it at a fairly high resolution. For example, we have a 640,000 year record of the coming and going of the Asian monsoon in Southeast China. For every decade in the last 640,000 years, we have a measure of what the monsoon was like in that particular decade.” 

There’s historical evidence for climate change... 

“There are two conclusions that we’ve reached. One is that abrupt climate change takes place and has taken place many times in the past. Climate changes that take place simultaneously around the world are a known phenomenon and that’s something that we should worry about in the future. 

...And it’s linked to carbon dioxide.

The other aspect of this is that the carbon dioxide concentration of the atmosphere matters. If we look back in time, the carbon dioxide concentration of the atmosphere has gone up and down through natural processes, and we can show that climate change is in concert with these changes. These are lessons from the past for the future.” 

Science makes sense. 

“There’s the idea that when you go out in nature, you might think, ‘Well this is all really complicated and there's no rhyme or reason,’ but there's an incredible order that emerges. If you look at the film, what you see is for the most part the very beginning of the process, people scuba diving and collecting samples under water and spelunking and going through cave. So there’s that idea that you can go out into the great out of doors and come back with some amazing stuff like climate records.”

Ancient Cavesis a Science Museum of Minnesota original IMAX production, in conjunction with the Giant Dome Theater Consortium and Oceanic Research Group Films, presented by MacGillivray Freeman Films. Narrated by popular actor Bryan Cranston and featuring the music of the Prague Philharmonic Orchestra, the film debuts in theaters nationwide on March 13, 2020, but Science Museum visitors will get the first look at this compelling view of our planet’s changing climate starting March 6. Get your tickets to see the film today!



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