I stand in the back corner of the small elevator, holding my son’s hand as we rattle our way down and slightly sideways to the 27th level. The tour guide shines her light on the gaps in the elevator cage door so that we can see the layers of rock interrupted by the inky darkness of closed levels. The previous time I’ve been in this elevator, there were no lights, and I stood next to my grandfather’s wheelchair. This time I am with my parents, my husband, my son, and a handful of other tourists. The elevator stops half a mile underground, and we step out.
This is the Tower-Soudan Underground Mine in Minnesota, once the oldest and deepest of Minnesota’s iron mines and now a state park. My great-grandfather died while working in a neighboring mine, and my grandfather left high school to work in that mine in order to support his mother and sisters. This is a pilgrimage to a place that represents one of the foundational stories of my childhood, and an attempt to convey to my young son where his family came from.
The thread of these rocks is woven into the fabric of my life. My grandparents’ house was right on the edge of an open-pit iron mine, and as a kid my dad sold little containers of rocks from the mine to visitors who stopped where the road ended to look into the pit. He brought an enthusiasm for geology to his marriage, and my mom picked it up and ran with it. I grew up hearing about how the rocks of my hometown in upstate New York were laid down in shallow seas and later shaped by ice sheets flowing across the surface. The rocks that I sat on when visiting the northeastern Minnesota shoreline were remnants of volcanic eruptions from over a billion years ago. The rocks I traveled past on our drives to my boarding school in New Hampshire once were attached to Africa. Is it any wonder that I ended up in a geology-adjacent career?
I remember being fascinated by the collection of rocks that my parents accumulated over the years. I, too, now pick up rocks wherever I go and display them around my house. One of my personal treasures, though, is not one that I carried back from a hike or purchased at a rock show. It is the (suprisingly heavy) core sample of iron from thousands of feet underground, from the iron mine. My grandfather brought it to the surface for my dad, who gave it to me.
Right now, there is a robot so much further away – millions of miles instead of thousands of feet – who is also collecting core samples that may someday be brought to the Earth’s surface. I have taken that tiny thread from my family and woven it into the vast tapestry that is the Mars Perseverance rover. Thousands of people all around the world worked together to create this rover, and we all brought our intellectual experience as well as our emotional resilience to the project. The Perseverance rover is many things (large, complex, ambitious), but I like to think that it includes that small, sparkling thread – a faint echo that resounds from outer space to the underground mine. I wish my grandfather and great-grandfather could hear it.