Cave Explorer

Penny Boston looks like an astronaut in the big orange suit she sometimes wears to work. But Boston has never been to outer space. Instead, she searches for alien life on Earth.

Boston is NASA’s head astrobiologist (as-troh-bye-AHL-uh-jist). That’s a scientist who explores the possibility of life on other planets. To understand where living things can and can’t survive, Boston hunts for life in extreme environments on our planet. “I get to go places that few people ever go,” she says.

This past February, Boston made a big announcement. Her team had found ancient microbes in a cave in northern Mexico. She thinks these tiny organisms could hold clues about life in outer space.

Penny Boston sometimes wears a big orange suit to work. She looks like an astronaut. But Boston has never been to outer space. Instead, she searches for alien life on Earth.

Boston is NASA’s head astrobiologist (as-troh-bye-AHL-uh-jist). That’s a scientist who explores the chances life exists on other planets. Boston hunts for life in extreme environments on Earth. That helps scientists understand where living things can and can’t survive. “I get to go places that few people ever go,” she says.

Boston had some big news this past February. Her team had found ancient microbes. They lived in a cave in northern Mexico. She thinks these tiny creatures could hold clues about life in outer space.

In 2008, Boston led a team of explorers into the Cave of the Crystals in Mexico. This cave is 300 meters (984 feet) below Earth’s surface. Inside, enormous crystals stick out from every surface. They grew over tens of thousands of years. 

The Cave of the Crystals is dangerously hot inside. Magma—liquid rock flowing inside Earth—heats the cave to 60°C (140°F). To keep cool, explorers wear special suits packed with ice. “You can’t spend more than 30 minutes inside even when wearing the suit,” says Boston. 

Boston led a team of explorers in 2008. They visited the Cave of the Crystals in Mexico. This cave is 300 meters (984 feet) below Earth’s surface. Inside, huge crystals stick out from every surface. They grew over tens of thousands of years.

The Cave of the Crystals is really hot. Magma heats the cave to 60°C (140°F). Magma is liquid rock flowing inside Earth. Explorers wear special suits. They’re packed with ice to keep cool. “You can’t spend more than 30 minutes inside even when wearing the suit,” says Boston. 

Could anything live in this harsh underground environment? Boston was determined to find out. Looking closely at the cave crystals, she noticed bubbles of water trapped inside. Her team drilled into the crystals and collected some of the liquid.

Back at her lab, Boston looked at the water under a microscope. She saw microbes, but they weren’t moving. She knew that some microbes enter an inactive state when there isn’t enough food. Were these microbes inactive or dead?

Boston decided to try feeding the microbes to see if they would grow. She had a hunch that they ate minerals, solid substances that form in rocks. She gave the microbes minerals such as iron and sulfur. After several months, they started to grow!

Could anything live in this harsh place? Boston wanted to find out. She looked closely at the cave crystals. She saw bubbles of water trapped inside. Her team drilled into the crystals. They collected some of the liquid.

Boston looked at the water under a microscope back at her lab. She saw microbes. But they weren’t moving. She knew that some microbes enter an inactive state. They do this when there isn’t enough food. Were these microbes inactive or dead?

Boston decided to try feeding the microbes to see if they would grow. She had an idea that they ate minerals. Minerals are solid substances that form in rocks. She gave the microbes minerals such as iron and sulfur. They started to grow after several months!