Living in a home by the ocean on the Moon may not be as pleasurable as it is here on Earth but it may be possible. Scientists have discovered a vertical hole on the surface of the Moon near the Marius Hills in the region known as the Ocean of Storms. This hole is evidence of the existence of an underground lava tube on the Moon. Lava tubes are hollow tubes that are formed by the flow of lava. Many of the caves seen in Hawaii and at the bottom of Mount Fuji are lava tubes. The rock that composes the Hawaiian Islands, Mount Fuji and seas of the moon is very similar so it is not surprising that lava tubes are also found on the Moon.
The hole is almost circular, has a diameter of about 200 feet and a depth of nearly 300 feet. With a computation method like those used here on Earth for measuring lava tubes, scientists estimate that beneath this hole is a lava tube that may be as much as 1200 feet wide. This particular lava tube has a thin sheet of lava that serves as a roof protecting the tube interior from dangerous radiation and micrometeorite collisions, which occur on the Moon.
During the formation of lava tubes, lava flowing down the sides of the tubes cools rapidly creating a smooth air-tight surface along the walls of the tube. The lava that coagulates at the bottom often creates a flat, naturally paved surface. With smooth walls and a flat bottom, it would be easy to seal the exits to create a pressurized space. In addition, the fine ash-like sand that covers the Moon’s surface, and has been known to hamper activities on the surface, would not be a concern inside a lava tube.
Since the temperatures on the Moon vary drastically it would be extremely difficult to build a lunar base or laboratory on the surface. Building underground may be a more viable solution because the temperatures underground remain constant as they do here on Earth. Information gathered from the Apollo program shows the temperatures a few feet under the surface of the landing area is constant at about -4 degrees Fahrenheit. That’s about the same temperature as the wintertime lows in Minnesota. Protection from radiation and meteorites, plus the lack of temperature extremes make lava tubes a good choice for building a lunar base.
The existence of lava tubes may not be limited to the Earth and the Moon. When lava tubes just below the surface collapse into the hollow of the tube, specific formations appear on the surface. Images of the Martian surface show formations with similar characteristics which may indicate that lava tubes exist on Mars, and perhaps, other planets as well.
In the future, lava tubes may have a variety of uses. They could be storage facilities for extraterrestrial samples collected from space. They could be used for the construction of ships and other equipment for space travel and exploration. Or, as some suggest, a laboratory for analyzing and studying space objects before bringing them back to Earth. Lava tubes may allow us the opportunity to build a variety of facilities including a manned lunar base giving new meaning to the term “the man in the Moon”.
For more information about the lunar lava tube read the report from Junichi Haruyama at the Japan Aerospace Exploration Agency.