Posts Tagged ‘Lava Tubes’

08/23/2021 – Ephemeris – Seeking shelter on the Moon

August 23, 2021 Comments off

This is Ephemeris for Monday, August 23rd. Today the Sun will be up for 13 hours and 39 minutes, setting at 8:34, and it will rise tomorrow at 6:56. The Moon, 1 day past full, will rise at 9:39 this evening.

The area of interest on the Moon for NASA’s Artemis crewed landing program and the target for Chinese lunar ambitions is the south pole, where signs of water ice have been detected in permanently shadowed craters. That is a valuable resource, if one wants to live off the land on the Moon. There’s another resource that is also valuable in finding: shelter from radiation and the Moon’s extreme temperature swings. Those are lava tubes. They are lava channels in which lava flowed, the top and sides cooled and crusted over. They emptied when the lava ran out, leaving a hollow tube. Sometimes part of the upper crust fails, leaving what is called a skylight. Several of these skylights have been found on the Moon and even Mars.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.


Lunar lava tube skylight

A skylight betrays the presence of a lunar lava tube. Credit NASA/LRO.

Lava tube in Hawai'i

Here’s an earthly lava tube on the Island of Hawai’i, I visited in 2012 with my wife. It was on the site of a coffee plantation south of Kona. Credit mine.

06/08/2018 – Ephemeris – A second Moon race?

June 18, 2018 Comments off

Ephemeris for Monday, June 18th. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:31, and it will rise tomorrow at 5:56. The Moon, 2 days before first quarter, will set at 1:30 tomorrow morning.

The Moon as a destination is becoming a hot topic among the space faring nations. Who will land humans first in this second wave since the United States landed there in the late 1960s and early 1970s: The Chinese, Russians, us? Or maybe someone else? Next year July 20th will be the 50th anniversary of Neil Armstrong’s first step onto the lunar surface. The goal this time is not to just visit, but to stay. The lunar surface is a harsh environment of extremes in temperatures and radiation from the Sun, and from the universe beyond. There is shelter beneath the surface, in lava tubes. There is one lava tube with a collapsed roof, a skylight, which could provide access in a place called the Marius Hills.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.


Marius Hils

An oblique view of the Marius Hills from the Lunar Orbiter 2, with an inset look into a skylight into a lava tube from the Lunar Reconnaissance Orbiter at the lower left. Click on image to enlarge. Credit NASA, Lunar Orbiter 2, Lunar Reconnaissance Orbiter.

The picture above was posted on Astronomy Picture of the Day (APOD) 2017 October 2017:, where there is more information.