The Moon Trees of Apollo 14

Apollo 14's splashdown in the Pacific on Feb. 9, 1971. (NASA/Ed Hengeveld)

On this day in 1971 Apollo 14 astronauts Alan Shepard, Jr., Stuart Roosa and Edgar Mitchell returned to Earth, splashing down in the Pacific Ocean at 21:05 UT (4:05 p.m. EST). They were recovered by the USS New Orleans, and returned to the U.S. by way of American Samoa. But the three men weren’t the only living creatures to come back from the Moon on Feb. 9, 1971… in fact, human astronauts were in the minority that day.

Al, Stu and Ed shared their lunar voyage with nearly 500 trees.

As Shepard and Mitchell gathered samples near their landing site in a region named Fra Mauro, Apollo 14 pilot and ex-smoke jumper Stuart Roosa orbited above in “Kitty Hawk”, the mission’s Command Module. It may sound like a lonely job, but he was far from alone. Within his personal kit were small containers containing 400-500 seeds, part of a joint NASA/USFS project to examine the effects, if any, of space travel on such organisms.

The seeds were selected from a variety of tree species: redwood, loblolly pine, sycamore, Douglas fir, and sweetgum seeds were all chosen to accompany Roosa on his 34 orbits around the Moon.

A control group of the same seed varieties were kept on Earth for comparison.

Stuart Roosa had worked for the Forest Service in the 1950s before becoming an Air Force test pilot and then eventually an Apollo astronaut. Being charged with the care of the seeds was a particularly symbolic assignment for Roosa, who had once fought wildfires as a smoke jumper.

Even though there was a mishap during the decontamination process after return to Earth, wherein some containers burst open and seeds were inadvertently mixed together, many of the seeds successfully germinated at Forest Service stations in Mississippi and California. The seedlings were eventually sent to locations around the country and around the world to commemorate the success of the Apollo program.

There was even a second generation, called half-moon trees.

A Moon Tree located outside Goddard Space Flight Center. (GSFC)

Many of these “Moon Trees” and their descendants still stand today. In some instances they are marked with a plaque or a sign… in others, no special marking denotes their significance. Those unmarked trees stand as silent reminders of an earlier and perhaps even bolder era of human space flight.

Me, Heather Archuletta, and Greg ___ in front of a 2nd-generation Moon Tree outside the Holliston Police Department in Massachusetts. (© Jason Major)
Me, Heather Archuletta, and Greg Riley in front of a 2nd-generation Moon Tree outside the Holliston Police Department in Massachusetts, Oct. 2013. (© Jason Major)

Read more about the Moon Trees on this page by David Williams of NASA’s Goddard Space Flight Center. And if you know of a Moon Tree that is not on Mr. William’s list, please contact him to have it included. Williams has endeavored to locate the whereabouts and status of these trees since 1996, as there had been no systematic records previously kept of them.

“I think when people are aware of the heritage of the trees, they usually take steps to preserve them,” said Williams in recollection of one tree that was nearly knocked down during a building renovation. “But sometimes people aren’t aware. That’s why we want to locate as many as we can soon. We want to have a record that these trees are — or were — a part of these communities, before they’re gone.”

A Blood-Red Moon

December 10 lunar eclipse by Joseph Brimacombe


Photographer Joseph Brimacombe created this stunning image of a ruddy Moon made during the total lunar eclipse of December 10, 2011. Images taken during the penumbral and total phases of the eclipse were combined to create a full-face image of the Moon in color. Beautiful!

The red tint of the Moon during an eclipse is caused by sunlight passing through Earth’s atmosphere, in effect projecting the colors of all the world’s sunsets onto the Moon’s near face. The vibrancy and particular hue seen depends on the clarity of the Earth’s atmosphere at the time of the eclipse.

Joseph’s location in Cairns, Australia allowed for great viewing of the eclipse in totality, whereas many areas of North and South America and Europe missed the full eclipse event.

See more images by Joseph on Flickr.

Image © Joseph Brimacombe. All rights reserved. Used with permission.

How the Moon Became Magnetized

astronauts faced possible radiation dangers on the Moon.
Apollo 17 astronaut Harrison "Jack" Schmitt at Tracy Rock on the lunar surface. If a solar storm had hit the Moon while the astronauts were on the surface exploring, it could have been a disaster. Credit: NASA.


It’s been a mystery ever since the Apollo astronauts brought back samples of lunar rocks in the early 1970s. Some of the rocks had magnetic properties, especially one collected by geologist Harrison “Jack” Schmitt. But how could this happen? The Moon has no magnetosphere, and most previously accepted theories state that it never did. Yet here we have these moon rocks with undeniable magnetic properties… there was definitely something missing in our understanding of Earth’s satellite.

Now a team of researchers at the University of California, Santa Cruz thinks they may have cracked this enigmatic magnetic mystery.

In order for a world to have a magnetic field, it needs to have a molten core. Earth has a multi-layered molten core, in which heat from the interior layer drives motion within the iron-rich outer layer, creating a magnetic field that extends far out into space. Without a magnetosphere Earth would have been left exposed to the solar wind and life as we know it could may never have developed.

Apollo 17 lunar rock sample

Simply put, Earth’s magnetic field is crucial to life… and it can imbue rocks with magnetic properties that are sensitive to the planet-wide field.

But the Moon is much smaller than Earth, and has no molten core, at least not anymore… or so it was once believed. Research of data from the seismic instruments left on the lunar surface during Apollo EVAs recently revealed that the Moon may in fact still have a partially-liquid core, and based on a paper published in the November 10 issue of Nature by Christina Dwyer, a graduate student in Earth and planetary sciences at the University of California, Santa Cruz, and her co-authors Francis Nimmo at UCSC and David Stevenson at the California Institute of Technology, this small liquid core may once have been able to produce a lunar magnetic field after all.

The Moon orbits on its axis at such a rate that the same side always faces Earth, but it also has a slight wobble in the alignment of its axis (as does Earth.) This wobble is called precession. Precession was stronger due to tidal forces when the Moon was closer to Earth early in its history. Dwyer et al. suggest that the Moon’s precession could have literally “stirred” its liquid core, since the surrounding solid mantle would have moved at a different rate.

This stirring effect – arising from the mechanical motions of the Moon’s rotation and precession, not internal convection – could have created a dynamo effect, resulting in a magnetic field.

This field may have persisted for some time but it couldn’t last forever, the team said. As the Moon gradually moved further away from Earth the precession rate slowed, bringing the stirring process – and the dynamo – to a halt.

“The further out the moon moves, the slower the stirring, and at a certain point the lunar dynamo shuts off,” said Christina Dwyer.

Still, the team’s model provides a basis for how such a dynamo could have existed, possibly for as long as a billion years. This would have been long enough to form rocks that would still exhibit some magnetic properties to this day.

The team admits that more paleomagnetic research is needed to know for sure if their proposed core/mantle interaction would have created the right kind of movements within the liquid core to create a lunar dynamo.

“Only certain types of fluid motions give rise to magnetic dynamos,” Dwyer said. “We calculated the power that’s available to drive the dynamo and the magnetic field strengths that could be generated. But we really need the dynamo experts to take this model to the next level of detail and see if it works.”

In other words, they’re still working towards a theory of lunar magnetism that really sticks.


Read the article by Tim Stephens on the UCSC website.


Look Inside a Lunar Crater

Brightening the shadowed area reveals details of the crater floor...and even more boulders!


The crater shown above is located in the lunar highlands and is filled with and surrounded by boulders of all sizes and shapes. It is approximately 550 meters (1800 feet) wide yet is still considered a small crater, and could have been caused by either a direct impact by a meteorite or by an ejected bit of material from another impact. Scientists studying the Moon attempt to figure out how small craters like this were formed by their shapes and the material seen around them…although sometimes the same results can be achieved by different events.

For example, when an object from space strikes the Moon, it is typically traveling around 20 km per second (12 miles/sec). If the impact site happens to have a very hard subsurface, it can make a crater with scattered bouldery chunks composed of the hard material around it. But, if a large piece of ejected material from another impact were to strike the lunar surface at a much slower speed, as ejecta typically do (since they travel slower than incoming space debris and the Moon’s escape velocity is fairly low, meaning any ejecta that does fall back to the surface must be traveling slower than 2.38 km/s,) then the ejected chunk could break apart on impact and scatter boulders of itself around the crater…regardless of subsurface composition.

Really the only way to tell for sure which scenario has taken place around a given crater – such as the one above – is to collect and return samples from the site so they can be tested. (Of course that’s much easier said than done!)

You can read more about this image on Arizona State University’s Lunar Reconnaissance Orbiter Camera site here.

And as an added treat, take a look deep into the shadows of the crater’s interior below…I tweaked the image curves in Photoshop to wrestle some of the details out of there!


Brightening the shadowed area reveals details of the crater floor...and even more boulders!

Image credit: NASA/GSFC/Arizona State University. (Edited by J. Major.)

P.S.: Want to see both image versions combined? Click here. (Thanks to Mike C. for the suggestion!)

First Quarter Moon

Flying Across the Moon
Flying Across the Moon


The first quarter moon is actually the third phase of the moon each cycle. In the Northern Hemisphere during this phase, the right hand 50% of the moon is visible during the afternoon and the early part of the night. In the Southern Hemisphere the left hand 50% of the moon can be seen. This lunar phase follows the new moon and the waxing crescent.

A lunar phase is the appearance of an illuminated portion of the moon as seen by an observer. For this article the observer is always on Earth. The lunar phases vary in a definite cycle as the moon orbits the Earth. The phases change based on the changing relative positions of the Earth, moon, and Sun. Half of the moon’s surface is always illuminated by the Sun, but the portion of the illuminated hemisphere that is visible to an observer can vary from 100%(full moon) to 0%(new moon). The only exception is during a lunar eclipse. The boundary between the light and dark portions of the moon is called the terminator.

There are 8 moon phases. These phases are: new moon, waxing crescent, first quarter moon, waxing gibbous, full moon, waning gibbous, last quarter moon, and waning crescent. The phases progress in the same manner each month. Earlier, it was mentioned that the lunar phase depends on the position of the Earth, moon, and Sun. During the new moon the Earth and Sun are on the opposite side of the moon. During the full moon the Earth and Sun are on the same sides of the Moon. The occasions when the Earth, Sun, and moon are in a straight line(new and full moon) are called syzygies.

When the moon passes between Earth and the Sun during a new moon, you might think that its shadow would cause a solar eclipse. On the other hand, you might think that during a full moon the Earth’s shadow would cause a lunar eclipse. The plane of the moon’s orbit around the Earth is tilted by about five degrees compared to the plane of Earth’s orbit around the Sun(called the ecliptic plane). This tilt prevents monthly eclipses. An eclipse can only occur when the moon is either new or full, but it also has to be positioned near the intersection of the Earth’s orbital plane about the Sun and the Moon’s orbit plane about the Earth, so there are between four and seven eclipses in a calendar year.

The first quarter moon is only one of eight lunar phases. You should research them all for a better understanding of the Earth/Moon system.

We have written many articles about the phases of the moon for Universe Today. Here’s an article about the 8 phases of the moon, and here’s an article about the moon phases for 2010.

If you’d like more info on the Moon, check out NASA’s Solar System Exploration Guide on the Moon, and here’s a link to NASA’s Lunar and Planetary Science page.

We’ve also recorded an entire episode of Astronomy Cast all about the Moon. Listen here, Episode 113: The Moon, Part 1.