The Moon Comes to Harvard-Cheese or Granite?
Searching For Secrets of Life In the Dull Dark Rocks
ON THE second floor of Hoffman Lab, at the end of the hall, there is a set of unimposing double doors to which only five people in the world have the key. The only outside clue to what goes on behind those doors is a black rubber mat on the hall floor which reads MOON ROOM in large white letters. At first sight, the two laboratories behind the locked doors appear no different than any other geology laboratory. However, one of the labs contains a large floor safe to which only two of the original five scientists have the combination. This safe contains some of the rarest treasures at Harvard-rock and durt samples brought back from the moon by the crews of Apollo 11, 12, and 14.
The moon samples, except those from Apollo 14 which have only been available for a few weeks, have probably been scrutinized more closely than any other material in the history of man. Special, clean, sealed laboratories, some far cleaner and more sophisticated than those at Harvard, have been built all over the world for the sole purpose of studying a few pounds of lunar dust and rock.
Now Apollo 14 has brought back a new shipment of material from a different part of the moon-the highlands-and these samples are slowly being distributed to the various research groups.
Within the next few weeks Harvard will receive the rest of its allotment of Apollo 14 samples, and the same extensive analyses already carried out on the Apollo 11 and 12 samples will be done on the new material. Then, at the end of July, Apollo 15 will bring back still more samples which, after undergoing six weeks of preliminary examination, will also be distributed by the Lunar Receiving Laboratory in Houston, Texas. Although Harvard's allotment will be small, the techniques used for studying the samples require very little material and much time. Considering the relatively short time between reception of the Apollo 14 and 15 samples, Clifiord Frondel, professor of Mineralogy and head of the investigating team at Hoffman Lab, was led to remark, "We are going to have lunar rocks coming out of our ears."
Frondel was also a member of the Preliminary Examination Team (PET) for Apollo 11 and 12. The PET is made up of scientists who have a broad knowledge of geology and are familiar with the various techniques of mineral identification and characterization.
On July 28, 1969, Frondel opened the first box of lunar samples as the world waited, open-mouthed, for his verdict. The world was disappointed. Immediate sight identification was made impossible by the adherent lunar dust covering and hiding the rocks. Frondel later remarked that the rocks were so covered with dust that, "You couldn't tell if they were Swiss cheese or granite."
After the rocks and dust were separated, in addition to undergoing the preliminary mineralogical examination, they were put through an exhaustive series of tests to ensure that they carried no organisms which might be harmful to man. During this time the samples were in complete isolation. Although there have been numerous incidents of isolation chamber leakage, most have been minor. The one major leak occurred during the quarantine of the Apollo 12 samples and required Frondel to enter quarantine for two weeks himself. Failure to find the lunar samples biologically dangerous has led to the quarantine being abandoned.
Following the initial tests, most of the samples were put in storage at the Lunar Receiving Laboratory for future study. The remaining material has been distributed to some 175 research teams all over the world.
THERE ARE three such groups at Harvard. One group headed by Frondel and Cornelius Klein Jr., associate professor of Mincralogy, is concerned with the mineralogy of the lunar samples. Another group headed by Edward L. Fireman, lecturer on Astronomy, has determined the time some samples have been exposed to cosmic rays by studying the radioactivity in the samples. Then, the very important subject of the organic substances and their possible implications about life are studied by Elso S. Barghoorn, professor of Botany. Finally, special types of moon rock called anorthosites which give clues about the moon's formation are studied by Ursula B. Marvin and John A. Wood, both associates of the Harvard College Observatory.
Over 500 scientists have been studying the lunar samples and have collected a formidable amount of information in the short time since July 24, 1969, when the first samples were returned to earth. They have used a variety of some of the most sophisticated techniques known and have developed new techniques when necessary.
The results of this effort are increases in knowledge about the moon itself and its history, about the earth-moon system, about the sun and the galaxy, and about some of the fundamental mysteries of the universe.
As the Apollo astronauts looked around them, they saw a true desert-devoid of life, devoid of water, devoid of atmosphere (some five per cent of the atmosphere of the moon is man-made). The level volcanic seas or mares of the Apollo 11 and 12 landing sites cover much of the near side of the moon and provided the first lunar samples. Here the volcanic bedrock has been repeatedly hit by meteorites and broken up so that a layer of broken rock and dust from 6 to 20 feet deep lies on the surface. Some of these rocks have been lying on the surface directly exposed to space for several million years, while the top inch of soil has been relatively unmixed for the last several hundred million years.
Its incredible unchanging nature makes the lunar surface a permanent record of solar flares, solar wind and ordinary cosmic ray activity over thelast several hundred million years. Such a record is invaluable for tracing the history of the sun and nothing on earth comes close to duplicating it.
The history of the moon is revealed by the different types of rock found there. Most of the rocks brought back from the lunar seas by Apollo 11 and 12 are titanium-rich basalt and gabbro. They appear to be once-molten lava from inside the moon which broke through the crust made of lighter anorthosite and crystallized to form the seas about 3.5 billion years ago.
The crust itself forms the lunar highlands and was crystallized about 4.5 billion years ago-about the same time the earth was formed. Recent Apollo 14 samples from the highlands are anorthositic and support the hypothesis of an anorthosite crust.
Today, the earth is still changing-continents move, now mountains are being made, volcanoes erupt periodically-all forming new rock. For the last three billion years (the age of the youngest lunar rock) the only apparent changes on the moon have been caused by meteorites. Constant impacting by meteorites has broken up the rock to form dust, compacted the dust to form rocks called breccia, and melted the rock sand dust to form glasses.
One of the very interesting forms the meteorite-produced glass takes is as thousands of tiny colored glass beads which are mostly less than 1/32 of an inch in diameter and appear to be splash droplets. Even these tiny objects have micro-craters on them caused by even smaller particles. Most of these beads are slightly transparent and may be colored red-brown, green or blue while others are opaque with a metallic looking surface. They are so numerous that they make up about 1/3 of the lunar dust.
Tektites, those mysterious glassy spheroids seemingly strewn across Asia and Australia from space, were also once thought to be splash droplets from some very large meteor hitting the moon. Now, because no lunar material resembles tektite glass in composition, most scientists agree that the tektites do not have a lunar origin. Instead, Frondel said. "It looks more and more that they may be of terrestrial origin." However, no definite theory such as the splash droplet theory for the glass beads on the moon, has been developed to explain the tektites' origin or formation.
SIMILARLY, new information has shaken formerly well established theories about the origin of the moon itself. Before Apollo II there were three main theories of lunar origin: the fission theory envisioning the moon once being part of the earth and breaking away, the capture theory which said the earth's gravity captured the moon as a satellite, and the accretion theory which maintained that the moon was formed by a ring of matter around the earth, similar to Saturn's rings, accumulating to form one body. These theories can now be tested by evidence from the moon itself.
The moon is now moving away from the earth at such a rate that it would be right next to the earth only 1.5 billion years ago, yet the youngest lunar rock is three billion years old. Since close capture would entail major rock forming disruptions, the capture theory has been pretty much disproved.
Then there are some composition and isotope ratio differences between lunar and terrestrial basalts which seem to indicate that the moon and earth could never be one body, thus disproving the fission theory. However, there is some controversey about the importance of the differences between terrestrial and lunar rocks.
Although the fission theory is not completely ruled out, most lunar researchers seem to favor the accretion theory because it explains the moon's origin with fewest inconsistencies.
Like all scientific research, studying moon rocks doesn't always yield positive results. One of the extensive tests run on the lunar samples-the search for magnetic monopoles-has demonstrated that such particles are very rare if they exist at all. People have never found one, yet think they exist and are willing to spend lots of money and time looking for them. So what is a magnetic monopole?
A magnetic monopole is a magnetized particle which has only one pole-either north or south-rather than both poles as all other known magnetic objects have. Since Dirac first proposed monopoles in 1931, these elusive particles have been surprisingly useful in answering some of the fundamental questions of the universe.
According to one theory, monopoles if they exist are the most fundamental particles from which all other particles and hence all matter can be made. The monopoles would also strongly support the only theory which explains why protons and electrons have a single specific electric charge.
Since the lunar surface has been continually exposed for so long to cosmic rays which might contain or produce a magnetic monopole, the moon samples have a greater chance of containing a monopole than anything on earth.
However, despite their efforts and hopes, the researchers found no indication of monopoles in the Apollo samples.
Unlike the elusive monopoles, ordinary magnetic dipoles are fairly common in the lunar samples. Much matter such as iron can be magnetized by a variety of naturally occurring processes, but all these processes require the presence of a magnetic field. The moon's present field is very small and could not have produced the measured magnetization of the lunar samples. The conclusion must be that either the moon once had a much stronger field or it was much closer to the earth.
PROBABLY the question most often asked about the moon before 1969 was, "Is there life or has there ever been life on the moon?" The answer can now be stated emphatically-No. As Barghoorn said, "The moon is an utterly dead body."
The initial quarantine tests at the Lunar Receiving Laboratory and subsequent tests which similarly tried to induce growth of native lunar organisms in a variety of environments established the absence of live or dormant organisms on the moon. Then careful microscopic examination of thin slices of lunar rock failed to reveal any remnants of fossils of once-living organisms. There were some crystal formations which resembled colonies of organisms but they were found to be caused by non-living natural processes.
Not only is there no life or indication of former life on the moon, but the essential ingredients to produce or sustain life as we know it are also absent. The presence of unoxidized iron on the moon-totally absent on earth-indicates that the moon has had negligible amounts of free oxygen if any at all. The analyses of the lunar rocks gives a concentration of carbon of 30 to 300 parts per million yhile earth rocks normally contain 100 times that much carbon.
Most of the lunar carbon appears to be in the form of gas bubbles-mostly carbon monoxide-inside the tiny glass beads. The samples also contain some methane and ethane-simple saturated hydrocarbons-which might be native to the moon. More complex hydrocarbons are concentrated in earth rocks at about 100 parts per million but were undetectable in the lunar rocks to an accuracy of one part per billion.
The existence of other more complex organic compounds such as amino acids-the basic building blocks of proteins-and porphyrins-related to hemoglobin, chlorophyll and some vitamins-is still open to debate. If these compounds exist, they are extremely rare and difficult to detect. This means contamination by terrestrial compounds is a real problem. Such contamination could occur if the sample containers leak, if the chemicals used in the test techniques are not absolutely pure, or if the rocket fuel burning produced complex organic contaminants.
According to Barghoorn, most researchers agree that amino acids are probably absent but that the story of porphyrins is still very unclear.
Compared to meteorites which have been analyzed, the moon is extremely lifeless. Some meteorites have as much as five per cent carbon (more than 200 times the moon quantity) and one-the Murchison meteorite which fell in Australia in 1967-contains substantial amounts of amino acids-some of which are biologically active. However, none of these carbonaceous meteorites show any indications of living organisms.
While a select few examine the lunar samples every day, thousands of other people stand in line for hours to get a glimpse of the rocks. Surrounded by other relics of the U. S. space program, guarded more carefully than the Mona Lisa, these small pieces of the moon sitting in their glass case draw crowds throughout the world. The moon samples are probably some of the most uninteresting looking objects ever to attract such attention. They are not strangely shaped or beautifully colored. They are just dull dark rocks which reveal secrets only to the experts. Indeed, there is little assurance that the rocks in the glass case actually came from the moon. Next time you trip over a dark piece of rock, smile knowingly.