Universe Today

July 21, 2009December 24, 2015 by Fraser Cain

Exploration of Mercury

The MESSENGER spacecraft at Mercury (NASA)

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As one of the planets visible with the unaided eye, Mercury has been known before recorded history. But until the development of the telescope, the exploration of the Mercury was only unaided eye observations. Early cultures like the Mayans and ancient Greeks were diligent astronomers, and calculated the motions and positions of Mercury with tremendous accuracy.

But the exploration of Mercury really began with the invention of the telescope. Galileo Galilei was the first to turn his telescope on the 1st planet, seeing nothing more than a small disk. Galileo’s telescope wasn’t powerful enough to see that Mercury has phases, like the Moon and Venus. In 1631, Pierre Gassendi made the first observations of Mercury’s transit across the surface of the Sun, and further observations by Giovanni Zupi revealed its phases. This helped astronomers to conclude the Mercury orbited the Sun, and not the Earth.

Because Mercury is so small, and located so close to the Sun, astronomers weren’t able image features on its surface with any accuracy. It wasn’t until the 1960s, when Soviet scientists bounced radio signals off the surface of Mercury that astronomers got any sense of what its surface was like. These radio reflections also helped astronomers discover that Mercury’s day length is 59 days; almost as long as its year of 88 days.

But the best Mercury exploration happened when NASA’s Mariner 10 spacecraft first flew past Mercury in 1974. It revealed that Mercury’s surface is pockmarked with craters like the Earth’s moon. And like the Moon it has flat regions filled in with lava flows. After two additional flybys Mariner 10 ended up mapping only 45% of Mercury’s surface.

The next mission to explore Mercury was NASA’s MESSENGER spacecraft, launched on August 3, 2004. It made its first Mercury flyby on January 14, 2008, mapping more of Mercury’s surface. MESSENGER will eventually go into orbit around Mercury, mapping its surface in great detail and answering many unknown questions about Mercury and its history.

We have written many stories about Mercury here on Universe Today. Here’s an article about a the discovery that Mercury’s core is liquid. And how Mercury is actually less like the Moon than previously believed.

Want more information on Mercury? Here’s a link to NASA’s MESSENGER Misson Page, and here’s NASA’s Solar System Exploration Guide to Mercury.

We have also recorded a whole episode of Astronomy Cast that’s just about planet Mercury. Listen to it here, Episode 49: Mercury.

References:
NASA Solar System Exploration: Missions to Mercury
NASA: Planetary Science

July 21, 2009April 26, 2016 by Anne Minard

Thirty-Meter Telescope Headed for Mauna Kea

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The Thirty Meter Telescope, which is vying to be the inaugural member of an emerging class of giant eyes in the sky, is headed for the Mauna Kea in Hawaii.

That means the other contending site, Cerro Armazones in Chile, is off the drawing board.

Richard Ellis, a TMT board member, said the choice was a tough one, but Mauna Kea had scientific advantages.

“Mauna Kea is a higher site. It is actually drier, and the average temperature fluctuates less from day to day and during the day to night cycle than the Chilean site,” he said, during a press conference this afternoon to announce the decision. “Much of the astronomy will be at infrared wavelengths, where the dryness is an advantage.”

He added that the Hawaii boasts slightly better atmospheric qualities, including lower turbulence over the site.

When completed in 2018, the TMT will enable astronomers to detect and study light from the earliest stars and galaxies, analyze the formation of planets around nearby stars, and test many of the fundamental laws of physics. Based on the scientific model of the twin Keck telescopes, the core technology of TMT will be a 30-meter primary mirror composed of 492 segments.

The TMT project is an international partnership among the California Institute of Technology, the University of California, and ACURA, an organization of Canadian universities. The National Astronomical Observatory of Japan (NAOJ) joined TMT as a Collaborating Institution in 2008.

The TMT project has completed its $77 million design development phase with primary financial support of $50 million from the Gordon and Betty Moore Foundation and $22 million from Canada. The project has now entered the early construction phase, with an additional $200 million pledge from the Gordon and Betty Moore Foundation. Caltech and the University of California each have agreed to raise matching funds of $50 million to bring the construction total to $300 million, and the Canadian partners propose to supply the enclosure, the telescope structure, and the first light adaptive optics.

The TMT faces competition from the Giant Magellan Telescope to usher in the age of the giants. See past Universe Today coverage of the race here.

Source: TMT site

July 21, 2009December 24, 2015 by Tega Jessa

First Rocket

Dr. Robert Goddar with on his early rockets in Roswell

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Rocketry is actually older than many people think. The first rockets originated in China and subsequently the Middle East with the discovery of gunpowder. These rockets were used for military purposes or as entertainment. The use of rockets and gunpowder would eventually transform warfare, and to this day we still use rockets in pretty much the same way they were used 700 years ago. The only difference is that when we use rockets for military purposes we call them missiles and when used for entertainment they can be toys or pyrotechnics.

The composition of the first rocket was what is now in aeronautics called a solid rocket. This rocket runs on a solid fuel that burned inside the rocket. The heated exhaust is expelled out the bottom the rocket, creating the thrust needed to fly. The composition of solid fuel rockets is still pretty much the same as in ancient times.

The casing is the body of the rocket. Rockets were made differently depending upon their end use. For example, solid rockets that were used in space programs had steel casings. The next important element of a solid rocket was the grain. The grain is the solid fuel needed to power the missile. The first types used had gunpowder as the grain but the formula could be altered. If you ever saw a fireworks display, this is why the explosions have different colors. The additions of different metals and composites in the grain of the rockets creates this effect. The final components; the fuse. This was the ignition device used to start the combustion process of the rockets fuel. Later as rocketry was further researched a nozzle was added to the design to better direct exhaust and improve thrust.

The first rockets that were used in modern rocketry was invented by Dr. Robert Goddard. For this he is known as the Father of Modern Rocketry. He created the first successful liquid fuel rocket, adding the nozzle design that is so common today. The liquid fuel rocket ran on a slightly different design than its predecessor with the fuel being released from a pressure tank to a combustion chamber where it was mixed with air or another oxidizer to burn and create heated exhaust which was directed away to create thrust. This would be the design that would pave the way for modern aeronautics and eventually space exploration.

So as we see rockets have come a long way from their earliest day. Nevertheless, they are still playing an important role in the development of human technology. Making new advances possible every day with the missions and experiments they support.

If you enjoyed this article there are other related articles on the Universe Today website you might want to checkout. Here is an article that talks more about solid fuel rockets. If you want to learn more about modern rockets this article on new advances made on liquid fuel rockets.

There are other interesting articles you can find on the web. Time magazine has a great profile article on Robert Goddard. Another good resource is the NASA website which has a brief article on the history of rockets.

You might also enjoy listening to an episode of Astronomy Cast. Episode 100 Rockets is relevant to the stuff talked about in the article.

Source: Wikipedia

July 21, 2009December 24, 2015 by Anne Minard

Heat-Shocked Diamonds Provide New Clue of Horse-Killing Impact

California's Channel Islands, where heat-shocked soot and diamonds are suggesting a killing comsic impact. Courtesy NOAA and UC Santa Barbara

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Archeologists have been divided about whether an extraterrestiral impact blasted North America about 12,900 years ago, wreaking havoc on Earth’s surface and sending scores of species — including a pygmy mammoth and the horse — into oblivion.

New clues from California’s Channel Islands should put any doubt to rest, says an international team of researchers.

This transmission electron microscopy close-up shows a single lonsdaleite crystal, left, and associated diffraction pattern. Credit: University of Oregon

The 17-member team, led by University of Oregon archaeologist Douglas J. Kennett, has found what may be the smoking gun.

The team has found shock-synthesized hexagonal diamonds in 12,900-year-old sediments on the Northern Channel Islands off the southern California coast.

The tiny diamonds and diamond clusters were buried deeply below four meters (13 feet) of sediment. They date to the end of Clovis — a Paleoindian culture long thought to be North America’s first human inhabitants. The nano-sized diamonds were pulled from Arlington Canyon on the island of Santa Rosa, which had once been joined with three other Northern Channel Islands in a landmass known as Santarosae.

The diamonds were found in association with soot that forms in extremely hot fires, and they suggest associated regional wildfires, based on nearby environmental records.

Such soot and diamonds are rare in the geological record. They were found in sediment dating to massive asteroid impacts 65 million years ago in a layer widely known as the K-T Boundary. The thin layer of iridium-and-quartz-rich sediment dates to the transition of the Cretaceous and Tertiary periods, which mark the end of the Mesozoic Era and the beginning of the Cenozoic Era.

“The type of diamond we have found — Lonsdaleite — is a shock-synthesized mineral defined by its hexagonal crystalline structure. It forms under very high temperatures and pressures consistent with a cosmic impact,” Kennett said. “These diamonds have only been found thus far in meteorites and impact craters on Earth and appear to be the strongest indicator yet of a significant cosmic impact [during Clovis].”

The age of this event also matches the extinction of the pygmy mammoth on the Northern Channel Islands, as well as numerous other North American mammals, including the horse, which Europeans later reintroduced. In all, an estimated 35 mammal and 19 bird genera became extinct near the end of the Pleistocene with some of them occurring very close in time to the proposed cosmic impact, first reported in October 2007 in PNAS.

Source: University of Oregon, via Eurekalert. The results appear in a paper online ahead of print in the Proceedings of the National Academy of Sciences.

July 21, 2009December 24, 2015 by Tammy Plotner

IYA Live Telescope Library: Jupiter & Neptune – The “Helix” Nebula

Hey, hey! We’re baaaaack… The IYA Live Telescope was on-line for the whole night “down under” and we had a chance to watch both Jupiter and Neptune accompanied by a nearby star for several hours – then a later view of the Helix nebula until dawn. If you didn’t get a chance to see it live, don’t worry. As always, we did a video capture to share…

When it comes to viewing Jupiter, sometimes there can always be a bit of a trade-off. In order to see dimmer Neptune, Jupiter must be over-exposed, thereby losing planetary details. Although the planetary pair has separated greatly over the last few days, it’s still nice to be able to catch them nearby each other in the same field of view!

Factual Information Courtesy of Wikipedia:

The Helix Nebula, also known as The Helix or NGC 7293, is a large planetary nebula (PN) located in the constellation of Aquarius. Discovered by Karl Ludwig Harding, probably before 1824, this object is one of the closest to the Earth of all the bright planetary nebulae. The estimated distance is about 215 parsecs or 700 light-years. It is similar in appearance to the Ring Nebula, whose size, age, and physical characteristics are similar to the Dumbbell Nebula, varying only in its relative proximity and the appearance from the equatorial viewing angle.

In this video, the Helix appear quite dim since it really requires a larger aperture telescope. However, you will find it slightly left of center where it makes a brief appearance haloed by faint stars when the image composites and resolves.

Once again, many, many thanks to our generous benefactor from the Mighty ETX group for donating the part needed to bring our IYA telescope back to life again! Please be sure to check the link to your left for future IYA “Live” telescope broadcasts!

July 21, 2009December 24, 2015 by Brian Ventrudo

A Table-Top Test of General Relativity?

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Even Albert Einstein might have been impressed. His theory of general relativity, which describes how the gravity of a massive object, such as a star, can curve space and time, has been used to predict small shifts in the orbit of Mercury, gravitational lensing by galaxies and black holes, and the existence of gravitational waves. Now, new research shows it may soon be possible to study the effects of general relativity in bench-top laboratory experiments.

Xiang Zhang, a faculty scientist with the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and professor at the University of California Berkeley, lead a study that shows the interactions of light and matter with spacetime, as predicted by general relativity, can be studied using the new breed of artificial optical materials that feature extraordinary abilities to bend light and other forms of electromagnetic radiation.

“We propose a link between the newly emerged field of artificial optical materials to that of celestial mechanics, thus opening a new possibility to investigate astronomical phenomena in a table-top laboratory setting,” says Zhang. “We have introduced a new class of specially designed optical media that can mimic the periodic, quasi-periodic and chaotic motions observed in celestial objects that have been subjected to complex gravitational fields.”

Zhang, a principal investigator with Berkeley Lab’s Materials Sciences Division and director of UC Berkeley’s Nano-scale Science and Engineering Center, has been one of the pioneers in the creation of artificial optical materials. Last year, he and his research group made headlines when they fashioned unique metamaterials – composites of metals and dielectrics – that were able to bend light backwards, a property known as a negative refraction that is unprecedented in nature. More recently, he and his group fashioned a “carpet cloak” from nanostructured silicon that concealed the presence of objects placed under it from optical detection. These efforts not only suggested that true invisibility materials are within reach, Zhang said, but also represented a major step towards transformation optics that would “open the door to manipulating light at will.”

Now he and his research group have demonstrated that a new class of metamaterials called “continuous-index photon traps” or CIPTs can serve as broadband and radiation-free “perfect” optical cavities. CIPTs can control, slow and trap light in a manner similar to such celestial phenomena as black holes and gravitational lenses. This equivalence between the motion of the stars in curved spacetime and propagation of the light in optical metamaterials engineered in a laboratory is referred to as the “optical-mechanical analogy.”

Zhang says that such specially designed metamaterials can be valuable tools for studying the motion of massive celestial bodies in gravitational potentials under a controlled laboratory environment. Observations of such celestial phenomena by astronomers are often impractical because of the long time scales of the interactions on a astronomical scale.

“If we twist our optical metamaterial space into new coordinates, the light that travels in straight lines in real space will be curved in the twisted space of our transformational optics,” says Zhang. “This is very similar to what happens to starlight when it moves through a gravitational potential and experiences curved spacetime. This analogue between classic electromagnetism and general relativity, may enable us to use optical metamaterials to study relativity phenomena such as gravitational lens.”

In their demonstration studies, the team used a composite structure of air and the semiconductor Gallium Indium Arsenide Phosphide (GaInAsP). This material provided operation at the infrared spectral range and featured a high refractive index with low absorption.

In their paper, Zhang and his coauthors cite as a particularly intriguing prospect for applying artificial optical materials to the optical-mechanical analogy the study of the phenomenon known as chaos. The onset of chaos in dynamic systems is one of the most fascinating problems in science and is observed in areas as diverse as molecular motion, population dynamics and optics. In particular, a planet around a star can undergo chaotic motion if a perturbation, such as another large planet, is present. However, because of the large spatial distances between the celestial bodies, and the long periods involved in the study of their dynamics, the direct observation of chaotic planetary motion has been a challenge. The use of the optical-mechanical analogy may enable such studies to be accomplished on demand in a bench-top laboratory setting.

“Unlike astronomers, we will not have to wait 100 years to get experimental results,” Zhang says.

The paper titled “Mimicking Celestial Mechanics in Metamaterials” is now available on-line in the journal Nature Physics.

Source: Lawrence Berkeley National Lab

July 20, 2009December 24, 2015 by Nancy Atkinson

Astro Art of the Week: Space Travelers

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Here’s the second installment of our new feature, showcasing our readers’ prowess with image editing software. This week’s Astro Art of the Week was submitted by Laura Gardiner from Tucson, Arizona USA. This seemed to be a perfect image to use, as during Apollo 11 festivities on Monday, astronauts repeatedly talked about inspiring the next generation of space explorers. This is a collage Laura created several months ago with Photoshop, using several PS brushes downloaded from deviantart.com, along with a photo of her daughter and nephew. “I’ve gotten a lot of positive comments about it,” she said. “I was new to Photoshop then, but I’ve been having fun learning new things. I probably would have done some things differently now, but all in all I think it turned out pretty neat. It was an experiment because I was fascinated by the idea of Photoshop’s “brushes,” so that’s where the stars/galaxies/etc. came from. I didn’t have any particular picture or project in mind when I made it…it just sort of came together after several hours of fooling around with stuff.”

In case you missed the news last week, “Astro ‘Shop” is a new feature on Universe Today where readers can submit astronomical images they have messed around with using image editing software. Interested in submitting? A few rules: the images submitted must be space or astronomy related and they must be in good taste. The images can be submitted to Nancy here. Also, we’re still contemplating a good title for this feature. We’ve tried “Astro ‘Shop of the Week,” (as in ‘Photoshop’) and now “Astro Art of the Week.” If you have any suggestions for a good title, post it in the comment section. Thanks!

July 20, 2009December 24, 2015 by Nancy Atkinson

Astronauts Don Protective Gear to Fix ISS Toilet

Tom Mashburn during Monday's EVA. Credit: NASA

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Space station astronauts repaired a broken toilet in the U.S Destiny laboratory today, avoiding a potentially messy situation. With the shuttle-space station complex currently home to a record combined crew of 13 astronauts and cosmonauts, fixing the toilet was of utmost importance. ISS crew members Gennady Padalka and Frank De Winne were told to don safety goggles and protective gear before opening the toilet’s access panels. They replaced a half-dozen components during work Sunday and Monday repairing the defective toilet with spare parts on the orbiting outpost.

While toilet repairs were going on, shuttle astronauts David Wolf and Thomas Marshburn completed the second spacewalk of the STS-127 mission, during a day filled with remembrances and tributes to the Apollo 11 moon landing.

The two astronauts transferred a spare KU-band antenna to long-term storage on the space station, along with a backup coolant system pump module and a spare drive motor for the station’s robot arm transporter. Installation of a television camera on the Japanese Exposed Facility experiment platform was deferred to a later spacewalk. This was the second of five STS-127 spacewalks, the 127th in support of International Space Station assembly and maintenance.

The STS-127 mission spacwalks will complete construction of the Japan Aerospace Exploration Agency’s Kibo laboratory.

The ISS has two toilets for its six-person crew, the one that malfunctioned in Destiny and another in the Russian Zvezda command module. The space shuttle Endeavour also is equipped with a toilet.
After tests to make sure the toilet was operating properly, flight controllers cleared the combined 13-member shuttle-station crew to resume normal use.

“The US Destiny lab toilet has been repaired and checked out. The crew has been given a “go” to use it. All three toilets are working,” NASA said in a post on Twitter.

July 20, 2009December 24, 2015 by Nancy Atkinson

Jupiter Impact Confirmed

This image shows a large impact shown on the bottom left on Jupiter's south polar region captured on July 20, 2009, by NASA's Infrared Telescope Facility in Mauna Kea, Hawaii. Credit: NASA/JPL/Infrared Telescope Facility

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As we reported yesterday, an amateur astronomer snapped evidence of an impact on Jupiter. Now, NASA has confirmed the black spot on the giant gas planet is in fact an impact and not just a weather-related disturbance. And Anthony Wesley has now made the biggest observation of his life.

“It still feels very surreal right now,” he told Universe Today. “I guess it will take some time to really sink in (pun intended). I guess it shows that persistence and many hours at the scope eventually pays off.”

The Infrared Telescope Facility at the summit of Mauna Kea, Hawaii, has imaged the south polar region Jupiter, confirming the impact, which occurred on July 19. New infrared images show the likely impact point, with a visibly dark “scar” and bright upwelling particles in the upper atmosphere detected in near-infrared wavelengths, and a warming of the upper troposphere with possible extra emission from ammonia gas detected at mid-infrared wavelengths.

Anthony said imaging Jupiter has been his main passion since 2004. “It’s such a dynamic system that every image I take shows something new and different,” he said, “It keeps me coming back year after year, with bigger and better equipment each time. I never expected to see anything like this of course, but even the routine imaging of Jupiter’s storm systems can reveal a tremendous wealth of detail.”

Anthony said this is one of the areas where amateurs can make a significant contribution to science. “The the study of planetary atmospherics is a very hot topic at the moment and nowhere are the dynamics more evident than on Jupiter,” he said. “Researchers are coming to rely on amateur images of Jupiter for much of their data, augmented by professional images whenever something truly significant occurs that justifies the cost of using the larger instruments.”

Anthony Wesley from Canberra, Australia has captured a new impact spot on Jupiter. Credit: Anthony Wesley — Anthony Wesley from Canberra, Australia has captured a new impact spot on Jupiter. Credit: Anthony Wesle

“It’s significant that in each of the last 3 years amateurs have made the initial discoveries of new features in the Jovian atmosphere, the colour change of the previously white Oval BA to red in 2007 by Chris Go of the Philippines, the formation of another (smaller) red spot last year by myself, and then this event in 2009. In all cases the amateur work was followed up with imagery from Hubble and other major telescopes.”

This new impact occurred exactly 15 years after the first impacts by the comet Shoemaker-Levy 9, and as the celebrations of the Apollo 11 moon landings are taking place.

Glenn Orton, a scientist at JPL and his team of astronomers kicked into gear early in Monday morning and haven’t stopped tracking the planet. They are downloading data now and are working to get additional observing time on this and other telescopes.

“We were extremely lucky to be seeing Jupiter at exactly the right time, the right hour, the right side of Jupiter to witness the event. We couldn’t have planned it better,” he said.

The top image taken by the Infrared Telescope Facility, was taken at 1.65 microns, a wavelength sensitive to sunlight reflected from high in Jupiter’s atmosphere, and it shows both the bright center of the scar (bottom left) and the debris to its northwest (upper left).

“It could be the impact of a comet, but we don’t know for sure yet,” said Orton. “It’s been a whirlwind of a day, and this on the anniversary of the Shoemaker-Levy 9 and Apollo anniversaries is amazing.”

Shoemaker-Levy 9 was a comet that had been seen to break into many pieces before the pieces hit Jupiter in 1994.

Sources: JPL, email exchange with Anthony Wesley

July 20, 2009December 24, 2015 by Nancy Atkinson

After 40 Years Moon Rocks Still Revealing Secrets

Scientists in the Lunar Receiving Laboratory. Credit: NASA

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Even though scientists have been able to study Moon rocks up close for almost 40 years, there are still many answers to be gleaned from the lunar samples collected by the Apollo astronauts. “We know even more now and can ask smarter questions as we research these samples,” says Randy Korotev from Washington University in St. Louis. “There are still some answers, we believe, in the Apollo 11 mission.” One possible clue the Moon rocks could provide is a better understanding of Earth’s history and when life actually began on our planet.

Korotev has been mainly interested in studying the impact history of the moon, how the moon’s surface has been affected by meteorite impacts and the nature of the early lunar crust.

“You can look at the moon and know that the moon has been hit a lot by very large meteorites,” he said. “We know this occurred some 3.9 billion years ago. We don’t know, however, the history of large meteorites hitting the Earth — we can’t see those impacts because they would have been erased by Earth’s active geology. We want to see if meteorite bombardment on the moon coincided with what was happening on Earth, and, in turn, with life starting on Earth.”

Recently, Korotev and his colleagues decided to begin taking a closer look at the Apollo samples to learn more about the Moon’s impact history. He says they still have much work to do with his samples, which have been chemically analyzed and are sealed in tubes and securely stored away for now.

Korotev expects the Apollo Moon rocks will provide scientific study for years to come, as our technology and understanding of the Moon improves. “We went to the moon and collected samples before we knew much about the moon,” he said. “We didn’t totally understand the big concept of what the moon was like until early 2000 as a result of missions that orbited the moon collecting mineralogical and compositional data.”
“Bringing samples back from the Moon wasn’t the point of the mission,” added Korotev. “It was really about politics. It took scientists like Bob Walker to bring these samples back — to show the value of them for research.”

Korotev credits Walker, also from Washington University and a handful of other scientists for the fact that there are even moon samples to study.

“Bob convinced them to build a receiving lab for the samples and advised them on the handling and storage of them. We didn’t go to the moon to collect rocks, so we scientists are really lucky that we have this collection.”

See Universe Today’s article on the history of the Lunar Receiving Lab.

Researchers in WUSTL's Laboratory for Space Sciences in Arts & Sciences have a long tradition of being among the first in the world to receive samples from a NASA mission. In this photo taken in 1969, the late Robert M. Walker, Ph.D., the McDonnell Professor of Physics and first director of the university's McDonnell Center for the Space Sciences in Arts & Sciences, displays photos and lunar samples from the Apollo 11 mission that year. Credit: WUSTL

Walker was recruited to serve on the scientific team that advised NASA on the handling and distribution of moon rocks and soil samples from the first Apollo missions. That team distributed Apollo 11 samples to some 150 laboratories worldwide, including Washington University, St. Louis (WUSTL).

Walker also briefed those early astronauts about what to expect on the rocky, dusty moon surface.

In an interview some months after the first moon samples arrived in WUSTL’s space sciences lab, Walker recalled the excitement of that momentous day in 1969: “We felt just like a bunch of kids who were suddenly given a brand new toy store … there was so much to do, we hardly knew where to begin.”

Ghislaine Crozaz, Ph.D., professor of earth and planetary sciences emerita in Arts & Sciences at Washington University and a member of Walker’s space sciences group that was one of those selected to study the first lunar samples, says the event is “as vivid in my mind as if it had happened yesterday.”

Crozaz says that the team studied the cosmic rays and radiation history of the lunar samples mainly using nuclear particle tracks, which were revealed by techniques invented by Walker.

“After we received the samples in early September, we worked like hell until the First Lunar Science Conference in early January 1970 in Houston, where we arrived with our Science paper after having worked ‘incommunicado’ for 4 months.”

In their study of the lunar materials, Walker’s laboratory led the way in deciphering their record of lunar, solar system and galactic evolution. Of special importance was the information they gave on the history of solar radiation and cosmic rays.

Crozaz says the lunar samples provided insights into the history of the solar system that couldn’t be achieved at the time by looking at meteorites found on Earth. The intense heat encountered during their passage through the atmosphere would have erased much of the record of radiation the meteorites carried.

Source: Washington University St. Louis