Explosive Tylenol™?

Your note to the question box surprised me. Explosive Tylenol? I had not read that display in its entirety, so I took a trip downstairs to look at this exhibit.

The photo shows explosives researcher, post-doc John Yeager, indeed examining a Tylenol™ crystal. Tylenol, the medication, has a crystalline structure similar to the structure of many crystalline high explosives, but is not itself explosive. Scientists at Los Alamos who study explosives can substitute Tylenol for safety reasons in some experiments. It appears to be a pretty green color. Thank you for bringing this to my attention, I had no idea.

OTOH, Alfred Nobel suffered from terrible headaches brought about by his contact with nitroglycerine, and he died of heart disease. His nitroglycerine is the same nitroglycerine used as heart medicine today.

To be absolutely clear, Tylenol is not explosive.

Does the Universe have an edge?

I don't think anyone really knows. There are lots of ideas, though. If there has only been one Big Bang (which in itself seems unlikely to me), then the Universe has an average radius, approximately the age of the universe times the speed of light, ignoring the possibility of stuff that travels faster than the speed of light. Intergalactic space is thought to have an average density of something like 1 hydrogen atom per cubic meter [citation needed] although recent news from the big telescopes suggests that there are stars and planets also outside of galaxies. 1 atom/m^3 is pretty empty.  If the universe is alone, I suspect there is no way we will ever see its edge, as it is receding from us at or faster than the speed of light.

There are cosmologists who believe in all seriousness that our universe is expanding like a bubble in a foam of universes, in which case it is possible, I suspect, that we will some day detect the boundary, where it impinges on another universe. Does the edge slow down? Is there a shock wave? Please forgive me for being so Newtonian about this, but I can't imagine a foam of universes where all of them can expand indefinitely at or above the speed of light. Not, at least if they all share the same dimensions*. Then the question begs to be asked, does the foam have a boundary? What would be beyond that?

"It's turtles all the way down."

*What if our three familiar dimensions are actually dimensions #38576027184365756392,  #38576027184365756393, and #38576027184365756394, and other universes are also three dimensional but occupy other dimensions than our particular three of length, width, and height? (I am ignoring the 9, 11, 17 or whatever dimensions are required by string theory.)

How many moons are there in space?

Space is a really big place. There are billions of galaxies and each one has billions of stars. Recent discoveries suggest that planetary systems are the rule and not the exception around stars. So the number of moons in space is uncountable.

I suspect you meant to ask how many moons there are in our solar system. When I was young, a long time ago, books about the solar system gave precise numbers for the moons of each planet. Then came the Pioneer and Voyager spacecraft and vastly better telescopes. The answer is no one knows. It seems every time we a get closer look at the distant planets, like Saturn, Uranus, or Neptune, we discover they have more moons than we previously thought. Even Pluto is now known to have at least two moons.

This Friday (March 6, 2015) the dwarf planet Ceres, the largest body in the Asteroid Belt, will get a new moon, or at least a satellite. NASA’s Dawn spacecraft will slip into orbit around this body for a visit.

Why is there so little information about the Navajo Code Talkers here?

Jourdan, I am so proud of you! Thank you for asking why we don't feature the Navajo Code Talkers at our museum. You are the first person to ask this in my ten years as the question answerer, and it is a good question. 

You are correct that we feature mostly Manhattan Project related information in our history exhibits, and that is actually the short answer. You might like to know that we occasionally get criticized for not talking more about the Holocaust in our museum. I am fascinated that while we seem to brag about "ending the war," very few people if any suggest we could talk more about the aspects that actually won the war, the Navajo Code Talkers being a major contribution along with, for example, shipbuilding and the secret developments of radar and code breaking.

WWII, particularly in the Pacific, was a truly horrible affair. I cannot imagine the feelings of the Marines who bore the brunt of one amphibious assault after another against entrenched and fanatical fighters. They were extremely lucky to have the Code Talkers with them, and the ability to communicate securely because the Navajo People, Your People, had protected and maintained their ability to speak in their own tongue, often in the face of harsh government opposition.

I will place a copy of this text in our answer book. It is not much, and nowhere near what they deserve, but the Navajo Code Talkers earned at least this little honor.

Why did Fat Man have dark paint markings?

You asked a terrific question about the black paint on Fat Man's protruding parts. Fat Man was delivered to Tinian Island in parts and assembled on the island. The implosion design had been tested in New Mexico, but had never been exposed to the kind of humidity it experienced in the Pacific. After assembly, but before loading it onto the bomber Bock's Car,  all of Fat man's seams were sprayed with a sealer. I think it was asphaltum or something similar. Many of the protruding parts were bolted on, so their seams were included in the treatment.

Was Flouride a by-product of the Manhattan Project?

 I love this question which I found this morning in our question box. So much in fact that I just had to share it with a Lab chemist I know. (Because I had no idea.) I have copied his response in full here. I recommend both of the links. Thank you for providing me with this opportunity to learn!

"I’m guessing that they are referring to the de-conversion of uranium hexafluoride to form uranium metal.  A byproduct of the de-conversion process would be fluorine – typically as a fluoride.

Here is a NRC web page providing some information on uranium de-conversion:

http://www.nrc.gov/materials/fuel-cycle-fac/ur-deconversion.html

Also web page for the company that is building a facility in southern New Mexico for uranium de-conversion:

http://www.intisoid.com/index.php/fep/more-information/1300-2/

For example the above facility apparently plans to produce the SiF4 (silicon hexafluoride) as the byproduct instead of a fluoride salt.  As mentioned SiF4 is typically used to make high purity silicon for electronic applications.

With regard to Manhattan Project I’m not sure where the de-conversion process took place and what form, e.g. fluoride salt, they produced at the time."

Are the Little Boy and Fat Man models at the BSM full scale?

Our replicas are full scale. Actually around 2005 ago we replaced our original models with two even better replicas that are more accurate in representing the appearances of the two weapons.  The two new versions, constructed of steel and fiber glass are actually ballasted with concrete to represent the actual weights of the original weapons. Not that we ever heft them.

How can we fix the ozone layer?

You asked a very interesting question about ozone and how can we fix the ozone layer.

It is true that lightning creates ozone. Any spark in air will do it. Ozone can also be created by certain forms of radiation. Ozone is a molecule of oxygen that consists of three atoms instead of the usual two. It has peculiar chemical properties, it is highly reactive, and at ground level it can be toxic to people and contribute to health hazards like smog.

Unfortunately, the ozone created by lightning is all in Earth's troposphere, below about 50,000 feet, the part of our atmosphere where weather happens and life flourishes. Fortunately, although thunderstorms are constantly happening all across Earth's surface, they don't create enough ozone to be much of a problem.

The ozone layer that protects organisms on the surface from ultraviolet radiation is in the stratosphere, above 50,000 feet. Here there is good and bad news, too. Ozone is created when oxygen absorbs the energy of ultraviolet light. So UV light makes ozone, and ozone absorbs even more UV light. Nature itself can take care of us, if we don't mess it up too much. That is the bad news. Some chemicals we have added to the atmosphere over many years react with ozone and break up the molecules. We have stopped using many of the nastiest ozone depleters but they break down very slowly and continue to destroy ozone. Eventually, we hope, these chemicals will wear out, and the stratosphere will be back to the way it once was, more or less. Human activity still continues, and we have to make intelligent decisions about risks.

While I was researching my answer, I found two interesting websites. http://www.weatherquestions.com/What_is_the_ozone_layer.htm has basic information about the ozone layer, and http://www2.epa.gov/sunwise/uv-index has an up-to-date ozone weather map.

Human battery exhibit

The exhibit you describe has four large metal plates, one each copper and aluminum on each side of a meter. The copper plate on the left is connected through the meter to the aluminum plate on the right and the other two plates are connected in the reverse direction. The meter measures micro amperes, or millionths of an amp of current, so it is very sensitive.

Placing one's hands on plates connected across the meter causes the needle to deflect. This is because we, the human, are acting as the electrolyte in a battery. The two metals have different affections for their electrons, and the one that is greedier steals electrons from the one more generous through our bodies. This causes an imbalance between the two plates which is corrected by the current through the meter.

A typical visitor gets a modest reading on the meter. Sometimes a person is able to easily pin the meter at one end of its range. There might be a number of reasons for this. Larger hands and greater pressure produce more current. Moister hands work better than dry hands. I don't know if this is a real affect, but I have an impression that it is common for women to get higher readings than men. I can't imagine an explanation for this, and I am pretty good at making stuff up. I doubt it is because the average man has a greater wingspan than the average woman, but I really don't know. There is also probably a day-to-day variation with an individual depending on personal chemistry, hydration, sweaty palms, etc. I have never studied that, either.

Some of my favorite questions are those I can answer, "I don't know."

How many babies were born in Post Office Box 1663?

This question sent us asking Alan, the Lab Historian, for help:

I received the following reply this afternoon from our historian. I am astounded! The 80 in the first year would mostly have been conceived off 'the hill.' The Manhattan Project arrived here in March. Many of the rest would have been the result of local efforts.

Quoth Alan:
"I haven’t been able to find an exact number, but you might find this quote from Jon Hunner’s, Inventing Los Alamos, helpful:

 'Eighty babies were born the first year, and ten newborns arrived every month thereafter' (p. 39)

 That’s essentially a shade under 300 babies born in Box 1663 during the war."

Stripes in video of atmospheric atomic bomb tests

We have been asked several times what are the vertical stripes in videos of atmospheric atomic bomb tests.

I wondered about this for a long time when I first came to the museum. The streamers you see in film of atmospheric nuclear weapons tests were smoke trails made by sounding rockets fired just before the detonation. They were used to make a sort of graph paper in the air for recording the propagation of shock waves and wind currents from the explosion.

A current project under way at Los Alamos uses something like confetti, numerous high definition video cameras, and super computers to try to build a three dimensional model of the turbulence downstream from a wind turbine tower. They are using the multiple points-of-view and the computers to track each individual speck of paper. I think the paper is dispersed upwind of the tower using a sounding rocket and a conventional firework explosive. Some technologies are just too much fun to leave on the shelf.

SOMA Cube

We are asked regularly about our puzzles. A visitor wanted more information about the SOMA Cube.

The puzzle you describe is called the Soma Cube. It was invented by Piet Hein, a very interesting mathematician. This Wikipedia entry scratches the surface.

We see many very reasonably priced versions of the cube on Ebay.

Once you have one, be sure you don't limit its use to making cubes, here is a link that leads to many Soma Cube puzzles.

It has been said that a person who works intensively with the pieces for two weeks won't need the blocks any more to solve puzzles. That we would like to see!

Impressions of Oppenheimer

How do Americans think about J. Robert Oppenheimer today? How do people in Los Alamos think about him?

My personal impression is that most Americans who know about him hold him in awe. I think most see him as a brilliant scientist. Fewer are aware that he served the country as an amazing administrator who came to Los Alamos on E. O. Lawrence's recommendation without a big reputation or even much experience managing. I think people who now think the atomic bombs should not have been used might feel ambivalent about Oppenheimer, but many of them still respect his scientific abilities. People also see him as a tragic victim of McCarthyism, if they know that story.

In Los Alamos he is revered. Some older people here remember him, and he enjoyed the respect and personal affection of many people at the laboratory in his day and in his later years. There are strong feelings about the security hearings, and most people here see the outcome as terribly unjust and even cruel. I don't think anyone here believes Robert Oppenheimer was ever a security threat.

If he didn't oppose it, Oppenheimer was not enthusiastic about the hydrogen bomb. He probably dragged his feet. Edward Teller was a proponent, impatient with Oppenheimer's views, a founder of Lawrence Livermore National Lab, and testified against Oppenheimer. Although he was a pretty colorful character, Teller is not fondly remembered here.  As is true with so many aspects of our history, this is a very complicated topic. To what extent Oppenheimer's communist connections played a role, vs. power struggles within the physics community and even in Congress and the military, as well as other factors that were involved, historians will never untangle the security hearings.

As to why the museum is named for Oppenheimer's successor, I will suggest two reasons.

Oppenheimer's name is all around Los Alamos. An award, a lecture series, a street, and several buildings all pay tribute to him. (Wouldn't you expect the Oppenheimer Science Museum to be found in the Oppenheimer Center?)

Norris Bradbury is credited with keeping Los Alamos Scientific (later National) Laboratory alive at a time when it is very possible the US government might have closed it. Many scientists, including Oppie, left shortly after the war to return to their university roles. Bradbury was director for 25 years, an extraordinary tenure, and was director when the original version of this museum opened. Bradbury as a person is also very fondly remembered by those who knew him.

ChemCam Question

What would happen if the ChemCam laser shot at a piece of glass?

ChemCam is a device on the Mars Science Laboratory rover, Curiosity. It consists of a powerful laser which is trained through a telescope on a mineral target, A tiny spot on the target is heated to a plasma, and flashes with wavelengths of light that give away its composition. The ChemCam telescope collects some of this light, relaying it to a fiber-optics cable to a series of spectrometers in the body of the rover. The spectrometers analyze the light and report their findings back to scientists on Earth.

We were asked this question by a student in one of our programs, and we asked our friend Roger Wiens, who is one of the co-principal investigators for ChemCam. Roger told us:

"These students have good heads on their shoulders! The laser would not spark on a piece of smooth glass. But if you roughen up the surface with sandpaper the glass would lose its transparency and you would get a spark."

We are reminded of the time we tried to roast a marshmallow in our solar furnace. The marshmallow is so white that it reflects the heat quite well. Then we tried rolling it in cocoa powder. . .

Trinitite

We are asked from time to time where one can get Trinitite, the glassy mineral caused by the test of the "Gadget" atomic device at Trinity Site on the White Sands Missile Range. For several years after the test, the material was poached from the site by the truckload. It was never officially distributed, and there is no guarantee that any glass called Trinitite is authentic without very exacting analysis well beyond this writer's understanding.
That said, we have been told that there is enough out there in circulation that it is unlikely that anyone would go to the trouble to try to make counterfeit Trinitite. As to where to buy it, we will leave that up to the resourcefulness of our readers.

Comparing Hardness of Rocks

We were asked how students can compare the hardness of different rocks, especially scoria and volcanic tuff.

To compare two different materials’ hardnesses, one approach is to try to scratch one with the other. We suspect, although we haven’t tried, that you will find the scoria scratches the tuff and not vice versa. This method is used by gemologists, who know that a rock that can be scratched by a common steel nail will be too soft to take a high polish. Steel is just about the perfect hardness to make this determination. Agate is harder than steel and polishes to a high luster, limestone is softer and remains dull no matter how long it is polished. A diamond should be able to scratch almost anything, and talc shouldn't scratch anything.

Ultimate Source Of Nuclear Energy

We have been asked during our energy program how nuclear energy fits into the mix when all of our other forms of energy derive ultimately from the sun.

The tie-in is actually pretty interesting. Most of the energy we use comes directly or indirectly from the sun, which is “burning” hydrogen created during the Big bang. Stars fuse hydrogen atoms into heavier elements only up to iron. The planets, and all the elements heavier than iron (further down the periodic table) are composed of stuff created in supernovae, dying exploding stars, that preceded the sun. Only a supernova is energetic enough to create the exotic and unstable elements up to uranium. So nuclear reactors, which run primarily on uranium, ultimately derive their energy also from stars, although not our sun.

Cross Puzzle with 4 pieces

You asked if the puzzle in TechLab with four pieces actually reassembles into one large square.

 Two small squares are easy.

The hint posted alongside this puzzle is that the square has twice the area of the cross. The only way this can be, using the same four pieces, is if the square has a hole in it with the same area as the cross. We will be the first to admit this is a sneaky solution.

In this case, the hole is actually the same shape as the cross. The drawing shows the cross pattern with one piece rotated into position as a corner of the square pattern.

Thorium Nuclear Power questions

We were pleased to get this question because we had just read an article about it. One of the challenges with thorium for reactor fuel is that it has been historically very expensive, monetarily and environmentally, to process. There is a project at LANL that has taken on thorium chemistry. It is called Th-ING, Thorium Is Now Green. This team has developed a much cleaner and much cheaper way to process thorium that avoids exotic chemistry, high temperatures, etc. It sounds very promising. There is a technical article about Th-ING at: http://www.lanl.gov/science/NSS/issue2_2011/story6full.shtml .

By the way, another development happening here is a program experimenting with sandwiches of materials with atom-thick layers of, for example, copper and niobium, that results in a sheet with not only extraordinary strength, but an ability to repair itself, or heal, from radiation damage. These materials may one day serve to shield or replace materials used in nuclear reactors today that become brittle with continued exposure to radiation.

"Work" and the scale of atoms

The word “work,” in physics has a special meaning, and is, as you said, defined as force multiplied by distance. Yes, if the object we are working on doesn’t move, we are not doing any work. This goes against the normal every day usage of the concept work. I sat all day today working at my computer, but I did very little physical “work.” There are a number of words that can get us tangled up like this. There is a wonderful glossary of misused science terms at http://www.lhup.edu/~dsimanek/scenario/physlang.htm

About things the size of atoms. An atom is less than one ten-billionth of a meter across. (Squeeze a meter stick into a millimeter on a second meter stick, and then squeeze the second meter stick into another millimeter, and the smallest meter stick can measure ten or twenty atoms across one of its millimeters!) If an atom were the size of a big football stadium, a proton or a neutron would be about the size of a tennis ball an entire nucleus may be the size of a soccer ball. At that scale an electron would still be nearly invisible, maybe actually invisible, but in any case still incredibly tiny. As I understand it, the strings people talk about in “string theory” are about as much smaller than an electron as the electron is smaller than the atom. Atoms are too small to see with light, so it is small wonder (ahem) that we have no direct evidence of strings.

Technology advances, though, and each step along the way, every lesson we learn, every question we ask opens up a world of new mysteries. The string theorists hope that the Large Hadron (Protons and neutrons are hadrons.) Collider in Switzerland and France will lead them to data confirming or at least supporting the theory. It is good to know there will still be questions and more bigger machines to build after the LHC is running. :-)