Tracking the Migration of a Strange Animal: The Scientist

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iStock

We have a lot of outdated notions of what a scientist looks like. Among them: that scientists stay in one laboratory room, bent over the same Bunsen burners, for decades. Now a new study suggests that researchers are far more mobile than we realized—and that this mobility is hugely beneficial for science. The research is part of a special issue of Science focused on human migration.

“Ideas do not carry passports,” the Science editors note in their introduction to the issue. “But lines on maps, as well as policies and pressures that influence who does or does not cross them, can be powerful determinants of whether and how ideas and skills align to advance scientific discovery and technological and economic progress.”

Like the naked gecko, which squirms out of its skin when cornered, the movements of individual scientists are often difficult to keep hold of. There are so many of them, many with the same names, often affiliated with multiple institutions. And while there have been studies of scientists’ travels, these are conducted anonymously, which makes it impossible to track any one person’s migration patterns.

Fortunately, a nonprofit organization called ORCID is now making the process a whole lot easier by offering each researcher their own unique ID code. In the nine years since its launch, ORCID has registered more than 3 million scientists, each with their own story and dashed line across the globe.

This is great for researchers with common names. It’s also great for social scientists, who used the data to survey 17,852 scientists working in 16 countries to find out where their careers were taking them.


Graphic: G. Grullón and J. You/Science; Data: ORCID

The answer seems to be “everywhere, man.” Survey respondents were highly mobile, often moving among several countries as their research progressed. Many of these moves were driven by necessity, author John Bohannon writes in Science. “You spend your days at the border of human knowledge. Depending on the topic, only a dozen people may deeply understand your research—let alone help you push it further—and they are scattered across the world. For many, completing a Ph.D., doing postdoctoral research, and landing a permanent job all in one country is impossible. And so you wander.”

But rather than disrupting the scientific enterprise, the researchers found, migration actually seems to enrich the quality of research. Survey respondents who moved more often were more successful in their research and publication, and departments with higher proportions of migratory researchers thrived. Conversely, countries hostile to immigration—including a post-9/11 U.S.—have taken a hit.

More research is needed to confirm these findings. The survey participants were not a representative sample, rather a self-selected group of researchers who use ORCID. Like many online database users, they’re younger than average, and it’s not clear how this affects the study results.

But individual researchers say the trends mirror their own experience of migration and its benefits, both professional and personal.

“Living and working in another country … makes you more humane and understanding,” biological engineer Helena Pinheiro told Bohannon. At the same time, she says, “crossing borders has always left me with the wish that borders would cease to exist.”

Does Sound Travel Faster or Slower in Space?

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iStock/BlackJack3D

Viktor T. Toth:

It is often said that sound doesn’t travel in space. And it is true … in empty space. Sound is pressure waves, that is, propagating changes in pressure. In the absence of pressure, there can be no pressure waves, so there is no sound.

But space is is not completely empty and not completely devoid of pressure. Hence, it carries sound. But not in a manner that would match our everyday experience.

For instance, if you were to put a speaker in interstellar space, its membrane may be moving back and forth, but it would be exceedingly rare for it to hit even a single atom or molecule. Hence, it would fail to transfer any noticeable sound energy to the thin interstellar medium. Even the somewhat denser interplanetary medium is too rarefied for sound to transfer efficiently from human scale objects; this is why astronauts cannot yell to each other during spacewalks. And just as it is impossible to transfer normal sound energy to this medium, it will also not transmit it efficiently, since its atoms and molecules are too far apart, and they just don’t bounce into each other that often. Any “normal” sound is attenuated to nothingness.

However, if you were to make your speaker a million times bigger, and let its membrane move a million times more slowly, it would be able to transfer sound energy more efficiently even to that thin medium. And that energy would propagate in the form of (tiny) changes in the (already very tiny) pressure of the interstellar medium, i.e., it would be sound.

So yes, sound can travel in the intergalactic, interstellar, interplanetary medium, and very, very low frequency sound (many octaves below anything you could possibly hear) plays an important role in the formation of structures (galaxies, solar systems). In fact, this is the mechanism through which a contracting cloud of gas can shed its excess kinetic energy and turn into something compact, such as a star.

How fast do such sounds travel, you ask? Why, there is no set speed. The general rule is that for a so-called perfect fluid (a medium that is characterized by its density and pressure, but has no viscosity or stresses) the square of the speed of sound is the ratio of the medium’s pressure to its energy density. The speed of sound, therefore, can be anything between 0 (for a pressureless medium, which does not carry sound) to the speed of light divided by the square root of three (for a very hot, so-called ultrarelativistic gas).

This post originally appeared on Quora. Click here to view.

How Fossil Fuel Use Is Making Carbon Dating Less Accurate

iStock.com/Harry Wedzinga
iStock.com/Harry Wedzinga

The scientific process of carbon dating has been used to determine the age of Ötzi the Iceman, seeds found in King Tutankhamun’s tomb, and many other archaeological finds under 60,000 years old. However, as SciShow points out in a recent episode, the excessive use of fossil fuels is making that method less reliable.

Carbon dating, also called radiocarbon or C-14 dating, involves analyzing the ratio of two isotopes of carbon: C-14 (a radioactive form of carbon that decays over time) and C-12 (a more stable form). By analyzing that ratio in a given object compared to a living organism, archaeologists, paleontologists, and other scientists can get a pretty clear idea of how old that first object is. However, as more and more fossil fuels are burned, more carbon dioxide is released into the environment. In turn, this releases more of another isotope, called C-12, which changes the ratio of carbon isotopes in the atmosphere and skews the carbon dating analysis. This phenomenon is called the Suess effect, and it’s been well-documented since the ‘70s. SciShow notes that the atmospheric carbon ratio has changed in the past, but it wasn’t anything drastic.

A recent study published in Nature Communications demonstrates the concept. Writing in The Conversation, the study authors suggest that volcanoes “can lie about their age." Ancient volcanic eruptions can be dated by comparing the “wiggly trace” of C-14 found in trees killed in the eruption to the reference "wiggle" of C-14 in the atmosphere. (This process is actually called wiggle-match dating.) But this method “is not valid if carbon dioxide gas from the volcano is affecting a tree’s version of the wiggle,” researchers write.

According to another paper cited by SciShow, we're adding so much C-12 to the atmosphere at the current rate of fossil fuel usage that by 2050 brand-new materials will seem like they're 1000 years old. Some scientists have suggested that levels of C-13 (a more stable isotope) be taken into account while doing carbon dating, but that’s only a stopgap measure. The real challenge will be to reduce our dependence on fossil fuels.

For more on how radiocarbon dating is becoming less predictable, check out SciShow’s video below.

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