It’s happened to me. I’m sitting, calmly enjoying a sandwich outside on a bench, and then …
A seagull swoops in and tries to steal my food.
It’s terrifying. Seagulls are scary, especially up close and especially in Dundee, where I used to live and frequently sit outside eating something or the other. They have mean eyes.
I remember the seagulls in Dundee being quite peculiar. An anecdote: I was walking along the sidewalk, edging close to a corner where a seagull was digging through a ripped trash bag. When I was a few meters away, the seagull looked up and did this little walk away from the bag, pretending as if they weren’t just digging through trash. After I passed the corner, I glanced back and saw that they’d done a u-turn and went back to digging.
Okay, maybe I’m giving the bird too much of a personality. But it was weird.
Back to the food stealing; a research conducted at the University of Exeter showed that if you stare at a gull, it is less likely to steal your chips (for US readers: french fries which are totally not from France but from Belgium and stop calling things the wrong name and, never mind, I’m okay).
Granted, the study had a limited scope. They tried to test 74 gulls, but more than half of them flew away. And it is likely that a lot of seagull related crime is due to a few bad seeds and most seagulls are perfectly happy leaving you and your food alone and digging through trash for snacks.
Nevertheless, seagulls that were “looked at” while they were approaching food, were a lot less likely to touch that food. In fact, only a quarter of seagulls that were being watched while they tried to approach and eat food actually touched the food.
Maybe they were just scared of getting caught while committing food theft. Maybe they hate the color of our eyes. Maybe our stare is truly terrifying (I certainly know a few people with a scary stare). But next time you see a seagull approaching your food, give them the death stare. Perhaps your meal will be saved.
There are two identical twins. One of them travels through space in a high-speed rocket. When they return home, the Earth-bound twin has aged more. This is a result of special relativity. Very briefly, this is due to time slowing down as higher speeds are reached, and why Matthew McConaughey returned to Earth only to find his 90-something year old daughter on her dying bed.
This thought experiment has long been exactly that, a though experiment. But recently, we actually were able to learn what happens to twins when one is in space (granted, not in a high-speed rocket, but on the ISS) for almost a year, while the other twin stays on Earth.
Real Space Twinsies
On March 27 2015, astronaut Scott Kelly arrived at the International Space Station (ISS), while his brother, astronaut Mark Kelly, remained on Earth. (One can have a discussion on who was the luckier of the two.) They did the same activities, ate the same things, and followed the same schedule*, the only difference being that Scott was 400 km from the Earth’s surface, travelling at a speed of 7.66 km/s, while Mark was 0 km from the Earth surface, travelling at a speed of merely 460 m/second, as we all are.
340 days later, March 1 2016, Scott returned to Earth. For the full duration of his time on the ISS, as well as after his return, numerous samples were collected and tests were conducted to monitor his health and compare the physiological and biological changes that happened as a consequence of spacelife. Using his twin brother, a perfect genetic duplicate, as a control.
The effects of space
There are many “unusual” aspects about living in space, compared to living on Earth, including the odd noises of the ISS, the isolation (Scott was in contact with a mere 12 people during those 340 days), the ultra-controlled environment, a disruption of the normal body clock (imagine perpetually being jet-lagged because of constant switching of time zones), living in micro gravity and the excess of radiation.
An ultra-combined effort, i.e. a major collaboration between a lot of different labs that looked at all possible aspects of physiological and biological function, the effects of 340 days in space (in this specific set of twins) was published last month. There are a lot of changes that occur to the human body in space, some more severe than others.
There are some changes that don’t really matter much, like changes in the gastrointestinal microbiome and changes in biomass, which were affected during Scott’s time in space, but rapidly returned to normal after he returned. Not much to worry about.
Mid-level risks included known effects of living in microgravity such changes in bone density (you don’t really need to use your skeletal muscles while floating around) and changes in how the heart pumps around blood (you don’t need to fight gravity to pump blood to the head). NASA already knows this and therefore has a rigorous rehabilitation program for returning astronauts to re-acclimatize to Earth’s gravity.
However, it’s the high-risk findings that we all have to worry about, which a mostly due to prolonged floating and prolonged radiation exposure. Due to changes in air pressure as well as that thing I mentioned about blood pumping, a lot of astronauts experience ocular issues after their return, a risk that only increases with increased dwell time off-Earth. This can severely compromise vision. There is also evidence of some cognitive decline. Both those aspects are worrying in the light of long term space travel, we would hope that space-explorers can see and think clearly while carrying out dangerous tasks in dangerous conditions. And that’s without considering a final severe risk…
Who’s the oldest twin?
In addition, the radiation that Scott experienced on ISS is pretty much equivalent to 50 years of normal exposure on Earth. This causes significant genomic instability and DNA damage, and consequentially an increased risk of developing cancer.
One example of this genomic instability has to do with telomeres**. Telomeres are bits of DNA that cap the end of chromosomes. Every time a cell divides, and in the process duplicates its whole DNA library, the telomeres get shorter. When they get too short, the cell can no longer divide. This is something that happens naturally during aging: shortening of telomeres phases out cells until they can no longer divide. Eventually, this leads to cell death.
1 year of space had an odd effect on Scott’s telomeres. Some of them grew longer, while others showed shortening. However, the lengthened telomere returned to normal after Scott’s landing on Earth, while the shortening persisted. So even though Scott was the space twin in our paradox, he seems to have ended up aging faster than Mark…
A lot happens to a body in space
Overall, the results are pretty surprising, prolonged living in space had more of an effect on the human body than researchers expected. And there is probably a lot more to learn, even just with the data collected from Scott and Mark.
On one hand, the twin study showed how resilient and robust the human body is. 91.3% of Scott’s gene expression levels returned to his baseline level within six months of landing, and some of the changes that occurred to his DNA and microbiome were no different than what occurs in high-stress situations on Earth. That’s amazing, the human body has not evolved to survive in space, but it seems to do pretty well considering how outlandish the conditions are!
On the other hand, the prolonged exposure to microgravity and high radiation does have severe effects on the human health, leading to increased risk for compromised vision, cardiovascular disease, and cancer development. Even with the rigorous preparation and rehabilitation programs astronauts go through before and after spaceflight, some of these effects will be impossible to avoid.
The massive study, combining the effort of 84 researchers in 12 different universities is a feat of collaboration (though nothing compared to the black hole telescope, if I’m honest) and it’s definitely a first that the genomes of space vs. Earth could be compared with a true genetic control. This compiled study, and the many pieces of research that are expected to be published in the next year with the results from the individual studies, provide crucial insight on the effects of space in the long term. If we think that it takes approximately 1 year for a return journey to Mars, this research is valuable for the health of future astronauts and mankind’s ambition to explore further into space.
Want to know more? Watch NASA’s video on the three key findings, or read more in the Science paper or the NASA website (links below).
Markus Löbrich and Penny A. Jeggo. Hazards of human spaceflight. Science 364 (6436) p. 127-128. 2019. DOI: 10.1126/science.aaw7086
Francine E. Garrett-Bakelman, et al.The NASA Twins Study: A multidimensional analysis of a year-long human spaceflight. Science 364 (6436) eaau8650. 2019. DOI: 10.1126/science.aau8650
Cover image: The International Space Station crosses the terminator above the Gulf of Guinea, image credit NASA
*I remember reading this somewhere, but I cannot find the source anymore. It is thus possible that Mark just went about his normal life. Regardless, it is amazing that NASA had the opportunity to do this experiment with a perfect genetic control.
** Fun fact, my spelling check does not know the word “telomeres” and suggests that I mean “omelettes”. Well, I guess they both get super scrambled up in space? (Eeeeh for an inaccurate joke, sorry).
It goes without saying that 3D printing is cool*. The ability to think up any three dimensional structure, design it in a 3D design software and have it materialize blows my mind. Granted, I’m making it sound like it’s a very easy and fast process and I know that’s often not the case, but I also know that for a lot of engineering and physics laboratories, the ability to relatively quickly print a model or prototype for anything is extremely useful. In addition, it’s an amazing educational resource. You can print model organs, molecular structures, planets, … and have something physical to show or throw around during a science demo.
Just to name a few reasons why 3D printing is cool.
What is possible even cooler is the potential of printing tissues and organs. And now, for the first time according to a group of researchers in Tel Aviv, it has happened: a complete 3D heart was printed.
They started with some cells isolated from a sheet of fatty tissuefrom a human patient. These cells were reprogrammed to what’s called pluripotent stem cells. Pluripotent stem cells have the potential to give rise to many different cell types , depending on the biochemical cues they get – for example by changing the formulation of the culture media, which contains nutrients, hormones and other components to “feed” the cells.
In this case, the cells were driven towards being heart muscle cells and blood vessel cells. By mixing these cells with a personalized hydrogel, consisting of collagen (remember, from the reindeer eyes?) and glycoproteins (proteins have a sugar molecule connected to it), the researchers created a “bioink”, a material that could be used to print cardiac tissue in the same way a 3D printer prints 3D structures using a plastic “ink”.
While the 3D printed heart – currently around the size of a rabbit’s heart – cannot beat yet, the possibility to be able to print custom organs, starting from a patient’s own cells and therefore eliminating an immune response, is of major importance for medical applications. To enable heart function, the heart cells would have to be taught how to contract in an organized manner, and create a beating heart.
Beating has already been achieved in heart organoids. Organoids are little mini-organs grown in a petri dish, that mimic the organization and function of an organ in a living organism. The difference between 3D printed organs and organoids, is that organoids are allowed to form their own structure and cell types, driven by the media cocktail they are given, while 3D printing positions already differentiated cells in a 3D scaffold. Heart organoids, starting from one or a few reprogrammed cells, grow into structured groups of cells that spontaneously start beating.
These organoids, however, don’t really mimic the structure of the heart unless you “force” structure by growing these mini-hearts in a mold, basically geometrically confining the cells to form a predefined structure.
A model of a pumping heart was developed last year, creating an in vitro biomimetic system that could help with drug discovery and studying cardiac diseases. While it doesn’t look as much as a heart as the 3D printed one developed by the Israeli research group, it’s still pretty amazing to watch this little blob of tissue beating under electrical stimulation:
In any case, I hope to see a combined version of all of the above: a 3D printed, functional heart. Nevertheless, this first (though debatable if they actually were the first) 3D printed heart is pretty awesome and has a lot of potential applications in medicine and clinical research. Not to mention that it looks pretty cool:
Noor N., Shapira A., Edri R., Gal I., Wertheim L., Dvir T. 3D Printing of Personalized Thick and Perfusable Cardiac Patches and Hearts. Adv. Sci. (2019), 1900344. https://doi.org/10.1002/advs.201900344
Ma Z., Wang J., Loskill P., Heubsch N., Koo S., Svedlund F.L., Marks N.C., Hua E.W., Grigoropoulos C.P., Conklin B.R., Healy K.E. Self-organizing human cardiac microchambers mediated by geometric confinement. Nat. Comm. 6 (2015), 7413. https://doi.org/10.1038/ncomms8413
Li R.A., Keung A., Cashman T.J., Backeris P.C., Johnson B.V., Bardot E.S., Wong A.O.T., Chan P.K.W., Chan C.W.Y, Costa K.D. Bioengineering an electro-mechanically functional miniature ventricular heart chamber from human pluripotent stem cells.Biomaterials 163 (2018), 116-127. https://doi.org/10.1016/j.biomaterials.2018.02.024
*Sudden realization that most (if not all) of this blog is me saying “Hey, did you hear about this science thing, it’s really cool!!”
Here’s a riddle for you: what hangs in every chemistry class in middle and high school, leads to the creation of several nerdy t-shirts, and celebrated is 150th birthday yesterday?
Okay, it’s not a very funny riddle. Nor is it a very difficult one. The answer is: the periodic table of elements, first published on the 6th of March 1869 – exactly 150 years minus-one-day ago – by the Russian chemist Dmitri Mendeleev.
From Alchemy to Chemistry
In the olden days, we would have turned to alchemists to ask our questions about fundamental elements and what stuff makes up stuff. Even though alchemy was not really a “science” in the pure sense of the word – it relied heavily on spiritualism, philosophy and even magic – it set the stage for what would later become chemistry. And while alchemists were mostly trying to turn random metallic rocks into gold, or brew an elixir for eternal life, they were the first that attempted to identify and organize the different substances occurring in nature. The Elements.
The earliest basic elements were considered to be earth, water, air and fire. The discovery of what we might call “chemical elements” really kicked off in 1669 in Germany, by a merchant by the name of Henning Brand. Like many chemists-avant-la-lettre (alchemists), he was trying to discovery the Philosopher’s stone. However, like many muggles, he was not acquainted with Nicolas Flamel and did not succeed (Side note: Nicolas Flamel was actually based on a real person!). In stead, while distilling urine – as you would while trying to create eternal life – he discovered a glow-in-the-dark substance: phosphorous. And with that, the element finding had begun.
Chemistry can be considered to have originated in 1789, when Antoine-Laurent de Lavoiser wrote what is said to be the first modern chemistry textbook. In this book, he defined an element as a substance that can not be broken down to a simpler substance. A fundamental particle. This definition lasted until the discovery of subatomic particles (electrons, protons and neutrons) in the 1930s. Lavoisier’s list of elements included things like oxygen, hydrogen and mercury, but also light.
Let’s glaze over most of the 19th century, where multiple different scientists realized that the atomic weights of elements were multiples of that of hydrogen (William Prout) and how there was a certain periodicity in terms of physical and chemical properties when the elements were arranged according to their atomic weights (Alexandre-Emile Béguyer de Chancourtois). The early attempts to classify the elements were based on this periodicity, and eventually, our Mendeleev came along.
The Russian chemist Dmitri Mendeleev is the father of the modern periodic table. In fact, in Belgium, we call the periodic table of elements “Mendeleev’s table of elements”. After (allegedly) playing “chemical solitaire” on long train journeys – quite common in Russia, I’m sure – he came up with a classification method based on arranging the elements by atomic mass and classifying them according to their properties. Elements in one group (column) have the same number of valance electrons: the number of electrons in the outer shell of the atom and available to react with other elements. Elements in the same column therefore from bonds with other elements in the same way, and form similar types of materials.
Because there were some gaps in the table – some atomic weights missing – he predicted the existence of elements that were yet to be discovered, and what their chemical properties would be. And this is what made his classification method so ground-breaking.
And indeed, in 1885 germanium was discovered, with properties – as predicted – similar to silicon. Same for gallium in 1875 (similar properties as aluminium) and scandium in 1879 (similar properties as boron), filling up some gaps in his periodic table.
The gaps are filled
Since 1869, the gaps in the periodic table have been filled, and new elements are discovered or created every few years adding to the high end of the table. The last update to the periodic table was in 2016, when the elements nihonium (113), moscovium (115), tennessene (117) and oganesson (118) were added to the list.
So today – okay, yesterday – we celebrated 150 years of chemical element classification, the anniversary of the periodic table of elements, and the collective pain of decades of highschoolers memorizing atomic masses and number of valance electrons.
It’s been the topic of a weighted discussion for quite some time, but today it has been decided: “Le Grand K” will no longer be used to define a kilogram.
“Le Grand K” is not a big box of Special K, but a platinum-iridium cylinder stored by the International Bureau of Weights and Measures in an underground vault in Paris that has defined a kilogram of mass since 1889. There are a few official copies, and many more copies, so each country has their own kilogram to calibrate to.
Last Friday (November 16th) the kilogram has been redefined so it no longer depends on a material object. Because a material object can be scratched, chipped or destroyed. Or stolen. Or accidentally thrown into the bin. And it can degrade – in fact, “Le Grand K” weighs about 50 µg lighter than its six official copies. You don’t really want to gold – ahem, I mean platinum-iridium – standard for weight to change in weight, right?
So now the kilogram will be defined based on a universal, unchangeable constant. Much better, I think you would agree. The constant of choice here is the Plank’s constant, a number that converts the macroscopic wavelength of light to the energy of individual constants of light. Representatives from 58 countries universally agreed on this new definition, so from next year, the kilogram will be constant forever.
The ampere (electrical current), the kelvin (temperature) and the mole (amount of chemical substance) have also been redefined. That means that all seven units in the International System of Units (S.I.) will be defined by universal constants:
unit of length
Originally defined as a 10-millionth of the distance between the North Pole and the Equator along the meridian through Paris, later as the distance between two scratches on a bar of platinum-iridium metal
Since 1983 defined as the distance traveled by a light beam in vacuum in 1/299,792,458th of a second, with 299,792,458 m/s being the universally constant speed of light.
unit of mass
Initially defined in terms of one liter of water, but since as a small ~47 cm3 cylinder stored in a basement in Paris.
Now redefined in terms of the Plank constant h = 6.62607015×10−34 J*s (J = kg*m2*s−2)
unit of time
Originally defined as 1/86,400th of a day
Since 1967 it has been defined as the time it takes an atom of cesium-133 to vibrate 9,192,631,770 times
unit of electrical current
Originally defined as a tenth of the electromagnetic current flowing through a 1 cm arc of a circle with a 1 cm radius creating a field of one oersted in the center
Now redefined in terms of the fixed numerical value of the elementary charge e (1.6602176634×10−19 C with C = A*s and second defined as above)
unit of temperature
The centigrade scale was originally defined by assigning the freezing and boiling point of water as 0 °C and 100 °C respectively. Note: absolute zero is the lowest temperature (0K = -273.16 °C)
Now redefined in terms of the Boltzmann constant k = 1.380649×10−23 J⋅K−1
unit to describe the amount of substance
Since 1967 defined as the amount of substance which has as many elementary particles as there are atoms in 0.012 kg of carbon-12.
Now one mole substance contains exactly 6.02214076 × 10^23 particles. This constant is known as Avogadro’s number*
unit to describe the intensity of light
Originally taken as the luminous intensity of a whale blubber candle in the late 19th century.
Since 1979 the light intensity of a monochromatic source that emits radiation with a frequency 5.4 x 1014 hertz and has a radiant intensity of 1/683 watt per steradian in a given direction **
So that was “this week in science.” I’ll leave y’all with a related joke: