Nature: Can It Save a Life?

by Harveen Kaur

The world as we know it is just like the human body. Just like how our body is made up of endless pieces of information that are unique to each one of us, the world is filled with endless versions of healing unique to generations, locations, and groups of people. Each piece of genetic material within us is there for a reason, and various medical philosophies in the world also exist for a reason. Now more than ever, alternative medicine practices rooted in ancient traditions have become more popular, and researching ethnomedicine has gained further acceptance in the medical community. Ethnomedicine is a subfield of medical anthropology that studies traditional and indigenous medicines, and this field specifically focuses on cultural philosophical perspectives in a less biomedical-based angle [1]. Such alternative forms of healing typically involve medicinal plants and herbs, many of which have been shown to contain important and novel pharmacologically active ingredients capable of treating several diseases [2]. This begs the question, what can plants do that the current field of medicine can’t do?

Throughout the course of multiple civilizations, ethnomedical practices have been the driving force of traditional Chinese medicine, Ayurveda medicine in India, Unani medical practices in Mughal India, Muti in Africa, and many more. Those who managed ethnomedical practices in traditional societies were often perceived as healers. These individuals were well-versed in herbalism, ethnobotany, and human nature based on anatomy, biochemistry, ethnopharmacology, and genetics [2]. In fact, the field of ethnobotany genomics is quite interesting because it conglomerates traditional and scientific knowledge through DNA barcoding, which examines certain individual genes to identify different cryptic plant species [3]. These species can play a tremendous role in preserving humankind through cures and ailments that developed nations had discarded thousands of years ago.

For instance, tuberculosis (TB) is one of the most prominent global infectious diseases that has caused significant morbidity and mortality to humans for decades [4]. However, there is still no official treatment plan to cure TB in any part of the world, and decades of research have failed to formulate a solution to this condition. But, what if we take a simple U-turn back to nature? Luckily, the Jakun community in Malaysia has been practicing various modes of TB treatment using 23 different species of medicinal plants — such as those classified within the Arecaceae (palm tree) and Rubiaceae (madder/flowering plant) botanical families — and they have succeeded on numerous accounts [4]. These plants were able to treat versions of an active TB disease and nine TB-related symptoms in a total of 100 participants through fresh preparations of traditional herbal remedies with plant roots rich in steroids, alkaloids, and volatile organic compounds [4]. Specifically, the plant-based concoctions were able to reduce and mitigate fever, cough, fatigue, respiratory distress and in some instances, helped treat active TB itself [4].  Now, take infectious diseases, congenital defects, facial and structural abnormalities, and poisoning [5]. These categories of conditions can be mapped to a respective ICD-9-CM code (a scoring system for metal, behavioral, and neurodevelopmental disorder), and their respective codes are high enough to reasonably infer a future association with plant species for ethnobotanical treatment according to Primary Health Care Manuals for Micronesian islands [5]. For example, the consumption of betel nuts was shown to make schizophrenic symptoms milder for males due to the presence of arecoline, an agent that activates a specific acetylcholine receptor in the body [5]. Understanding the importance of betel nuts may be helpful for enhancing social activity in schizophrenia patients, which begs the question if the effectiveness of betel nuts can also reduce the symptoms of other conditions that affect cognitive abilities [5].  Is this not enough?

If not, plants have yet to be appreciated for possibly their most astonishing ability - antiviral therapy. Various plants which are used for ethnomedical purposes, such as those from the botanical families mentioned earlier, are able to produce a large array of secondary metabolites, such as proteins, peptides, terpenoids, and phenolics, that are primarily used to shield away pathogens [2]. While these categories may stem from a section of medicine that has never been openly discussed before, plants have demonstrated the potential to prevent heavily contagious and antiviral-resistant qualities in HIV (human immunodeficiency virus) and SARS-CoV (severe acute respiratory syndrome associated coronavirus) strains [2]. Specifically, plant-derived products are currently being studied as potential reservoirs for medicines containing anti-HIV agents, and species that show great anti-HIV activity include Justicia gendarussa (willow-leaved shrubs) and Terminalia paniculata (kindal trees native to southwest India) [6]. For SARS-CoV, 25 Chinese herbal families, such as species from the Magnoliaceae (magnolia) and Polygonaceae (buckwheat) botanical families primarily found in Asia, were able to have great inhibitory effects for the ACE-2 receptor on certain viral strains which is required to infect human cells [7]. These discoveries, while astonishing, are very seriously underestimated in the realm of medicine that we live in, despite the fact that natural alternatives were once the only available and successful form of medical knowledge. 

To date, many individuals are unaware of the fact that the grass they mow each week, the trees that are cut down next to their homes, and the flowers that they unknowingly step on could all possibly be the reasons why an individual will one day be healthy. Currently, some organizations in developed countries have begun to formulate databases of medicinal and holistic plants and their plans to slowly grow them, but none of this is on a scale extensive enough to provide for a large population. Growing such plants has proven to be more feasible in comparison to modern medical practices, especially since developing countries implement these practices in the absence of a fully-functioning medical industry. Why, then, can’t developed countries do this too? What we know now regarding medical advancements, artificial intelligence, and costly treatment plans could all be replaced with the force of nature.

Works Cited

[1] Wimmer, R. Acupuncture Today, 2008.

[2] Mahapatra, A. D. et al. Science Direct. 2019, 35–61.

[3] Newmaster, S. G., & Ragupathy, S. Journal of Ethnobio. 2010, 6, 2. 

[4] Sabran, S. F. et al. Evidence-Based Complement. Altern. Med. 2016, 1-2. 

[5] Sharma, V., Law, W., Balick, M. J., & Sarkar, I. N. AMIA Jt. Summits Transl. Sci. 2016, 84–93

[6] Salehi, B. et al. International Journal of Molecular Sci. 2018, 19, 5.

[7] Benarba, B., & Pandiella, A. Frontiers in Pharmacology. 2020, 11.

Houston Humidity or Too Much Chocolate: What’s Making Your Migraines Worse?

by Anika Sonig

As college students who are regularly plagued with stress, irregular sleep schedules, and minor caffeine addictions, it is likely that some of us have experienced a headache at some point. However, could you imagine having extremely painful headaches that recur frequently, coupled with symptoms like nausea and vision impairment? 

Well, believe it or not, this describes about 12% of the global population, of which 1% is further classified as having chronic migraines—having 15 or more headaches per month.1 Usually, these migraines are caused by genetic factors, with about 90% of the affected population having migraines prevalent in their family history. Migraines are also more frequent in women, making up 85% of the general population of chronic migraineurs.2 The most common symptoms that migraineurs experience include: auras (visual disturbances where vision loss or impairment occurs), dizziness, photophobia (increased sensitivity to light), and phonophobia (increased sensitivity to sound).3

Interestingly enough, even though many migraineurs use various treatments, such as triptan drugs to increase serotonin and over-the-counter drugs like aspirin and ibuprofen, they still experience severe headaches and symptoms when major changes occur in their environment.3 This begs the question: do environmental factors such as the weather really affect headache frequency and symptom severity? This question was addressed by a study published in 2009 by Friedman et al. at the University of Rochester which revealed that about 50-75% of migraineurs are able to identify specific factors that provoke their headaches.4 This is largely due to their increased sensitivity to various environmental stimuli. Furthermore, a  case-crossover study at the Harvard School of Public Health conducted by Mukamal et al. with 7,054 patients showed that the most commonly identified environmental triggers include changes in the weather, high altitude and humidity, smoke, loud noises, and exposure to bright lights.5 

While these environmental factors are known to correlate with headaches, lifestyle changes, such as avoiding triggering food and beverages, have been shown to greatly reduce the frequency and severity of migraines. In fact, around 20% of migraineurs reported certain foods as being triggering.6 A food can qualify as a trigger when a headache occurs within 24 hours of consumption.7 The most common foods and beverages reported are unfortunately some of the things that we love the most: chocolate, cheese, citrus fruits, alcohol, and junk foods. The main reason why they affect us so much is because most of these triggers contain reactive chemicals that release various neurotransmitters, eventually resulting in the dilation or constriction of cerebral blood vessels often correlated with migraine pathology.8

One such chemical is caffeine, a stimulant that increases alertness and energy but can also induce insomnia. Additionally, withdrawal from caffeine may cause long-lasting migraines, since caffeine constricts the blood vessels in the brain.9 Phenylethylamine, a compound present in chocolate, can also alter blood flow in the brain and lead to a migraine.7,10 Another influential food additive is monosodium glutamate (MSG), often used to enhance the flavor of frozen foods, salad dressings, and other sauces. MSG has been found to constrict blood vessels in the brain and stimulate certain cellular receptors that cause the release of nitric oxide, a chemical that is linked with migraines.11 Thus, while these foods are extremely appealing, they contain chemicals that may alter the chemistry of our brain pathways and result in painful migraines. 

In order to identify triggering foods and beverages, migraineurs are advised to use a headache diary to keep track of meal times, changes to their diet, severity and frequency of headaches, and foods that they were eating or avoiding when the headaches occur. However, through all this pain, there is some good news for migraineurs: a study conducted by Bunner et al. through the Physicians Committee for Responsible Medicine in 2014 showed that a plant-based diet can reduce migraine pain.12 In this experiment, 42 migraineurs were randomly assigned to consume either a low-fat, plant-based diet or a placebo supplement. The study concluded that the intensity of the most severe headache pain decreased significantly when the migraineur consumed a plant-based diet. 

Knowing how various diets can affect migraine severity allows scientists to develop new strategies. These tools personalize migraine treatments based on a patient’s lifestyle and triggers. New research has also focused on understanding ways to limit the effect of migraine triggers from our environment, such as optimizing light intensity, humidity, and loud noises on migraine symptoms. 

So, if you experience migraines, make sure to sleep well, eat meals regularly, drink lots of water, destress, and maybe try not to eat too much chocolate because, as it turns out, when it comes to migraines, we truly are what we eat.

Works Cited

[1] “Chronic Migraine.” American Migraine Foundation, americanmigrainefoundation.org/resource-library/chronic-migraine/

[2] “Migraine Facts.” Migraine Research Foundation, migraineresearchfoundation.org/about-migraine/migraine-facts/.

[3] “Headache: Hope Through Research.” National Institute of Neurological Disorders and Stroke, U.S. Department of Health and Human Services, www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Hope-Through-Research/Headache-Hope-Through-Research.

[4] Friedman, Deborah I., and Timothy De Ver Dye. “Migraine and the Environment.” Headache: The Journal of Head and Face Pain, vol. 49, no. 6, 2009, pp. 941–952., doi:10.1111/j.1526-4610.2009.01443.x. 

[5] Kenneth J. Mukamal, Gregory A. Wellenius, Helen H. Suh, and Murray A. Mittleman. Weather and air pollution as triggers of severe headaches. Neurology, 2009; 72 (10): 922 DOI: 10.1212/01.wnl.0000344152.56020.94 

[6] Headaches and Food. Cleveland Clinic, 3 July 2019, my.clevelandclinic.org/health/articles/9648-headaches-and-food.

[7] “Migraine Triggers: Food and Drinks.” Migraine, migraine.com/migraine-triggers/food-and-drinks/.

[8] Skaer, T L. “Clinical Presentation and Treatment of Migraine.” Clinical Therapeutics, U.S. National Library of Medicine, 18 Mar. 1996, www.ncbi.nlm.nih.gov/pubmed/8733984.

[9] Ann I. Scher, Walter F. Stewart, Richard B. Lipton. Neurology Dec 2004, 63 (11) 2022-2027; DOI: 10.1212/01.WNL.0000145760.37852.ED 

[10] Smyres, Kerrie. “Which Foods Are Potential Triggers? Understanding Food Chemicals.” Migraine, 29 May 2018, migraine.com/blog/foods-potential-migraine-triggers-understanding-food-chemicals/.

[11] “Living With Migraine: Diet and Migraine.” American Migraine Foundation, americanmigrainefoundation.org/resource-library/understanding-migraineliving-with-migraine-diet-and-migraine/. 

[12] Bunner A, Agarwal U, Gonzales JF, Valente F, Barnard ND. Nutrition intervention for migraine: a randomized crossover trial. J of Headache and Pain. 2014;15:69. doi:10.1186/1129-2377-15-69. 

Far Out: The Application of Psychedelic Drugs and Hallucinogens for Depression and Anxiety Treatment

by Neha Tallapragada

LSD. Shrooms. Ayahuasca. Peyote. Dizzy spells. Trips. Hallucinations. These are all things we associate with psychedelics, which were popular during the Woodstock years but faded out of the zeitgeist due to various health and social stigmas. While modern medicine has made significant progress in treating mental illness, some people remain resistant to available treatments and still struggle with anxiety, depression, and other mental health issues. Today, these drugs may have an unexpected benefit for mental health conditions such as anxiety and depression. 

Beyond prescription medications like Lexapro and Zoloft, a new, controversial alternative has emerged–psychedelics. LSD, for instance, could be a feasible alternative for long-time patients who no longer respond to their current medications.1 These drugs could also be valuable for terminally ill individuals, as well as for those experiencing extreme levels of depression and anxiety. 

A Johns Hopkins University double-blind study from 2018 treated 51 randomly-selected cancer patients who had potentially life-threatening diagnoses and symptoms of anxiety and/or depression with psilocybin, an eminent psychedelic drug more commonly known as  “magic mushrooms,” to alter their emotional and mental states. The researchers compared the effects of administering a low “placebo” dose (1 or 3 mg/70 kg) of psilocybin to the effects of a higher dose (22 or 30 mg/70 kg), using a low dose to solve for any expectancy bias that might be introduced by the staff.  They found that the higher dose caused statistically significant decreases in both self-measured and clinician-measured anxiety. Over 80% of the participants reported that they had a greater satisfaction with life and overall well-being following administration of the higher dosage.2 These effects carried over to a 6-month follow-up period. Clinicians rated the measures of clinical response to depression and rate of symptom remission for depression at 78% and 65%, respectively. For anxiety, these rates were 83% and 75%. 

Scientists and psychologists are trying to uncover exactly what happens to your brain when you are under the influence of a psychedelic. Utilizing functional magnetic resonance imaging scans and a set of homological scaffolds (computational structures which signal differences between data sets), King’s College London researchers constructed a representation of brain activity under the influence of psilocybin. They discovered that the structure of brain activity is fundamentally altered to create a greater number of connections between cortical regions of the brain.3 This project gives proof that psychedelics indeed have the potential to have somatic effects on our mind that don’t just work on our psychology, but also on our actual brain anatomy–one more piece of evidence that compels one to look more seriously at these drugs and the effects they may have. 

A 2016 study from Washington University in St. Louis supports this fact. Scientists used multimodal neuroimaging to examine the change in brain activity after an LSD dosage. They found out two critical things. Firstly, they saw that there was greater functional connectivity in the visual cortex and in cerebral blood flow, which provides a potential explanation for the reported visual hallucinations experienced while on LSD, as well as supporting the King’s College London study on increased cortical connections. However, the St. Louis study goes one step further in studying the specific activity of the default mode network (DMN),  a cortical region that has been associated with memories and emotions. The DMN has been hypothesized to be connected to anxious feelings, as well as to the development of a “self-identity.” There were signs of decreased activity in the DMN, which correlated with an altered state of consciousness associated with an altered or “lost” sense of self, often deemed as “ego-dissolution.”4 Interestingly enough, these findings parallel similar relationships between psilocybin usage and “ego-dissolution.” By experiencing a loss of their “ego,” or their traditional self-perception, subjects may also be losing the feelings of anxiety and depression that accompany this sense of self. Researcher and author Michael Pollan sums up this inadvertent consequence: “We tell ourselves that we’re not worthy of love, that we can’t get through the next hour without a cigarette...psychedelic experiences shake us out of these patterns because suddenly we see them from a new perspective.”5 Sometimes, a new point of view may be all that one needs to break out of destructive thought patterns. Psychedelics may facilitate this shift. 

While drugs like LSD and psilocybin still retain the cultural stigma that they had back in the 1970s, they may prove to be a recourse for many, from the treatment-resistant to the terminally ill. Two of the studies discussed above demonstrate that, even if the specific correlation between brain connectivity and psychedelic usage has not been completely determined yet, there is significant evidence that suggests that psychedelics have the ability to rewire the structure of the human brain, which is hugely impactful in and of itself. In a safe and supportive clinical setting, these hallucinogenic “trips” could actually be more helpful than harmful. Further studies continue to reveal more and more about the ways in which these drugs can restructure our brain function. This would certainly flip the way we see the world upside down. 

Works Cited

[1] Begley, S. Scientists Are Starting to Test Claims About "Microdosing." Scientific American,  August 23, 2018. https://www.scientificamerican.com/article/scientists-are-starting-to-test-claims-about-microdosing/ (accessed October 2019). 

[2] Griffiths, R. R., Johnson, M. W., Carducci, M. A., Umbricht, A., Richards, W. A., Richards, B. D., . . . Klinedinst, M. A. Journal of Psychopharmacology. 2016, 30, 1181-1197. 

[3] Petri, G., Turkheimer, F., Carhart-Harris, R., Nutt, D., Hellyer, P. J., & Vaccarino, F. The Royal Society. [Online] 2014. https://doi.org/10.1098/rsif.2014.0873

[4] Carhart-Harris, R. L…..Nutt, D. J. Proceedings of the National Academy of Sciences of the United States of America. 2016, 113, 4853-4858. https://doi.org/10.1073/pnas.1518377113

[5] Illing, S.). Why Psychedelic Drugs Could Transform How We Treat Depression and Mental Illness. Vox Media, August 25, 2018.https://www.vox.com/science-and-health/2018/5/21/17339488/psychedelics-mental-health-michael-pollan-lsd-psilocybin (accessed October 24, 2019).

More Than Meets the Mask: The Controversy of Face Masks in the COVID-19 Pandemic

by Vincent Lai

In a matter of months, the world has been overtaken by the coronavirus disease 2019 (COVID-19) pandemic. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19, spreads from person to person through droplets or direct contact and can cause symptoms including cough, fever, muscle pain, difficulty breathing, and even pneumonia [1]. Furthermore, asymptomatic carriers help spread the virus even more effectively because they can still infect others despite showing no symptoms [1]. The many challenges people must face during the COVID-19 pandemic include loneliness, financial burdens, and bereavement [2]. To cope, the world has drastically changed. Hand sanitizer dispensers are stationed at nearly every wall. Hugs and handshakes are relics of the past. Pulling on a face mask before leaving the house has become second nature.. Although face masks have been recommended as a protective measure against COVID-19, their use has been met with considerable controversy, especially in the United States [3]. To protect the general public during the pandemic, we must consider the effectiveness of face masks, the specific reasons that make them so controversial, and ways to increase the public’s willingness to wear face masks.

One of the reasons that face masks are so controversial is because of the belief that they are not effective in reducing or preventing the spread of COVID-19. However, researchers have found preliminary evidence to suggest that this may not be the case. For example, when using model simulations of New York, Eikenberry et al. (2020) found that an 80% adoption of moderately-effective masks had the potential to prevent 17-45% of projected deaths over two months as well as decrease the daily death rate by 34-58% [4]. Researchers have also looked beyond models to find evidence for the effectiveness of face masks. In a study looking at the relationships between mask-wearing and COVID-19 cases in different areas, Cheng et al. (2020) compared the Hong Kong Special Administrative Region (HKSAR), which practices community-wide mask-wearing, with countries such as the United States (U.S.) where mask-wearing was not widely adopted in the community at the time of the study [5]. They found that the incidence of COVID-19 in HKSR was lower than that of Spain, Italy, Germany, France, the U.S., and the United Kingdom (U.K.) [5]. By preventing the spread of COVID-19, face masks have the potential to slow infection rates and prevent deaths.

With evidence that face masks are effective in helping control the spread of COVID-19, their ineffectiveness is not sufficient to explain the controversy surrounding face masks. Researchers have identified a number of other potential reasons that people may object to wearing face masks. One of these reasons is physical discomfort—specifically, headaches and adverse skin reactions such as dry skin, itching, and rashes can result from wearing face masks for prolonged periods of time [6,7]. Additional, psychological reasons also exist as Scheid, Lupien, Ford, and West (2020) describe how face masks threaten three things: people’s sense of freedom, their need to relate to others, and their ability to control their circumstances [3]. Specifically, face masks may cause people to feel that their freedoms are restricted and create divisions between people of different opinions towards mask-wearing, which can be exacerbated by mixed messages regarding mask-wearing [3]. Face masks may also hinder forming empathetic connections since they cover the mouth, which is important for recognizing emotions [8]. The importance of the mouth in emotion recognition was supported by a study where participants were instructed to assign emotions to covered faces that were sequentially unmasked, where Wegrzyn et al. (2017) found that the parts of the face that were most important for recognizing emotion were the eye and mouth regions [8]. Finally, compliance with mask-wearing may also be influenced by people’s trust in the government, and people who do not trust their government may be less likely to wear masks [9, 10]. In a study looking at data from the 2014 Taiwan Social Change Survey, Chuang et al. (2015) found that respondents who reported having higher general trust in their government were more likely to have the intention to wear a face mask when encountering a potential influenza pandemic [10]. 

Despite the many reasons that lead people to oppose mask-wearing, people must comply with mask-wearing mandates and policies to protect themselves and others from COVID-19. One way to increase compliance is to establish a mandatory mask-wearing policy rather than a voluntary one. In a study looking at German participants, Betsch et al. (2020) found that a mandatory mask-wearing policy increased compliance despite not being highly accepted and that mask-wearing was related to other protective behaviors such as physically distancing from others, handwashing, and avoiding handshakes [11]. They also found that a voluntary policy was associated with less compliance because the policy was seen as unfair since some people may comply while others may not [11]. Furthermore, a voluntary policy could increase the stigmatization associated with not wearing a face mask, which could potentially lead to further polarization and conflict [11]. Meanwhile, a widespread mandatory policy may help establish mask-wearing as a social norm. In fact, Olivera-La Rosa et al. (2020) found that during the COVID-19 pandemic, people found masked faces more trustworthy and more socially desirable than the same unmasked faces [12]. Following a mask-wearing norm may also decrease anxiety related to wearing masks [13]. In a study of Japanese participants, Nakayachi et al. (2020) found that  Finally, mask-wearing should be used in addition to other practices such as physically distancing to maximize its effectiveness in helping control the spread of COVID-19 [4]. 

Looking forward, efforts should be directed at increasing compliance to mask-wearing policies. Progress has already been made; in January of 2021, U.S. President Joseph Biden issued orders requiring mask-wearing on public transportation and on federal property [14, 15]. However, there is still much more work to be done. As of March 2021, a number of states have stopped requiring masks [16]. Among these states are Texas and Mississippi, where Governors Greg Abbott and Tate Reeves respectively have ended mandates requiring their states’ residents to wear face masks, citing declining cases and the increasing availability of COVID-19 vaccines [16]. These decisions may put even more people in danger and reverse the progress that has been made. To prevent even more deaths from COVID-19, state and local governments must instead endorse policies that protect people from the virus, including mask mandates. Businesses should also continue to enforce their own protective policies, including mask-wearing and physical distancing, to protect their employees and customers while reconsidering serving those who do not comply with their policies. 

References

[1] Lai, C., Shih, T., Ko, W., Tang, H., Hsueh, P. Int. J. Antimicrob. Agents. 2020, 55, 105924. 

[2] Marmarosh, C. L., Forsyth, D. R., Strauss, B., Burlingame, G. M. Group Dyn. Theory Res. Pract. 2020, 24, 122-138.

[3] Scheid, J. L., Lupien, S. P., Ford, G. S., West, S. L. Int. J. Environ. Res. Public Health. 2020, 17, 6655.

[4] Eikenberry, S. E., Mancuso, M., Iboi, E., Phan, T., Eikenberry, K., Kuang, Y., Kostelich, E., Gumel, A. B. Infect. Dis. Model. 2020, 5, 293-308.

[5] Cheng, V. C., Wong, S., Chuang, V. W., So, S. Y., Chen, J. H., Sridhar, S., To, K. K., Chan, J. F., Hung, I. F., Ho, P., Yuen, K. J. Infect. 2020, 81, 107-114.

[6] Lim, E. C. H., Seet, R. C. S., Lee, K.-H., Wilder-Smith, E. P. V., Chuah, B. Y. S., Ong, B. K. C. Acta Neurol. Scand. 2020, 113, 199-202.

[7] Hu, K., Fan, J., Li, X., Gou, X., Li, X., Zhou, X. Medicine (Baltimore). 2020, 99.

[8] Wegrzyn, M., Vogt, M., Kireclioglu, B., Schneider, J., Kissler, J. PLoS ONE. 2017, 12.

[9] Condon, B. J., Sinha, T. Health Policy. 2010, 95, 50-56.

[10] Chuang, Y., Huang, Y., Tseng, K., Yen, C., Yang, L. PLoS ONE. 2015, 10, e0122970.

[11] Betsch, C., Korn, L., Sprengholz, P., Felgendreff, L., Eitze, S., Schmid, P., and Böhm, R. Proc. Natl. Acad. Sci. U.S.A. 2020, 117, 21851-21853.

[12] Olivera-La Rosa, A., Chuquichambi, E. G., Ingram, G. P. D. Pers. Individ. Differ. 2020, 166, 110200.

[13] Nakayachi, K., Ozaki, T., Shibata, Y., Yokoi, R. Front. Psychol. 2020, 11, 1918.

[14] The White House. https://www.whitehouse.gov/briefing-room/presidential-actions/
2021/01/20/executive-order-protecting-the-federal-workforce-and-requiring-mask-wearing/ (accessed Feb. 10, 2021).

[15] The White House. https://www.whitehouse.gov/briefing-room/presidential-actions/
2021/01/21/executive-order-promoting-covid-19-safety-in-domestic-and-international-travel/ (accessed Feb. 10, 2021).

[16] Shammas, B.; Wan, W.; Fowler, S.; Moravec, E. ‘Masks required’ signs are coming down after Texas, Mississippi lift coronavirus restrictions. The Washington Post, Mar 4, 2021. https://www.washingtonpost.com/health/2021/03/03/texas-mississippi-covid-restrictions-masks/ (accessed Mar 7, 2021).

From Dust to Dust: The Life Cycle of Stars

by Michelle Sekili

Have you ever wondered how there came to be billions and billions of stars in the sky? Or why some stars violently explode, while some just quietly fade out of existence? The answer to these questions lies in the life cycle of a star, a long but magnificent journey. It all begins inside a nebula. 

Nebulae are the nurseries of stars. They are large, colorful clouds of cosmic dust and gases. One of such is the Orion Nebula, whose beautiful colors are formed by neutral and ionized gas particles of elements such as hydrogen and oxygen drifting in the cloud. Inside of a nebula, significant turbulence causes dust and gases to pile up unevenly into a central clump. When the clump is massive enough, it begins to collapse under the pull of its own gravity. [1] For the next few million years, with enough heat and pressure, it continues to collapse, until the hot core in the center of a star—the protostar—forms. 

The star’s core is made up of mainly hydrogen. Therefore, when it gets hot enough, nuclear fusion begins. During fusion, the tremendous amount of heat and pressure in the core forces hydrogen atoms together and overcomes the natural repulsion of protons, creating helium. This fusion in the core releases an enormous amount of energy and outward gas pressure that counter the inward force of gravity. As long as the outward and inward forces are equal, a star remains the same in size. [2] Hydrogen fusion marks the beginning of the longest phase of a star’s life: the Main Sequence stage. In fact, stars spend about 90% of their lives in this stage and most of the stars in the universe are in this stage, including our Sun. [3] It has been calculated that the Sun will remain in its Main Sequence stage for about 5 billion more years. [4] Specifically, this calculation predicts how long it will take hydrogen in the Sun’s core to run out and stop the fusion process, in which the star would transition into the next phase of its life cycle: the Red Giant Phase. 

In this Red Giant phase, a star is like an onion. It is composed of several layers: the center is a hot and dense helium core, while each additional layer is a shell containing hydrogen. When fusion stops in the core, the inward force of gravity overpowers the declining outward pressure, forcing the core to shrink. First, we’ll take a look at what happens in the shells, or layers surrounding the core of the star. The innermost layer of hydrogen begins heating up and eventually begins fusion. As fusion in the shells produces additional energy, the increased outward pressure overcomes the inward force of gravity, causing the less dense outer layers of the star to expand and cool down. Meanwhile, the helium produced by the shells’ hydrogen fusion is dumped on the shrunken core, thus increasing its mass. [5] Once the core reaches a high enough temperature, helium atoms now have enough energy to overcome their natural repulsion. Helium fusion begins, producing carbon and releasing remarkable amounts of energy and pressure. The process cascades through the layers: each layer takes turns carrying out hydrogen and helium fusions, and the pressure produced pushes the cooler, less dense outer layers further outward, resulting in the massive size of the Red Giant stars observed today. For example, when the Sun becomes a Red Giant, it will be about a hundred times its current size! [5] Red giants will continue to enlarge as long as there is helium in the core. Once this helium runs out, the star—depending on its mass—transitions to either one of two final stages.

Stars that are less than three times the mass of our Sun are considered low mass stars. In a star like this, fusion stops when helium runs out and all that is left in the core is carbon. The extremely dense leftover carbon core of a low mass star is called a white dwarf. In the outer layers, clouds of gas are only weakly held to the star by gravity, so they eventually drift away and form new planetary nebulae. Though fusion no longer produces an outward force in the core, the star does not collapse further because another new force balances out gravity. This force, called electron degeneracy pressure, is created when electrons, crammed in a small space, are forced into higher energy levels and thus move faster. [1] White dwarfs are relatively small—they are about the size of Earth—and lose their luminosity over time. Isolated white dwarfs will eventually fade quietly out of existence, dying a quiet and peaceful death. However, if a white dwarf happens to be orbiting another white dwarf, the stronger gravity of one white dwarf will suck up the mass of the other one and add to its own mass. Gravity from too much mass pushing down on the core will overwhelm the electron degeneracy pressure and crush the core in seconds. The core, then, explodes as a brilliant white dwarf supernova, marking the end of the star’s life. 

On the other hand, we have high mass stars—stars with mass greater than or equal to three times the mass of the Sun. These stars have enough gravity to continue fusion of elements heavier than carbon. Each time a fusion reaction occurs in the core or layers, the released outward pressure pushes the outer layers further, creating enormous stars known as supergiants. In supergiants, fusion reactions which produce oxygen, then silicon and other heavy elements in the core happen so quickly that the star becomes unstable. Nevertheless, when it is iron that makes up the core, fusing the heavy iron atoms together uses up more energy than it produces, and gravity pulling inward overcomes the opposing outward pressure. [1] The core collapses in a fourth of a second, becoming so dense that when the outer layers fall down on the core, they “bounce” off rapidly into space in a giant supernova explosion. In the remaining hyper-dense core, protons and electrons actually merge together to form neutrons. The core is now a neutron star. Similar to electron degeneracy pressure, neutron degeneracy pressure in neutron stars combats gravity. However, if gravity manages to overwhelm neutron degeneracy pressure, gravity wins the final battle of the forces and the star forever collapses on itself in what is known as a black hole. Meanwhile, the blown off outer layers of the supergiant become nebulae, where a cosmic recycling process occurs: gravity regathers remnants and debris to form new stars and planets.

Thus, after billions of years, the life cycle of a star comes to an end. Nonetheless, remnants of many stars live on in us. Supernovae explosions have created the elements and life as we know it. Even our planet and the oxygen we breathe were created in a high mass star supernova. There are bits of the stars inside us. In the words of famous astrophysicist Neil Degrasse Tyson, “we are stardust.” [6] When we are gone, the cycle continues, going from dust to dust.

Works Cited:

[1] Bolles, Dana. “Stars.” NASA, NASA, https://science.nasa.gov/astrophysics/focus-areas/how-do-stars-form-and-evolve. 

[2]“How Is a Star Born?” Scientific American, Scientific American, 6 Dec. 1999, https://www.scientificamerican.com/article/how-is-a-star-born/. 

[3] Zuckerman, Catherine. “Everything You Wanted To Know About Stars.” Science, National Geographic, 3 May 2021, https://www.nationalgeographic.com/science/article/stars. 

[4] Redd, Nola Taylor. “Red Giant Stars: Facts, Definition & the Future of the Sun.” Space.com, Space, 28 Mar. 2018, https://www.space.com/22471-red-giant-stars.html. 

[5]“Post-Main Sequence Stars.” Post-Main Sequence Stars, Australia Telescope National Facility, 21 July 2021, https://www.atnf.csiro.au/outreach/education/senior/astrophysics/stellarevolution_postmain.html. 

[6] Tyson, Neil deGrasse, and Gregory Mone. Astrophysics for Young People in a Hurry. W.W. Norton & Company, Incorporated, 2019. 

[7] “Infographic: Life Cycles of Stars.” 3.0—How Were Stars Formed? Khan Academy 2016,

https://cdn.kastatic.org/KA-share/BigHistory/KU3.0.9_Life_Cycle_of_Stars.pdf