Serendipity, when accidental discoveries happen
Stars and beyond
DNL 1S
AIM: To understand that scientific discoveries are not always the work of years of research. Even though scientists formulate and test their explanations of nature using observation, experimentation, theoretical and mathematical models, all scientific ideas are subject to change and improvement in how we understand them. For most major ideas in science, there is much experimental and observational confirmation. But every once in a while, there are accidental discoveries in science.
Example 1: discovery of quinine as an anti-malaria drug Document 1: Discovery of quinine The story behind the chance discovery of the anti-malarial drug quinine may be more legend than fact, but is nevertheless a story worthy of note. According to legend, a South American Indian who was suffering of malarial fever in a jungle high in the Andes needed desperately to quench his thirst. He found a small pool of water and drank his fill from it. The water was bitter-tasting, and he noticed that, nearby, stood one or more varieties of cinchona, a tree which grows from Columbia to Bolivia on humid slopes above 5,000 feet, and the bark of which the indigenous people knew as quina-quina. The man had unwittingly ingested quinine. The indigenous people thought the bark to be poisonous, but when this man’s fever broke, he brought news of the medicinal tree back to his tribe, which began to use its bark to treat malaria. Since the first officially noted use of quinine to fight malaria occurred in a community of Jesuit missionaries in Lima, Peru in 1630, historians have supposed that Indian tribes taught the missionaries how to extract the chemical quinine from the cinchona bark. In any case, the Jesuits’ use of quinine as a malaria medication was the first documented use of a chemical compound to successfully treat an infectious disease. To this day Quinine-based anti-malarial medication (which we can now fabricate in laboratories) are widely used as effective treatments against the growth and reproduction of malarial parasites in humans. 1. Do you know what malaria is? What is it due to? Cite one of the symptom. 2. Vocabulary : find equivalents in the passage for the following French words/expressions : Bon à remarquer
Etancher sa soif
Se désaltérer
Flaque d’eau
Involontairement
Pente
Composé chimique
Ecorce
3. Is quinine a natural, artificial and/or synthetic chemical compound? Justify your answer. 4. Make a summary of the text in three sentences or less.
Example 2: discovery of gamma-ray bursts Useful vocabulary A burst – Un sursaut, un éclat A blast – Une explosion To collapse – S’écrouler Mere – A peine quelque Intent on – Dont l’objectif est Afterglow – Les derniers reflets Magnitude – Ordre de grandeur Document 2: Discovery of gamma-ray bursts Gamma-ray bursts (GRB) happen when a massive star, at the end of its life, collapses onto itself (we say that it goes supernova). When they flash, they are as bright as a billion of billion stars. GRB have been happening for billions of years, but like many scientific discoveries, GRBs were discovered by accident. In the 1960s, during the cold war, military officers, intent on protecting America, launched a series of satellites to detect powerful blasts of nuclear energy. They found the blasts, but not where they expected! They were occurring in random places in the sky, and very frequently. The bursts never appeared in the same place twice. They lasted mere seconds, much shorter than bursts coming from nuclear weapons. In 1971, astronomers announced their discovery of gamma-ray bursts in our universe.
Document 3: The SWIFT space telescope Gamma rays are a type of electromagnetic wave (just like light) with a wavelength in the femto-meter range.
Gamma-ray bursts are one of the consequences of the death of a massive star. They last only a few seconds, but in that time, the amount of radiation energy the gamma ray produces is equal to the amount of energy our sun produces during its entire lifetime. And, since gamma ray bursts occur approximately once a day, there is evidence of a lot of explosive activity! Swift is a satellite designed by Penn State researchers and launched by NASA to study gamma-ray bursts. Launched in November of 2005, the satellite was named after the swift, a small, quickly moving bird. Catching a GRB is no easy task. The burst can appear from any direction without warning and can last for only a few milliseconds to just over a minute. So, the satellite has to move quickly and be in position to capture the data. According to NASA, no other satellite turns faster. The Swift satellite is comprised of three telescopes: the Burst Alert Telescope (BAT); the X-ray Telescope (XRT); and the Ultraviolet/Optical Telescope (UVOT). The BAT detects and locates the GRBs. Once one is identified, Swift repositions itself so that the other two telescopes can collect data on the afterglow of the burst. All the data is transmitted to earth and is available publicly within 30 minutes of the GRB detection. 1. What is a gamma-ray burst? 2. How long does it last? Give a range in magnitudes of seconds. 3. Why did the military officers discover the GRBs before the scientists? What were they looking for? 4. Why do you think researchers named this satellite “Swift”? 5. Explain what Swift does and how it works. 6. Why does Swift do observations at X-ray and ultraviolet wavelength?
