Science & Technology: November 2021 Current Affairs | Science & Technology for UPSC CSE

1. Computer Tomography

On Oct. 1, 1971, the first computed tomography picture — a CT scan – of the human brain was created.

Computer Tomography (CT)

• A CT scan is a diagnostic imaging technology used in radiology to provide comprehensive pictures of the body without causing any pain. 
• The tomographic (cross-sectional) pictures (virtual "slices") of a body are created by processing several X-ray data collected from various angles on a computer using reconstruction methods.

Does Computer Tomography Work?

• A small X-ray beam revolves around one region of your body. This generates a sequence of photos from various perspectives.

• This data is used by a computer to build a cross-sectional image. This two-dimensional (2D) scan reveals a "slice" of the inside of your body, like one piece of bread. 
• This procedure is repeated to obtain many slices. 
• To build a detailed image of your organs, bones, or blood arteries, the computer layers these images one on top of the other. 
• A surgeon, for example, would utilise this sort of scan to examine all sides of a tumour in preparation for a surgery.

Development of CT

• CT has proved to be a versatile imaging method since its inception in the 1970s. 
• CT is mostly utilised in diagnostic medicine, but it may also be used to create pictures of non-living things. 
• Allan M. Cormack, a South African American physicist, and Godfrey N. Hounsfield, a British electrical engineer, were jointly awarded the Nobel Prize in Physiology or Medicine in 1979 "for the creation of computer-assisted tomography."

Threats

• X-rays, which create ionising radiation, are used in CT scans. Such radiation has the potential to harm your DNA and cause cancer. 
• Children may be more vulnerable to ionising radiation.

2. Border Gateway Protocol (BGP)

An issue with the company's domain name system caused downtime on Facebook, WhatsApp, and Instagram. It all sprang from a BGP (Border Gateway Protocol) problem.

About Border Gateway Protocol

• Simply described, it is the protocol that runs or makes the internet function. 
• BGP is the technology that binds the internet together since it is a network of networks. 
• When BGP fails, internet routers are unable to determine what to do, resulting in the internet becoming unavailable. 
• The routers, especially the huge ones, maintain track of alternative possible routes for delivering network packets to the final possible source. 
• Facebook platforms were the last point of destination in this situation, and the BGP failure meant that Facebook was unable to inform other networks that it was online.

How BGP Works?

• The BGP is a type of organisation that oversees constructing and, more critically, maintaining maps that link to Google, Facebook, and YouTube. 
• So, if someone oversees creating and updating the map and makes a mistake, traffic — or users — will not be able to access that location.

How Did a BGP Issue Affect Facebook?

• A BGP update message notifies a router of any modifications you've made to prefix advertising or removes the prefix completely. 
• Facebook had made several routing modifications, and then routes were removed, and Facebook's Domain Name Server fell. ROLE OF DNS 
• DNS is the Internet's phone book. Domain names such as timesofindia.com or facebook.com are used to access information on the internet. 
• Internet browsers employ IP addresses, or Internet Protocol addresses, and DNS converts domain names to IP addresses so that browsers may access Internet resources. 
• BGP is the internet's postal service, if DNS is its phone book. 
• BGP identifies the best accessible pathways for data to travel when a user submits data on the internet.

3. James Webb Telescope

After years of delays, the James Webb Space Telescope is set to go into orbit on December 18, 2021, ushering in the next age of astronomy.

James Webb Space Telescope

• JWST is a NASA–ESA–CSA space telescope that will take over as NASA's flagship astrophysics mission from the Hubble Space Telescope. 
• It is the world's most powerful space telescope. 
• It will enable a wide range of astronomical and cosmological investigations, including the observation of some of the universe's most distant events and objects. 
• It will aid in the understanding of events such as the formation of the first galaxies and detailed atmospheric characterization of potentially habitable exoplanets.

Significance

• Some have termed JSWT the "telescope that ate astronomy." 
• It is thought to peer back in time to the universe's Dark Ages.

‘Dark Ages’ of The Universe

• Evidence suggests that the universe began 13.8 billion years ago with an event known as the Big Bang, which left it in an ultra-hot, ultra-dense condition. 
• Following the Big Bang, the cosmos began expanding and cooling. 
• The cosmos was a hundred trillion miles across one second after the Big Bang, with an average temperature of an astonishing 18 billion degrees Fahrenheit (10 billion C). 
• The cosmos was 10 million light-years vast and the temperature had dropped to 5,500 degrees Fahrenheit around 400,000 years after the Big Bang (3,000 C). 
• Space was filled with a smooth soup of high-energy particles, radiation, hydrogen, and helium throughout this epoch. 
• There was no framework to speak of. The soup thinned out as the expanding cosmos grew wider and colder, and everything faded to darkness.

How Will JWST Study This

• The Dark Ages came to an end when gravity created the first stars and galaxies, which then began to radiate light. 
• Astronomers want to learn more about this interesting and significant period of the cosmos but identifying first light is extremely difficult. 
• The initial objects were tiny in comparison to today's big, luminous galaxies, and they're now tens of billions of light years away from Earth owing to the universe's ongoing expansion. 
• In addition, the first stars were surrounded by gas left over from their birth, which behaved like fog and absorbed most of the light. 
• It took hundreds of millions of years for radiation to clear the fog. By the time it reaches Earth, this early light is quite dim.

4. Physiology Nobel for Work on Temperature and Touch

The Nobel Medicine Prize has been awarded to David Julius and Ardem Patapoutian of the United States for their findings on temperature and touch receptors.

What Did They Discover?

• In the late 1990s and early 2000s, David Julius and Ardem Patapoutian, discovered our bodies' touch detectors and the process by which they interact with the nervous system to recognise and respond to certain touches. 
• They identified molecular sensors in the human body that are sensitive to heat and mechanical pressure and allow us to "feel" hot or cold, as well as the contact of a sharp item on our skin. 
• Dr. Julius and his colleagues published a paper in Nature in 1997 that explained how capsaicin, a chemical compound found in chilli peppers, causes the burning sensation. 
• They built a library of DNA fragments to decipher the related genes and eventually uncovered TRPV1, a novel capsaicin receptor. 
• Many more temperature-sensing receptors have since been discovered because of this finding. 
• They also discovered a novel receptor called TRPM8, which is triggered by cold. It's only found in a small number of pain- and temperature-sensing neurons. 
• They discovered a single gene, PIEZO2, that when silenced rendered the cells immune to probing. Piezo1 is the name given to this novel mechanosensitive ion channel.

How Do They Work?

• The capacity of humans to perceive heat, cold, and pressure is like the operation of many detectors that we are familiar with. 
• When anything hot or cold encounters the body, heat sensors allow certain molecules, such as calcium ions, to flow through the nerve cell membrane. 
• It's like a gate that only opens when a certain request is made. The chemical's entrance into the cell generates a slight change in electrical potential, which the nervous system detects. 
• There are several distinct types of receptors that are sensitive to different temperature ranges. 
• Greater channels open up to facilitate the flow of ions when there is more heat, and the brain can perceive higher temperatures.

Therapeutic Implications

• Physiological breakthroughs have frequently improved our ability to battle illnesses and disorders. This one is no exception. 
• There are receptors in our bodies that cause us to sense pain. The participant felt less pain if these receptors could be suppressed or rendered less effective. 
• A variety of diseases and ailments cause chronic pain. Previously, the sensation of pain was a mystery. 
• However, as we learn more about these receptors, it's likely that we'll be able to control them in such a manner that pain is reduced.

5. Chemistry Nobel to Duo for Developing Organo-Catalysis

For their work on inventing an organo-catalyst, German scientist Benjamin List of the Max Planck Institute and Scotland-born scientist David WC MacMillan of Princeton University have been awarded the Nobel Prize in Chemistry.

What are Catalysts?

• Other chemicals that do not change but assist speed up the reaction are commonly used to help two or more compounds react to produce new molecules. 
• These catalysts have been around since the middle of the nineteenth century and are currently employed in almost every chemical process. 
• Only two types of compounds were known to operate as efficient catalysts until approximately the year 2000: metals, primarily heavier metals, and enzymes, naturally occurring heavy molecules that aid all life sustaining biochemical processes. 
• Both catalysts have their drawbacks.

Issues With Conventional Catalysts

• Heavy metals are costly, difficult to mine, and harmful to persons and the environment. 
• Despite the best methods, residues persisted in the final product, posing a challenge in circumstances when extremely pure chemicals were required, such as in the creation of pharmaceuticals. 
• Metals also required a dry, oxygen-free atmosphere, which was difficult to provide on a large scale. 
• Enzymes, on the other hand, perform best when the chemical reaction is carried out in water. 
• However, that is not an ideal setting for many chemical processes.

Organo-Catalysis

• Organic molecules are generally found in nature and are made up of carbon atoms with hydrogen, oxygen, nitrogen, sulphur, or phosphorus as minor components. 
• Proteins, which are lengthy sequences of amino acids (carbon molecules containing nitrogen and oxygen) that support life, are organic. 
• Enzymes are organic substances because they are proteins. 
• List and MacMillan began studying individual amino acids in enzymes and discovered gold.

What is Asymmetric Catalysis?

• Substances with same chemical composition and molecular formula can have vastly different characteristics. They're referred to as isomers. 
• Isomers that differ in the orientation of individual atoms in three-dimensional space are one sort of isomer. 
• Two molecules might be identical if they weren't mirror reflections of each other, as our hands are. 
• Scientists commonly refer to these molecules as left handed or right-handed for ease of understanding. 
• When molecules interact with other molecules, this small change can have huge repercussions because it permits them to connect in various places. 
• In most chemical reactions, the final result is a combination of left-handed and right-handed molecules. 
• By employing a natural chemical like an amino acid as a catalyst, List and MacMillan realised that they could only get one unique mirror image of the end-product.

Organo-Catalysis

• Organic molecules are generally found in nature and are made up of carbon atoms with hydrogen, oxygen, nitrogen, sulphur, or phosphorus as minor components. 
• Proteins, which are lengthy sequences of amino acids (carbon molecules containing nitrogen and oxygen) that support life, are organic. 
• Enzymes are organic substances because they are proteins. 
• List and MacMillan began studying individual amino acids in enzymes and discovered gold.

What is Asymmetric Catalysis?

• Substances with same chemical composition and molecular formula can have vastly different characteristics. They're referred to as isomers. 
• Isomers that differ in the orientation of individual atoms in three-dimensional space are one sort of isomer. 
• Two molecules might be identical if they weren't mirror reflections of each other, as our hands are. 
• Scientists commonly refer to these molecules as left handed or right-handed for ease of understanding. 
• When molecules interact with other molecules, this small change can have huge repercussions because it permits them to connect in various places. 
• In most chemical reactions, the final result is a combination of left-handed and right-handed molecules. 
• By employing a natural chemical like an amino acid as a catalyst, List and MacMillan realised that they could only get one unique mirror image of the end-product.

6. White Dwarf

Astronomers have discovered many white dwarfs throughout the years using the Hubble Space Telescope and the Transiting Exoplanet Survey Satellite (TESS).

• When a star, such as the Sun, runs out of nuclear fuel, it becomes a white dwarf. 
• This type of star expels most of its outer material at the conclusion of its nuclear burning cycle, forming a planetary nebula. 
• Only the star's scorching core remains. With a temperature of above 100,000 Kelvin, its core transforms into an extremely hot white dwarf. 
• The white dwarf cools down during the next billion years or so unless it is accreting stuff from a neighbouring star.

Limits For White Dwarf

• When a star, such as the Sun, runs out of nuclear fuel, it becomes a white dwarf. 
• This type of star expels most of its outer material at the conclusion of its nuclear burning cycle, forming a planetary nebula. 
• Only the star's scorching core remains. With a temperature of above 100,000 Kelvin, its core transforms into an extremely hot white dwarf. 
• The white dwarf cools down during the next billion years or so unless it is accreting stuff from a neighbouring star.

Observing White Dwarf

• Soft, or lower-energy, X-rays have been identified from several nearby young white dwarfs. 
• Soft X-ray and extreme ultraviolet measurements have recently become a strong tool for studying the chemistry and structure of these stars' thin atmospheres. TESS 
• The Transiting Exoplanet Survey Satellite was used to observe this phenomenon (TESS). 
• TESS is a NASA Explorer-class satellite telescope that uses the transit technique to look for extrasolar planets. 
• TESS' primary mission goal is to search for transiting exoplanets over a two-year period by surveying the brightest stars near Earth. 
• The TESS project will conduct an all-sky scan with a variety of wide-field cameras. It will look for exoplanets around neighbouring stars.

How Does White Dwarf ‘Switch on And Off’?

• In these settings, the accretion disc is fed by the donor star's orbit around the white dwarf. 
• The accretion disc material grows brighter as it steadily descends closer to the white dwarf. 
• Donor stars in some systems have been found to quit feeding the disc.