Science and Technology: September 2023 UPSC Current Affairs | Science & Technology for UPSC CSE PDF Download

Aditya-L1 Mission

Why in News?

Recently, the Indian Space Research Organisation (ISRO) has accomplished the launch of Aditya-L1, its inaugural Solar Mission.

• The launch was conducted using the PSLV-C57 rocket. The PSLV's fourth stage was fired twice, a first in ISRO's history, to precisely insert the spacecraft into its elliptical orbit.

What is Aditya-L1 Mission?

• About:
  • Aditya-L1 is the first space based observatory class Indian solar mission to study the Sun from a substantial distance of 1.5 million kilometers. It will take approximately 125 days to reach the L1 point.
    • Aditya-L1 is also ISRO’s second astronomy observatory-class mission after AstroSat (2015).
    • The mission's journey is notably shorter than India's previous Mars orbiter mission, Mangalyaan.
  • The spacecraft is planned to be placed in a halo orbit around the Lagrangian point 1 (L1) of the Sun-Earth system.
• Payloads:

• Objective:
  • The mission aims to provide valuable insights into the solar corona, photosphere, chromosphere, and solar wind.
  • The primary objective of Aditya-L1 is to gain a deeper understanding of the Sun's behavior, including its radiation, heat, particle flow, and magnetic fields, and how they impact Earth.

What is the Significance of Exploring the Sun?

• Understanding Our Solar System: The Sun is the center of our solar system, and its characteristics greatly influence the behavior of all other celestial bodies. Studying the Sun enhances our understanding of the dynamics of our solar neighborhood.
• Space Weather Prediction: Solar activities, such as solar flares and coronal mass ejections, can impact Earth's space environment.
  • Understanding these phenomena is crucial for predicting and mitigating potential disruptions to communication systems, navigation, and power grids.
• Advancing Solar Physics: Exploring the Sun's complex behavior, including its magnetic fields, heating mechanisms, and plasma dynamics, contributes to advances in fundamental physics and astrophysics.
• Enhancing Energy Research: The Sun is a natural fusion reactor. Insights gained from studying its core and nuclear reactions can inform our pursuit of clean and sustainable fusion energy on Earth.
• Improving Satellite Operations: Solar radiation and solar wind affect the functioning of satellites and spacecraft. Understanding these solar interactions allows for better spacecraft design and operation.

Picoflare Jets

Central Idea

• A recent revelation from the Solar Orbiter Aircraft, a collaborative endeavour between the European Space Agency and NASA, has illuminated the Picoflare jets erupting from the sun’s outer atmosphere.
• These jets, marked by their supersonic emergence and brief durations of 20 to 100 seconds, have captured the attention of scientists and space enthusiasts alike.

What are Picoflare Jets?

• Picoflare jets, observed amidst emissions from the observed coronal hole, are diminutive in scale but pack a potent punch.
• Their ephemeral existence belies their significance, as scientists have calculated that they contribute a substantial portion of the solar winds’ energy.
• These solar emanations earned their name, “picoflare jets,” owing to their energy levels, which hover around one-trillionth of the solar flares’ immense energy potential.
• Solar winds, driven by strong gusts, can not only craft auroras in Polar Regions but also disrupt Earth’s magnetic field and jeopardize electronic systems on satellites and terrestrial circuits.

About Solar Orbiter Aircraft

• A Stellar Journey: Launched in 2020, the Solar Orbiter Aircraft embarks on a mission to capture unprecedented images of the Sun, propelling closer than any previous spacecraft.
• Instrumentation Excellence: Equipped with six remote-sensing instruments and four sets of in situ instruments, the spacecraft is primed for comprehensive solar exploration.
• Mission Objectives: The Solar Orbiter Aircraft carries two primary objectives: to scrutinize the Sun’s 11-year cycle of magnetic activity ebbs and flows and to delve into the mysteries of the solar corona, the upper echelon of the Sun’s atmosphere.

Enhancing Mosquito Control through Genetic Engineering

Context

Genetic engineering is being used to upgrade mosquito control efforts due to the ongoing threat of mosquito-borne diseases.

• Recent advancements in genome sequencing technology have provided researchers with access to mosquito genomes, particularly Anopheles stephensi, a major malaria vector mosquito.
• Genetic manipulation, including gene-drive technology, is employed to control mosquito populations by interfering with their reproduction.

Gene-drive technology, originally conceived by Austin Burt in 2003, alters mosquito DNA to reduce their reproductive capabilities or make them sterile, preventing the transmission of diseases like malaria. Some approaches involve enhancing genes in mosquitoes to produce antimicrobial substances, disrupting disease transmission.
Genetically modified mosquitoes, such as OX5034, have been released in certain areas to reduce mosquito populations, showing promising results in decreasing disease incidence. However, these technologies come with potential risks, such as ecological disruptions and unintended consequences in the ecosystem.

Lab-Grown Human Embryo Model

Central Idea

• Scientists have successfully developed a “human embryo” in a laboratory without using traditional egg or sperm cells.
• The model was constructed using a combination of stem cells, which possess the ability to differentiate into various cell types, resulting in a structure resembling an early human embryo.

Creating Human Embryo Artificially

• This model is considered one of the most comprehensive representations of a 14-day-old human embryo.
• Multiple research teams worldwide have been working on similar embryo-like models, with approximately six such models published in the current year.
• While none fully replicate early embryo development processes, they collectively contribute to scientific understanding.

Challenges in Creating the Model

• Researchers in Israel utilized stem cells and chemical components, but only a small fraction spontaneously assembled into different cell types.
• Approximately 1% of the mixture exhibited this spontaneous assembly, making the process inefficient.

Importance of Embryo Models and Research

• Ethical constraints prevent direct research on early embryo development after implantation in the uterus.
• Understanding early stages of embryo development is crucial as most miscarriages and birth defects occur during this period.
• Such research aids in the comprehension of genetic and hereditary diseases.
• Insights into why some embryos develop normally and implant successfully can enhance in vitro fertilization success rates.

Potential of Embryo-Like Models

• These models enable the study of genetic, epigenetic, and environmental influences on embryo development.
• They facilitate the investigation of genetic defects and the development of potential genetic therapies.

Limits of Lab-Grown Embryos

• Lab-grown embryos are solely for studying the early stages of foetal development.
• Implantation attempts are prohibited, and these models are typically destroyed after 14 days.
• Originating from a UK committee proposal in 1979, the 14-day limit aligns with natural embryo implantation completion.
• Beyond this point, embryos begin exhibiting characteristics of individuality and cannot split into twins.
• The ethical considerations shift as embryos progress from a clump of cells to entities with individual potential, often marked by the Primitive Streak.

Insights from Embryo Models

• Models like the one developed in Israel shed light on DNA duplication errors and chromosome imbalances.
• These errors are now understood to occur earlier in the development process, during ongoing DNA duplication.
• Such models aid in identifying the roles of various genes in fetal development, enabling gene manipulation for research purposes.

Conclusion

• Lab-grown human embryo models represent a significant scientific achievement.
• They provide a unique window into early embryo development and the understanding of genetic and developmental processes.
• While not suitable for reproduction, these models hold promise for advancing genetic and medical research.

String of Pearls Supernova

Context 

Exploring the Universe: The James Webb Space Telescope's New Revelation of SN1987A Supernova.

Introduction

In recent news, the James Webb Space Telescope (JWST) has made headlines by capturing a captivating image of SN1987A, a supernova that exploded more than three decades ago. This celestial event offers us a unique opportunity to gain fresh insights into its history and evolution. But what exactly is SN1987A, and why is this discovery so important?

SN1987A Supernova

An Overview: SN1987A, which burst onto the cosmic stage in the year 1987, is a supernova – a colossal explosion of a dying star. What makes this supernova particularly special is that it became the nearest and brightest one visible from Earth in almost four centuries. Situated at a staggering distance of 170,000 light-years away from our planet in the Large Magellanic Cloud, SN1987A has long fascinated astronomers.

The Significance of Magellanic Clouds

• Large Magellanic Cloud (LMC), is where SN1987A is located. The Magellanic Clouds are two irregular, satellite galaxies that orbit our Milky Way. While they are visible to the naked eye in the Southern Hemisphere, most people in the northern latitudes cannot observe them.
• These clouds serve as excellent laboratories for studying the formation and evolution of stars due to their very active stellar processes.

The 'String of Pearls' Phenomenon

• SN1987A is often referred to as the "string of pearls." This captivating name stems from its appearance, which showcases a series of luminous rings composed of gases and dust. These rings were expelled by the dying star in various phases of its collapse and explosion.
• What's fascinating is that these "pearls" of light comprise material that was ejected approximately 20,000 years before the actual supernova event. This revelation provides us with invaluable insights into the star's history and the intricate processes leading to its ultimate demise.

Unusual Facts about SN1987A

• This supernova has some rather unusual characteristics that have piqued the curiosity of scientists. It defied conventional theories by exploding as a blue supergiant star, whereas it was generally believed that only red supergiant stars could undergo such an explosive transformation.
• Additionally, the emission of molecular hydrogen in the ring surrounding SN1987A was unexpected and could not have been observed without the advanced capabilities of the JWST.

The James Webb Space Telescope (JWST)

• The JWST is often hailed as the successor to the Hubble Telescope and represents the pinnacle of NASA's space-based astronomical observatories. This cutting-edge telescope is a product of international collaboration between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA).
• Unlike the Hubble Telescope, the JWST primarily operates in the infrared part of the electromagnetic spectrum, allowing it to peer through cosmic dust clouds and observe celestial objects with incredible precision.

Conclusion

The James Webb Space Telescope's recent image of SN1987A has brought this decades-old supernova back into the spotlight. It has allowed us to unlock the secrets of this cosmic event and challenge our existing understanding of the universe. As we continue to explore the cosmos with the JWST, we can look forward to more breathtaking discoveries that will expand our knowledge of the cosmos and our place within it.

The Bottleneck in Human Evolution

Why in News?

Recently, a study published in Science sheds light on a crucial period in human evolution marked by a population bottleneck, providing insights into the challenges our early ancestors faced and the genetic changes that shaped modern humans.

• Researchers from China, Italy, and the U.S. used a novel genomic analysis technique called Fast Infinitesimal Time Coalescent Process (FitCoal) to examine this bottleneck.

What are the Key Highlights of the Study?

• Population Bottleneck:
  • A population bottleneck is a sharp reduction in the size of a population due to environmental events or human activities that kill or prevent the reproduction of a large percentage of the population.
  • This reduces the genetic diversity and the ability to adapt to changing conditions of the remaining population.
  • The study reveals that a severe population bottleneck occurred between 800,000 to 900,000 years ago, nearly driving the human species to the brink of extinction.
  • During this bottleneck, only approximately 1,280 breeding individuals sustained the entire human population, and this situation persisted for about 117,000 years.
• Causes of Bottleneck:
  • Environmental Factors:
    • Glaciation events, changes in temperature, and severe droughts were suggested as reasons for the downturn in the size of the human ancestral population.
    • The study suggests that humans persisted in presumably dangerous conditions during the bottleneck period, around 930,000-813,000 years ago.
    • Loss of other species, potentially food sources for ancestral humans, also contributed to the bottleneck.
  • Loss of Genetic Diversity:
    • Early human ancestors experienced significant loss of life during the bottleneck period.
    • This resulted in a substantial loss of genetic diversity, with an estimated 65.85% of humans' current genetic diversity potentially lost during the early to middle Pleistocene era (from two million to 11,000 years ago).
  • Speciation Event:
    • The bottleneck event in human evolution resulted in the fusion of two ancestral chromosomes, forming chromosome 2 in modern humans, a distinct trait not found in other primates.

New Method to Determine Hubble Constant

Central Idea

• Researchers from India and the US have come up with a new way to answer a big question about the universe.
• This question is about how fast the universe is getting bigger.

Story of Our Universe

• The universe began around 13.8 billion years ago with a massive explosion called the Big Bang.
• As time passed, the universe kept getting bigger, with moments of speeding up and slowing down.
• Scientists want to understand this expansion to figure out what’s happening in the universe.

Hubble Constant: A Big Question

• The Hubble constant is a special number that tells us how quickly the universe is expanding.
• This number was first talked about by a scientist named Edwin Hubble in 1929.
• But scientists today are still not sure about its value.

Two Important Things to Measure

To know the Hubble constant, we need to measure two things carefully:

• How far away things in space are from us.
• How fast these things are moving away from us because of the universe’s expansion.

Old Ways vs. New Idea

Until now, scientists used a few methods to measure the Hubble constant:

• Looking at bright explosions in space called supernovae.
• Using special light from the early universe.
• Studying waves created by big crashes in space.

But now, a fresh idea has been propounded by Indian researchers:

• To measure using a thing called “gravitational lensing.”

Gravitational Lensing: A New Approach

• Gravitational lensing is like bending light using gravity. Imagine it like a magnifying glass in space.
• This idea came from a long time ago but got better recently.
• Scientists think they can use this lensing trick to measure the Hubble constant.
• They want to look at waves from space collisions that get bent by gravity.
• These bent waves could tell us about how fast the universe is expanding.

The Big Idea: A Bridge between Time

• This new idea is cool because it connects different times in the universe’s history.
• It could give us a good answer about the Hubble constant.

Challenges

• While this idea is exciting, there are some challenges to solve:
  • Making sure the signals are clear enough to measure.
  • Using the new method to answer other questions too.
• If this new way works, it could help us learn about things like dark matter and other universe stuff.

Minimal-Genome Cells Evolve as Fast as Normal Cells

Introduction

• Dairy farming introduced gene mutations in humans to digest milk.
• Mutations in non-essential genes can drive evolution in complex organisms.
• Challenge: How does a simple organism with essential genes evolve with minimal targets for selection?

Experimental Setup

• Mycoplasma mycoides Genome (Sourced from goat, cattle gut)
• Created minimal cell (Mycoplasma mycoides JCVI-syn3.B) with 493 genes compared to non-minimal cell (JCVI-syn1.0).
• Genome minimization reduced minimal cell fitness by over 50%.

Testing Evolution

• Minimal and non-minimal cells grown separately for 300 days, equivalent to 40,000 years of human evolution.
• Minimal cells showed mutation rates comparable to non-minimal cells.
• Despite the minimal cell’s reduced fitness due to genome minimization, the researchers found that it could evolve as fast as a normal cell.

Comparison and Genetic Pathways

• Size difference: Non-minimal cells increased by 80%, while minimal cells remained the same size.
• Examination of genomes of adapted cells reveals distinct genetic pathways.

Significance of Findings

• Significant contribution to microbial evolution.
• Relevance to synthetic biology and the adaptability of engineered cells.
• Life’s robustness and adaptability even with minimal genomes.
• Implications for treating clinical pathogens, engineered microorganisms, and the origin of life.

Key terms

• Gene Mutation: A gene mutation is a permanent alteration in the DNA sequence that makes up a gene. Mutations can result from changes in the nucleotide sequence of DNA and can lead to variations in an organism’s characteristics.
• Evolution: Evolution is the process by which species change over time through the gradual accumulation of genetic changes. It leads to the development of new species from pre-existing ones.
• Genome: A genome is the complete set of an organism’s genetic material, including all of its genes and non-coding sequences of DNA.
• Synthetic Biology: Synthetic biology is an interdisciplinary field that combines principles from biology, engineering, and computer science to design and construct new biological parts, devices, and systems, or to redesign existing biological systems for useful purposes.
• Minimal Cell: A minimal cell is a simplified version of a biological cell that contains only the essential genes and components required for life.
• Natural Selection: Natural selection is the process by which organisms with traits that confer a reproductive advantage in a given environment are more likely to survive, reproduce, and pass on their genes to the next generation.
• Fitness: Fitness in an evolutionary context refers to an organism’s ability to survive, reproduce, and pass on its genes to the next generation. It is a measure of how well an organism is adapted to its environment.
• Genetic Variation: Genetic variation refers to the diversity of genetic material within a population. It arises from mutations, genetic recombination, and other processes and is a source of genetic diversity within a species.