08 November 2020
- India successfully launches earth observation satellite EOS-01
- NEET quota in T.N. (Polity & Governance)
- Ancient skeleton offers clues on prehistoric era (Ancient History)
- Soak in the Sun, sleep early and tight to avoid myopia - (Science & Technology)
- Lessons from Ladakh glacial lake outburst - (Science & Technology)
- Question for the day (Science & Technology)
UPSC Current Affairs: India successfully launches earth observation satellite EOS-01|Page 1
UPSC Syllabus: Prelims: Current events of national and international importance | Mains – GS Paper III – Technology
Sub Theme: Achievements of Indians in science & technology; indigenization of technology and developing new technology | UPSC
India successfully launched its latest Earth Observation Satellite EOS-01 and nine customer satellites from the United States, Lithuania and Luxembourg, on board Polar Satellite Launch Vehicle (PSLV-C49). This is ISRO’s first mission in 2020 after the COVID-19 pandemic induced lockdown disturbed 10 missions planned by the agency.
This is ISRO’s first mission since the launch of RISAT-2BR1, another earth observation satellite similar to EOS-01, on December 11 last year. After that, ISRO had also sent communication satellite GSAT-30 in space in January this year, but that was done using an Ariane rocket launched from French Guiana.
All satellites were placed precisely into 575 km orbit.
With EOS-01, ISRO is moving to a new naming system for its earth observation satellites which till now have been named thematically, according to the purpose they are meant for. For example, the Cartosat series of satellites were meant to provide data for land topography and mapping, while the Oceansat satellites were meant for observations over sea. Some INSAT-series, Resourcesat series, GISAT, Scatsat, and some more are all earth observation satellites, named differently for the specific jobs they are assigned to do, or the different instruments that they use to do their jobs.
Earth Observation Satellite
- Earth observation is the gathering of information about Earth's physical, chemical and biological systems. Earth observation satellites are the satellites equipped with remote sensing technology.
- Most earth observation satellites are in sun-synchronous orbit.
- A polar orbit is one in which a satellite passes above or nearly above both poles on each revolution. It therefore has an inclination of (or very close to) 90 degrees to the body's equator. A satellite in a polar orbit will pass over the equator at a different longitude on each of its orbits.
- A Sun-synchronous orbit is a nearly polar orbit around a planet, which combines altitude and inclination in such a way that an object on that orbit ascends or descends over any given Earth latitude at the same local mean solar time. This consistent lighting is a useful characteristic for satellites that image the Earth’s surface in visible or infrared wavelengths .
- Typical Sun-synchronous orbits around Earth are about 600–800 km in altitude, with periods in the 96–100-minute range, and inclinations of around 98°.
- To get (nearly) global coverage with a low orbit it must be a polar orbit or nearly so. A low orbit will have an orbital period of roughly 100 minutes and the Earth will rotate around its polar axis with about 25° between successive orbits, with the result that the ground track is shifted towards west with these 25° in longitude.
- Spacecraft carrying instruments for which an altitude of 36000 km is suitable sometimes use a geostationary orbit. Such an orbit allows uninterrupted coverage of more than 1/3 of the Earth. Three geostationary spacecraft at longitudes separated with 120° can cover the whole Earth except the extreme polar regions. This type of orbit is mainly used for meteorological satellites.
- Starting with IRS-1A in 1988, ISRO has launched many operational remote sensing satellites. Today, India has one of the largest constellations of remote sensing satellites in operation.
- Currently, 13 operational satellites are in Sun-synchronous orbit – RESOURCESAT-1, 2, 2A CARTOSAT-1, 2, 2A, 2B, RISAT-1 and 2, OCEANSAT-2, Megha-Tropiques, SARAL and SCATSAT-1,
- 4 in Geostationary orbit - INSAT-3D, Kalpana& INSAT 3A, INSAT -3DR.
- Land and forest mapping and monitoring, mapping of resources like water or minerals or fishes, weather and climate observations, soil assessment, geospatial contour mapping are all done through earth-observation satellites.
- RISAT (Radar Imaging Satellite) is a series of Indian radar imaging reconnaissance satellites built by ISRO.
- They provide all-weather surveillance using synthetic aperture radars (SAR).
- Synthetic-aperture radar is a form of radar that is used to create two-dimensional images or three-dimensional reconstructions of objects, such as landscapes.
- RADAR (Radio Detection and Ranging System) is a detection system that uses radio waves to determine the range, angle, or velocity of objects. Sunlight, clouds, and rain do not affect radio waves observations.
- The RISAT series are the first all-weather Earth observation satellitesfrom ISRO.
- Previous Indian observation satellites relied primarily on optical and spectral sensors which were hampered by cloud cover.
EOS-01 will have applications in agriculture, forestry and disaster management support. EOS-01 is nothing but another Radar Imaging Satellite (RISAT) that will work together with RISAT-2B and RISAT-2BR1 launched last year. EOS-01 was initially named RISAT-2BR2, and was supposed to be the third of the three-spacecraft constellation aimed at providing all-weather round-the-clock service for high-resolution images.
For the launch of EOS-01, ISRO used a new variant of its PSLV rocket. This variant of PSLV does not become waste after depositing its satellite in the orbit. Instead, the last stage of the rocket, the one that remains after the satellite is separated, can acquire its own orbit and be used as an orbital platform for other onboard instruments to perform experiments in space. In effect, the fourth stage acts like another satellite, with a life span of about six months.
Polar Satellite Launch Vehicle
- India’s Polar Satellite Launch Vehicle (PSLV) is the third generationlaunch vehicle.
- It is a four-staged launch vehicle with first and third stage using solid rocket motors and second and fourth stages using liquid rocket engines.
- PSLV is the first launch vehicle which is equipped with liquid stages.
- PSLV’s first successful launch was in October 1994. PSLV was used for two of the most important missions. These are Chandrayaan-1in 2008 and Mars Orbiter Spacecraft in 2013.
- The PSLV has helped take payloads into almost all the orbits in space including Geo-Stationary Transfer Orbit (GTO),the Moon, Mars and would soon be launching a mission to the Sun.
- Between 1994 and 2019, the PSLV launched 50 Indian satellites and 222 foreign satellites for over 70 international customers from 20 countries.
UPSC Current Affairs:NEET quota in T.N. – Article| Page 13
UPSC Syllabus: Prelims: Indian Polity | Mains – GS Paper II – Polity
Sub Theme: Reservation |UPSC
Context:What does the news highlight about Horizontal Reservation in NEET by Tamil Nadu?
- On October 30, the Tamil Nadu (T.N.) Governor gave his assent to a Bill that sought to reserve 7.5% seats in undergraduate medical admissions for government-school students who qualified NEET.
- The Horizontal Reservation will reduce the “de facto inequalities” between government-school students and private-school students.
- The state believes that students from government schools and rural areas would not be able to afford the coaching that would be essential for the competitive test and accordingly are at disadvantage.
- 32 per cent schools in the state have been run by the government. 41 per cent students in higher secondary courses were in government-run schools. Of the 5,550 medical seats in Tamil Nadu, 4,043 are of state quota. Of this, only 0.15 percent of seats have been given to students hailing from poor economic backgrounds who study in government schools.
- Earlier, the state government even ran free coaching centres for NEET to help students prepare for the examination.
Decision of Horizontal Reservation is based on Justice Kalaiyarasan’s Report
- The decision is based on report by one person commission headed by former Madras High Court Justice P. Kalaiyarasan.
- The commission’s role was to analyse the socio-economic background of students and submit recommendations to the state government on how to increase the number of government school students securing MBBS seats in the state.
- The Commission, in its report, made the observation that students from government schools are placed at a disadvantage, compared to their counterparts in private schools due to a cognitive gap created by socio-economic factors such as caste, wealth, parental occupation, parental education, gender, etc.
- The Report mentioned that these psychological and socio-economic barriers cannot be bridged by a few months of intensive coaching for NEET, even if provided for free by the state.
- The Committee recommended setting aside 10% seats for government students earlier suggested by the state.
Which Students will benefit from the Horizontal Reservation provided by Tamil Nadu?
- The NEET quota bill will provide 7.5% horizontal reservation in undergraduate courses in medicine, dentistry, Indian medicine and homeopathy for government school students who have cleared NEET and who have studied in government schools from Class VI onwards.
What is the meaning of Horizontal Reservation?
- The concept of vertical and horizontal reservation was explained by the Supreme Court in the famous IndraSawhney judgment.
- The Court held that all reservations are not of the same nature. There are two types of reservations which can be referred as 'vertical reservations' and 'horizontal reservations'.
- The reservations in favour of Scheduled Castes, the Scheduled Tribes and the other backward classes [under Article 16(4)] may be called vertical reservations.
- Whereas reservations in favour of physically handicapped [under Clause (1) of Article 16] can be referred to as horizontal reservations.
- So, we can say that horizontal reservations cut across the vertical reservations - what is called inter-locking reservations.
- For students of Tamil Nadu, horizontal reservations will be applied irrespective of the community a student belongs to, just as in the case of quota for persons with disability or wards of ex-service personnel. The government also specified that if a government-school student has scored high marks, she or he could also opt to be allotted a seat based on their community reservation.
UPSC Current Affairs: Ancient skeleton offers clues on prehistoric era| Page12
UPSC Syllabus: Prelims: History of India | Mains: GS Paper-I – Indian Heritage and Culture
Sub Theme: Architecture from ancient time| UPSC
German researchers are piecing together the life of a prehistoric woman who died more than 5,000 years ago in the Neolithic period, after her skeleton was found when excavating for wind turbines.
She has been named, the “Lady of Bietikow”.
Investigations have shown that she was between 30 and 45 years old and died more than 5,000 years ago.
All that is left of the skeleton are bones and some fragments of clothing.
Observation - Lady of Bietikow's teeth are severely eroded and missing completely in some places.
Inference - It was during the Neolithic period that humans first introduced grains into their diet, since they could be stored more easily than meat and could also be used as a means of payment. However, this led to a deterioration in people's general health. This can be seen in the state of the Lady of Bietikow's teeth.
Prehistoric Age refers to the time where there was no writing and development. It consists of five period, divided according to the tools used by people then –
- Paleolithic Period: 2 million BC – 10,000 BC
- Mesolithic Period: 10,000 BC – 8000 BC
- Neolithic Period: 8000 BC – 4000 BC
- Chalcolithic Period: 4000 BC – 1500 BC
- Iron Age: 1500 BC – 200 BC
Neolithic Period (New Stone Age)
- Starting of agriculture
- Moving from nomadic to settled life
- Wheel discovered. Ragi, wheat and horse gram were cultivated
- They knew to make fire
- Knew pottery
- Also, shows first intentional disposal of the dead
- Important sites:
- One of the most important Neolithic agricultural settlements in Indian subcontinent is Mehrgarh. It is now considered oldest agricultural settlement in the Indian subcontinent. It flourished in the seventh millennium B.C. It is located on the Bolan River, a tributary of the Indus, at the eastern edge of the Baluchistan plateau.
- Other important Neolithic sites include –
- Gufkral and Burzahom in Kashmir
- The people in Burzahomlived in pit dwellings, rather than building houses on the ground.
- Mahgara, ChopaniMando,and Koldihwa in Belan valley in Uttar Pradesh;
- Belan valley sites have provided oldest evidence of rice cultivation in any part of the world
- Chirandin Bihar
- In South India, the important Neolithic sites include Kodekal, Utnur, Nagatjunikonda, Palavoy in Andhra Pradesh; Tekkalkolta, Maski, Narsipur, Sangankallu, Hallur, and Brahmagiri in Karnataka; Pariamlpalli in Tamil Nadu etc.
- Gufkral and Burzahom in Kashmir
UPSC Current Affairs: Soak in the Sun, sleep early and tight to avoid myopia|Page 12
UPSC Syllabus: Prelims: General science | Mains – GS Paper II – Technology
Sub Theme: Science and Technology- applications and effects in everyday life | UPSC
Myopia or short sightedness is turning out to be an epidemic across India. In the year 2000, about 25% of the world’s population was near-sighted or myopic, but it is expected to increase to above 50% by 2050 (30 years from now).
It occurs because of the potential role of myopic genes and also local environmental conditions such as the prolonged ‘near work’ and/or less sunlight exposure. So, less time spent outdoors to be a risk factor for myopia.
Myopia occurs when the eyeball becomes longer, relative to the focusing power of the cornea and the lens; this leads to focus not on the surface of the retina, but at a point before it. This leads one to find it difficult to focus distant objects clearly, though one can see close-up objects such.
There are various ways in which such outdoor brightness helps protect the human eye from becoming myopic –
- If you are in an open space, and not performing any ‘near work’, the stress on the eye is reduced.
- Outdoor environment provides equal optical stimuli to various parts of the peripheral retina (the posterior part of the eye) and also enables exposure to different colours equally well, while indoor lighting using artificial sources that cut off specific wavelengths.
- Upon bright illumination in sunlight, the pupil reduces its size and reduces blur, and increase the depth of focus.
- Sunlight exposure helps the biology of the eye, helping it to produce more vitamin D.
- Exposure to bright light releases the hormone dopamine, which controls the length of the eye ball; the shorter it is, myopia might set in.
UPSC Current Affairs: Lessons from Ladakh’s glacial lake outburst |Page 12
UPSC Syllabus: Prelims: General issues on Environmental and Climate Change| Mains – GS Paper III – Environment
Sub Theme: Glacial lake outburst| UPSC
A glacial lake outburst flood (GLOF) is a release of melt water from a moraine- or ice-dam glacial lake due to dam failure. GLOFs often result in catastrophic flooding downstream, with major geomorphic and socioeconomic impacts.
GLOFs have three main features:
- They involve sudden (and sometimes cyclic) releases of water.
- They tend to be rapid events, lasting hours to days.
- They result in large downstream river discharges (which often increase by an order of magnitude).
The general global trend of glacier shrinkage has seen the number and size of glacial lakes increase at the same time as human activities have expanded further into glaciated catchments. The study of how GLOFs occur and their impacts is therefore important for future hazard mitigation.
Using remote sensing data, researchers from Germany have mapped the evolution of 2014 Gya glacial lake(Ladakh) and cause of the flood.
Finding of the study
- The cause of the flood — was not a spill over but rather a tunnelling drainage process.
For Example - Imagine a bucket full of water. It can overflow when you drop a stone, or the water can drain if there is a hole under the bucket.
Similarly, here the flooding did not happen due to the spill over due to an avalanche or landslide, rather there was a thawing of the ice cores in the moraine [a field of dirt and rocks that have been pushed along by the glacier as it moves] which drained through the subsurface tunnels.
- Such thawing of ice cores may accelerate in the future due to global climate change. warning.
- It is almost certain that other glacial lake outburst floods will happen all over the Indian Himalaya. However, not all of these events have catastrophic outcomes. It largely depends on urban planning, the size of the lake, the distance between the lake and affected villages, the valley section and some more aspects. In some cases, cloudbursts can also trigger glacial lake outburst flood events like in Kedarnath in 2013.
- In different sections of the Himalaya the occurrence of such floods has received different attention. While these events have been regarded as a major risk in the central Himalayan region including Sikkim, the arid Trans-Himalayan regions of Ladakh have received attention only recently.
Here the glaciers are located at high altitudes and most glaciers are of small size. Likewise, the glacial lakes are quite small in size. In the case of the Gya lake the lake is almost always ice-covered, even during summer –still event of glacial lake outburst was seen to occur.
- To take more bathymetric studies to analyse lake volumes.
- To undertake regularly monitoring of lake development.
- Study to understand stability of the moraines that dam the lake.
- Use multiple methods for better risk assessment and early warning.
- Need of proper land use planning.