UPSC Quiz – 2020: IAS Daily Current Affairs Quiz Day 110

Solution (d)

The heliosphere is the vast, bubble-like region of space which surrounds and is created by the Sun. In plasma physics terms, this is the cavity formed by the Sun in the surrounding interstellar medium. The “bubble” of the heliosphere is continuously “inflated” by plasma originating from the Sun, known as the solar wind. Outside the heliosphere, this solar plasma gives way to the interstellar plasma permeating our galaxy. Radiation levels inside and outside the heliosphere differ; in particular, the galactic cosmic rays are less abundant inside the heliosphere, so that the planets inside (including Earth) are partly shielded from their impact.

Despite its name, the heliosphere’s shape is not a perfect sphere.[6] Its shape is determined by three factors: the interstellar medium (ISM), the solar wind, and the overall motion of the Sun and heliosphere as it passes through the ISM. Because the solar wind and the ISM are both fluids, the heliosphere’s shape and size are also fluid. Changes in the solar wind, however, more strongly alter the fluctuating position of the boundaries on short timescales (hours to a few years). The solar wind’s pressure varies far more rapidly than the outside pressure of the ISM at any given location. In particular, the effect of the 11-year solar cycle, which sees a distinct maximum and minimum of solar wind activity, is thought to be significant.

On a broader scale, the motion of the heliosphere through the fluid medium of the ISM results in an overall comet-like shape. The solar wind plasma which is moving roughly “upstream” (in the same direction as the Sun’s motion through the galaxy) is compressed into a nearly-spherical form, whereas the plasma moving “downstream” (opposite the Sun’s motion) flows out for a much greater distance before giving way to the ISM, defining the long, trailing shape of the heliotail.

Solution (c)

The termination shock is the point in the heliosphere where the solar wind slows down to subsonic speed (relative to the Sun) because of interactions with the local interstellar medium. This causes compression, heating, and a change in the magnetic field. In the Solar System, the termination shock is believed to be 75 to 90 astronomical units from the Sun. In 2004, Voyager 1 crossed the Sun’s termination shock, followed by Voyager 2 in 2007

The heliosheath is the region of the heliosphere beyond the termination shock. Here the wind is slowed, compressed and made turbulent by its interaction with the interstellar medium. At its closest point, the inner edge of the heliosheath lies approximately 80 to 100 AU from the Sun.

Solution (a)

Realizing the importance of availability of reliable database on the wastelands of the country, the Ministry of Rural Development has released the Wastelands Atlas – 2019.

The new wastelands mapping exercise, carried out by NRSC using the Indian Remote Sensing Satellite data is brought out as the fifth edition of Wastelands Atlas – 2019.

The department of land resources in collaboration with National Remote Sensing Centre (NRSC), Department of Space has published Wastelands Atlases of India – 2000, 2005, 2010 & 2011 editions. The new wastelands mapping exercise, carried out by NRSC using the Indian Remote Sensing Satellite data is the fifth edition of Wastelands Atlas – 2019.

Solution (a)

Carbon fibers or carbon fibres (alternatively CF, graphite fiber or graphite fibre) are fibers about 5–10 micrometres in diameter and composed mostly of carbon atoms. Carbon fibers have several advantages including high stiffness, high tensile strength, low weight, high chemical resistance, high temperature tolerance and low thermal expansion. These properties have made carbon fiber very popular in aerospace, civil engineering, military, and motorsports, along with other competition sports. However, they are relatively expensive when compared with similar fibers, such as glass fibers or plastic fibers.

Solution (b)

Shadow banning (also called stealth banning, ghost banning or comment ghosting) is the act of blocking or partially blocking a user or their content from an online community such that it will not be readily apparent to the user that they have been banned.