Astronomy

Explanation

Statement 1 is correct: VELC (Visible Emission Line Coronagraph) is the primary payload of Aditya-L1 and functions as a coronagraph — an instrument that blocks the bright solar disk to observe the dimmer surrounding corona. It operates in spectroscopic mode, measuring emission lines to derive plasma properties such as density and temperature. Statement 2 is incorrect: Coronal mass ejections originate from the Sun's corona (the outermost layer of the solar atmosphere), not from the photosphere (the visible surface). The corona is the source of the plasma and magnetic field expelled in these events; confusing the photosphere with the corona is a common misconception because the corona is far less visible under normal conditions. Statement 3 is correct: Aditya-L1 is placed in a halo orbit around the Sun-Earth Lagrange point L1, located approximately 1.5 million km from Earth toward the Sun. This placement ensures that the spacecraft is never in Earth's shadow and can maintain an uninterrupted, continuous view of the Sun — a key advantage for monitoring solar events like CMEs in real time.

Explanation

All three pairs are correctly matched. A gravity-assist manoeuvre (also called a slingshot manoeuvre) exploits a planet's gravity to change a spacecraft's velocity and direction, saving significant propellant — a standard technique used extensively by deep-space missions such as Voyager, Cassini, and now the UAE's MBR Explorer (which uses gravity assists at Venus, Earth and Mars). The main asteroid belt is the well-established region between the orbits of Mars and Jupiter, containing the vast majority of the solar system's asteroids ranging from small rocky bodies to dwarf planets like Ceres. An elliptical orbit, by definition, has two foci and varies in altitude, meaning a spacecraft in such an orbit passes closer to and farther from the body it orbits — this is precisely why the UAE's Hope probe could observe the Martian atmosphere across different altitudes and produce the first global atmospheric map of Mars. All three descriptions accurately reflect static orbital-mechanics and solar-system concepts.