Astronomy and Space Science

Solar wind contains hydrogen ions (protons) that bombard the lunar surface. When these H+ ions interact with oxygen-rich minerals in the lunar regolith (soil and rocks), they form water molecules (H2O). The oxygen is chemically bound in oxides within lunar surface materials, not in the atmosphere (which the Moon barely has) or coming from solar wind itself.

The Indian National Satellite (INSAT) system is a series of multipurpose geostationary satellites used primarily for telecommunications, broadcasting, and meteorology. Improving the communication system is its core function, unlike IRS which manages natural resources.

A star's color directly indicates its surface temperature, following Wien's displacement law. Blue stars are hottest (over 30,000 K), white stars are moderate (around 10,000 K), and red stars are coolest (below 3,500 K). Distance and size do not directly determine a star's apparent color, though they affect brightness.

Earth is visible from space because it reflects sunlight - it doesn't produce its own light. The Sun is the closest star to Earth, and its light reflects off Earth's surface (oceans, land, clouds) back to observers. Option A is wrong because Earth doesn't generate light. Option B is incorrect - crust heat doesn't produce visible light. Option D uses 'refracted' incorrectly - reflection is the correct phenomenon.

Since stars and galaxies are incredibly far away, we cannot send probes to them or conduct in-situ experiments. Instead, almost all astronomical knowledge is gathered by analyzing the electromagnetic radiation (including visible light, radio waves, and X-rays) emitted by these distant objects that reaches Earth or space-based telescopes.

Phobos and Deimos, the two moons of Mars, are named after the Greek gods who personified fear and terror respectively - Phobos meaning fear/panic and Deimos meaning dread/terror. In Greek mythology, they were sons of Ares (the Greek equivalent of Mars), accompanying him in battle. This naming convention reflects the martial association of Mars, the Roman god of war.

Earth orbits the Sun at an average speed of approximately 66,700 miles per hour (about 107,200 kilometers per hour).

The actual amount of cosmic dust and meteoritic material entering Earth's atmosphere is estimated at around 40,000 tons per year, far exceeding the claimed 1,000 tons. This makes the statement false.

X-ray astronomy is the study of X-rays emitted by celestial bodies such as stars, galaxies, black holes, and neutron stars. Since Earth's atmosphere blocks X-rays, this requires space-based telescopes. Options A, B, and D are incorrect or nonsensical.

X-ray astronomy is the study of X-rays emitted by celestial bodies including stars, galaxies, black holes, and neutron stars. These high-energy X-rays are absorbed by Earth's atmosphere, so X-ray telescopes must be placed in space. It is not the study of X-rays of planets themselves or human X-rays in space.

The corona is the outermost layer of the Sun's atmosphere, extending millions of kilometers into space. It consists of extremely hot plasma (temperatures around 1-3 million K) and is visible during a total solar eclipse as a pearly white crown. The photosphere is the visible surface, the chromosphere is a thin layer above it, and the ionosphere is Earth's atmospheric layer, not the Sun's.

A bolide is an extremely bright meteor that explodes in the atmosphere, often producing a sonic boom. The term comes from Greek and refers to a projectile. Regular meteors are fainter, comets are icy objects with tails, meteorites are objects that reach the ground, and 'No such object' is incorrect - bolides are a real classification of bright meteors.

Retrograde motion describes an object moving in the opposite direction of the prevailing rotation or orbit. In astronomy, planets can exhibit retrograde motion when they appear to move backwards against the background stars from Earth's perspective.