Astronomy and Cosmology

A nebula is a giant cloud of dust and gas in space. Some nebulae are regions where new stars are beginning to form, while others are the remnants of dead or dying stars. Atoms and molecules combine under gravity to form these vast clouds.

A nebula is a giant cloud of dust and gas in space, primarily composed of hydrogen and helium, that serves as the birthplace of stars. Gravitational collapse within these clouds leads to stellar formation, making nebulae fundamental to our understanding of cosmic evolution.

Asteroids are also called planetoids or minor planets, as they are small planet-like bodies orbiting the Sun. Constellations are star patterns, nebulae are interstellar gas clouds, and meteors are atmospheric light phenomena - none are alternative names for asteroids.

Alpha Centauri is a triple star system located about 4.37 light-years from Earth, making it the closest star system to our Sun. It consists of three stars: Alpha Centauri A, Alpha Centauri B, and Proxima Centauri (the closest of the three). The Pole star (Polaris) is much farther away at about 433 light-years.

After a star exhausts the hydrogen in its core and passes through the red giant phase, low to medium mass stars (like our Sun) shed their outer layers and become white dwarfs. A white dwarf is the hot, dense core remnant that slowly cools over billions of years.

Luminosity is the measure of the total energy emitted by a star per second across all wavelengths. The apparent brightness of a star as seen from Earth depends on both its intrinsic luminosity and its distance from us. More luminous stars appear brighter when viewed from the same distance.

A star's lifespan is determined by its initial mass (which determines how much hydrogen fuel it has) and its rate of consuming that fuel through nuclear fusion. More massive stars burn through their hydrogen much faster despite having more of it, leading to shorter lifespans.

A supernova is the catastrophic explosion of a massive star at the end of its life cycle, releasing an enormous amount of energy and often outshining its entire host galaxy for weeks. This occurs when the star's core collapses after iron accumulation, causing a rebound explosion.

When a neutron star spins rapidly, it emits beams of electromagnetic radiation from its magnetic poles. As these beams sweep across Earth like a lighthouse, we detect regular pulses of radio waves, earning it the name 'pulsar' (pulsating star).

Ursa Major (the Great Bear) contains the well-known asterism called the Big Dipper, which consists of seven bright stars forming a ladle or dipper shape. The Big Dipper is one of the most recognizable star patterns in the northern sky and has been used for navigation for centuries.

The Paschen, Brackett, and Pfund series of lines are found in the infrared region.

Planets are not luminous objects. They do not give light energy of their own. Thus, this is the correct option.

The glow worm is a medium to large sized invertebrate that is famous for having a green and yellow coloured light on the end of it's tail. This is the correct option.