GENERAL KNOWLEDGE

Detailed explanation-1: -The most common method astronomers use to determine the composition of stars, planets, and other objects is spectroscopy. Each element absorbs light at specific wavelengths unique to that atom. When astronomers look at an object’s spectrum, they can determine its composition based on these wavelengths.

Detailed explanation-2: -To determine which chemical elements are formed inside stars, scientists use a technique known as visible spectroscopy. It is based on a device, called a spectroscope, which spreads visible light into its component colors by passing it through a prism or grating.

Detailed explanation-3: -Astronomers in the US believe they have figured out how stars form from clouds of gas.

Detailed explanation-4: -Using powerful telescopes, scientists have made extensive spectroscopic surveys of distant stars and galaxies. The data indicates that hydrogen and helium make up nearly all of the nuclear matter in the universe. The most abundant element, hydrogen, accounts for 74% of the mass while helium contributes 25%.