key term - Helium

Definition

Helium is a colorless, odorless, and inert gas that is the second most abundant element in the universe, after hydrogen. It is a crucial component in various scientific and technological applications, as well as in the understanding of the universe and the evolution of stars and planets.

5 Must Know Facts For Your Next Test

1. Helium is the second-lightest and second-most-abundant element in the observable universe, after hydrogen.
2. Helium is used in cryogenic applications, such as cooling superconducting magnets, due to its low boiling point of -268.9°C.
3. The spectral lines of helium were first observed in the solar chromosphere during a solar eclipse, leading to the discovery of the element.
4. Helium is a key component in the atmospheres of the giant planets, such as Jupiter and Saturn, where it contributes to their unique characteristics.
5. The fusion of hydrogen into helium is the primary energy source powering the Sun and other stars, driving their evolution and eventual death.

Review Questions

• Explain the role of helium in the formation of spectral lines and how it is used to identify the element's presence.
  • Helium, like other elements, emits or absorbs specific wavelengths of light, known as spectral lines, when its atoms are excited or de-excited. These spectral lines are unique to each element and can be used to identify the presence of helium in various astronomical and laboratory settings. The observation of helium's spectral lines in the solar chromosphere during a solar eclipse led to the discovery of the element, as these lines did not match any known element at the time.
• Describe the role of helium in the atmospheres of the giant planets and how it contributes to their unique characteristics.
  • Helium is a significant component in the atmospheres of the giant planets, such as Jupiter and Saturn. Its presence, along with hydrogen, helps to determine the overall composition and structure of these planets' atmospheres. Helium's low density and inert nature contribute to the unique characteristics of the giant planets, including their banded appearance, powerful winds, and complex weather patterns. The relative abundance of helium in these planets' atmospheres is also an important factor in understanding their formation and evolution.
• Analyze the importance of helium in the fusion process that powers the Sun and other stars, and how this relates to the evolution and eventual death of these celestial bodies.
  • The fusion of hydrogen into helium is the primary energy source that powers the Sun and other stars. This process, known as nuclear fusion, releases a tremendous amount of energy that sustains the stars' luminosity and drives their evolution over billions of years. As stars age, the helium produced through this fusion process accumulates in their cores, eventually leading to the expansion of the star into a red giant. The further fusion of helium into heavier elements, and the eventual collapse and explosion of the star, are all part of the stellar life cycle that is intimately linked to the role of helium in the energy-producing reactions within these celestial bodies.

Related terms

Atomic Number:

The number of protons in the nucleus of an atom, which defines the element's identity.

Spectral Lines:

Specific wavelengths of light emitted or absorbed by an element, which can be used to identify its presence.

Fusion:

The process of combining light atomic nuclei to form heavier nuclei, releasing a large amount of energy.