Question

Choose the best answer to each of the following. Explain your reasoning with one or more complete sentences. Oxygen and carbon are (a) rarer than almost all other elements; (b) found only on worlds close to a star; (c) the third-and fourth-most-abundant elements in the universe.

Short answer

Option (c) is correct as oxygen and carbon are the third-and fourth-most-abundant elements in the universe.

Step-by-step solution

Understand the Options

We have three options to choose from. Option (a) states that oxygen and carbon are rarer than almost all other elements. Option (b) claims they are found only on worlds close to a star. Option (c) suggests they are the third-and fourth-most-abundant elements in the universe.

Evaluate Option (a)

Option (a) is incorrect because both oxygen and carbon are quite abundant in the universe, particularly given their roles in life processes and the formation of molecules. Therefore, it doesn't make sense to consider them rarer than almost all other elements.

Evaluate Option (b)

Option (b) claims that oxygen and carbon are found only on worlds close to a star. This is inaccurate because oxygen and carbon are distributed throughout the universe and can be found in various environments, not just close to stars.

Evaluate Option (c)

Option (c) states that oxygen and carbon are the third-and fourth-most-abundant elements in the universe. This statement is generally accurate as hydrogen and helium are the most abundant, followed by oxygen and carbon in many cosmic environments.

Conclusion

After evaluating the options, option (c) is the most accurate statement regarding the abundance of oxygen and carbon in the universe. This conclusion is based on known cosmic element abundance patterns.

Key concepts

Cosmic Chemistry

Cosmic Chemistry is the study of chemical processes that occur in space. It helps us understand how the elements in the universe came to be and how they interact with one another. At the heart of this field is the notion that the universe's chemistry is driven by a few fundamental forces and processes.

• Stellar nucleosynthesis, where stars serve as cosmic factories creating heavier elements from hydrogen and helium.
• Supernova explosions, which scatter these elements across space, seeding new stars and planets.
• The role of gravity, magnetic fields, and cosmic radiation in shaping chemical reactions over vast distances.

Cosmic chemistry isn't confined to mere theoretical studies. It provides practical insights into the birth and death of stars, formation of planetary systems, and even the potential for life elsewhere. As such, it enriches our understanding of both the universe's evolution and the materials that comprise it.

Chemical Elements in Astronomy

Chemical elements in astronomy form the building blocks of everything in the universe. Elements like hydrogen, helium, oxygen, and carbon play critical roles in constructing cosmic structures.
Elements are categorically established based on their abundance and roles primarily:

• Hydrogen and helium, formed shortly after the Big Bang, are the most abundant elements.
• Carbon and oxygen, resulting from stellar processes, are crucial for forming molecules necessary for life.

Astronomical spectroscopy allows us to determine chemical compositions of stars, galaxies, and nebulae. By analyzing light from these celestial bodies, astronomers can infer their chemical makeup. This data helps scientists understand the age and evolution of various cosmic entities. Understanding the composition of these bodies is essential for studying the universe's history and predicting its future.

Oxygen and Carbon Abundance

Oxygen and carbon are among the most abundant elements in the cosmos, ranking just behind hydrogen and helium. This abundance is no surprise due to their substantial roles in cosmic and biological processes.

Let's dive into why these elements are so prevalent:

• They are products of nucleosynthesis in stars. As stars age, they fuse hydrogen and helium into heavier elements like carbon and oxygen.
• During the explosive end of certain stars, these elements are expelled into space, distributing them across galaxies.

Their roles are designated not only by their quantity in the universe but also by their functionality. Carbon is the backbone of life as it forms complex molecules essential for organic compounds. Oxygen is necessary for water and key respiratory processes in living organisms. Thus, understanding their abundance explains many physical and biological phenomena we observe in our universe.