Gravitational attraction

Definition

Gravitational attraction is the force that pulls two masses toward each other, determined by their mass and the distance between them. This force is fundamental in shaping the structure and evolution of the universe, influencing the motion of celestial bodies and the behavior of galaxies over cosmic time.

5 Must Know Facts For Your Next Test

1. Gravitational attraction is responsible for keeping planets in orbit around stars, as well as moons in orbit around planets.
2. The strength of gravitational attraction decreases with increasing distance between masses, which is described by the inverse-square law.
3. In cosmology, gravitational attraction is essential for understanding the large-scale structure of the universe, including galaxy clusters and superclusters.
4. Gravitational attraction can lead to phenomena like gravitational lensing, where light from distant objects is bent around massive objects, revealing information about the distribution of mass in the universe.
5. The role of gravitational attraction in cosmic expansion has evolved; initially it slowed down the expansion, but now dark energy dominates and causes an accelerated expansion.

Review Questions

• How does gravitational attraction influence the formation and evolution of galaxies?
  • Gravitational attraction plays a critical role in the formation and evolution of galaxies by pulling together gas and dust to form stars and stellar clusters. As these structures grow larger, their combined gravitational pull can attract more matter, leading to further growth. Over time, this process shapes galaxies into various forms, influencing their size, structure, and even interactions with neighboring galaxies.
• Discuss how Newton's Law of Universal Gravitation applies to our understanding of celestial motion and the structure of the universe.
  • Newton's Law of Universal Gravitation provides a framework for understanding how celestial bodies interact through gravitational attraction. By calculating the forces between objects based on their masses and distances, we can predict their orbits and movements. This law lays the groundwork for more complex theories in cosmology, such as those involving dark matter and cosmic expansion, helping us understand large-scale structures like galaxy clusters.
• Evaluate the implications of gravitational attraction on cosmic expansion and its interaction with dark energy over time.
  • Gravitational attraction initially countered cosmic expansion by pulling matter together, helping to form galaxies and large-scale structures. However, as the universe expanded, dark energy emerged as a dominant force causing acceleration in this expansion. The interplay between gravitational attraction and dark energy leads to a dynamic evolution of the universe's structure, resulting in a complex relationship where gravitational forces compete against the repulsive effects of dark energy on large scales.

Related terms

Newton's Law of Universal Gravitation:

A fundamental principle stating that every point mass attracts every other point mass in the universe with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

Dark Matter:

An unknown form of matter that does not emit light or energy, yet exerts gravitational attraction on visible matter, influencing the structure and dynamics of galaxies.

Cosmic Microwave Background (CMB): The afterglow radiation from the Big Bang, providing a snapshot of the early universe, where gravitational attraction played a key role in the formation of large-scale structures.