Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 22: Problem 19

If the universe is being forced apart by dark energy, why isn't the Milky Way Galaxy, the Solar System, or the planet Earth being torn apart?

Short Answer

Expert verified
Gravitational forces within galaxies, solar systems, and planets are strong enough to counteract the expansive effects of dark energy.

Step by step solution

01

Understand Dark Energy

Dark energy is a mysterious form of energy that is causing the accelerated expansion of the universe. Its effects are significant on a cosmological scale.
02

Gravitational Forces at Play

Gravitational forces within structures like galaxies, solar systems, and planets are strong enough to keep these systems intact against the expansive force of dark energy.
03

Explain the Scale of Dark Energy's Effects

Dark energy primarily affects the large-scale structure of the universe. On smaller scales, such as galaxies, solar systems, and planets, gravitational forces dominate, which prevents these structures from being torn apart.
04

Result

The gravitational forces within the Milky Way Galaxy, the Solar System, and the planet Earth are sufficiently strong to counteract the effects of dark energy, keeping them intact.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Cosmological Scale
The cosmological scale refers to the vast distances and sizes involved when studying the Universe as a whole. When we talk about the cosmos, we think in terms of billions of light-years.
Dark energy comes into play on this grand scale. It exerts its mysterious force across the broad expanse of space, causing the Universe to expand faster and faster.
On such a massive scale, dark energy has the power to stretch the very fabric of the cosmos. However, its influence decreases dramatically when we zoom in to look at smaller structures like galaxies or solar systems.
Galactic Structures
Galactic structures, such as the Milky Way, are bound together by gravitational forces. These forces are exceptionally strong within galaxies because they contain massive amounts of matter, including stars, gas, and dark matter.
This gravitational pull is what keeps galaxies intact, despite the expanding nature of the Universe driven by dark energy. Inside a galaxy, the gravitational attractions among its components counteract the expansive force of dark energy.
So while the Universe is expanding, galaxies like the Milky Way remain gravitationally bound and are not 'torn apart.'
Accelerated Expansion of the Universe
The accelerated expansion of the Universe is a phenomenon driven by dark energy. Since the late 1990s, scientists have observed that galaxies are moving away from each other at an increasing rate.
This is due to dark energy, which exerts a repulsive force counteracting gravity on vast scales. It affects the overall structure of the Universe, making it grow larger over time.
The important thing to note is that this expansion is most pronounced between galaxy clusters, not within them. Thus, local structures like galaxies and solar systems are largely unaffected by this cosmic push-and-pull on smaller scales.
Gravitational Dominance
Gravitational dominance means that within certain scales, gravity overwhelms the influence of dark energy.
For instance, within a galaxy, the gravitational pull between stars, planets, and other celestial bodies is strong enough to hold everything together.
In smaller systems, like our Solar System or even the planet Earth, gravity is vastly more influential than dark energy. This gravitational dominance ensures these structures remain stable and bound, unaffected by the accelerating expansion of the Universe.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

What is the flatness problem, and why has it created difficulties for cosmologists?

During the period of inflation, the universe may have briefly expanded at \(10^{30}\) (a million trillion trillion) or more times the speed of light. Why did this ultra-rapid expansion not violate Einstein's special theory of relativity, which says that neither matter nor communication can travel faster than the speed of light?

Suppose you brought together a gram of ordinary-matter hydrogen atoms (each composed of a proton and an electron) and a gram of antimatter hydrogen atoms (each composed of an antiproton and a positron). Keeping in mind that 2 grams is less than the mass of a dime: a. Calculate how much energy (in joules) would be released as the ordinary- matter and antimatter hydrogen atoms annihilated one another. b. Compare this amount of energy with the energy released by a 1-megaton hydrogen bomb \(\left(4.2 \times 10^{15} \mathrm{J}\right)\)

Astronomers will never directly observe the first few minutes of the universe because a. the universe was opaque at that time. b. the universe is too large now. c. there were no particles or other matter to see. d. there were no photons.

The standard model cannot explain why neutrinos have mass or why electron- positron asymmetry existed in the early universe. Do these failings make it an incomplete theory? Should all of its predictions be ignored until the theory can resolve these remaining issues?
See all solutions

Recommended explanations on Physics Textbooks

Physical Quantities And Units

Read Explanation

Engineering Physics

Read Explanation

Energy Physics

Read Explanation

Turning Points in Physics

Read Explanation

Thermodynamics

Read Explanation

Waves Physics

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free