Question 1: Define dark mass and dark energy and explain their significance in the universe.

Answer: Dark mass, also known as dark matter, is a mysterious form of matter that does not emit light but exerts gravitational pull; dark energy is a form of energy causing the accelerated expansion of the universe. Both are significant because they make up most of the universe's total mass-energy content and influence its structure and evolution.

Question 2: What percentage of the universe is estimated to be composed of dark matter and dark energy combined?

Answer: Approximately 95% of the universe's total mass-energy content is composed of dark matter and dark energy combined.

Question 3: Multiple Choice: Which of the following best describes dark energy?

Answer: A mysterious energy causing accelerated expansion

Question 4: Fill in the blank: Dark matter cannot be directly observed because it does not emit, absorb, or reflect __________.

Answer: light

Question 5: Explain in your own words how dark matter affects the movement of galaxies.

Answer: Dark matter exerts gravitational pull on galaxies, helping to hold galaxy clusters together and influencing their rotational speeds. Without dark matter, galaxies would not have enough visible mass to account for the observed gravitational effects and would fly apart.

Question 6: Calculate the gravitational force exerted by a dark matter halo of mass 5 x 10^14 kg on a star of mass 2 x 10^30 kg located 10^20 meters away. Use Newton's Law of Gravitation: F = G * (m1 * m2) / r^2, where G = 6.674 x 10^-11 N·m^2/kg^2.

Answer: F = 6.674 x 10^-11 * (5 x 10^14) * (2 x 10^30) / (10^20)^2 = 6.674 x 10^-11 * 1 x 10^45 / 1 x 10^40 = 6.674 x 10^-11 * 1 x 10^5 = 6.674 x 10^-6 N

Question 7: Identify three experimental methods scientists use to detect or study dark matter.

Answer: Scientists use direct detection experiments with sensitive detectors underground, observations of gravitational effects on galaxy rotation curves, and particle collider experiments to produce or detect dark matter particles.

Question 8: Describe a real-world application or technology that relies on the understanding of dark energy or dark matter.

Answer: Understanding dark energy is crucial for cosmology and could influence future technologies related to space travel and energy. While direct applications are limited, ongoing research into dark matter may lead to advancements in particle physics, medical imaging, and materials science.

Question 9: Which statement best explains why dark energy causes the universe to expand at an accelerating rate?

Answer: Because it has a negative pressure that pushes space outward