Expanding Horizons: A Quiz on Hubble's Law and Cosmology

The astronomer credited with discovering the expansion of the universe is Edwin Hubble. He observed the red shifts in the light from distant galaxies, indicating their motion away from us.

The red shift in light from distant galaxies indicates that "The galaxies are moving away from Earth." This phenomenon is a fundamental observation that provides evidence for the expansion of the universe, consistent with Hubble's Law. As galaxies move away from us, the light they emit is shifted toward longer wavelengths, which appears redshifted.

Hubble's law is defined as: "The law that states galaxies are moving away from each other at a speed proportional to their distance." This fundamental principle in cosmology, formulated by Edwin Hubble in the early 20th century, describes the expansion of the universe. It's a key concept in modern astrophysics and cosmology.

The slope of the Hubble's Law graph represents the rate of expansion of the universe. It quantifies how fast galaxies are moving away from us as a function of their distance. The Hubble constant, denoted as "H₀," is the slope of this relationship and is a crucial parameter in cosmology for understanding the rate of cosmic expansion.

Based on current observations, the estimated age of the universe is approximately 13.7 billion years. This determination is made using various methods such as measuring the cosmic microwave background radiation.

An expanding universe is characterized by galaxies moving away from each other. This movement is evidenced by the observed red shifts in their light.

The significance of the blue shift in light from nearby galaxies is that it indicates: The galaxies are moving closer to Earth. A blue shift occurs when the light emitted by objects, such as galaxies, is shifted toward shorter wavelengths, which is a result of the objects moving closer to the observer. 

The expansion of the universe is accelerating. This conclusion is based on observations of distant supernovae and the measurements of cosmic microwave background radiation.

The term 'cosmology' refers to the study of the origins and structure of the universe. It involves understanding the large-scale properties of the universe, its composition, and its evolution.

The theory that explains the expansion of the universe is called the Big Bang theory. It states that the universe originated from a highly dense and hot state approximately 13.8 billion years ago.

The primary evidence for the expansion of the universe is the observed red shift in light from distant galaxies. This phenomenon indicates that galaxies are moving away from us and supports the concept of an expanding universe.

Dark energy is believed to be the force responsible for the expansion of the universe. It is a hypothetical form of energy that permeates space and is causing the acceleration of the universe's expansion.

The term used to describe the apparent change in frequency of light due to the relative motion between the source and the observer is the Doppler effect. It is responsible for the observed red and blue shifts in light from celestial objects.

The law of conservation of angular momentum states that the angular momentum of a system remains constant unless acted upon by an external torque. This principle is important in understanding the rotational motion of celestial objects.