Which component that makes up the bulk of all galaxies?(1 point) Responses stars stars gas gas dust dust dark matter
stars
How does the appearance of spiral galaxies vary? Select the two correct answers.(1 point) Responses They vary in the brightness of stars located on their arms. They vary in the brightness of stars located on their arms. They vary in how tightly their arms are wound. They vary in how tightly their arms are wound. Some are more elongated in shape than others. Some are more elongated in shape than others. Some have a band of stars and materials through their middle, but others do not.
They vary in the brightness of stars located on their arms.
Some are more elongated in shape than others.
Which statements describe elliptical galaxies? Select the two correct answers.(1 point) Responses They include the Milky Way. They include the Milky Way. They typically contain very little gas and dust. They typically contain very little gas and dust. They include the universe's largest galaxies. They include the universe's largest galaxies. They are the most common galaxy type.
They typically contain very little gas and dust.
They are the most common galaxy type.
The component that makes up the bulk of all galaxies is stars.
The component that makes up the bulk of all galaxies is dark matter. To determine this answer, scientists have conducted numerous observations and measurements of galaxies using various techniques.
One of the most important methods is gravitational lensing, which involves studying the bending of light caused by the gravity of massive objects. By observing how light from distant galaxies is distorted as it passes through the foreground galaxies, scientists can estimate the total mass of the intervening galaxies. These observations have consistently revealed that the visible matter in galaxies, such as stars, gas, and dust, is not sufficient to explain the observed gravitational effects.
Dark matter is a type of matter that does not interact with light or other electromagnetic radiation, making it invisible to our current detection methods. However, its presence is inferred from its gravitational effects. Dark matter is thought to make up about 85% of the total matter in the universe, with the remaining 15% being ordinary matter, including the visible components of galaxies.
To summarize, by studying the gravitational effects on light and analyzing the movements of galaxies, scientists have determined that dark matter is the primary component that makes up the bulk of all galaxies.