The stars at the edges of a galaxy are rotating around the galaxy’s center at the same speed as the stars in the middle of the galaxy. How does this provide evidence of dark matter?(1 point)
Responses
Dark matter provides the gravity that allows the stars to rotate at the same speed.
Dark matter provides the gravity that allows the stars to rotate at the same speed.
Dark matter subtracts gravity, which allows the stars to rotate at the same speed.
Dark matter subtracts gravity, which allows the stars to rotate at the same speed.
Dark matter absorbs light from outside the galaxy, allowing the light of the stars in the galaxy to show the orbital speeds of the stars.
Dark matter absorbs light from outside the galaxy, allowing the light of the stars in the galaxy to show the orbital speeds of the stars.
Dark matter emits the light that astronomers need to see the orbital speeds of the stars.
Dark matter emits the light that astronomers need to see the orbital speeds of the stars.
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Dark matter provides the gravity that allows the stars to rotate at the same speed.
The correct answer is: Dark matter provides the gravity that allows the stars to rotate at the same speed.
The correct answer is:
Dark matter provides the gravity that allows the stars to rotate at the same speed.
This is evidence of dark matter because according to Newton's laws of motion, objects that are farther away from the center of rotation should rotate slower due to the decrease in gravitational pull. However, in a galaxy, the stars at the edges are observed to rotate at the same speed as the stars in the middle. This indicates the presence of invisible matter, known as dark matter, that provides the necessary gravitational force to maintain the uniform rotation. Dark matter is believed to make up a significant portion of the total mass in a galaxy, explaining this observation.