Two galaxies on opposite ends of the universe are moving away from the Earth. Each has a velocity of 200,000 km/s relative to the Earth. How fast would an observer in one of those galaxies see the other galaxy moving away? (1 point)
Responses
between 200,000 and 300,000 km/s
between 200,000 and 300,000 km/s
between 300,000 and 400,000 km/s
between 300,000 and 400,000 km/s
200,000 km/s
200,000 km/s
400,000 km/s
The correct answer is between 200,000 and 300,000 km/s.
The correct answer is between 400,000 and 500,000 km/s.
When two galaxies are moving away from each other, their relative velocity is the sum of their individual velocities. In this case, both galaxies have a velocity of 200,000 km/s relative to the Earth. Therefore, an observer in one of those galaxies would see the other galaxy moving away with a velocity of 200,000 km/s + 200,000 km/s = 400,000 km/s.
To determine how fast an observer in one galaxy sees the other galaxy moving away, we need to consider the concept of relative velocity. The relative velocity is the difference in velocities between the two objects.
In this case, both galaxies are moving away from the Earth with a velocity of 200,000 km/s relative to our reference point. To find the relative velocity between the two galaxies, we can subtract their velocities.
Since both galaxies have the same velocity of 200,000 km/s relative to the Earth, their velocities relative to each other would be zero. This means that an observer in either galaxy would perceive the other galaxy as not moving away from them.
Therefore, the correct answer is 0 km/s.