Answer to Question 1
Interstellar dust obscures most of the light from the galactic center and blocks light from many parts of the disk. Until modern telescopes were able to look at other parts of the electromagnetic spectrum, the galaxy could not be studied and understood in detail.
Answer to Question 2
Speed is the pace at which an object moves through a distance (regardless of direction).Velocity is the pace at which an object moves through a distance, including a specific direction. Acceleration is the rate at which an object's velocity changes. The distinguishing feature between speed and velocity is that speed does not include a direction, whereas velocity specifies a direction.
Illustration of the Milky Way galaxy, showing the location of the Sun
The continents were not always in their present positions. The position of the continents is importa
In 2008, the U.S. economy suffered a gaping wound as several trillion dollars were ripped out of it.
Prisoners from the front (1866) established Winslow Homer's reputation for spare truthfulness.
The three stages we go through to develop the ability of taking the role of the other.
Mirror recognition and self-naming develop at almost exactly the same time