Answer: is constant
Explanation:
In order to analyze the velocity of the stars within a galaxy, the <u>galaxy rotation curves</u> (developed by the American astronomer Vera Rubin) are used. These graphs are elaborated as a scatter diagram in which the orbital velocity of the stars present in a galaxy is represented on the Y axis and the distance of these stars to the center of the galaxy on the X axis.
Thanks to this diagram, it has been possible to observe a characteristic behavior in the rotation speed of the stars (and gas) present in the galaxies, which differs from the rules of the orbital movement of the planetary systems postulated by Newton and Kepler.
This means that in these galaxy rotation curves it has been observed that the rotation speed of stars and gas is "constant", regardless of the distance to the center of the galaxy. This discrepancy and these results were then used to demonstrate the existence of dark matter in the universe.
The same thing humans used to do before technological advancements. African tribal people mostly consist of hunger gathers
This statement is false!
Around 90% of all the ozone contained in the atmosphere is accumulated in the stratosphere - this area is also called the ozone layer due to the high concentration of ozone.
Troposphere is below the stratosphere, and it's the one that's closest to the earth.
<span>Jewish nationalist movement that has
had as its goal the creation and support of a Jewish national state in
Palestine, the ancient homeland of the Jews</span>
