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.
Answer:
B. An atom is a solid sphere
Explanation:
The idea that the atom was a solid sphere paved back to the first atomic model in the <em>19th century</em> theorized by <em>John Dalton</em>. According to him, an atom is <u>intact and hard and cannot be broken down or divided</u>.
However, many scientists continued to research and it was found that <em>the atom was not actually a solid sphere.</em> It was made up of<em> protons (positively-charged), electrons (negatively-charged) and neutrons (neutrally-charged). </em>This invalidated Dalton's solid sphere model.
There are various ways, you can recycle or the use of hydroelectricity. Hydroelectricity is energy of water turning turbines or wheels in a dam. There is also air power through windmills. <span />
Answer:
If the intrusive igneous rock is uplifted or the material around it erodes and is carried off, the igneous rock can end up on the surface of the Earth.
Answer:
the Pacific Ocean has the ring of fire around it
