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:
Earth's greenhouse gases trap heat in the atmosphere and warm the planet.
Explanation:
I hope that helped
Soil liquefaction describes a phenomenon whereby a saturated or partially saturated substantially loses strength and stiffness in response to an applied stress, usually earthquake shaking or other sudden change in stress condition, causing it to behave like a liquid.
Answer:
Seafloor spreading results from intense activity in the upper mantle which cracks the crust and pushes it away.
Explanation:
Seafloor spreading is a process that was first noticed by Alfred Wegener and was used by him in his theory of plate tectonics. There are three types of plate boundaries; convergent boundary, transform boundary, and divergent boundary. The last one is the one where seafloor spreading occurs.
The convection currents in the mantle are the process that breaks up the crust and move the tectonic plates, and when there is higher activity than usual at some place it results in break up the crust of an already existing tectonic plate. Basically, magma rises at a higher rate and pushes through the crust, in this case, the oceanic crust, and it manages to gradually break through it and come out on the seafloor. By doing so, the magma and the pressure from below are pushing the two now divided parts of the plate. As the space between the two different parts becomes larger and large the density of the crust becomes smaller and smaller so more and more magma rises through. The magma quickly solidifies on the ocean floor and piles up, thus creating an underwater mountain range known as a mid-ocean ridge.
D Eurasian plate and Australian plate
