Answer:
b. flat rotation curves in spiral galaxies
Explanation:
Dark matter accounts for majority of the matter in the universe (about 85%). It is considered to be composed of subatomic particles which are yet to be discovered. Dark matter cannot be observed because it does not emit light that can be detected. Only its gravitational effect is visible.
Astronomers when calculated the mass of the visible matter and tried to account for the observed speed of stars in the galaxy, there was a mismatch. To understand what caused this mismatch, astronomers gave name to the invisible matter as the Dark Matter.
The expected velocity of stars should decrease away from the near the center of the galaxy but a constant velocity of stars was observed that is a relatively flat rotation curve was obtained.
Thus, flat rotation curves in spiral galaxies in an evidence of Dark Matter.
Explanation is in a file
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Answer:
The instruments' ability to extract iron from surroundings
Explanation:
In the book One Hundred Years of Solitude written by Gabriel Garcia Marquez, it was revealed that Jose Arcadio Buendia was fascinated by two magnetized ingots he bought from Melquíades the gypsy.
Hence, due to the ability of the magnetized ingots to draw irons, Jose Arcadio Buendia thought he could use the instrument's ability to extract gold from the underneath of the earth. He, therefore, traded his mule and pair of goats to buy the magnetized instruments.
Answer:
In a divergent plate boundary, two plates move away from one another. Due to this divergent movement of plates, seafloor spreading takes place in the ocean basin along the mid-oceanic ridge and rifting take place in the continental areas. Due to the stretching of the crust, the lithosphere becomes thin, and with more progressive spreading, it results in the eruption of magma at the seafloor. This magma is basaltic in nature, that reaches the surface due to the force exerted by the uprising magma forming convection cells in the mantle. This type of plate motion results in the expansion of the ocean basin and the rift valley in the continental areas forms seas and oceans with increasing time.
The rocks that are formed at the mid-oceanic ridge are the youngest as the magma cools and solidifies very rapidly here. With further moving away from this spreading center the age of the rocks increases.
The divergent plate boundaries are also responsible for the occurrence of deep-focus earthquakes, and it also leads to the formation of volcanoes in its adjacent sides.
