Edwin Hubble used the Doppler effect to determine that the universe is expanding. After years of scientific research and observation of different celestial bodies through a telescope, Hubble found that the light from distant galaxies was shifted towards the red end of the spectrum. This red shift indicates that stars are moving away from us and from each other. This phenomenon is called the 'expansion of the universe', also known as the big band theory.
Answer:
I think the answer is B, Rivers. Mountain ranges don't really help the environment much as can mostly only change the climate.
The complete statement made by Stephen Hawking is: "though much of its behaviour through out history, has been pretty stupid, and not calculated to aid the survival of the species."
If one looks at our history, there are some events that defy our capacity for logical thinking. One would think that, as we possess this capacity, we would be able to direct our decisions towards the survival of the human species.
However, in many cases greed and the desire for personal gain have taken precedence. One good example was the burning of the great library of Alexandria, one of the most significant libraries in the ancient world. This magnificent collection was lost during the siege of Alexandria, when Julius Caesar set on fire the ships in the harbor.
Another example is the atomic bomb, when science has been used to invent one of the most destructive weapons known to us. Atomic warfare is still a threat that may end all life on Earth.
Furthermore, the greed of some corporations has led to multiple ecological catastrophes that endanger not only other species but our own future as well. One example is the Bhopal gas leak in India, where in 1984, due to poor maintenance, the chemical plant released 30 metric tons of methyl isocyanite into the atmosphere.
In a Solid, particles are tighly packed together.
In a Liquid, they are farther apart
In a Gas, they are even farther apart.
*Melting = Liquid
*Freezing = Solid
* (E)vaporation = Gas
