This means that at earlier times objects would have been closer together. In fact, it seemed that there was a time, about ten or twenty thousand million years ago, when they were all at exactly the same place and when, therefore, the density of the universe was infinite.

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I have experimental evidence that time travel is not possible.

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What is important is that we have the ability to create.

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Nothing is better than reading and gaining more and more knowledge.

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I would see the end of physics as we know it, but now I think the wonder of discovery will continue long after I am gone. We are close to some of these answers, but we are not there yet.

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We spend a great deal of time studying history, which, let’s face it, is mostly the history of stupidity. So

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You can’t get to a time before the Big Bang because there was no time before the Big Bang. We have finally found something that doesn’t have a cause, because there was no time for a cause to exist in.

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I think the human race has no future if it doesn't go into space.

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Unfortunately, however, these two theories are known to be inconsistent with each other—they cannot both be correct.

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How difficult life may seem, while there’s life, there is hope.

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