Lawrence M. Krauss

More often than you might think, teaching science is inseparable from teaching doubt.

The one thing that I want every single child to have experienced at some point in their life, as part of their education, is to have some idea they hold to be true, and at the very basis of their being, proved to be wrong.Because that opens your mind to the realization that the world is different than you thought it would be, and you have to begin to open your mind to the possibilities of existence.And opening your mind frees you, it doesn't constrain you. It makes the world more wonderful, more exciting, and more worth living in.

Of course, supernatural acts are what miracles are all about. They are, after all, precisely those things that circumvent the laws of nature. A god who can create the laws of nature can presumably also circumvent them at will. Although why they would have been circumvented so liberally thousands of years ago, before the invention of modern communication instruments that could have recorded them, and not today, is still something to wonder about.

If we wish to draw philosophical conclusions about our own existence, our significance, and the significance of the universe itself, our conclusions should be based on empirical knowledge. A truly open mind means forcing our imaginations to conform to the evidence of reality, and not vice versa, whether or not we like the implications.

[I]n science we have to be particularly cautious about 'why' questions. When we ask, 'Why?' we usually mean 'How?' If we can answer the latter, that generally suffices for our purposes. For example, we might ask: 'Why is the Earth 93 million miles from the Sun?' but what we really probably mean is, 'How is the Earth 93 million miles from the Sun?' That is, we are interested in what physical processes led to the Earth ending up in its present position. 'Why' implicitly suggests purpose, and when we try to understand the solar system in scientific terms, we do not generally ascribe purpose to it.

It's hard to imagine a more extraordinary claim than that some hidden intelligence created a universe of more than a hundred billion galaxies, each containing more than a hundred billion stars, and then waited more than 13.7 billion years until a planet in a remote corner of a single galaxy evolved an atmosphere sufficiently oxygenated to support life, only to then reveal his existence to an assortment of violent tribal groups before disappearing again.

For most people, the central questions of existence ultimately come down to transcendental ones: Why is there a universe at all? Why are we here?Whatever presumptions one might bring to the question "Why?," if we understand the "how" better, "why" will come into sharper focus.

The universe has a much greater imagination than we do, which is why the real story of the universe is far more interesting than any of the fairy tales we have invented to describe it.

Now, almost one hundred years later, it is difficult to fully appreciate how much our picture of the universe has changed in the span of a single human lifetime. As far as the scientific community in 1917 was concerned, the universe was static and eternal, and consisted of a one single galaxy, our Milky Way, surrounded by vast, infinite, dark, and empty space. This is, after all, what you would guess by looking up at the night sky with your eyes, or with a small telescope, and at the time there was little reason to suspect otherwise.

Metaphysical speculation is independent of the physical validity of the Big Bang itself and is irrelevant to our understanding of it.

In 5 billion years, the expansion of the universe will have progressed to the point where all other galaxies will have receded beyond detection. Indeed, they will be receding faster than the speed of light, so detection will be impossible. Future civilizations will discover science and all its laws, and never know about other galaxies or the cosmic background radiation. They will inevitably come to the wrong conclusion about the universe......We live in a special time, the only time, where we can observationally verify that we live in a special time.

The amazing thing is that every atom in your body came from a star that exploded. And, the atoms in your left hand probably came from a different star than your right hand. It really is the most poetic thing I know about physics: You are all stardust. You couldn__ be here if stars hadn__ exploded, because the elements - the carbon, nitrogen, oxygen, iron, all the things that matter for evolution - weren__ created at the beginning of time. They were created in the nuclear furnaces of stars, and the only way they could get into your body is if those stars were kind enough to explode. So, forget Jesus. The stars died so that you could be here today.

The purpose of education is not to validate ignorance but to overcome it

Neutrinos alone, among all the known particles, have ethereal properties that are striking and romantic enough both to have inspired a poem by John Updike and to have sent teams of scientists deep underground for 50 years to build huge science-fiction-like contraptions to unravel their mysteries.

By no definition of any modern scientist is intelligent design science, and it's a waste of our students' time to subject them to it.

The illusion of purpose and design is perhaps the most pervasive illusion about nature that science has to confront on a daily basis.

It never ceases to amaze me that every second of every day, more than 6,000 billion neutrinos coming from nuclear reactions inside the sun whiz through my body, almost all of which will travel right through the earth without interruption.

The root cause of the looming energy problem - and the key to easing environmental, economic and religious tensions while improving public health - is to address the unending, and unequal, growth of the human population. And the one proven way to reduce fertility rates is to empower young women by educating them.