Lisa Randall


American Theoretical Physicist, Expert on Particle Physics and Cosmology, Frank B. Baird, Jr. Professor of Science on the Physics Faculty of Harvard University

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However, you will need to know about flavors and generations because of the strong constraints on the particles? properties, which give us vital clues and constraints on the physics that lies beyond the Standard Model. Chief among these constraints is that different flavors of quarks and leptons with the same charges rarely, if ever, turn into one another.

I would say it's important for scientists to speak out when they can and when they can be listened to.

Most people think of "seeing" and "observing" directly with their senses. But for physicists, these words refer to much more indirect measurements involving a train of theoretical logic by which we can interpret what is "seen."

Physics has entered a remarkable era. Ideas that were once the realm of science fiction are now entering our theoretical — and maybe even experimental — grasp. Brand-new theoretical discoveries about extra dimensions have irreversibly changed how particle physicists, astrophysicists, and cosmologists now think about the world. The sheer number and pace of discoveries tells us that we've most likely only scratched the surface of the wondrous possibilities that lie in store. Ideas have taken on a life of their own.

The answer is that in RS2, the influence of four-dimensional gravity is inescapable, no matter where you are in the fifth dimension. Although the graviton?s probability function is largest on the Gravitybrane, objects everywhere can interact with one another by exchanging a graviton, and therefore all objects would experience four-dimensional gravity, independently of location. Gravity everywhere looks four-dimensional because the graviton?s probability function is never actually zero?it continues on for ever. In the localized scenario, objects far from a brane would have extremely weak gravitational interactions, but weak gravity would nonetheless behave in a four-dimensional manner.

Both religions and musicals work best with energetic and committed believers. Cynicism or detachment would have destroyed the magic - something true of religion, too.

I actually like seeing how the world - trying to figure out how the world works, how it all fits together. Also, it makes me happy when I feel like things are consistent, when there's some sort of order to the universe.

If an extra dimension is rolled up into a circle, the mass of the lightest such particle would differ from the electron?s mass by an amount inversely proportional to the extra dimension?s size. That means that, the larger the extra dimension, the smaller the particle?s mass.

Most people want to feel empowered and to experience a sense of belonging. The question each individual faces is whether religion or science offers a greater sense of control over the world. Where do you find trust, comfort, and understanding? Do you prefer to believe that you can figure things out for yourself or at least trust fellow humans to do so? People want answers and guidance that science can?t yet provide.

Religion asks questions about morals, whereas science just asks questions about the natural world. But when people try to use religion to address the natural world, science pushes back on it, and religion has to accommodate the results. Beliefs can be permanent, but beliefs can also be flexible. Personally, if I find out my belief is wrong, I change my mind. I think that's a good way to live.

The best science frequently combines an awareness of broad and significant problems with focus on an apparently small issue or detail that someone very much wants to solve or understand. Sometimes these little problems or inconsistencies turn out to be the clues to big advances.

But speculation is the only way to make progress in our understanding.

I can be a good listener. I can ask the right questions a lot of the time.

If large extra dimensions solve the hierarchy problem, higher-dimensional gravity would become strong at about a TeV.

Most physicists like myself won't believe the result until every possible caveat has been investigated and/or the result is confirmed elsewhere.

Religion can have psychological and social roles, but in terms of really explaining how things work, science works differently. Science is based on material elements at the core.

The ceremonial key to the city of Padua is engraved with a quote from Galileo that is also on display at the physics department of the university...'I deem it of more value to find out a truth about however light a matter than to engage in long disputes about the greatest questions without achieving any truth.

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American Theoretical Physicist, Expert on Particle Physics and Cosmology, Frank B. Baird, Jr. Professor of Science on the Physics Faculty of Harvard University