Anyone announcing the successful sale of tourist trips around the moon would attract ridicule and laughter. Unless your name is Elon Musk. In that case the announcement amounts to nothing more than a logical and rather modest step towards Musk's promise of getting a million people to live on Mars.
Today I have a decision problem for you.
Today I took delivery of my copy of Tony Zee’s third contribution to the Princeton University Press In a Nutshell series: “
Lots of people have asked me for my views on Erik Verlinde’s latest paper “Emergent Gravity and the Dark Universe“. This fifty-one pages long preprint has attracted a fair bit of media attention. Particularly in the Netherlands, Verlinde’s name being attached to the draft paper has caused a true hype.
Black holes are hot. Well, thermodynamically these suckers are freaking cold, but they do attract more attention than hot supernovae. And with attention comes recognition. As announced last month, as much as 97% of the $ 6.3 mln 2016 Breakthrough Prize money for physics went to black hole research.
--- repost due to previous version not surviving server maintenance ---Black holes are hot. Well, thermodynamically these suckers are freaking cold, but they do attract more attention than hot supernovae. And with attention comes recognition. As announced last month, as much as 97% of the $ 6.3 mln 2016 Breakthrough Prize money for physics went to black hole research.
In a world where individuals have ranked preferences, it is not possible to create a voting procedure that is guaranteed to yield a fair selection between more than two alternatives. This is a mathematical certainty: in 1951 Nobel laureate Kenneth Arrow gave the mathematical proof.
We power humanity mostly by burning fossil fuels, thereby turning chemical energy into heat that ultimately gets radiated into space. In doing so we achieve some results deemed useful: we cook food, we keep our homes and offices at comfortable temperatures, we watch television, listen to music, take hot showers, generate light during dark hours, and move from A to B and back.
Leonard: "The holographic principle suggests that what we all experience every day in three dimensions may really just be information on a surface located at the farthest reaches of our cosmos. So it's possible that our lives are really just acting out a painting on the largest canvas in the universe." Penny: "Hmmm..."Is our universe holographic? Is what is happening in the universe somehow encoded on its boundary? Are we 3D renderings of some distant 2D image? Black hole physics certainly suggests so. But how does such an encoding work? Can we visualize a system that "just acts out" a painting on its boundary?
Science is what scientist do. And the scientific method is the method scientists follow. A tautology you say? Not according to George Ellis and Joe Silk. In an opinion paper in Nature under the title 'Scientific method: Defend the integrity of physics' Ellis and Silk argue that string theorists and cosmologists contributing to inflationary cosmology are rapidly turning physics into "a no-man's-land between mathematics, physics and philosophy that does not truly meet the requirements of any". The two authors play the 'testability card' and claim the high ground of scientific integrity, thereby dismissing a vast body of contemporary science as unscientific.
Our universe is eternal, expanding indefinitely, and not threatened by any form of 'heath death'. All evidence points into this direction. In fact, at the end of the nineteenth century Ludwig Boltzmann had collected all the evidence to draw such conclusions. His consistent reasoning on how to render the reversible laws of physics compatible with the second law of thermodynamics brought him close, but he failed to make the final decisive steps. Ok, I realize that at Boltzmann's time our knowledge of the universe didn't stretch beyond the Milky Way, the island of stars that we inhabit. And yes, I admit reasoning here with the benefit of a heap of hindsight. But even now, in the twenty-first century, this hindsight is apparently not distributed uniformly.
An infinite number of mathematicians walk into a bar. The first mathematician orders a beer. The second orders two beers. The next orders four. Followed by the next who orders eight. The bartender interrupts them: "ok guys, cut the crap: you owe me one beer". ---------------------------------------------
A recently posted Numberphile video is heading towards 2 million hits on YouTube. That is an impressive score for a video focusing on a math subject. The two physicists in the video try to convince the viewer that all positive integers add up to -1/12. Yes, you read that correctly: these damn physicists dare to argue that 1 + 2 + 3 + 4 + ... = -1/12.
In 1937, Dirac made the bold conjecture that since the big bang, gravity has been weakening. The cold reception that greeted his highly speculative and numerology-based cosmology paper didn't seem to hurt him much. This was a decade after Dirac discovered the quantum relativistic equation for the electron, and his mega-stardom status could take a few hits without getting eroded significantly. Still, during the rest of his productive life, Dirac stayed away from cosmology and shrinking gravity models.
