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.
So how dangerous is the Large Hadron Collider? How likely is it that when operated at maximum energy the LHC will create a black hole and wipe out earth? Eric Johnson, assistant professor of law at the University of North Dakota and author of the report The Black Hole Case: The Injunction Against The End Of The World, writes in a recent edition of New Scientist:
Two and a half months since Erik Verlinde submitted his entropic gravity paper, and all of physics and cosmology has turned into entropy. Well, I am exaggerating a bit, and perhaps more than just a bit. Yet, fact is that within two weeks of Erik's publication a steady stream of 'entropic everything' papers has developed at a rate of close to one paper per day. Gravity, Einstein's equations, cosmic expansion, dark energy, primordial inflation, dark mass: it's all entropic. Chaos rules.
We live in an expanding universe. Distant galaxies move away from us, and these galaxies see us moving away from them. If we reverse time and trace back this expansion, it follows that the universe has evolved from a dense primeval/primordial state. The big bang concept summarized in three sentences.Sounds easy?
Our universe expands, and this expansion is accelerating. Current consensus is to attribute this acceleration to a mysterious form of energy: dark energy. This dark energy density is very tiny and therefore only notable at cosmic length scales. When expressed in natural units, the cosmic dark energy density has a value of 10-123. This tiny value presents a big mystery. Straightforward estimates for the dark energy density based on quantum field theoretical considerations result in values (again in natural units) close to unity.
Three weeks of speculations have come to an end. Since this morning Verlinde's paper is available on arXiv.
“Room for one please!”
With the first decade of the millennium coming to a close, it is time to take stock. What have 'The Noughties' brought us in terms of scientific advances?
Three days ago I wrote a blog about a new theory that seems to lead to the conclusion that gravity is an effect emerging from quantum mechanical principles.
Holographic Hot Horizons
You are in a game show with nineteen other players. You don't know the other players, you can't see them, and you can't communicate with them. The game you are in is called 'Greed!', and is straightforward to explain. You are asked to write down a whole dollar amount in the range $1 - $1,000,000 on a piece of paper. You will be paid the amount you asked for if it is deemed to be 'non-greedy'. Whether your request is indeed 'non-greedy' will be decided once all twenty request have been received by the host of the show. Your requested amount will be labeled 'non-greedy' if no other player has asked for less, and at least one player has asked for more.
What is the size of the universe? How heavy is it? How big can black holes grow? How small are subatomic particles? How many orders of magnitude will I cross when going from the microscopic quantum world to the edge of the universe? Are we humans somewhere in the middle between all these length scales?
Will the $ 1,000,000 Randi Challenge Prize soon be awarded? The prize, administered by the James Randi Educational Foundation (JREF), is offered to anyone who can prove in scientifically controlled tests some form of paranormal power. So far, Randi's prize has not been claimed, but rumour has it that under supervision of the JREF an elaborate telepathy test is being conducted with shocking results.A JREF staff member, who wishes to remain anonymous, commented on the ongoing tests with the words “I have never witnessed anything like this, this is deeply disturbing”.
