David Kirkpatrick

August 2, 2010

Ever heard of a white hole?

Filed under: Science — Tags: , , , , , — David Kirkpatrick @ 6:22 pm

Me neither.

(And to be clear, the link goes to the physics arXiv blog and an astronomy story and not a NSFW site.)

June 13, 2010

World Cup fans of Spain …

Filed under: Science, Sports — Tags: , , , , , , — David Kirkpatrick @ 12:27 pm

don’t start celebrating just yet.

From the link:

The World Cup offers fans of the globe’s most popular sport the chance to thrill and agonize over the ups and downs of their nations’ teams. For scientists, whether or not they are fans, it’s another chance to collect data and test hypotheses about how close the final match results reflected the relative skill and performance of the two teams — and if they used the best possible winning strategies.

When the dust clears after the  concludes next month, it’s likely that the champion will not be the team that played the best, said Gerald Skinner, an astrophysicist at the University of Maryland in College Park.

Following up on a lunchroom discussion with his avid fan tablemates, Skinner, who admits not being a great sports enthusiast, published a research paper in 2009 that worked out the details of his claim using statistical techniques familiar to astronomers. The findings backed up his posturing.

“It’s not entirely a , but the result of an individual football match has got a very large element of chance and  in it,” said Skinner.

June 11, 2010

A bit on that other type of singularity

Filed under: Science — Tags: , , , , , — David Kirkpatrick @ 2:47 pm

I do a fair bit of blogging about the technological Singularity, but this post is about one the better known scientific singularities —  in this case the singularity that lies at the heart of a black hole and how to go about getting a glimpse of one in all its glory. All that would take is to destroy the black hole that hides the singularity. This physics arXiv blog post is something of an instructional guide on how to go about snuffing out a black hole. Pretty simple in theory, but you know the rest.

From the last link:

In general relativity, the mathematical condition for the existence of a black hole with an event horizon is simple. It is given by the following inequality: M^2 > (J/M)^2 + Q^2, where M is the mass of the black hole, J is its angular momentum and Q is its charge.

Getting rid of the event horizon is simply a question of increasing the angular momentum and/or charge of this object until the inequality is reversed. When that happens the event horizon disappears and the exotic object beneath emerges.

At first sight, that seems straightforward. The inequality suggests that to destroy a black hole, all you need to do is to feed it angular momentum and charge.

And:

To any ordinary physicist, a singularity is an indication that a theory has broken down and some new theory is needed to describe what is going on. It is a matter of principle that singularities are mathematical objects, not physical ones and that any ‘hole’ they suggest exists not in the fabric of the Universe but in our understanding of it.

Astrophysicists are different. They have such extraordinary faith in their theories that they believe singularities actually exist inside black holes. The likes of Roger Penrose and Stephen Hawking have even proved that singularities are inevitable in gravitational collapse.

For them, removing the event horizon around a black hole raises the exciting prospect of revealing a singularity in all its naked glory. When that happens, we will be able to gaze at infinity.