origins of the dark flow

From New Scientist: Dark flow: Proof of another universe?

First off: did you know 45 billion light years is the furthest we can observe from Earth? I did not, and I don't quite understand how considering the universe is only supposed to be a little less than 14 billion years old. (I've heard of inflation and all that, but I'm still boggled.)

Anyway, this is a pretty interesting article about something called dark flow. Apparently, a team from NASA led by Dr. Sasha Kashlinsky noticed that there are a lot of galaxy clusters (they were studying almost 800) "racing at up to 1000 kilometres per second" "toward a small patch of sky between the constellations of Centaurus and Vela." (They're southern constellations; take a look at this map around -40˚.) This is strange because galaxies and galaxies clusters should be moving along with the expansion of space. Kashlinsky thinks something on the "cosmic horizon" is causing this, where conditions could be totally different from what they are in the observable universe, where matter and energy are fairly evenly distributed.

Other theories: "the dark flow is caused by other universes exerting a gravitational pull on galaxy clusters in our universe[;]" "dark flow could be a sign that our bubble universe crashed into another bubble just after the big bang[;]" or that the current cosmological model is wrong, matter is not evenly distributed, and "that at large scales matter is like a fractal."

It makes me a little sad that we might never know.

indecent singularities

From Scientific American: Do Naked Singularities Break the Rules of Physics?

In this article, Dr. Pankaj Joshi at the Tata Institute of Fundamental Research in Mumbai discusses the possibility of naked singularities. (I know that sounds a little naughty, but bear with me, because it actually is thrilling in its own way.) Naked singularities are basically black holes, without an event horizon. So, there would be a point of infinity density without the same effect on gravity; there would not be the same "point of no return" as there is with black holes. In addition, if naked singularities do exist, it would be possible for them to be observed directly. Theoretical models seem to show that with a certain inhomogeneity of density in a star, this type of singularity could be formed.

m theory, dark matter, and a phoenix universe

From New Scientist: Did dark energy give us our cosmos?

This theory puts together a couple of my favorite ideas. First, in M theory, our universe is just a part of a larger structure. The article talks about it "exists on a 3D region called a 'brane' separated from similar branes by a fourth spatial dimension." Sometimes, these branes collide, causing something like the big bang. Next, the universe is in a never-ending cycle of bang, expansion, and then contraction. (I like this because not only does it answer the question of what came before the big bang, but it also eliminates eternal expansion and eternal death of heat, light, etc., which scares me in a way it shouldn't considering I won't live that long.)

The problem with this idea is that all the different parts of the extended 'verse would have to move to fit expanding and contracting branes, so "large areas of the brane become warped, so that most of it ends up as black holes and only a tiny proportion as ordinary, habitable space." But! Add the element of dominant, pervasive dark matter, and the theory starts to come together. Sweet.

blowing my mind

From New Scientist: Our world may be a giant hologram

I can't even begin to talk about this crazy, amazing research. So I'll just quote from the article.

For the past seven years, this German set-up has been looking for gravitational waves - ripples in space-time thrown off by super-dense astronomical objects such as neutron stars and black holes. GEO600 has not detected any gravitational waves so far, but it might inadvertently have made the most important discovery in physics for half a century.

For many months, the GEO600 team-members had been scratching their heads over inexplicable noise that is plaguing their giant detector. Then, out of the blue, a researcher approached them with an explanation. In fact, he had even predicted the noise before he knew they were detecting it. According to Craig Hogan, a physicist at the Fermilab particle physics lab in Batavia, Illinois, GEO600 has stumbled upon the fundamental limit of space-time - the point where space-time stops behaving like the smooth continuum Einstein described and instead dissolves into "grains", just as a newspaper photograph dissolves into dots as you zoom in. "It looks like GEO600 is being buffeted by the microscopic quantum convulsions of space-time," says Hogan.

If this doesn't blow your socks off, then Hogan, who has just been appointed director of Fermilab's Center for Particle Astrophysics, has an even bigger shock in store: "If the GEO600 result is what I suspect it is, then we are all living in a giant cosmic hologram."

I can't decide if I'm freaked out, or amazed, or both.