As I’ve written about before, the existence of dark matter is well supported by observational evidence. There isn’t much debate in the astronomical community on the existence of dark matter and the fact that it makes up a large part of the mass of galaxies. We’d still like to have a direct observation of dark matter to be certain sure, but there is general consensus on dark matter.
Higgs Goes the Theory
Recently in the news there’s been talk of a new cosmological model known as Higgsogenesis. A paper outlining this model has been recently been published Physical Review Letters. The term Higgsogenesis refers to the first appearance of Higgs particles in the early universe, just as baryogenesis refers to the appearance of baryons (protons and neutrons) in the early moments after the big bang. While baryogenesis is a fairly well understood process, Higgsogenesis is still very hypothetical.
The Gripping Hand
The image above shows a pair of colliding spiral galaxies known as Arp 274. What’s interesting is not that they happen to be colliding, but that the two galaxies are spiraling in opposite directions. The one on the left spirals in a clockwise direction, while the one on the right spins in a counterclockwise direction. Sometimes we’ll refer to the left galaxy as left-handed, while the right one is right-handed. The reason is that if you hold hands up with your thumbs pointing at yourself, you’ll see the fingers on your left hand curve clockwise, and the fingers on your right hand curve counterclockwise.
Walk the Planck
One of the recent sagas in cosmology began with the BICEP2 press conference announcing evidence of early cosmic inflation. There was some controversy since the press release was held before the paper was peer reviewed. The results were eventually published in Physical Review Letters, though with a more cautious conclusion than the original press release. Now the Planck team has released more of their data. This new work hasn’t yet been peer reviewed, but it doesn’t look good for BICEP2.
Big Bang Burger Bar
Lately there’s been news of a radical new theory proposing that the universe began from a hyper-dimensional black hole. Most of the reports seem to stem from an article posted a while back on the Nature blog, which references the original paper. So let’s have a little reality check.
Getting Bent
One of the big questions in cosmology regards the shape of the universe. “Shape” in this case is not the distribution of galaxies, but rather the shape of space and time itself. In general relativity, space and time can be warped by masses (producing the effect of gravity), and it can be warped by dark energy (producing cosmic expansion). Knowing the shape of the cosmos lets us determine if it is finite in size or infinite, and whether it will expand forever or collapse back upon itself.
Cold Comfort
The cosmic microwave background (CMB) is the thermal afterglow of the primordial fireball we call the big bang. One of the striking features of the CMB is how remarkably uniform it is. Still, there are some small variations in temperature at various points in the sky. This is actually expected, and in fact the scale at which these fluctuations occur tells us a great deal about the structure of the universe. But there is also a fluctuation that isn’t expected, and its cause is a bit of a mystery. It is known as the CMB cold spot, and there has been much speculation as to its cause.
Sound It Out
Imagine a stadium filled with people. With everyone is in their seats, waiting for the game to begin, there is an undercurrent of noise. A few words between friends, the scuffle of shoes, the creak of a chair. All of these little sounds fill the stadium with a background of white noise. A similar “white noise” occurs with galaxies in our universe, and it helps us understand dark energy.
Calling the Question
A couple days ago I wrote about a rather large cluster of quasars, and how it seemed to be larger than we’d expect for the universe as we know it. The post gathered the attention of an anonymous commenter, who pointed out an opposing view regarding this research. The rebuttal to the cluster research was published in MNRAS, and makes a rather simple claim: not all patterns are real. In other words, if you look deep enough for a pattern in your data, you are bound to find one, even if it is really just noise.