Over the holiday period, the physics arxiv blog is re-running the most popular blogs (by page views) of 2007.<\/p>\n
The incredible galactic foxtrot
\n<\/a>30 August
\n<\/a><\/p>\nYa\u2019ll know the laws of physics are symmetrical\u2013they have no preferred direction. The speed of light (and more or less everything else) is the same whichever way it is pointin\u2019, right?<\/p>\n
So it\u2019d be surprisin\u2019 if the universe turned out to be asymmetric, shockin\u2019 if it had a prefered axis and stunnin\u2019 if it had a direction in which things were different.<\/p>\n
But it\u2019s beginning to look that way. Two years ago, you could hear astro-jaws dropping all over the planet when a couple of upstarts suggested that data from a giant space-thermometer called the Wilkinson Microwave Cosmic Anisotropy Probe or WMAP looked as if it were aligned in a certain direction.<\/p>\n
A-babblin and a-brayin, critics pointed out that the alignment matched the galactic co-ordinate system and so was probably an imprint of the Milky Way. Subtract this properly and the alignment would go away.<\/p>\n
But it didn\u2019t. And that left theorists a-scratchin their heads and a-rubbin their chins in amazement.<\/p>\n
Now they gotta do a whole lot more a-broodin and a-worryin. Michael \u201cBongo\u201d Longo at the University of Michigan has spotted another kind of alignment by a-meterin and a-measurin the orientation of 200,000 elliptical galaxies. That\u2019s a lotta galaxies and it turns out they\u2019re all aligned in the same direction too. We just ain\u2019t noticed before now.<\/p>\n
That\u2019s put a \u2018gator in the pool.<\/p>\n
So what\u2019s been causin this cosmic foxtrot? Ain\u2019t nobody sure but we\u2019re gonna be hearin a lot more about it in the weeks and months to come. Betcha!<\/p>\n