April 22, 2009

Galaxies like Toilet Flushes Spin Left or Right

Polar plot of net asymmetries A in 30° sectors in right ascension and slices in z. Segments with positive A are indicated in red and negative A in blue. [blue are left hand spinning and red are right hand spinning] The A for segments with <10 galaxies are not shown. The larger numbers near the periphery give the overall asymmetry for that sector; the black numbers in parentheses are the total number of spiral galaxies in the sector. The NGP is the north pole of our Galaxy, so that the left half of the plot corresponds roughly to the northern Galactic hemisphere. The black arrow shows the most probable dipole axis. Declinations between -19° and +60° were used.

11 page survey of galaxies and how many spin counter-clockwise (left handed) and how many spin clockwise (right handed)

Table I. Number counts and net asymmetries A =(NR– NL)/NTot for the right ascension ranges indicated. The last two columns give the number of standard deviations for the A and the probability.

α Range NR NL NTot A ± σ A / σ Prob.
-15° to 45° 495 490 985 0.005 ±0.032 +0.16 0.87
165° to 225° 2890 3322 6212 –0.0695±0.0127 –5.48 2.1x10-8
Overall 7197 -0.0607±0.0118 –5.15 2.5x10-7

A positive A value means more right hand galaxies. A negative A value means more left handed galaxies.

The evidence seems to indicate that left handed spirals are more common in the northern hemisphere, above the northern galactic pole. And although the signal is less strong, right-handed spirals appear more frequently in the south.

Quote from the Princess Bride
Inigo Montoya: You are wonderful.
Man in Black: Thank you; I've worked hard to become so.
Inigo Montoya: I admit it, you are better than I am.
Man in Black: Then why are you smiling?
Inigo Montoya: Because I know something you don't know.
Man in Black: And what is that?
Inigo Montoya: I... am not left-handed.
[Moves his sword to his right hand and gains an advantage]
Man in Black: You are amazing.
Inigo Montoya: I ought to be, after 20 years.
Man in Black: Oh, there's something I ought to tell you.
Inigo Montoya: Tell me.
Man in Black: I'm not left-handed either.
[Moves his sword to his right hand and regains his advantage]

The handedness preference was previously seen in an analysis of over 2600 nearby spiral galaxies and now in an analysis of 15,000 more.

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