Our Lumpy Universe
June 6, 2014
Children of my generation were faced with quite a few inconveniences associated with growing up in the 1950s. Aside from having to walk miles to school, both ways uphill, in the snow, and working our math homework problems with chalk on the back of a coal shovel, we had lumpy pancakes.
Food processors weren't consumer items until well into the 1970s, but blenders were available long before then. However, when a newlywed's gift blender broke, it was seldom replaced, leading to the poignant First World tragedy of lumpy pancakes.
Because of atomic and molecular forces, things in nature, such as the ingredients in pancake batter, tend to agglomerate and are seldom homogeneous. Gravitational forces have that same affect in large scale structures such as our Milky Way Galaxy. When distance measurements of galaxies using cosmological redshift became routine in 1989, Margaret Geller and John Huchra of the Harvard–Smithsonian Center for Astrophysics discovered the first large-scale structure of the universe.
This structure, known as the Great Wall (more properly, the CfA2 Great Wall, named after the Center for Astrophysics, which was responsible for both the redshift survey and the analysis), is a 500 million light-year's wide shell of galaxies just 16 million light years thick about 200 million light-years distant from Earth. The extent of this shell, which may be the boundary of a giant "bubble," might be larger, but our own galaxy prevents further observations.
A much larger wall, the Sloan Great Wall, named after the Sloan Digital Sky Survey, was discovered in 2003. This wall was observed to extend 1.38 billion light-years, which is nearly three times larger than the CfA2 Great Wall. For comparison, the diameter of the observable universe is about 93 billion light-years.
Nor is the Sloan Great Wall the last wall found. The farther we look, the more walls we find, the last being the Hercules–Corona Borealis Great Wall, measuring more than ten billion light-years across, or more than 10% of the diameter of the observable universe. The discovery was made by mapping gamma ray bursts.
Data such as these suggest that the universe is far from homogeneous, and it consists, instead, of immense voids with galaxies defining their boundaries. It's as if the universe is actually a foam, and the galaxies are aligned as a "cosmic web." It's conjectured that the matter we see is aligned with a superstructure of dark matter that gravitationally attracts the normal matter. Simulations show that the voids might contain faint filaments of galaxies (see figure).[2-3]
Do such inhomogeneities average out when we get to the scale of the entire universe? Analysis of the cosmic microwave background radiation (CMBR) indicates that the universe as a whole might be anisotropic, divided in half by a poetically named "Axis of Evil."[4-6] The evil, if it scales with the degree of anisotropy, is actually quite small. The temperature variation found in the CMBR is just a few millionths of a degree out of 2.73 kelvin.
This anisotropy might be connected with something in the early universe, but there are other possibilities. It might be caused by an object between us and the CMBR photons, and this possibility is buttressed by the fact that the "Axis of Evil" is closely aligned with the ecliptic, the plane of planetary orbits in the Solar System (see figure).
It might also be that we are seeing random fluctuations in the observable Universe, which is a small part of the entire universe. You will see variation by looking too closely at anything.
|Anomalies in the Cosmic Microwave Background Radiation, as detected by the Planck spacecraft. There is slightly higher average temperatures (red) in the southern ecliptic hemisphere and slightly lower average temperatures (blue) in the northern ecliptic hemisphere. The line marks the ecliptic, which is closely associated with the "Axis of Evil." A surprisingly cold patch is circled. (ESA and the Planck Collaboration image, used with permission.)|
- Margaret J. Geller and John P. Huchra, "Mapping the Universe," Science, vol. 246, no. 4932 (November 17, 1989), pp. 897-903.
- E. Tempel, R. S. Stoica, V. J. Martínez, L. J. Liivamägi, G. Castellan and E. Saar, "Detecting filamentary pattern in the cosmic web: a catalogue of filaments for the SDSS," MNRAS, vol. 438, no. 4 (March 11, 2014), pp. 3465-3482.
- These aren't the voids you're looking for, International Centre for Radio Astronomy Research Press Release, March 10, 2014.
- Kate Land and Joäo Magueijo, "Examination of Evidence for a Preferred Axis in the Cosmic Radiation Anisotropy," Phys. Rev. Lett., vol. 95, no. 7 (August 11, 2005), Document No. 071301 [4 pages].
- Kate Land and Joao Magueijo, "The axis of evil," arXiv Preprint Server, February 22, 2005.
- Matthew Francis, "Is the lopsided Universe telling us we need new theories?" Arstechnica, March 10, 2014.
- Craig J Copi, Multipole Vectors Web Site, Case Western-Reserve University.
Permanent Link to this article
Linked Keywords: Child; children; baby boomer; 1950s; mile; school; snow; mathematics; math; homework problem; chalk; coal; shovel; pancake; food processor; consumer; 1970s; blender; newlywed; First World; tragedy; atomic; van der Waals force; molecular force; nature; ingredient; batter; homogeneity; homogeneous; Newton's law of universal gravitation; gravitational force; Milky Way Galaxy; galaxy; cosmological redshift; Margaret Geller; John Huchra; Harvard–Smithsonian Center for Astrophysics; universe; Hubble Space Telescope; spiral galaxy; 2MASX J00482185-2507365; NASA; European Space Agency; ESA; The Hubble Heritage Team (STScI/AURA); Wikimedia Commons; Great Wall; CfA Redshift Survey; light-year; Earth; Sloan Great Wall; Sloan Digital Sky Survey; diameter; observable universe; 2dF Galaxy Redshift Survey; Willem Schaap; Hercules–Corona Borealis Great Wall; gamma ray burst; data; void; foam; matter; dark matter; International Centre for Radio Astronomy Research (ICRAR); cosmic microwave background radiation; anisotropy; anisotropic; poetry; poetically; temperature; kelvin; photon; ecliptic; plane; planetary orbit; Solar System; Planck spacecraft; Planck Collaboration; random.
Latest Books by Dev Gualtieri
Thanks to Cory Doctorow of BoingBoing for his favorable review of Secret Codes!
Blog Article Directory on a Single Page
- The Wisdom of Composite Crowds - April 27, 2017
- J. Robert Oppenheimer and Black Holes - April 24, 2017
- Modeling Leaf Mass - April 20, 2017
- Easter, Chicks and Eggs - April 13, 2017
- You, Robot - April 10, 2017
- Collisions - April 6, 2017
- Eugene Garfield (1925-2017) - April 3, 2017
- Old Fossils - March 30, 2017
- Levitation - March 27, 2017
- Soybean Graphene - March 23, 2017
- Income Inequality and Geometrical Frustration - March 20, 2017
- Wireless Power - March 16, 2017
- Trilobite Sex - March 13, 2017
- Freezing, Outside-In - March 9, 2017
- Ammonia Synthesis - March 6, 2017
- High Altitude Radiation - March 2, 2017
- C.N. Yang - February 27, 2017
- VOC Detection with Nanocrystals - February 23, 2017
- Molecular Fountains - February 20, 2017
- Jet Lag - February 16, 2017
- Highly Flexible Conductors - February 13, 2017
- Graphene Friction - February 9, 2017
- Dynamic Range - February 6, 2017
- Robert Boyle's To-Do List for Science - February 2, 2017
- Nanowire Ink - January 30, 2017
- Random Triangles - January 26, 2017
- Torricelli's law - January 23, 2017
- Magnetic Memory - January 19, 2017
- Graphene Putty - January 16, 2017
- Seahorse Genome - January 12, 2017
- Infinite c - January 9, 2017
- 150 Years of Transatlantic Telegraphy - January 5, 2017
- Cold Work on the Nanoscale - January 2, 2017
- Holidays 2016 - December 22, 2016
- Ballistics - December 19, 2016
- Salted Frogs - December 15, 2016
- Negative Thermal Expansion - December 12, 2016
- Verbal Cues and Stereotypes - December 8, 2016
- Capacitance Sensing - December 5, 2016
- Gallium Nitride Tribology - December 1, 2016
- Lunar Origin - November 27, 2016
- Pumpkin Propagation - November 24, 2016
- Math Anxiety - November 21, 2016
- Borophene - November 17, 2016
- Forced Innovation - November 14, 2016
- Combating Glare - November 10, 2016
- Solar Tilt and Planet Nine - November 7, 2016
- The Proton Size Problem - November 3, 2016
Deep Archive 2006-2008