What is the significance of the Eridanus Supervoid in the universe?

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The Eridanus Supervoid is a significant cold spot in the cosmic microwave background (CMB) detected by the WMAP satellite, showing temperatures around 70μK lower than the average 2.7K of the universe. The likelihood of this cold spot arising from quantum fluctuations is estimated at only 1.85%. Controversy surrounds the interpretation of this phenomenon, particularly a hypothesis by cosmologist Laura Mersini-Houghton suggesting it could be influenced by another universe. Critics argue against this view, citing a lack of convincing statistical evidence for CMB anomalies. The ongoing debate highlights the complexities and uncertainties in understanding cosmic structures and their implications for cosmology.
BOAS
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Hello,

I came across a thread on Reddit the other day highlighting something that is either absolutely fascinating or bad reporting on what was said/found. I would really appreciate some discussion on the relevance and significance of the "Eridanus Supervoid".

As far as I can tell it goes like this;

The WMAP satellite data shows us that the average temperature of the universe is about 2.7K. There exists a large portion of the night sky that is significantly colder than it's surroundings ~70μK. If you look at a gaussian distribution of this data, the likelihood of this coldspot arising out of quantum fluctuations in the inflationary period are ~1.85%.

The Wikipedia entry on this cites a controversial claim made by cosmologist Laura Mersini-Houghton that this cold spot could be explained by another universe pushing against our own. I assume it is considered controversial because most scientists in the field do not hold that view. She does however seem to think that her hypothesis can be tested.

So, please could someone explain in layman's terms what the 'normal' causes of these cold spots are and what they think about this.

http://en.wikipedia.org/wiki/CMB_cold_spot#Supervoid

Thank you very much!

BOAS
 
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The Eridanus supervoid has been steeped in controversy since its detection was announced. Probably the most stinging criticism was leveled in http://arxiv.org/abs/0908.3988, Disks in the sky: A reassessment of the WMAP "cold spot". A frenzy of papers followed both in condemnation and support of Zhang and Huterer. Among the more credible of these was http://arxiv.org/abs/1001.4758, Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Are There Cosmic Microwave Background Anomalies? They concluded there is no convincing statistical evidence of CMB anomalies.
 
Chronos said:
The Eridanus supervoid has been steeped in controversy since its detection was announced. Probably the most stinging criticism was leveled in http://arxiv.org/abs/0908.3988, Disks in the sky: A reassessment of the WMAP "cold spot". A frenzy of papers followed both in condemnation and support of Zhang and Huterer. Among the more credible of these was http://arxiv.org/abs/1001.4758, Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Are There Cosmic Microwave Background Anomalies? They concluded there is no convincing statistical evidence of CMB anomalies.

Thank you - I appreciate being able to see some of the discussion on both sides of the fence. It will however take me a while to get my head around these papers though, being a first year physics student :)
 
https://en.wikipedia.org/wiki/Recombination_(cosmology) Was a matter density right after the decoupling low enough to consider the vacuum as the actual vacuum, and not the medium through which the light propagates with the speed lower than ##({\epsilon_0\mu_0})^{-1/2}##? I'm asking this in context of the calculation of the observable universe radius, where the time integral of the inverse of the scale factor is multiplied by the constant speed of light ##c##.
Why was the Hubble constant assumed to be decreasing and slowing down (decelerating) the expansion rate of the Universe, while at the same time Dark Energy is presumably accelerating the expansion? And to thicken the plot. recent news from NASA indicates that the Hubble constant is now increasing. Can you clarify this enigma? Also., if the Hubble constant eventually decreases, why is there a lower limit to its value?
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