<p>The CMB is a snapshot of the universe from when it was just about 380,000 years old, shortly after the Big Bang. It provides us with information about the early conditions of the universe, including the density fluctuations that eventually led to the formation of galaxies, stars, and larger cosmic structures like voids and clusters of galaxies.</p>
<p>The Big Cold Spot refers to a large, unusually cold region in the CMB, which is the afterglow of the Big Bang. This spot is cooler than the surrounding areas by about 100 mK. The CMB is generally uniform, with tiny fluctuations that reflect the early conditions of the universe.</p>
<p>Some <strong>potential explanations</strong> of the Big Cold Spot include:</p>
<ol>
<li><strong>Random fluctuations:</strong> It might be one of the many fluctuations seen in the CMBR.</li>
<li><strong>The Integrated Sachs-Wolfe Effect:</strong> It occurs when the CMB photons pass through large cosmic structures, like superclusters or voids. A void is basically a region with fewer galaxies and matter. The travelling photons can be redshifted and lose energy hence it is a blue spot.</li>
<li><strong>Collision with another universe:</strong> A less accepted solution but might be possible, another bubble universe collided with our universe leading to the spot, however this hasn't been demonstrated yet.</li>
</ol>
<p><strong>Why is it not indicative of the End of the Universe:</strong></p>
<p>The end of the universe isn't linked to a particular direction. It refers to scenarios like the Heat Death, Big Crunch, or Big Rip. As the expansion of the universe is isotropic, it is the same in all directions. Similarly, the end of the universe as theorized, doesn't occur in any particular direction. The universe will end in all directions simultaneously.</p>

CC BY-SA 4.0
2024-12-16T19:20:43.007Z
I think the question, and I might be wrong, meant "end" as in "the boundary" of the universe. See Shakesbeer and Gremlin above.
JohnHunt
CC BY-SA 4.0
2024-12-16T19:38:15.190Z
Most probably, yes. But still, the other reasons I mentioned above are the most probable reasons for the appearance of the Big Clod Spot. The boundary would be isotropic so we should see it everywhere which is not a valid answer.
sheyahi
CC BY-SA 4.0
2024-12-17T20:20:57.610Z
I certainly agree.  I thought the question might have been about the very isotropism itself, but no argument on your actual response.
JohnHunt
CC BY-SA 4.0
2024-12-16T18:00:08.457Z
2024-12-16T18:00:08.457Z
sheyahi
<p>Could the big <a href="https://en.wikipedia.org/wiki/CMB_cold_spot" rel="nofollow noreferrer">cold spot in the CMBR map</a> be a sign that almost all radiation from that direction has already passed us, and that be a sign that the end of the universe is closest to earth in that direction?</p>

CC BY-SA 4.0
2022-06-29T21:33:35.037Z
Can you provide a reference? Where did you hear about the cold spot?
Jim421616
CC BY-SA 4.0
2022-06-29T21:46:21.540Z
I have to say I'm not into physics but fascinated by cosmological hypotheses. Nevertheless the cold spot seems to be part of well established astrophysics, see for instance https://www.telegiz.com/articles/23750/20170519/scientists-reveal-first-evidence-multiverse-indeed-exists.htm
Shakesbeer
CC BY-SA 4.0
2022-06-30T04:25:15.830Z
@Jim421616 I've added a link to the Cold Spot's Wikipedia page
uhoh
CC BY-SA 4.0
2022-06-30T13:10:51.723Z
There isn't an end/edge of the universe in the sense you mean it.
Dave Gremlin
CC BY-SA 4.0
2022-06-30T15:08:52.227Z
I'm not sure myself how I mean it. But there are countless articles in the WWW talking about the size, radius, and similar, of the universe. So there should also be some kind of end to it, as long as one does not assume an infinite universe, or one that has a geometry that leads to a "pacman"-effect. The professor in the article I linked above claims that the cold spot is an imprint of a neighbouring universe, which also implies that our universe ends at some point.
Shakesbeer
CC BY-SA 4.0
2022-06-30T15:26:13.807Z
Even the professionals are divided on the question whether there is some end or edge to the universe and how to define it. https://www.quora.com/Does-the-universe-have-an-edge?share=1 is a thread on that topic.
Shakesbeer
<universe><cosmic-microwave-background>
CMBR: Is the cold spot a hint at the edge of the universe?
Shakesbeer
# CMBR: Is the cold spot a hint at the edge of the universe?

(Asked by: username_0 on 2022-06-29)

Could the big [cold spot in the CMBR map](https://en.wikipedia.org/wiki/CMB_cold_spot) be a sign that almost all radiation from that direction has already passed us, and that be a sign that the end of the universe is closest to earth in that direction?

**Tags:** universe, cosmic-microwave-background

> **Comments:**
> **username_1**: Can you provide a reference? Where did you hear about the cold spot?  
> **username_0**: I have to say I'm not into physics but fascinated by cosmological hypotheses. Nevertheless the cold spot seems to be part of well established astrophysics, see for instance https://www.telegiz.com/articles/23750/20170519/scientists-reveal-first-evidence-multiverse-indeed-exists.htm  
> **username_2**: @username_1 I've added a link to the Cold Spot's Wikipedia page  
> **username_3**: There isn't an end/edge of the universe in the sense you mean it.  
> **username_0**: I'm not sure myself how I mean it. But there are countless articles in the WWW talking about the size, radius, and similar, of the universe. So there should also be some kind of end to it, as long as one does not assume an infinite universe, or one that has a geometry that leads to a "pacman"-effect. The professor in the article I linked above claims that the cold spot is an imprint of a neighbouring universe, which also implies that our universe ends at some point.  
> **username_0**: Even the professionals are divided on the question whether there is some end or edge to the universe and how to define it. https://www.quora.com/Does-the-universe-have-an-edge?share=1 is a thread on that topic.  

---

## 1 answers

### Answer by username_4 on 2024-12-16. Score: 2

The CMB is a snapshot of the universe from when it was just about 380,000 years old, shortly after the Big Bang. It provides us with information about the early conditions of the universe, including the density fluctuations that eventually led to the formation of galaxies, stars, and larger cosmic structures like voids and clusters of galaxies.

The Big Cold Spot refers to a large, unusually cold region in the CMB, which is the afterglow of the Big Bang. This spot is cooler than the surrounding areas by about 100 mK. The CMB is generally uniform, with tiny fluctuations that reflect the early conditions of the universe.

Some **potential explanations** of the Big Cold Spot include:

1. **Random fluctuations:** It might be one of the many fluctuations seen in the CMBR.
2. **The Integrated Sachs-Wolfe Effect:** It occurs when the CMB photons pass through large cosmic structures, like superclusters or voids. A void is basically a region with fewer galaxies and matter. The travelling photons can be redshifted and lose energy hence it is a blue spot.
3. **Collision with another universe:** A less accepted solution but might be possible, another bubble universe collided with our universe leading to the spot, however this hasn't been demonstrated yet.

**Why is it not indicative of the End of the Universe:**

The end of the universe isn't linked to a particular direction. It refers to scenarios like the Heat Death, Big Crunch, or Big Rip. As the expansion of the universe is isotropic, it is the same in all directions. Similarly, the end of the universe as theorized, doesn't occur in any particular direction. The universe will end in all directions simultaneously.

> **Comments:**
> **username_5**: I think the question, and I might be wrong, meant "end" as in "the boundary" of the universe. See username_0 and Gremlin above.  
> **username_4**: Most probably, yes. But still, the other reasons I mentioned above are the most probable reasons for the appearance of the Big Clod Spot. The boundary would be isotropic so we should see it everywhere which is not a valid answer.  
> **username_5**: I certainly agree.  I thought the question might have been about the very isotropism itself, but no argument on your actual response.  

---

