<p>I think <a href="https://astronomy.stackexchange.com/a/18898/2153">my deleted answer</a> to <a href="https://astronomy.stackexchange.com/q/18893/2153">your previous question</a> covers this well, so I'll add it here.</p>
<p>These two spots are known as <strong>the east and west bays</strong> of the Crab Nebula. They appear to be the result of a torus partially encircling a section of the nebula. The pulsar's magnetic field interacts with the gas and dust in the torus, which blocks <a href="https://en.wikipedia.org/wiki/Synchrotron_radiation" rel="noreferrer">synchrotron radiation</a> from gases in the nebula. It has been conjectured that the torus is the result of a <span class="math-container">$\sim0.1M_{\odot}$</span> ejection of material from a circumstellar disk prior to the supernova, based on studies of the proper motion of gas on the edges of both bays.</p>
<h3>References</h3>
<ul>
<li><a href="http://adsabs.harvard.edu/full/1992ApJ...399..599F" rel="noreferrer">Fesen et al. (1992)</a></li>
<li><a href="http://authors.library.caltech.edu/53632/" rel="noreferrer">Hester et al. (1995)</a></li>
</ul>
<p>We can also rule out that this is the result of a defect in Hubble, because these features have been observed in <a href="https://en.wikipedia.org/wiki/File:Crab_Nebula_in_Multiple_Wavelengths.png" rel="noreferrer">different wavelengths</a>, including infrared, visible, ultraviolet, and x-ray (though not in radio or gamma-ray wavelengths):</p>
<p><a href="https://i.sstatic.net/wVPyR.jpg" rel="noreferrer"><img src="https://i.sstatic.net/wVPyR.jpg" alt="enter image description here" /></a>
<br>
<sup>Image courtesy of Wikipedia user Hunster under <a href="https://creativecommons.org/licenses/by-sa/3.0/deed.en" rel="noreferrer">the Creative Commons Attribution-Share Alike 3.0 Unported license</a>.</sup></p>
<p>The infrared, ultraviolet, and x-ray images come from the Spitzer Space Telescope, the SWIFT observatory, and the Chandra observatory, respectively.</p>

CC BY-SA 3.0
2016-10-30T17:59:49.807Z
Beautiful!  I've "borrowed" the image and info for [this question](http://astronomy.stackexchange.com/q/18905/7982).
uhoh
CC BY-SA 3.0
2016-10-30T16:50:38.707Z
2016-10-30T16:50:38.707Z
2020-06-17T09:47:40.653Z
HDE 226868
<p>I came across this image of the Crab Nebula taken from NASA Hubble telescope. What are the large round "holes" and how are they formed?</p>

<p><a href="https://i.sstatic.net/acNS5.jpg" rel="noreferrer"><img src="https://i.sstatic.net/acNS5.jpg" alt="enter image description here"></a></p>

CC BY-SA 3.0
2016-10-31T17:37:10.620Z
What a great question - the arrows make it really clear.
Fattie
<hubble-telescope><nebula>
What are the large round dark "holes" in this NASA Hubble image of the Crab Nebula?
Martin
# What are the large round dark "holes" in this NASA Hubble image of the Crab Nebula?

(Asked by: username_0 on 2016-10-30)

I came across this image of the Crab Nebula taken from NASA Hubble telescope. What are the large round "holes" and how are they formed?

[![enter image description here](https://i.sstatic.net/acNS5.jpg)](https://i.sstatic.net/acNS5.jpg)

**Tags:** hubble-telescope, nebula

> **Comments:**
> **username_1**: What a great question - the arrows make it really clear.  

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## 1 answers

### Answer by username_2 on 2016-10-30. Score: 13 | Accepted answer

I think [my deleted answer](https://astronomy.stackexchange.com/a/18898/2153) to [your previous question](https://astronomy.stackexchange.com/q/18893/2153) covers this well, so I'll add it here.

These two spots are known as **the east and west bays** of the Crab Nebula. They appear to be the result of a torus partially encircling a section of the nebula. The pulsar's magnetic field interacts with the gas and dust in the torus, which blocks [synchrotron radiation](https://en.wikipedia.org/wiki/Synchrotron_radiation) from gases in the nebula. It has been conjectured that the torus is the result of a $\sim0.1M\_{\odot}$ ejection of material from a circumstellar disk prior to the supernova, based on studies of the proper motion of gas on the edges of both bays.

### References

* [Fesen et al. (1992)](http://adsabs.harvard.edu/full/1992ApJ...399..599F)
* [Hester et al. (1995)](http://authors.library.caltech.edu/53632/)

We can also rule out that this is the result of a defect in Hubble, because these features have been observed in [different wavelengths](https://en.wikipedia.org/wiki/File:Crab_Nebula_in_Multiple_Wavelengths.png), including infrared, visible, ultraviolet, and x-ray (though not in radio or gamma-ray wavelengths):

[![enter image description here](https://i.sstatic.net/wVPyR.jpg)](https://i.sstatic.net/wVPyR.jpg)
  
Image courtesy of Wikipedia user Hunster under [the Creative Commons Attribution-Share Alike 3.0 Unported license](https://creativecommons.org/licenses/by-sa/3.0/deed.en).

The infrared, ultraviolet, and x-ray images come from the Spitzer Space Telescope, the SWIFT observatory, and the Chandra observatory, respectively.

> **Comments:**
> **username_3**: Beautiful!  I've "borrowed" the image and info for [this question](http://astronomy.stackexchange.com/q/18905/7982).  

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