<p>A brighter comet may exhibit two tails. The brighter tail is made up of gases and vapors, many times water. The molecules are light. Light from the Sun puts pressure on the vapor and pushes it directly away from the Sun. In fact, a comet in its orbit receding from the Sun, the vapors in the tail actually be pushed ahead of the body. The dust tail, which is not always visible is composed of small particles, but way heavier than the vapor molecules. As the dust particles exit the comet body, the very thin gas that pervades the solar system produces a drag on the dust particles slowing them down, and they end up trailing the comet’s orbit.
It’s the dust that produces meteors if the Earth passes through or close to the comet’s orbit later.</p>

CC BY-SA 4.0
2024-11-04T06:31:50.907Z
I'm not sure this really answers "How does (it) spread out within the plane of its orbit *but not perpendicular to it? Why so broad except when viewed edge-on?*"
uhoh
CC BY-SA 4.0
2024-11-04T02:06:31.077Z
2024-11-04T02:06:31.077Z
Pogo
<p>Scitech Daily's October 30, 2024 <a href="https://scitechdaily.com/epic-comet-pass-tsuchinshan-atlas-outshines-expectations-with-brilliant-solar-passage/" rel="nofollow noreferrer">Epic Comet Pass: Tsuchinshan-ATLAS Outshines Expectations With Brilliant Solar Passage</a> includes the following:</p>
<blockquote>
<p>Rare Observation by LASCO</p>
<p>Despite having seen thousands of comets in its almost 29 years of solar observing, comet Tsuchinshan-ATLAS’ passage revealed a rare facet of comet dust that LASCO has never seen before.</p>
<p>For a brief period on October 14, the extensive dusty trail of the comet coalesced into a narrow, dense trail spanning the entire field of view. This unique density enhancement was the result of the SOHO spacecraft crossing the comet’s orbital plane and observing the comet’s vast dust sheet edge-on. The dust plane then moved into the lower half of the data, where it could be seen globally illuminating half of the field of view.</p>
<p>“LASCO has seen many beautiful comet transits during its decades of operations, but seeing a side-on view of a comet’s dust plane absolutely ranks as one of the most spectacular that we have seen,” said NRL scientist and LASCO Principal Investigator Karl Battams, Ph.D.</p>
</blockquote>
<p><strong>Question:</strong> How does the dust tail of a comet spread out within the plane of its orbit but not perpendicular to it? Why so broad except when viewed edge-on?</p>
<p>There is a related question: <a href="https://astronomy.stackexchange.com/q/35919/7982">Why do particles from a comet that result in meteor showers spread out mostly along the comet&#39;s orbit?</a> but nothing there seems to address this. The images below from the article illustrate the effect.</p>
<p><a href="https://i.sstatic.net/WplohRwX.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/WplohRwX.jpg" alt="U.S. Naval Research Laboratory (NRL) Large Angle and Spectrometric Coronagraph (LASCO) imaging instrument captured sequences of comet C/2023 A3, known as Tsuchinshan-ATLAS, as it passed between the Earth and the Sun on October 9 and 10, 2024. Coronal mass ejections can be seen in both images. Credit: U.S. Navy Photo" /></a></p>
<p><strong>above:</strong> &quot;U.S. Naval Research Laboratory (NRL) Large Angle and Spectrometric Coronagraph (LASCO) imaging instrument captured sequences of comet C/2023 A3, known as Tsuchinshan-ATLAS, as it passed between the Earth and the Sun on October 9 and 10, 2024. Coronal mass ejections can be seen in both images. Credit: U.S. Navy Photo&quot;</p>
<p><strong>below:</strong> same except &quot;...on October 14, 2024. The LASCO C3 telescope perfectly captures the dust plane of the comet edge-on. Credit: U.S. Navy Photo&quot;</p>
<p><a href="https://i.sstatic.net/LYf9rmdr.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/LYf9rmdr.jpg" alt="U.S. Naval Research Laboratory (NRL) Large Angle and Spectrometric Coronagraph (LASCO) imaging instrument captured sequences of comet C/2023 A3, known as Tsuchinshan-ATLAS, as it passed between the Earth and the Sun on October 14, 2024. The LASCO C3 telescope perfectly captures the dust plane of the comet edge-on. Credit: U.S. Navy Photo" /></a></p>

CC BY-SA 4.0
2024-11-05T03:12:25.757Z
Conservation of angular momentum tends to preserve the orbital plane, and I guess there aren't many forces acting perpendicular to the plane. But it would be nice to see a proper analysis...
PM 2Ring
CC BY-SA 4.0
2024-11-06T18:56:06.297Z
Aren't the "above" and "below" frames the same pictures?
Beer Me
CC BY-SA 4.0
2024-11-06T23:18:24.567Z
@BeerMe you are right, *thank you!* These are supposed to be identical - I'd edited one but not the other https://i.sstatic.net/L7VJJIdr.png The effect is really dramatic, but nobody saw it. :-(
uhoh
CC BY-SA 4.0
2024-11-07T19:33:47.743Z
@uhoh Much better!
Beer Me
CC BY-SA 4.0
2024-11-08T09:59:04.697Z
I suspect this is really the same thing as the ["anti tail"](https://en.wikipedia.org/wiki/Anti-tail) phenomenon; indeed, there are numerous examples of optical photographs showing an anti tail for this comet at the same time. (I suspect "the plane containing most of the comet's dust" would be a bit more accurate than "the dust plane", which is admittedly a bit confusing.)
Peter Erwin
<solar-system><comets><dust><solar-wind>
How does the dust tail of a comet spread out within the plane of its orbit but not perpendicular to it? Why so broad except when viewed edge-on?
uhoh
# How does the dust tail of a comet spread out within the plane of its orbit but not perpendicular to it? Why so broad except when viewed edge-on?

(Asked by: username_0 on 2024-10-31)

Scitech Daily's October 30, 2024 [Epic Comet Pass: Tsuchinshan-ATLAS Outshines Expectations With Brilliant Solar Passage](https://scitechdaily.com/epic-comet-pass-tsuchinshan-atlas-outshines-expectations-with-brilliant-solar-passage/) includes the following:

> Rare Observation by LASCO
>
> Despite having seen thousands of comets in its almost 29 years of solar observing, comet Tsuchinshan-ATLAS’ passage revealed a rare facet of comet dust that LASCO has never seen before.
>
> For a brief period on October 14, the extensive dusty trail of the comet coalesced into a narrow, dense trail spanning the entire field of view. This unique density enhancement was the result of the SOHO spacecraft crossing the comet’s orbital plane and observing the comet’s vast dust sheet edge-on. The dust plane then moved into the lower half of the data, where it could be seen globally illuminating half of the field of view.
>
> “LASCO has seen many beautiful comet transits during its decades of operations, but seeing a side-on view of a comet’s dust plane absolutely ranks as one of the most spectacular that we have seen,” said NRL scientist and LASCO Principal Investigator Karl Battams, Ph.D.

**Question:** How does the dust tail of a comet spread out within the plane of its orbit but not perpendicular to it? Why so broad except when viewed edge-on?

There is a related question: [Why do particles from a comet that result in meteor showers spread out mostly along the comet's orbit?](https://astronomy.stackexchange.com/q/35919/7982) but nothing there seems to address this. The images below from the article illustrate the effect.

[![U.S. Naval Research Laboratory (NRL) Large Angle and Spectrometric Coronagraph (LASCO) imaging instrument captured sequences of comet C/2023 A3, known as Tsuchinshan-ATLAS, as it passed between the Earth and the Sun on October 9 and 10, 2024. Coronal mass ejections can be seen in both images. Credit: U.S. Navy Photo](https://i.sstatic.net/WplohRwX.jpg)](https://i.sstatic.net/WplohRwX.jpg)

**above:** "U.S. Naval Research Laboratory (NRL) Large Angle and Spectrometric Coronagraph (LASCO) imaging instrument captured sequences of comet C/2023 A3, known as Tsuchinshan-ATLAS, as it passed between the Earth and the Sun on October 9 and 10, 2024. Coronal mass ejections can be seen in both images. Credit: U.S. Navy Photo"

**below:** same except "...on October 14, 2024. The LASCO C3 telescope perfectly captures the dust plane of the comet edge-on. Credit: U.S. Navy Photo"

[![U.S. Naval Research Laboratory (NRL) Large Angle and Spectrometric Coronagraph (LASCO) imaging instrument captured sequences of comet C/2023 A3, known as Tsuchinshan-ATLAS, as it passed between the Earth and the Sun on October 14, 2024. The LASCO C3 telescope perfectly captures the dust plane of the comet edge-on. Credit: U.S. Navy Photo](https://i.sstatic.net/LYf9rmdr.jpg)](https://i.sstatic.net/LYf9rmdr.jpg)

**Tags:** solar-system, comets, dust, solar-wind
> **Comments:**
> **username_1**: Conservation of angular momentum tends to preserve the orbital plane, and I guess there aren't many forces acting perpendicular to the plane. But it would be nice to see a proper analysis...  
> **username_2**: Aren't the "above" and "below" frames the same pictures?  
> **username_0**: @BeerMe you are right, *thank you!* These are supposed to be identical - I'd edited one but not the other https://i.sstatic.net/L7VJJIdr.png The effect is really dramatic, but nobody saw it. :-(  
> **username_2**: @uhoh Much better!  
> **username_3**: I suspect this is really the same thing as the ["anti tail"](https://en.wikipedia.org/wiki/Anti-tail) phenomenon; indeed, there are numerous examples of optical photographs showing an anti tail for this comet at the same time. (I suspect "the plane containing most of the comet's dust" would be a bit more accurate than "the dust plane", which is admittedly a bit confusing.)  

---

## 1 answers

### Answer by username_4 on 2024-11-04. Score: 0

A brighter comet may exhibit two tails. The brighter tail is made up of gases and vapors, many times water. The molecules are light. Light from the Sun puts pressure on the vapor and pushes it directly away from the Sun. In fact, a comet in its orbit receding from the Sun, the vapors in the tail actually be pushed ahead of the body. The dust tail, which is not always visible is composed of small particles, but way heavier than the vapor molecules. As the dust particles exit the comet body, the very thin gas that pervades the solar system produces a drag on the dust particles slowing them down, and they end up trailing the comet’s orbit.
It’s the dust that produces meteors if the Earth passes through or close to the comet’s orbit later.

> **Comments:**
> **username_0**: I'm not sure this really answers "How does (it) spread out within the plane of its orbit *but not perpendicular to it? Why so broad except when viewed edge-on?*"  

---

