APOD: Perseus and the Lost Meteors (2021 Aug 09)

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APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by APOD Robot » Mon Aug 09, 2021 4:05 am

Image Perseus and the Lost Meteors

Explanation: What's the best way to watch a meteor shower? This question might come up later this week when the annual Perseid Meteor Shower peaks. One thing that is helpful is a dark sky, as demonstrated in the featured composite image of last year's Perseids. Many more faint meteors are visible on the left image, taken through a very dark sky in Slovakia, than on the right image, taken through a moderately dark sky in the Czech Republic. The band of the Milky Way Galaxy bridges the two coordinated images, while the meteor shower radiant in the constellation of Perseus is clearly visible on the left. In sum, many faint meteors are lost through a bright sky. Light pollution is shrinking areas across our Earth with dark skies, although inexpensive ways to combat this might be implemented.

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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by Ann » Mon Aug 09, 2021 4:52 am

Lovely image, particularly the dark-sky half on the left. A lot of cosmic light has been washed out in the light-polluted half on the right.

But Vega stands out like a blue beacon, nonetheless.

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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by beryllium732 » Mon Aug 09, 2021 7:22 am

I wonder the name of the particular Milky Way band we see in these pictures and do we look at it to the center of the Milky way or to the outside? It looks so fascinating with the pink blobs of hydrogen clouds.

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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by Ann » Mon Aug 09, 2021 9:33 am

beryllium732 wrote:
Mon Aug 09, 2021 7:22 am
I wonder the name of the particular Milky Way band we see in these pictures and do we look at it to the center of the Milky way or to the outside? It looks so fascinating with the pink blobs of hydrogen clouds.
Perseid Milky Way annotated.png

1) The Alpha Persei moving cluster in constellation Perseus.

2) The Double Cluster in Perseus. Note the red nebulas, the Heart and Soul nebulas, to the left of the Double Cluster. But the Heart and Soul nebulas are actually in Cassiopeia.

3) The "W" of Cassiopeia.

4) The Elephant Trunk Nebula and the deep orange Garnet Star in Cepheus.

5) The North America Nebula (left) and supergiant star Deneb in Cygnus.

6) Constellation Lyra, with bright blue beacon Vega.

7) Altair of the Summer Triangle (with Deneb and Vega). Altair is in constellation Aquila.

8) The yellow Scutum star cloud.

9) Nebula M16 in Serpens and nebula M17 in Sagittarius.

10) The bluish Small Sagittarius star cloud.

11) The Lagoon Nebula (bottom) and the Trifid Nebula (top). The center of the Milky Way is just a little below (south of) the Lagoon Nebula and the Trifid Nebula, hidden behind light-years upon light-years of dust.

Ann
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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by Eclectic Man » Mon Aug 09, 2021 11:15 am

I once saw a very faint Perseid meteor through binoculars (8x42). It appeared brown and tumbled across my field of vision in what appeared to be a corkscrew flightpath. I've never managed to see any others through binoculars, so count myself very fortunate in that respect.

NCTom

Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by NCTom » Mon Aug 09, 2021 12:09 pm

Thanks, Ann, for the annotation. Always appreciative of the extra information and the time you take to provide it.

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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by De58te » Mon Aug 09, 2021 12:30 pm

I have seen a few Perseid meteor showers over the years and true to the divided picture on the left the meteors seem to go in every direction When you see one go to the left, the next one will go to the right on the other side of the sky. Then some go up and down. But I have never seen one like on the right side of the photo that have a shallow but noticeable curve. Every one I seen is straight as an arrow. Are those curved Perseids very rare?

Also reading Ann's annotation the thought struck me. If you imagine time running backwards and the Perseid meteors running in the opposite direction away from the Earth, they all seem to be heading in the same direction. Right near where Ann said the Perseus constellation is located. What a coincidence the names being so similar.

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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by orin stepanek » Mon Aug 09, 2021 12:44 pm

PerseidsLost_SlovinskyHoralek_1080.jpg
Nice work fitting the Milky Way and the terrain together like that! 8-)
I wasn't ever interested in watching for meteor showers but the one
that blew up over Russia a couple of years ago got my attention!
It is amazing though that pebbles the size of peas can create so much
light!
travelling-cuddling-stray-cats-istanbul-orin-fb12-png__700.jpg
Kitty Love?
Is that a vehicle in th3e water behind the cats? :shock:
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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by Ann » Mon Aug 09, 2021 1:08 pm

De58te wrote:
Mon Aug 09, 2021 12:30 pm
I have seen a few Perseid meteor showers over the years and true to the divided picture on the left the meteors seem to go in every direction When you see one go to the left, the next one will go to the right on the other side of the sky. Then some go up and down. But I have never seen one like on the right side of the photo that have a shallow but noticeable curve. Every one I seen is straight as an arrow. Are those curved Perseids very rare?

Also reading Ann's annotation the thought struck me. If you imagine time running backwards and the Perseid meteors running in the opposite direction away from the Earth, they all seem to be heading in the same direction. Right near where Ann said the Perseus constellation is located. What a coincidence the names being so similar.
Yeah... that's why they are called the Perseids! :D :wink:

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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by Chris Peterson » Mon Aug 09, 2021 1:24 pm

Eclectic Man wrote:
Mon Aug 09, 2021 11:15 am
I once saw a very faint Perseid meteor through binoculars (8x42). It appeared brown and tumbled across my field of vision in what appeared to be a corkscrew flightpath. I've never managed to see any others through binoculars, so count myself very fortunate in that respect.
That doesn't happen. It was a consequence of your eyes or wiggling the binoculars.
Chris

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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by beryllium732 » Mon Aug 09, 2021 2:07 pm

Ann wrote:
Mon Aug 09, 2021 9:33 am
beryllium732 wrote:
Mon Aug 09, 2021 7:22 am
I wonder the name of the particular Milky Way band we see in these pictures and do we look at it to the center of the Milky way or to the outside? It looks so fascinating with the pink blobs of hydrogen clouds.
Perseid Milky Way annotated.png

1) The Alpha Persei moving cluster in constellation Perseus.

2) The Double Cluster in Perseus. Note the red nebulas, the Heart and Soul nebulas, to the left of the Double Cluster. But the Heart and Soul nebulas are actually in Cassiopeia.

3) The "W" of Cassiopeia.

4) The Elephant Trunk Nebula and the deep orange Garnet Star in Cepheus.

5) The North America Nebula (left) and supergiant star Deneb in Cygnus.

6) Constellation Lyra, with bright blue beacon Vega.

7) Altair of the Summer Triangle (with Deneb and Vega). Altair is in constellation Aquila.

8) The yellow Scutum star cloud.

9) Nebula M16 in Serpens and nebula M17 in Sagittarius.

10) The bluish Small Sagittarius star cloud.

11) The Lagoon Nebula (bottom) and the Trifid Nebula (top). The center of the Milky Way is just a little below (south of) the Lagoon Nebula and the Trifid Nebula, hidden behind light-years upon light-years of dust.

Ann
Thank you so much for the drawing the details of the arm and explaining what we are looking at! I find the Mu Cephei or the Garnet Star to be really cool looking with it's intense orange light and that it's so big it expands further than Jupiters orbit. It's so very fascinating!

Do you know the name of the spiral arm where these nebulas and stars are located? Are we looking inwards or outwards from the galaxy when looking at that particular arm? I guess it's the Perseus arm because the Perseus constellation lies in it between the Auriga and the Cassiopeia constellation and that we are looking outwards?

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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by Ann » Mon Aug 09, 2021 2:50 pm

beryllium732 wrote:
Mon Aug 09, 2021 2:07 pm
Ann wrote:
Mon Aug 09, 2021 9:33 am
beryllium732 wrote:
Mon Aug 09, 2021 7:22 am
I wonder the name of the particular Milky Way band we see in these pictures and do we look at it to the center of the Milky way or to the outside? It looks so fascinating with the pink blobs of hydrogen clouds.
Perseid Milky Way annotated.png

1) The Alpha Persei moving cluster in constellation Perseus.

2) The Double Cluster in Perseus. Note the red nebulas, the Heart and Soul nebulas, to the left of the Double Cluster. But the Heart and Soul nebulas are actually in Cassiopeia.

3) The "W" of Cassiopeia.

4) The Elephant Trunk Nebula and the deep orange Garnet Star in Cepheus.

5) The North America Nebula (left) and supergiant star Deneb in Cygnus.

6) Constellation Lyra, with bright blue beacon Vega.

7) Altair of the Summer Triangle (with Deneb and Vega). Altair is in constellation Aquila.

8) The yellow Scutum star cloud.

9) Nebula M16 in Serpens and nebula M17 in Sagittarius.

10) The bluish Small Sagittarius star cloud.

11) The Lagoon Nebula (bottom) and the Trifid Nebula (top). The center of the Milky Way is just a little below (south of) the Lagoon Nebula and the Trifid Nebula, hidden behind light-years upon light-years of dust.

Ann
Thank you so much for the drawing the details of the arm and explaining what we are looking at! I find the Mu Cephei or the Garnet Star to be really cool looking with it's intense orange light and that it's so big it expands further than Jupiters orbit. It's so very fascinating!

Do you know the name of the spiral arm where these nebulas and stars are located? Are we looking inwards or outwards from the galaxy when looking at that particular arm? I guess it's the Perseus arm because the Perseus constellation lies in it between the Auriga and the Cassiopeia constellation and that we are looking outwards?
galaxymw[1].png
OUR GALAXY has two main spiral arms (Scutum-Centaurus and Perseus)
attached to the ends of a thick central bar. Two minor arms (Norma and Sagittarius),
where star formation occurs, lie between the major arms.
Image: NASA/JPL-Caltech/ R. Hurt (SSC-Caltech

The Double Cluster of Perseus (and, I think, the Heart and Soul Nebulas) are located in the Perseus Arm, which is located farther out in the Milky Way than Solar system is. I also think that many of the bright nebulas in Sagittarius are located in the Sagittarius Arm.

Ann
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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by neufer » Mon Aug 09, 2021 3:04 pm

Chris Peterson wrote:
Mon Aug 09, 2021 1:24 pm
Eclectic Man wrote:
Mon Aug 09, 2021 11:15 am

I once saw a very faint Perseid meteor through binoculars (8x42). It appeared brown and tumbled across my field of vision in what appeared to be a corkscrew flightpath. I've never managed to see any others through binoculars, so count myself very fortunate in that respect.
That doesn't happen. It was a consequence of your eyes or wiggling the binoculars.
The curious case of the corkscrew meteors....
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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by Eclectic Man » Mon Aug 09, 2021 7:23 pm

neufer wrote:
Mon Aug 09, 2021 3:04 pm
Chris Peterson wrote:
Mon Aug 09, 2021 1:24 pm
Eclectic Man wrote:
Mon Aug 09, 2021 11:15 am

I once saw a very faint Perseid meteor through binoculars (8x42). It appeared brown and tumbled across my field of vision in what appeared to be a corkscrew flightpath. I've never managed to see any others through binoculars, so count myself very fortunate in that respect.
That doesn't happen. It was a consequence of your eyes or wiggling the binoculars.
The curious case of the corkscrew meteors....
neufer, thanks for the reference. Lovely images.

@ Chris Peterson: The meteor was far too quick for any possibility of my eyes or the binoculars 'wiggling' and causing any illusion of corkscrew motion. Meteors are not aerodynamically stable like an Apollo capsule, and it is highly likely that they are spinning when they hit the atmosphere. It was very faint and so must have been a small one and therefore its trajectory was more affected by resistance on its path through the atmosphere. Large meteors may have enough mass to be untroubled by aerodynamic turbulence, but small ones, irregular in shape will be buffeted about and therefore not follow a straight line flight path. Not only that but the ram pressure and heating on a meteor is unevenly distributed, causing partial or eventually complete melting of a small item travelling at high supersonic velocity. The only things that don't tumble when entering the atmosphere are either very big or carefully designed to be stable. Note that cannon balls and lead shot are notoriously inaccurate over long distances due to aerodynamic pressures on non-gyroscopically stabilised objects travelling at supersonic speeds (which is why the invention of the rifle was significant for hunting and warfare). I hope this explanation helps.

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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by MarkBour » Tue Aug 10, 2021 12:33 am

NCTom wrote:
Mon Aug 09, 2021 12:09 pm
Thanks, Ann, for the annotation. Always appreciative of the extra information and the time you take to provide it.
Agreed!
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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by Chris Peterson » Tue Aug 10, 2021 2:20 am

Eclectic Man wrote:
Mon Aug 09, 2021 7:23 pm
neufer wrote:
Mon Aug 09, 2021 3:04 pm
Chris Peterson wrote:
Mon Aug 09, 2021 1:24 pm

That doesn't happen. It was a consequence of your eyes or wiggling the binoculars.
The curious case of the corkscrew meteors....
neufer, thanks for the reference. Lovely images.

@ Chris Peterson: The meteor was far too quick for any possibility of my eyes or the binoculars 'wiggling' and causing any illusion of corkscrew motion. Meteors are not aerodynamically stable like an Apollo capsule, and it is highly likely that they are spinning when they hit the atmosphere. It was very faint and so must have been a small one and therefore its trajectory was more affected by resistance on its path through the atmosphere. Large meteors may have enough mass to be untroubled by aerodynamic turbulence, but small ones, irregular in shape will be buffeted about and therefore not follow a straight line flight path. Not only that but the ram pressure and heating on a meteor is unevenly distributed, causing partial or eventually complete melting of a small item travelling at high supersonic velocity. The only things that don't tumble when entering the atmosphere are either very big or carefully designed to be stable. Note that cannon balls and lead shot are notoriously inaccurate over long distances due to aerodynamic pressures on non-gyroscopically stabilised objects travelling at supersonic speeds (which is why the invention of the rifle was significant for hunting and warfare). I hope this explanation helps.
A meteor cannot move more than a few meters back and forth as it "corkscrews". This has occasionally been recorded with some fancy meteor tracking telescopes. It is potentially something that might be seen in a chance crossing of a meteor through a telescopic field. It isn't visible to the naked eye, or to a camera with a lens having a focal length consistent with normal photography. And it isn't going to be visible through binoculars.

What you saw was an illusion.
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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by Eclectic Man » Tue Aug 10, 2021 10:26 am

Chris Peterson wrote:
Tue Aug 10, 2021 2:20 am
Eclectic Man wrote:
Mon Aug 09, 2021 7:23 pm
neufer, thanks for the reference. Lovely images.

@ Chris Peterson: The meteor was far too quick for any possibility of my eyes or the binoculars 'wiggling' and causing any illusion of corkscrew motion. Meteors are not aerodynamically stable like an Apollo capsule, and it is highly likely that they are spinning when they hit the atmosphere. It was very faint and so must have been a small one and therefore its trajectory was more affected by resistance on its path through the atmosphere. Large meteors may have enough mass to be untroubled by aerodynamic turbulence, but small ones, irregular in shape will be buffeted about and therefore not follow a straight line flight path. Not only that but the ram pressure and heating on a meteor is unevenly distributed, causing partial or eventually complete melting of a small item travelling at high supersonic velocity. The only things that don't tumble when entering the atmosphere are either very big or carefully designed to be stable. Note that cannon balls and lead shot are notoriously inaccurate over long distances due to aerodynamic pressures on non-gyroscopically stabilised objects travelling at supersonic speeds (which is why the invention of the rifle was significant for hunting and warfare). I hope this explanation helps.
A meteor cannot move more than a few meters back and forth as it "corkscrews". This has occasionally been recorded with some fancy meteor tracking telescopes. It is potentially something that might be seen in a chance crossing of a meteor through a telescopic field. It isn't visible to the naked eye, or to a camera with a lens having a focal length consistent with normal photography. And it isn't going to be visible through binoculars.

What you saw was an illusion.
OK, Mr Peterson. Firstly, your posts do come across as rather aggressive, so maybe you could, in future, consider how you express yourself. Stating things like "That doesn't happen", and "What you saw was an illusion" could certainly be put more politely. Science is full of people denying things happened when they actually did.

Secondly, please read my original posting more carefully. I wrote that the meteor "appeared' to follow a corkscrew path. I note that you originally claimed that the appearance was due to my eyes or wiggling the binoculars. Maybe you could provide an explanation of how you claim such an illusion may be created. Reference to a published, peer-reviewed academic article in a respected journal would be appreciated. (A reference to a learned article on the sideways motion of meteors in flight supporting your assertions about that would also be appreciated.)

Thirdly, why are you so intent on denying what happened? Maybe I was just very lucky, once, in my over 60 years of inhabiting this planet, to see something extraordinary. Extraordinary events do happen, like the parachutist who was nearly hit by a meteorite in dark flight: https://www.smithsonianmag.com/smart-ne ... 180950397/ (Skip to about 2m in to see the meteorite drop past.)

Fourthly, I expect that you will insist on 'having the last word', so maybe consider making it a nice one?

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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by Chris Peterson » Tue Aug 10, 2021 1:43 pm

Eclectic Man wrote:
Tue Aug 10, 2021 10:26 am
Chris Peterson wrote:
Tue Aug 10, 2021 2:20 am
Eclectic Man wrote:
Mon Aug 09, 2021 7:23 pm


neufer, thanks for the reference. Lovely images.

@ Chris Peterson: The meteor was far too quick for any possibility of my eyes or the binoculars 'wiggling' and causing any illusion of corkscrew motion. Meteors are not aerodynamically stable like an Apollo capsule, and it is highly likely that they are spinning when they hit the atmosphere. It was very faint and so must have been a small one and therefore its trajectory was more affected by resistance on its path through the atmosphere. Large meteors may have enough mass to be untroubled by aerodynamic turbulence, but small ones, irregular in shape will be buffeted about and therefore not follow a straight line flight path. Not only that but the ram pressure and heating on a meteor is unevenly distributed, causing partial or eventually complete melting of a small item travelling at high supersonic velocity. The only things that don't tumble when entering the atmosphere are either very big or carefully designed to be stable. Note that cannon balls and lead shot are notoriously inaccurate over long distances due to aerodynamic pressures on non-gyroscopically stabilised objects travelling at supersonic speeds (which is why the invention of the rifle was significant for hunting and warfare). I hope this explanation helps.
A meteor cannot move more than a few meters back and forth as it "corkscrews". This has occasionally been recorded with some fancy meteor tracking telescopes. It is potentially something that might be seen in a chance crossing of a meteor through a telescopic field. It isn't visible to the naked eye, or to a camera with a lens having a focal length consistent with normal photography. And it isn't going to be visible through binoculars.

What you saw was an illusion.
OK, Mr Peterson. Firstly, your posts do come across as rather aggressive, so maybe you could, in future, consider how you express yourself. Stating things like "That doesn't happen", and "What you saw was an illusion" could certainly be put more politely. Science is full of people denying things happened when they actually did.

Secondly, please read my original posting more carefully. I wrote that the meteor "appeared' to follow a corkscrew path. I note that you originally claimed that the appearance was due to my eyes or wiggling the binoculars. Maybe you could provide an explanation of how you claim such an illusion may be created. Reference to a published, peer-reviewed academic article in a respected journal would be appreciated. (A reference to a learned article on the sideways motion of meteors in flight supporting your assertions about that would also be appreciated.)

Thirdly, why are you so intent on denying what happened? Maybe I was just very lucky, once, in my over 60 years of inhabiting this planet, to see something extraordinary. Extraordinary events do happen, like the parachutist who was nearly hit by a meteorite in dark flight: https://www.smithsonianmag.com/smart-ne ... 180950397/ (Skip to about 2m in to see the meteorite drop past.)

Fourthly, I expect that you will insist on 'having the last word', so maybe consider making it a nice one?
Take it as you wish. I'm just giving you the science. And FWIW, that skydiver took a picture of a rock accidentally packed in his parachute. That was the conclusion once the image was closely examined. Once in a lifetime, maybe, but not all that remarkable.
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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by bystander » Tue Aug 10, 2021 6:23 pm

Eclectic Man wrote:
Tue Aug 10, 2021 10:26 am
... Extraordinary events do happen, like the parachutist who was nearly hit by a meteorite in dark flight: https://www.smithsonianmag.com/smart-ne ... 180950397/ (Skip to about 2m in to see the meteorite drop past.) ...
Chris Peterson wrote:
Tue Aug 10, 2021 1:43 pm
... FWIW, that skydiver took a picture of a rock accidentally packed in his parachute. That was the conclusion once the image was closely examined. Once in a lifetime, maybe, but not all that remarkable.
Astro Bob: Norwegian skydiver update: It's a rock, not a meteorite
Steinar's blog: Fireballs vs. eyeballs

All in all, probably less remarkable than almost being "hit by a meteorite in dark flight"
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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by neufer » Tue Aug 10, 2021 9:23 pm

The curious case of the corkscrew meteors....
seems to conclude that the pictures taken in gusty winds & should not be relied upon.

If only the meteors weren't both hypersonic & disintegrating:
https://en.wikipedia.org/wiki/Maple wrote:
<<Acer is a genus of trees and shrubs commonly known as maples. The distinctive fruits are called samaras, "maple keys", "helicopters", "whirlybirds" or "polynoses". These seeds occur in distinctive pairs each containing one seed enclosed in a "nutlet" attached to a flattened wing of fibrous, papery tissue. They are shaped to spin as they fall and to carry the seeds a considerable distance on the wind. People often call them "helicopters" due to the way that they spin as they fall. During World War II, the US Army developed a special airdrop supply carrier that could carry up to 65 pounds of supplies and was based on the maple seed. Seed maturation is usually in a few weeks to six months after flowering, with seed dispersal shortly after maturity. However, one tree can release hundreds of thousands of seeds at a time. Depending on the species, the seeds can be small and green to orange and big with thicker seed pods. The green seeds are released in pairs, sometimes with the stems still connected. The yellow seeds are released individually and almost always without the stems. Most species require stratification in order to germinate, and some seeds can remain dormant in the soil for several years before germinating.>>
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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by Eclectic Man » Wed Aug 11, 2021 9:56 am

neufer wrote:
Tue Aug 10, 2021 9:23 pm
The curious case of the corkscrew meteors....
seems to conclude that the pictures taken in gusty winds & should not be relied upon.

If only the meteors weren't both hypersonic & disintegrating:
https://en.wikipedia.org/wiki/Maple wrote:
<<Acer is a genus of trees and shrubs commonly known as maples. The distinctive fruits are called samaras, "maple keys", "helicopters", "whirlybirds" or "polynoses". These seeds occur in distinctive pairs each containing one seed enclosed in a "nutlet" attached to a flattened wing of fibrous, papery tissue. They are shaped to spin as they fall and to carry the seeds a considerable distance on the wind. People often call them "helicopters" due to the way that they spin as they fall. During World War II, the US Army developed a special airdrop supply carrier that could carry up to 65 pounds of supplies and was based on the maple seed. Seed maturation is usually in a few weeks to six months after flowering, with seed dispersal shortly after maturity. However, one tree can release hundreds of thousands of seeds at a time. Depending on the species, the seeds can be small and green to orange and big with thicker seed pods. The green seeds are released in pairs, sometimes with the stems still connected. The yellow seeds are released individually and almost always without the stems. Most species require stratification in order to germinate, and some seeds can remain dormant in the soil for several years before germinating.>>
Very interesting links. My observation was made in still air. It would be interesting to know at what frequency the telescope would have to oscillate to produce the images as an effect. There is also the added complication of the angle a which the meteor's path is viewed. The closer to 'head on' the shorter the wavelength of any actual in the path oscillation would appear.

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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by neufer » Wed Aug 11, 2021 1:01 pm

Eclectic Man wrote:
Wed Aug 11, 2021 9:56 am

My observation was made in still air. It would be interesting to know at what frequency the telescope would have to oscillate to produce the images as an effect. There is also the added complication of the angle a which the meteor's path is viewed. The closer to 'head on' the shorter the wavelength of any actual in the path oscillation would appear.
Speaking of frequency... centripetal forces are on the order of (2πf)2R

Assuming that your meteor's corkscrew R is on the order of kilometers
one is talking about centripetal forces of thousands of g's :!:

It is fortunate that our returning Apollo astronauts only had to undergo
a few g's of deceleration and not any noticeable side to side buffeting.
Art Neuendorffer

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Chris Peterson
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Re: APOD: Perseus and the Lost Meteors (2021 Aug 09)

Post by Chris Peterson » Wed Aug 11, 2021 1:14 pm

neufer wrote:
Wed Aug 11, 2021 1:01 pm
Eclectic Man wrote:
Wed Aug 11, 2021 9:56 am

My observation was made in still air. It would be interesting to know at what frequency the telescope would have to oscillate to produce the images as an effect. There is also the added complication of the angle a which the meteor's path is viewed. The closer to 'head on' the shorter the wavelength of any actual in the path oscillation would appear.
Speaking of frequency... centripetal forces are on the order of (2πf)2R

Assuming that your meteor's corkscrew R is on the order of kilometers
one is talking about centripetal forces of thousands of g's :!:

It is fortunate that our returning Apollo astronauts only had to undergo
a few g's of deceleration and not any noticeable side to side buffeting.
This is how we analyzed the images back at that meeting in 2010 (and how we continue to examine claims). Once the lateral excursion from the descent path exceeds a few meter (i.e. too small to see except at high magnification, given a body tens to hundreds of kilometers away), the forces on the body exceed the material strength of even iron meteoroids. We would get fragmentation. And indeed, at high magnification, with tracking cameras, we do see meteoroids split off into separate pieces as a consequence of aerodynamics and tumbling.
Chris

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