Perseid Meteors This Weekend

Berzerker

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Surely we should rename them the Perseid Hammered Bracelet?
 
Surely we should rename them the Perseid Hammered Bracelet?
Shh. Let's not start that again.


Between the overcast skies and smoky air (due to smoke from the forest fires west of here), I won't be watching the Perseids this year.
 
Surely we should rename them the Perseid Hammered Bracelet?

debris found in comet tails wasn't hammered loose

but there is growing evidence comets formed close to the sun and not out in some vast cloud surrounding the solar system far beyond the planets reaching almost half way to the next star.
 
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They're finding minerals in comets that required intense heat, so they think they formed closer but got tossed out there by the gas giants, primarily Jupiter. But researchers are still attached to the Oort Cloud theory so something's got to give. Its unlikely trillions of comets formed close to the sun and were ejected by Jupiter to form this vast cloud.
 
That's really cool - do you know of any articles on it? I'd like to read one and then dig up the papers it references.

The Oort cloud remains a working theory that is our best guess as to where comets normally reside, but since it's almost impossible to observe anything so small and far away, it's not really observable. I've always found it kind of strange myself. Are they thinking that it does exist roughly as believed, but the material originated much closer to the Sun and migrated outward due to gravitational interactions with Jupiter and the other gas giants?

The Wiki article on the Oort cloud mentions a variety of possibilities for its origin, including that a lot of it may be material that originated in other solar systems within the nebula the Sun accreted out of, and that the Sun may have ended up "stealing" many of their comets (and vice versa) shortly after its formation.
 
https://phys.org/news/2011-07-comet-material-high-temperatures.html

On 15 January 2006, after an eight-year voyage, NASA's Stardust Mission (Discovery program) brought dust from Comet Wild 2 back to Earth. Comets are formed at very low temperatures (around 50 Kelvin, i.e. -223 C). However, analyses have revealed that Comet Wild 2 is made of crystalline silicates and CAIs (Calcium-Aluminium-rich Inclusions). Considering that the synthesis of these minerals requires very high temperatures (above 1 000 Kelvin or 727 C), how can this composition be explained?

I was wrong about the sequence... that article is rather old but they say the minerals formed under very hot conditions and could have migrated outward to become part of comets

Analyses of the comet dust particles showed aggregate mixtures of both mineral grains and relatively volatile organics, which are organics that evaporate easily.

Scientists observed that some of the minerals are very well crystallized, which can only happen at high temperatures. At low temperatures, these minerals would form some kind of "glass." Therefore, scientists believe the minerals had to form near the sun.

Conversely, scientists theorize that the new organics could not have formed in such a hot environment because of their volatility. Instead, these organics probably formed in the cold, dense interstellar medium, or in the very outer reaches of the protosolar nebula from which the Solar System formed, according to Sandford.

Finding both high-temperature minerals and low-temperature volatile organics in the same comet indicates that materials moved great distances, both inwards and outwards, in the disk of gas and dusk that formed the Solar System, said Sandford.

"It was like a washing machine where everything got mixed up.

https://www.nasa.gov/mission_pages/stardust/news/stardust_results.html

They're trying to explain why comets show evidence of high temperatures combined with volatile material that gets burned off easily. There is another explanation - large collisions would release plenty of both.
 
Should be prime viewing here...the peak for this meteor shower extends for both tonight and tomorrow night. The responsible comet leaves a wide trail that takes us a couple days to move thru. I can understand why our ancestors feared comets. What would happen if we traveled thru a comet's tail and dangerous stuff like cyanide entered our atmosphere? Could it approach the ground killing critters or just disperse high up?
 
Our ancestors feared comets because charlatans told them to, and sold them useless garbage like "comet pills".

The only reason we have to fear them now is physics.
 
Did anyone here get to see the Perseids? It was too cloudy and smoky here to see anything.
 
On what basis are you saying it is unlikely?

That form of the mineral is only created in liquid water below a temperature of 210˚C, they note. The group concludes that the watery alteration most likely occurred in the comet when heat from either an impact or radioactive decay melted pockets of ice, which then quickly refroze.

http://www.sciencemag.org/news/2011/04/stardust-reveals-comets-were-once-wet

Or impacts involving larger bodies with water present produced comets

Besides olivine, the dust from Wild 2 also contains exotic, high-temperature minerals rich in calcium, aluminum and titanium.

"I would say these materials came from the inner, warmest parts of the solar system or from hot regions around other stars," Brownlee said

https://phys.org/news/2006-03-comet-coldest-solar-material-hottest.html

If trillions of comets formed close to the sun and it's equatorial plane and were ejected by Jupiter to form the Oort Cloud I'd expect thousands, maybe millions captured by the other planets as moons. If Jupiter scattered trillions and has only 100+ satellites something doesn't add up. And if Jupiter flung them outward how did they acquire roughly circular orbits in every direction? I'd expect a more disc-like pattern centered around Jupiter's orbital plane with highly elliptical orbits.

Their formation is constrained by the fact they show evidence of intense heat while retaining volatiles that should have burned off. That suggests comets were not the product of primitive accretion but debris from collisions between larger bodies, so I'd imagine they numbered in the thousands or millions, not trillions. If the crust of Europa was sheared off during a collision rock and water/ice would form comets.
 
Did anyone here get to see the Perseids? It was too cloudy and smoky here to see anything.

Yeah I climbed up to Elk Lake in Banff. Lucked out, was overcast/raining Sunday night when I headed to my tent, but got back up around 1am and got a bunch of clear skies. No good photos though, turns out my camera is lacking useful software features for good star/meteor shots.
 
:cry: overcast.

I saw it once in LA. I drove out into the Mojave Desert.

Driving back at 04:00, I found myself trapped in a massive traffic jam of morning commuters from Palmdale heading into L.A. :wow:
 
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If trillions of comets formed close to the sun and it's equatorial plane and were ejected by Jupiter to form the Oort Cloud I'd expect thousands, maybe millions captured by the other planets as moons. If Jupiter scattered trillions and has only 100+ satellites something doesn't add up. And if Jupiter flung them outward how did they acquire roughly circular orbits in every direction? I'd expect a more disc-like pattern centered around Jupiter's orbital plane with highly elliptical orbits.

So I believe I have asked you this question before and not gotten an answer - what do you know about orbital mechanics?
 
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