Oort cloud and comets

[Helio]

So Cat et al. We have a flexible size (and mass) for the Oort cloud we do not see and other solar systems documented now that we do not see Oort clouds there either. It is always good to be flexible when explaining How The Universe Works

It is understandable that we can't yet see Oort objects in other star systems. Only objects close to the host star are bright enough to reflect light for trillions of miles and be bright enough for our imaging.

But, one advantage we have in looking elsewhere is that we will see the light enhanced along the edge of the cloud since the no. of objects per unit area are so much greater than what we can see for our own Oort objects. [new "o" record perhaps. :]

We have imaged other Kuiper belts. The Oort object models are extensions of the Kuiper models, so I wouldn't bet an ice cream sundae against the Oort objects being someday imaged.

 

[Helio]

Watching one of my science programs gave this estimate and suggested that the Oort cloud of our Sun actually intermingles with the Oort cloud of Proxima Centauri.

-Wolf sends

That's a bit surprising. I think 1 light year is the upper end of our Oort cloud. Does a triple star system suggest they can support 3x that radius?

But, in only about 15,000 27,671 years, I calculate, IIRC, that our nearest neighbor will be only a little more than 3 light years away. So mingling seems more likely then.

 

[Wolfshadw]

Does a triple star system suggest they can support 3x that radius?

I would think that would depend on the mass of each star in the system as well as the distance between them.

-Wolf sends

 

[vincenzosassone]

Unless I am out of date (very possible) the Oort Cloud cannot be seen.

Hi Cat,
as I'm used to say, there is never too late. We can always add something else since what we know about the Universe isn't never enough!

So alpha and Proxima are not far from average distance. Of course it does not mean that every star has another star about 5ly away in every direction (allowing for spacing) but it could mean, following what Wolfshadw posted, that there is a network of Oort Clouds permeating large tracts (or all) of the galaxy. If there is anything in the idea of life being spread by comets . . . . . . . . . . . . . . . that has some mighty implications.

Good point. I have studied the topic (and I must say that I studied it a lot!) for this reason I can say that I thought something of this kind too. I have read that a reasonable part of the Oort Cloud is made of materials that actually come from other systems. The closest to us is, as you all alread know, Proxima Cetauri. I don't know a lot about Alpha Centauri, but I don't think this is so important. Anyways, talking about this network of Oort Clouds, I want you to know that this is an impressive idea. The most important force of the Universe, that is gravity, has created an equilibrium (dinamic equilibrium) meant to rule the entire Universe for all the time (for this reason everything is connected in a complex way but cannot change according to the laws of gravity). This is also important because it gives the possibility to have materials of another system to us, that in future can be useful. And what's more, we can use it in future to travell too.
One more thing: is possible that the Oort Cloud doesn't actually exist?

 

[vincenzosassone]

I have enjoyed reading a number of books on him. I have close to a dozen.

Great! Galileo was one of the greatest ones even because his story.

 

[rod]

vincenzosassone in post #29 asked, "One more thing: is possible that the Oort Cloud doesn't actually exist?"

My answer is yes. My observation here. If the Oort cloud does not exist, that would be catastrophic for solar nebula and accretion disk model for our solar system in my thinking. Comets do not last billions of years in the solar system so could not be dated back 4.56 billion years old age used since mid-1950s established by Clair Patterson for the age of the Earth and solar system. Comets could not represent primordial pieces of the early solar system then, not at least in the current solar nebula paradigm and age dating accepted. Here is an example where something could wrong if no Oort cloud.

Comet Catalina suggests comets delivered carbon to rocky planets, https://phys.org/news/2021-03-comet-catalina-comets-carbon-rocky.html, March 2021.

My observation. Carbon could not form on Earth in the early accretion disk because it was too hot so carbon must be delivered to Earth from the outer solar system regions like comets coming from the Oort cloud. No Oort cloud - serious consequences here for the origin science model presented to the public.

 

[Helio]

I would think that would depend on the mass of each star in the system as well as the distance between them.

Yes, and this system is more massive. I suspect models will show much stronger tossing action from the inner binary, thus producing a greater Oort radius, but I’m only guessing.

 

[Helio]

Comets do not last billions of years in the solar system so could not be dated back 4.56 billion years old age used since mid-1950s established by Clair Patterson for the age of the Earth and solar system.

If asteroids and meteoroids are billions of years in age, why not the same, but icier, objects past the Frost line?

Comets could not represent primordial pieces of the early solar system then, not at least in the current solar nebula paradigm and age dating accepted.

Comets that have a close perihelion will disintegrate more and more with each swing near the Sun. But a long period comet with a perihelion outside that of, say, Pluto — very close to the Sun given an aphelion if at least 10,000 AU — will hold its volatiles and survive for billions of years, IMO.

My observation. Carbon could not form on Earth in the early accretion disk because it was too hot so carbon must be delivered to Earth from the outer solar system regions like comets coming from the Oort cloud. No Oort cloud - serious consequences here for the origin science model presented to the public.

Carbon and oxygen are the most abundant “metals” (not H or He). I don’t see how it would not be abundant throughout the solar accretion disk.

 

[rod]

Helio in post #33 says "Comets that have a close perihelion will disintegrate more and more with each swing near the Sun. But a long period comet with a perihelion outside that of, say, Pluto — very close to the Sun given an aphelion if at least 10,000 AU — will hold its volatiles and survive for billions of years, IMO."

Applying the Galileo standard of direct observation like the Galilean moons, which comet(s) is documented showing what you just said? Example, Halley's comet? This does not fit. What about this comet, NEOWISE (C/2020 F3)? I observed that back in July 2020 with my telescope. There was also C/2020 M3 Atlas that I viewed with my telescope back in November 2020.

Do you have a specific comet(s) here or is this just a long age model interpretation without objective observations (of real comets) to support the statement? The comet example used in post #33 appears to assume it originated in the Oort cloud and returns to the Oort cloud perhaps. I need to see a real comet example and how many observations were made of the comet(s) like observations of the Galilean moons.

Comet NEOWISE is a good example, https://en.wikipedia.org/wiki/Comet_NEOWISE, reports 376 observations made but an orbital period perhaps 4400 to 6700 years. There is no way to show the comet completed > 600,000 perihelion passages in the past to match with the radiometric ages of meteorites. Even if NEOWISE completes perihelion passage every 11,000 years, still > 400,000 revolutions in the past required.

I used Jean Meeus algorithms and calculated an orbital period for a model comet with a = 5,000 au, e=0.999, mass ~ 6 x 10^17 g. Perihelion ~ 5.0 au, aphelion ~ 9995 au, P ~ 354,000 years so in 4.5 billion years, ~ 12700 revolutions around the Sun. Demonstrating that a comet like this (if documented by observations like NEOWISE) completed many thousands of past revolutions around the Sun is not observable but an extrapolation.

 

[Helio]

Applying the Galileo standard of direct observation like the Galilean moons, which comet(s) is documented showing what you just said?

No, ( but see the list link below), but a legitimate hypothesis Galileo would respect only must predict such observations in the future. He did this with his hypothesis for Saturn having moons, but he knew he lacked enough resolution to verify such a major claim, so he stayed humble about it, AFAIK.

The Kuiper belt was an unseen hypothesis based on dynamic modeling, and its predictions have proven fruitful. The Oort Cloud is the same sort of thing.

But we do have objective evidence for extremely distant objects. Here is a list of about 30.

I need to see a real comet example and how many observations were made of the comet(s) like observations of the Galilean moons.

Yes, that would help. . But we don’t have scopes that powerful, yet, though that listis interesting evidence.

Also, remember that “absence of evidence isn’t evidence for absence.” The hypothesis seems easily justified. But, who knows what we will discover. Interestingly, the more we look, the more amazing are the findings.

 

[rod]

As an hypothesis, Oort cloud is okay. Helio's post #35 provides a list of comets with projected aphelion distances. It is important to note what the report states upfront. "This is a list of Solar System objects by greatest aphelion or the greatest distance from the Sun that the orbit takes it. For the purposes of this list, it is implied that the object is orbiting the Sun in a two-body solution without the influence of the planets or passing stars. The aphelion can change significantly due to the gravitational influence of planets and other stars. Most of these objects are comets on a calculated path and may not be directly observable.[1] For instance, comet Hale-Bopp was last seen in 2013 at magnitude 24[2] and continues to fade, making it invisible to all but the most powerful telescopes."

I used Jean Meeus again and calculated a = 200,000 au, e=0.999, and same comet mass as before. If a closed orbit, perhaps a period > 89 million years for one perihelion passage. In 4.5 billion years, perhaps 50 perihelion passages. The aphelion ~ 399,800 au, heliocentric projection vs. barycentric used in the Wikipedia report.

These are potential orbit projections and do not confirm comets like this have completed multiple perihelion passages in the solar system (or migrated from the Oort cloud). Such orbit projections could require many millions of years for one perihelion passage or assume the comet could survive multiple perihelion passes. The perihelion distance about 200 au.

Helio said in post #35, "But we do have objective evidence for extremely distant objects. Here is a list of about 30."

As already discussed here, these are projected aphelion distances, not directly observed or imaged out there

 

[Helio]

I used Jean Meeus again and calculated a = 200,000 au, e=0.999, and same comet mass as before. If a closed orbit, perhaps a period > 89 million years for one perihelion passage. In 4.5 billion years, perhaps 50 perihelion passages. The aphelion ~ 399,800 au, heliocentric projection vs. barycentric used in the Wikipedia report.

Ok. Now change your value by a hair, to e = 0.998. Perihelion now becomes 200 AU, keeping it safe from solar harm. [200k AU seems beyond the Sun’s grip, however. I thought 60k AU was the limit but there are some reports it’s greater.]

These are potential orbit projections and do not confirm comets like this have completed multiple perihelion passages in the solar system (or migrated from the Oort cloud). Such orbit projections could require many millions of years for one perihelion passage or assume the comet could survive multiple perihelion passes. The perihelion distance about 200 au.

. Right.

 

[Catastrophe]

NASA:
"https://solarsystem.nasa.gov/asteroids-comets-and-meteors/overview/"

" Asteroids and comets—and the meteors that sometimes come from them—are leftovers from the formation of our solar system 4.6 billion years ago. While the planets and moons have changed over the millennia, many of these small chunks of ice, rock and metal have not. They are a lot like a fossil record of planetary evolution."

Cat

 

[rod]

FYI. When it comes to observing the present population of asteroids, meteoroids, and comets in the solar system, there is a great difference between what we see in astronomy today vs. what is used in various models said to exist some 4.6 billion years ago in the ecliptic (what I call origins science teaching). There is great mass difference used in the models vs. present day observations in the ecliptic. This problem is seen in other stars too. Example DM Tau. A Spatially Resolved au-scale Inner Disk around DM Tau, https://ui.adsabs.harvard.edu/abs/2018ApJ...868L...5K/abstract, Nov-2018. Perhaps 13 earth masses.

Astronomers find evidence planets start to form while infant stars are still growing, https://phys.org/news/2020-10-astronomers-evidence-planets-infant-stars.html, Oct-2020. My observation. The system is 470 LY distance or 144.1 pc. 20 AU resolution ~ 140 mas at that distance from Earth. Also the total dust mass could be 15,900 earth masses but the 0.5 Jupiter size is only about 159 earth masses. Another report, HOPS 383: X-rays from a newborn star hint at our sun's earliest days, https://phys.org/news/2020-06-x-rays-newborn-star-hint-sun.html, Jun-2020. My note, the model uses close to 16650 earth masses for the disk in this Class 0 protostar.

Fast-moving gas flowing away from young star caused by icy comet vaporisation, https://phys.org/news/2020-11-fast-moving-gas-young-star-icy.html, Nov-2020. Also, Rapid CO gas dispersal from NO Lup's class III circumstellar disc, https://ui.adsabs.harvard.edu/abs/2020arXiv201113229L/abstract, November 2020. My observation. The attached arXiv paper indicates the star mass is ~ 0.7 solar masses and dust disk mass estimate 0.036 earth masses. This is a very low mass with ALMA indicating rapid CO gas movement away from the star and disk. The arXiv paper shows the distance is 133.7 pc.

There is significant mass differences between what is measured today in the solar system's ecliptic (about 446.7 earth masses according to Allen's Astrophysical Quantities Fourth Edition) and what is used in models, simulating accretion 4.6 billion years ago. Current dust disk mass observations of various stars can range quite a bit here in earth masses, from very small to some near 16,000 earth masses. I feel issues like this should be clearly presented to the public, i.e. transparent