"Massive dark object 'lurking on edge of solar system hurling comets at Earth" (?)

[xfahctor]

I was refered to an article in thge Daily Mail (yes, I know,the U.K.'s answer to the enquirer) today about this. I know this notion has been kicked around for a number of years, but this seems to be a more recent calculation. Just wondering what your thoughts are on it. Also a couple question for you guys. Can the ort cloud be directly observed other than the ocaisional comet that comes in from it? How, other than comets being hurled at us from time to time, do we know of the existence of the ort cloud? By math?
Article here: http://www.dailymail.co.uk/sciencete...ets-Earth.html

[antoniseb]

This Daily Mail article is not a scoop, we've been discussing it here.

[astromark]

Use of the word 'Massive' is the first clue to a grossly misleading perception intent.
Tabloid media views of astronomical information is to the e nth degree 'misleading'
Yes there is a Oort cloud. No, it is not hurling comets at Earth.
Science is often exaggerated to levels of unsupported hysteria... Fools and foolishness abounds.
Lets try to sprinkle a little factual information into this conversation...
Gasses, dust particles, ices, and many objects of lesser mass than car sized rocks abound in the orbital paths around this solar system.
It is mostly debris remaining from the formation process of this solar system.
That material that was not swept up or ejected by the major planets.
Do not think of it as a area of asteroids and comets... You would be disappointed.
Sparsely populated by remnants of debris and ices...
Yes they are so distant from the central mass of the solar system so as a small movement of a near by rocky mass might introduce a action that might result in a object beginning a ellipse path in towards the central gravity mass of this solar system...
and in doing so might interact with existing orbiting objects... Earth being just one.
Many comets are born of this action. To state a massive dark object is acting as to direct comets towards Earth is wrong.

[xfahctor]

I apreciate the responses. I don't generaly jump on an astronomy story or lend it validity, especially when it's in a tabloid like the Daily Mail, untill I ask actual astronomers. I know what the ort cloud is, I was just asked by someone else how we know it actually exists if we can't directly observe it and I didn't have a good answer for them. *edit *the best answer I could give them was "math and physics tells us it should exist"

[loglo]

Can I just add that it is Oort, not Ort, after Jan Oort the great Dutch astronomer.

[Tenshu]

more nibiru propaganda?

[Jens]

more nibiru propaganda?

No, it's a serious field of research. The way it's written in the Daily Mail is a problem, but the actual mechanism of why comets are moved out of the Oort's cloud is an actual field of research, and there are various theories, I think.

[Tenshu]

No, it's a serious field of research. The way it's written in the Daily Mail is a problem, but the actual mechanism of why comets are moved out of the Oort's cloud is an actual field of research, and there are various theories, I think.

I read the article myself and saw nothing being said about "movement" of said "object" but you already got one person who commented it being Nibiru and i'm sure if more people read it, it's going to cause a debate war.

Jens are you saying we need to fear this because of how it's written?

[Jens]

Jens are you saying we need to fear this because of how it's written?

No, no, no, nothing about fear. It's just this: we know that comets come from the outer solar system into the inner solar system, and always have, and there's nothing to fear about them, really. The thing that's stupid about the Daily Mail article is the use of "hurling at earth." They're not "hurled" "at earth." But there is a legitimate question of why comets come into the inner solar system. And I think that one theory is that there is a body out there that disrupts their orbits. So it wouldn't be anything to fear, just a scientific interest. That's my interpretation, though, and the details might be wrong.

[Tenshu]

^ at least your interpretation is better than what some people tend to say about articles like this, you my friend are very intelligent.

[astromark]

Can I just add that it is Oort, not Ort, after Jan Oort the great Dutch astronomer.

Thankyou Loglo... I ort to have said Oort when I said ort. I ort to be corrected from time to time...

[xfahctor]

Can I just add that it is Oort, not Ort, after Jan Oort the great Dutch astronomer.

DOH!
Sorry

[Inclusa]

In a matter of fact, even "reputed", "mainstream" media give misleading information from time to time.

[Hernalt]

What ever happened to the theory of periodic mass extinctions, which stated that major extinctions occur every 26 million years?
"Overall, scientists have found little evidence that extraterrestrial impacts coincided with most of the major and minor extinctions, the Cretaceous-Tertiary boundary being a major exception. There are a few other hints of other impacts associated with extinctions in the geologic record, but most of these are poorly substantiated or very localized and there are many extinction events that do not correlate with any evidence of impact. Likewise, there are many records of impact (craters, for instance) that seem to have produced little or no biotic effect. So the search for a single common cause to all biological crises has come up rather empty."

[Tenshu]

What ever happened to the theory of periodic mass extinctions, which stated that major extinctions occur every 26 million years?
"Overall, scientists have found little evidence that extraterrestrial impacts coincided with most of the major and minor extinctions, the Cretaceous-Tertiary boundary being a major exception. There are a few other hints of other impacts associated with extinctions in the geologic record, but most of these are poorly substantiated or very localized and there are many extinction events that do not correlate with any evidence of impact. Likewise, there are many records of impact (craters, for instance) that seem to have produced little or no biotic effect. So the search for a single common cause to all biological crises has come up rather empty."

What is being emphasised here exactly?

[Hungry4info]

Probably the idea of an eccentric sub-stellar companion to the Sun ("Nemesis"). It has been proposed that it may be to blame for the mass extinctions, if it has an eccentric orbit and swinging into the inner Oort cloud, dislodging comets that come our way.

But I recall this idea was recently refuted because the orbital period required would result in such a high semi-major axis that the body would be so weakly bound to the Sun that it would be subject to all sorts of interstellar perturbations.

[Hernalt]

The Daily Mail headline includes the phrase "hurling ... at earth". It is trivial to deduce the desired effect of this word choice.
The Daily Mail article includes the line, "These occasional comet showers could be why the mass extinctions on Earth are so regular, some scientists believe."
The article I linked illuminates this seminal basis for Nemsis.
Other observational indicators for Nemesis remain, and their effectiveness for selling headlines is probably not large.

[Tenshu]

Probably the idea of an eccentric sub-stellar companion to the Sun ("Nemesis"). It has been proposed that it may be to blame for the mass extinctions, if it has an eccentric orbit and swinging into the inner Oort cloud, dislodging comets that come our way.

Still the discussion of these massive extinctions doesn't really end well either because more people than not will try and link them to a doomsday scenario like say 2012 for example as some people say that's when the next 36,000 years comes to ahead and therefore something should happen.

I really don't see the fascination in finding planets that can hurt us, ones that can't on the other hand go ahead.

[Jens]

Still the discussion of these massive extinctions doesn't really end well either because more people than not will try and link them to a doomsday scenario like say 2012 for example as some people say that's when the next 36,000 years comes to ahead and therefore something should happen.

Just to give you some comfort, because I know you worry about things: it's not 36,000, it's 26 million years. And the last major event was about five million, so that means the next would be due in like 20 million years! It's somewhat unlikely that anybody on this board will be alive at that time.

I really don't see the fascination in finding planets that can hurt us, ones that can't on the other hand go ahead.

There's no fascination involved. It's just observation of what is out there. There is a theory that there is a dwarf star that orbits the sun and occasionally disrupts the Oort cloud, but it hasn't been demonstrated to be true, so it's just speculation.

Perhaps when you talk about "fascination," you are really thinking about the press. It is true that newspapers tend to report things that have a "dangerous" element. When scientists discover that there is a 1 in 30,000 chance or whatever that an asteroid will impact the earth in 50 years, some newspapers will print "SCIENTISTS DISCOVER KILLER ASTEROID COMING OUR WAY!" It's just the way the media is, and it's not a cause for alarm.

[Tenshu]

^that does give me some comfort, thank you as always Jens, and btw sorry about the PM.

your right about the media, heck I think the other day a new conspiricy theory was actually caught and killed before it could take off due to the information being outdated.

[Hernalt]

Alternate theory for extinctions: Earth Biodiversity Pattern May Trace Back to Bobbing Solar System Path

[baric]

Alternate theory for extinctions: Earth Biodiversity Pattern May Trace Back to Bobbing Solar System Path

These "periodic extinction" theories always come with very vague hints about the timelines of the actual extinctions. What killed the Nemesis theory originally was the realization that these extinctions were not as neatly periodic as the theorists suggested.

Unless the biological timeline of Earth's evolution has inexplicably changed in the past 20 or so years, I see no need to assign a root cause for a problem that has been demonstrated to not exist.

[A.DIM]

These "periodic extinction" theories always come with very vague hints about the timelines of the actual extinctions. What killed the Nemesis theory originally was the realization that these extinctions were not as neatly periodic as the theorists suggested.

Unless the biological timeline of Earth's evolution has inexplicably changed in the past 20 or so years, I see no need to assign a root cause for a problem that has been demonstrated to not exist.

So there's no evidence for a ~60M yr periodicity, whether it's our solar system rising above the galactic plane or extinction events?

[baric]

So there's no evidence for a ~60M yr periodicity, whether it's our solar system rising above the galactic plane or extinction events?

I'm not saying that our solar system doesn't rise out of the galactic plane every 60M years. It may certainly do so.

What I'm saying is that there is no evidence of periodic extinctions along that timeline.

[A.DIM]

I'm not saying that our solar system doesn't rise out of the galactic plane every 60M years. It may certainly do so.

What I'm saying is that there is no evidence of periodic extinctions along that timeline.

Hmm, I think there are those who would argue otherwise.
From Cycles in Fossil Diversity:

It is well known that the diversity of life appears to fluctuate during the course of the Phanerozoic, the eon during which hard shells and skeletons left abundant fossils (0–542 million years ago). Here we show, using Sepkoski's compendium1 of the first and last stratigraphic appearances of 36,380 marine genera, a strong 62 ± 3-million-year cycle, which is particularly evident in the shorter-lived genera. The five great extinctions enumerated by Raup and Sepkoski2 may be an aspect of this cycle. Because of the high statistical significance we also consider the contributions of environmental factors, and possible causes.

[baric]

Hmm, I think there are those who would argue otherwise.
From Cycles in Fossil Diversity:

It is well known that the diversity of life appears to fluctuate during the course of the Phanerozoic, the eon during which hard shells and skeletons left abundant fossils (0–542 million years ago). Here we show, using Sepkoski's compendium1 of the first and last stratigraphic appearances of 36,380 marine genera, a strong 62 ± 3-million-year cycle, which is particularly evident in the shorter-lived genera. The five great extinctions enumerated by Raup and Sepkoski2 may be an aspect of this cycle. Because of the high statistical significance we also consider the contributions of environmental factors, and possible causes.

Paywall.

Here is a graphical depiction of genera extinction through the history of life on Earth:


I see the K-T extinction at 65Mya. This has a known cause, unrelated to a galactic cycle.

Ignoring that, where is the extinction at 120-130MYa?

We don't have one at 180-195MYa, but we do have one at 205MYa. Is that it? Unfortunately, it's off by about 10-15My despite the large error bars already provided.

We have one at 251Mya, which fits the pattern. Unfortunately, it's only 46 My from the previous event -- which violates the periodicity of 62 Mya.

After this, we have a broad mix of lesser extinctions, any of which can be fitted within the error bars of a period.

I would like to see the r-value for any theory trying to correlate extinctions. I'm sure it's going to be rather low unless it comes saddled with qualifiers and conditions.

[Hernalt]

Baric, I thought it most important to link to the new degree of freedom in solar motion, which I had been unaware of. To what degree it causes biodiversity flux, caveat emptor. (On your chart I think I can see a 60My cycle if I use the 65My event as a rough bisector of two smaller peaks which if traced backwards in time seem to match a rough 60 My cycle of at least 8 peaks.)

[Tenshu]

so what does this all mean? Is this object going to cause an extinction event soon or something by the chart? I just don't get it.

[baric]

Baric, I thought it most important to link to the new degree of freedom in solar motion, which I had been unaware of. To what degree it causes biodiversity flux, caveat emptor. (On your chart I think I can see a 60My cycle if I use the 65My event as a rough bisector of two smaller peaks which if traced backwards in time seem to match a rough 60 My cycle of at least 8 peaks.)

First one is at 65My.. the 2nd one looks around 145My. Already, you do not have a 60My cycle.

You are seeing patterns in what is essentially noise. If you want to make a case for periodicity, you must do the following things first:

1) From a suspected cause of extinction, determine an expected rate of periodicity

2) Define "extinction" -- how much of a % drop in genera qualifies? 50%? 70%? 90%? Which time periods are considered? Is anything 500+ Mya too old?

3) Based on 2), determine the dates of extinctions in your samples.

4) Correlate the dates in 3) with the predictions in 1)

5) If your r value from 4) is > 0.5, then you have at least a weak correlation. At this point, you need to start building an evidentiary case for 1)

[Tenshu]

definitely no simple answer to this i'm guessing, man one minute a post is calming the next one scares me.