QUESTIONS: Comet 209P/LINEAR

many different sources | Feb 27, 2014 | Yosemitest

[Errant]

I need to get a copy of Stellarium for myself.

The issue, as I see it with Linear, is the fact that it has broken up. That means there could be some large objects hiding in the dust trail, trailing the main body of debris. Since the earth is crossing through that same trail close behind this main body passage (relatively), it should mean the chances of encountering larger objects in this particular comet's dust trail are greater than normal, or of say a single body comet's trail in which the main nucleus passed months before the earth encounters its dust trail.

No model is going to be able to predict this. It's something we'll just have to wait to see if we do or don't encounter larger objects, unless of course NASA wishes to share radar returns or observations with us. Not likely of that happening if there is something coming our way and they thought it might cause a panic.

There was a comet that we watched breakup some years back (I forget the name now) which now consists of about 60 objects NASA is tracking. The pieces are presently scattered over a trail with millions of miles between the separated chunks.

Which brings up another question in my mind: Why isn't NASA putting out more detailed data on Linear? Just seems kind of strange, if you ask me.

Btw, good work on the numbers!

[Yosemitest]

I like Stellarium, the free version, and there's a $49.99 SkySafari Pro that I plan on purchasing.
Thanks, for noticing the math.

"Since the earth is crossing through that same trail close behind this main body passage (relatively),
it should mean the chances of encountering larger objects in this particular comet's dust trail are greater than normal, ...

No model is going to be able to predict this.
It's something we'll just have to wait to see if we do or don't encounter larger objects,
unless of course NASA wishes to share radar returns or observations with us.
Not likely of that happening
if there is something coming our way and they thought it might cause a panic. ...

... Why isn't NASA putting out more detailed data on Linear?
Just seems kind of strange, if you ask me. "

I agree.
My mother talks of an event in the 40s or 50s of watching many shooting stars, 100s at a time, when she was a little girl, one night.
But she can't remember what Comet it was associated with.

The Figure 2 Chart on page 5 of that .pdf probably shows more information about the cumulative threat from all those different Comet 209P/Linear Orbital Passes through time, that we'll go through.
I can only assume that it shows only the level of the Earth's Orbital Plane as it intersects with all those combined Comet trails, and where their model predicted the debris to be.
I also assume that its cross-section is a top-down view from 209P/Linear's trailing tail being blown out from the Sun, even though Linear is traveling at a slight angle as it crosses below Earth;s Orbital Plane.

[Yosemitest]

Ping.

[messierhunter]

You suck at math. Badly. You really haven’t learned ANYTHING from your ISON experience. Log10(radius(m)) = -1.0 means the largest possible fragment size in their model is 1*10^-1.0 m, or 100 cm. The peak particle size on that chart is about 1 cm or less.

[messierhunter]

You guys should know better than to trust BPearthwatch. I guess you don’t though.
http://www.youtube.com/watch?v=-Kcuxcn9BYE

[Yosemitest]

I was under the impression that you multiplied the radius of the object by the log.

[messierhunter]

Can you not read? It plainly says log(radius(m)). Log of the radius in meters.

[Yosemitest]

"The peak particle size on that chart is about 1 cm or less."

If your statement is true, what would particles sizes be from figure 4 oftheir paper that state:

"Mean = 3.20971"

"Mode = 2.93205"

I don't believe they use the letter "m" to mean meter, but I could be wrong, as I am not schooled in this field.

Explain their statement to me that states:

"An equal amount of dust is assumed to be released between the sizes of 10−9 to 10−1 m in radius,
though only particles larger than 10−5 m are simulated:
given our assumed size distribution,
this gives a fraction > 0.99999 of the mass and 4×10−7 of the number of particles simulated. "

[messierhunter]

It’s a simple log function. Log(Radius(m)) = -3 would be 1 cm. 1*10^-3 m = 0.1 cm. At Log(Radius(m)) = -2 where most of the density ends, the radius would be 1 cm.

Their statement is pretty self-explanatory. If you don’t get it then you need to go back and take some remedial science and math courses. Your constant confusion with log functions suggests you probably should do so anyway. Please, drop this nonsense, it’s making free republic look ridiculous. There are plenty of forums on the internet for pseudoscientific discussions. I’m begging you, this is embarrassing.

[messierhunter]

Should be .1 cm, not 1 cm.

[messierhunter]

Aka 1 mm. Sorry, didn’t get enough sleep.

[Yosemitest]

"1*10^-1.0 m, or 100 cm. The peak particle size on that chart is about 1 cm or less.",

Wouldn't that be 1 decimeter ?

deci- (d-) 10-1
1 tenth

centi- (c-) 10-2
1 hundredth

milli- (m-) 10-3
1 thousandth

micro- (µ-) 10-6
1 millionth

nano- (n-) 10-9
1 billionth

pico- (p-) 10-12
1 trillionth

Notes:
I am often asked about prefixes for other multiples, such as 104, 105, 10-4, and 10-5.
The prefix myria- (my-) was formerly used for 104, but it is now considered obsolete and it is not accepted in the SI.
To the best of my knowledge, no prefixes were ever accepted generally for 105, 10-4, or 10-5.

[Yosemitest]

Go get some sleep and answer me tomorrow.
I really want to understand this particle math. This doesn't explain large pieces that break off that are larger (+1 meter) than their model.

I hate the metric system.
For religious reasons, I hate it, I hate it, I hate it, I hate it, I hate it, I hate it, ...

[Errant]

I’m begging you, this is embarrassing.

Should be .1 cm, not 1 cm.

Aka 1 mm. Sorry, didn’t get enough sleep.

It's not lack of sleep that's causing you to embarrass yourself, it's the natural outcome of mixing a heaping of idiocy with too much arrogance and impatience.

Yosemitest was upfront and was asking for help in understanding the math and expressions.

While you may have learned a few mathematical symbols and operations, it surely hasn't helped with your lack of maturity or common sense.

[Errant]

You guys should know better than to trust BPearthwatch.

He's pretty far out in left field on some things. On others, he is dang close. He is also sincere, humble, hard working, and entertaining. Not everyone can be the perfect, all understanding, tolerant human like yourself...

[Yosemitest]

Thanks, but let him get some sleep.
I've been too tired to think myself, before.

[Errant]

I don't believe they use the letter "m" to mean meter...

Now you're getting somewhere... Don't feel bad about confusing metric symbols. Even NASA gets symbols wrong sometimes. They once crashed into Mars because of confusion not between metric units, but between the two systems .

The great thing about metrics is once you know what you're dealing with, it's easy to convert between the units.

:-)

Still, the model you're using only predicts dust particles. It isn't going to help much in predicting how many large rocks are trailing a fragmented comet nucleus. Best to use observation/radio returns for that.

[Yosemitest]

You'd think they be able to model those larger pieces also.
It's not like things don't collide in space.

[Errant]

You'd think they be able to model those larger pieces also.

Too many variables, beginning with the composition of the comet itself. At best, they're able to get somewhat of a useable calculation based on size, speed, distance from the sun, and repeated observations of the dust particles being emitted. And this all based on an intact nucleus. A breakup creates more surface area that is exposed and no really good way to even calculate the increased area with that model. And again, we're taking dust particles, not the big chunks dependent upon the comet's makeup.

Take another look at ISON's breakup. How do you calculate that? Look at the comet that impacted Jupiter and the one I was telling you about that has broken into about 60 pieces, the last piece coming near to earth. I think this might be it: http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=73P-C

[Errant]

It's not like things don't collide in space.

Like what they are saying caused this: