I commend you on your video, because of your detailed links and your logical approach to put out honest information.
But I do have a few points to discuss with you about it.
First, instead of being "Unlisted", you should do some minor changes to make it "List-able", and add links to your programs that show the orbital models you display.
I want to know more about the
Orbit Reconstruction, Simulation and Analysis software and how to use it.
How does it compare to
Stellarium and to
SkySafari Pro ?
Why did you choose it over the others ?
Pasquale Tricarico, Ph.D., Senior Scientist of the Planetary Science Institute is someone I 'd like to know more about.
I get the impression you're him.
The overall impression I got from your video is that you're stating
"No threat, no danger from Comet 209P/Linear.
Just a new "meteor shower" to view, that's all."
But, at 16 minutes and 54 seconds into of your 23:30 unlisted video, your
"OpenGL viewer: 209P Back to 1803", clearly shows
M01D: 0.256LD
Time: 1810 Dec 4 00:00:00 TDT
Central Object: Sun
Observer Position: Free
So Comet 209P/Linear's orbital distance from Earth's orbital plane is 0.256LD Lunar Distance, from it's 1810 Dec 4 orbit.
A lunar distance (LD) is
384,400 km (238,900 miles) and 0.256LD LD is only
61,158.5 miles.
Now to you question "WHERE the "2.1 Million Miles Wide" came from".
BPEarthWatch addressed it Feb 16, 2014 at
from 3:09 to 4:33 of the 5:22 video where he states:
" The Earth is moving at 67,000 miles per hour.
It will take 30 hours to pass thru Comet Linear's Debris Field.
The Earth travels 1.6 million miles per day.
This meals the Debris Field is 2 Million Miles Wide.
It's actually 2 Million 10 Thousand Milers Wide, to get it right down and accurate.
That's a wide debris field, guys.
... Time inside the thickest part of the debris field will be 8-12 hours. "
I think it came from
Figure 2 on page 5 of
Quanshi Ye and Paul A. Wiegert .pdf and is a compilation of ALL 209P/Linear's Orbital debris trails.
My guess on his statement about
"an arc" it that he's talking about when Comet 209P/Linear starts its downward turn on the outbound leg of its orbit.
Where you address "Comet Lovejoy vs Comet 209P/Linear" and the mistaken identity, you convinced me, with your presentation and the detailed links you presented.
Where you present the width of
Come 209P/Linear as a diameter of only 4,000 miles, you again convinced me.
BUT, you appear to be talking about just ONE orbit's width, and NOT ALL the accumulated orbital debris fields left behind from Comet 209P/Linear, that we're going to enter May 24, 2014.
That's where, I think, he gets the "2.1 million miles wide" figure.
You addressed
Comet IRAS–Araki–Alcock (formal designation C/1983 H1, formerly 1983 VII) making a closer approach to Earth, almost twice as close as 209p, was okay.
But there are several different estimates of 209P's closeness with Earth's orbit, however, your XORSA model is the most believable I've seen so far.
I enjoyed reading:
"about 0.0312 AU (4,670,000 km; 2,900,000 mi) of any comet in 200 years; only Lexell's Comet, in 1770, and 55P/Tempel-Tuttle, in 1366, are thought to have come closer."
That was an interesting read.
But your"Comet 209P/Linear's orbital distance from Earth's orbital plane is 0.256LD Lunar Distance, from it's 1810 Dec 4 orbit."
is only 61,158.5 miles and that's closer.
Your presentation of 209P interacting with Jupiter's orbit around Jan 2010, bringing it closer to Earth, was informing.
Overall, I have more respect for you, but your questioning of BPEarthWatch's motives seems strange.
I believe he's sincere, but I didn't know people made money from YouTube.com,
and your http://socialblade.com/youtube/user/(name) is one I want to remember.
Overall, you did a good job with your presentation.
Just don't fault people for trying to make money in their retirement years.
Some truly are sincere, even if they;re mislead, and are NOT trying to "Scare the masses"so much as they're trying to serve the people as a "Watchman on the wall".
“First, instead of being “Unlisted”, you should do some minor changes to make it “List-able”, and add links to your programs that show the orbital models you display.”
No thanks. I gave it to some friends of mine to put on their channels publicly, which they did. As I expected, one of them is currently receiving threats from BPearthwatch claiming that he will file a DMCA takedown notice if they do not remove it since “I did not have authorization to use his video.” I don’t need authorization. Criticism is fair use in copyright law. Anyway, the friend who is being threatened has much more experience handling this and a lawyer who will gladly and quickly respond in kind if it comes to that. I’ll keep in mind the idea of adding links to the programs I use in the future.
“I want to know more about the Orbit Reconstruction, Simulation and Analysis software and how to use it.
How does it compare to Stellarium and to SkySafari Pro ?
Why did you choose it over the others ?”
ORSA is a solar system numerical integrator. It can integrate the motions of objects over time, taking into account their gravity. Stellarium, SkySafari Pro, and similar programs all use 2-body methods for comets and asteroids. Therefore they only give accurate results for the positions of those objects at timepoints close to the epoch of the orbital elements used. To see the long term evolution of 209P’s orbit, one must use numerical integratioin, which is what I did with ORSA. Different tools for different jobs. Starry Night Pro is like Stellarium and SkySafari Pro, so it’s useful for identifying comets in current images using current orbital elements, but it cannot accurately show where 209P was 100 or 200 years ago using current orbital elements.
“I get the impression you’re him.”
I value my anonymity. I have a PhD in a scientific field, not astronomy. I am an amateur astronomer, I do this because I enjoy it, not because I’m paid to do it, but I am involved in professional science. Professional science is my “day job” (actually it’s frequently a night job because of what I do) which pays for my “astronomy habit.” That is all you need to know.
“But, at 16 minutes and 54 seconds into of your 23:30 unlisted video, your “OpenGL viewer: 209P Back to 1803”, clearly shows
M01D: 0.256LD
Time: 1810 Dec 4 00:00:00 TDT
Central Object: Sun
Observer Position: Free
So Comet 209P/Linear’s orbital distance from Earth’s orbital plane is 0.256LD Lunar Distance, from it’s 1810 Dec 4 orbit.
A lunar distance (LD) is 384,400 km (238,900 miles) and 0.256LD LD is only 61,158.5 miles.”
Which as I discuss in the video, is why we may be encountering meteors from the comet’s perihelion approaches during that era this year. Meteoroids laid down by the comet 100~200 years ago are the source, not recent activity. If the comet was dormant at that time though we won’t see anything at all. Either way the meteor shower or lack thereof will tell us about the history of this comet.
“I think it came from Figure 2 on page 5 of Quanshi Ye and Paul A. Wiegert .pdf and is a compilation of ALL 209P/Linear’s Orbital debris trails.”
Yes, I recently found that he was using that figure. He calls it a radar image. Furthermore, as I showed in my video, he directly labels what he thinks is 209P and creates a diagram claiming it’s 2.1 million miles wide. He is essentially claiming that Figure 2 AND the STEREO image of 209P show the same thing, that the comet IS a “debris field 2.1 million miles wide.” The truth is it isn’t a radar image at all, it’s the result of a simulation, numerical integration similar to what I did, to figure out when we will encounter any previous meteoroid streams and how many meteors we might get. It is not the same thing as the comet itself, but that is what BP is claiming (whether stated explicitly or not, that IS what he shows). It’s also not a radar image, he just made that up on his own (ie, lied). Figure 2 shows that at maximum the density of material is about 1 particle per 10 km squared in the cross-section of the ecliptic presented in that figure. The true particle density could be much less though, as they state in the paper.
“However, given the current relatively weak dust production of
the comet, rates could be much lower. Of course, absent in-
formation on the activity of the parent body during the per-
ihelion passages during which the arriving meteoroids were
produced we cannot say much about expected rates, nev-
ertheless we conclude that a meteor storm is unlikely.”
“I enjoyed reading:
“about 0.0312 AU (4,670,000 km; 2,900,000 mi) of any comet in 200 years; only Lexell’s Comet, in 1770, and 55P/Tempel-Tuttle, in 1366, are thought to have come closer.”
That was an interesting read.
But your
“Comet 209P/Linear’s orbital distance from Earth’s orbital plane is 0.256LD Lunar Distance, from it’s 1810 Dec 4 orbit.”
is only 61,158.5 miles and that’s closer.”
You’re confusing the MOID distance and close approach distance. They’re not the same. The comets mentioned did come closer than 209P did, even back then. 209P’s MOID distance was low, but that is not the same as close approach distance, that is only the distance from our orbit, not from our planet.
