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Old 2012-12-21, 21:55   #749
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Default Asteroid will not hit Earth. Film at 11

http://neo.jpl.nasa.gov/news/news176.html
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Old 2012-12-21, 23:31   #750
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Quote:
Originally Posted by xilman View Post
I enjoy the way the article is written as though the asteroid were some quantum-mechanical particle whose state is significantly affected by the act of observation:
Quote:
NASA scientists have announced that new observations of 2011 AG5 show that this asteroid, once thought to have a worrisome potential to threaten Earth, no longer poses a significant risk of impact. The orbital uncertainties of the 140m diameter near-Earth asteroid had previously allowed a 0.2% chance of collision in Feb. 2040, leading to a call for more observations to better constrain the asteroid's future course.

Answering the call, University of Hawaii astronomers Dave Tholen, Richard Wainscoat and Marco Micheli used the Gemini 8-meter telescope at Mauna Kea, Hawaii to successfully recover and observe the small and very faint asteroid on October 20, 21 and 27, 2012. In addition to improving our knowledge of the orbit, the Gemini observations also suggest the asteroid varies in brightness as it rotates and therefore may be elongated. Gemini is managed by the Association of Universities for Research in Astronomy (AURA). In addition to the Gemini measurements, Tholen, Micheli and Garrett Elliott obtained less conclusive observations on October 9 & 10 with the University of Hawaii 2.2-meter telescope, also situated on the summit of Mauna Kea. After extensive astrometric analysis by the team in Hawaii, all observations were then sent to the International Astronomical Union's Minor Planet Center in Cambridge, Massachusetts.

An analysis of the new data conducted by NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, California, shows that the risk of collision in 2040 has been eliminated. The updated trajectory of 2011 AG5 is not significantly different, but the new observations have reduced the orbit uncertainties by more than a factor of 60, meaning that the Earth's position in February 2040 no longer falls within the range of possible future paths for the asteroid. With the updated orbit, the asteroid will pass no closer than 890,000 km (over twice the distance to the moon) in Feb. 2040, the epoch of the prior potential collision.
So is the asteroid's orbit updated automatically by the observations, or is there some kind of formal notification mechanism?

"Dear Object 2011 AG5: Due to recent Earth-based observations, we are requesting that you alter your course onto the attached heading in order to meet the latest constraints. Your co-operation in undertaking the required prompt corrective action in this matter is appreciated.
Hugs and smooches,
your IAU MPC NEO monitoring team"

Last fiddled with by ewmayer on 2012-12-21 at 23:32
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Old 2012-12-22, 08:23   #751
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Quote:
Originally Posted by ewmayer View Post
I enjoy the way the article is written as though the asteroid were some quantum-mechanical particle whose state is significantly affected by the act of observation:

So is the asteroid's orbit updated automatically by the observations, or is there some kind of formal notification mechanism?

"Dear Object 2011 AG5: Due to recent Earth-based observations, we are requesting that you alter your course onto the attached heading in order to meet the latest constraints. Your co-operation in undertaking the required prompt corrective action in this matter is appreciated.
Hugs and smooches,
your IAU MPC NEO monitoring team"
Ernst, you being a scientist, should know better than that. Unless you are counting a small number of discrete objects, you should always quote error bars on your observations. An orbit of an asteroid consists not only of the elements themselves --- eccentricity, longitude of ascending node, etc, but also the estimated errors. Inevitably, updated observations update an orbit if they significantly alter the errors in its elements.
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Old 2012-12-22, 22:08   #752
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Quote:
Originally Posted by xilman View Post
Ernst, you being a scientist, should know better than that. Unless you are counting a small number of discrete objects, you should always quote error bars on your observations. An orbit of an asteroid consists not only of the elements themselves --- eccentricity, longitude of ascending node, etc, but also the estimated errors. Inevitably, updated observations update an orbit if they significantly alter the errors in its elements.
Of course I "know better" ... I just find it amusing how the common abbreviation of "orbital parameterization" as "orbit" leads to a quite different meaning if the result is read without 'assumption of insider jargon".
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Old 2012-12-24, 04:59   #753
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Quote:
Originally Posted by ewmayer View Post
So is the asteroid's orbit updated automatically by the observations, or is there some kind of formal notification mechanism?
I'm sure that Dave Tholen computed his own orbit before submitting the
observations to the Minor Planet Center, but the orbit we published on
MPEC 2012-Y14 was computed at the MPC. JPL computed
its own orbit in-house.


Gareth
(who didn't compute this particular orbit, as it was computed by
an automated process, so the answers to Ernst's questions are
"Yes" and "Yes")
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Old 2012-12-24, 05:33   #754
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Quote:
Originally Posted by ewmayer View Post
So is the asteroid's orbit updated automatically by the observations, or is there some kind of formal notification mechanism?

"Dear Object 2011 AG5: Due to recent Earth-based observations, we are requesting that you alter your course onto the attached heading in order to meet the latest constraints. Your co-operation in undertaking the required prompt corrective action in this matter is appreciated.
Hugs and smooches,
your IAU MPC NEO monitoring team"
Some people would believe this how it works. I know of people that think that the Sun's position is altered by the "authorities" when daylight saving is started and ended. They even complain that daylight saving is burning the plants or fading the curtains (and other such misconceptions) and demand that daylight saving be cancelled to stop the extra daylight hours.

So maybe the way the press is wording things is aiding people to believe that their government is controlling the asteroids and can thus decide when and where, or if, to slam it into the planet. Let the conspiracy theories begin ...

Last fiddled with by retina on 2012-12-24 at 05:33
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Old 2012-12-24, 18:05   #755
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Quote:
Originally Posted by xilman View Post
From the article:
Quote:
... the experience gained by studying this potential real-world deflection problem has demonstrated that NASA is well situated to predict the trajectories of Earth threatening asteroids.
... meaning that NASA is situated on the potential target?
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Old 2012-12-24, 18:28   #756
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Quote:
Originally Posted by cheesehead View Post
From the article:
... meaning that NASA is situated on the potential target?
Yup.

To a very good approximation, NASA is situated on the earth and is therefore situated on the targets of earth-threatening asteroids.
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Old 2012-12-26, 02:20   #757
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A "green, natural" alternative to petroleum-based synthetic fabrics such as nylon and polyester !!

"Hagfish slime could slink to the height of fashion "

http://www.newscientist.com/article/...f-fashion.html

Quote:
. . .

Synthetic fabrics such as nylon and polyester are made from petroleum. A green, natural alternative would be a protein-based cloth made from spider silk - or the thick slime made by the hagfish (Myxine glutinosa) to help it escape predators. The slime contains myriad protein threads 100 times thinner than a human hair.

Douglas Fudge at the University of Guelph in Ontario, Canada, and colleagues previously isolated some of these threads and found them to be 10 times the strength of nylon. Now they have gone a step further, using forceps to draw a slender cord of protein fibres from a dried solution of hagfish slime (Biomacromolecules, doi.org/jwh).

. . .
"Hagfish Slime Makes Super-Clothes"

http://news.discovery.com/tech/hagfi...es-121203.html

Quote:
One of the world’s creepiest creatures may be the source of new kinds of petroleum-free plastics and super-strong fabrics, according to research by scientists in Canada studying the hagfish, a bottom-dwelling creature that hasn’t evolved for 300 million years and produces a sticky slime when threatened. The gooey material is actually a kind of protein that turns into choking strands of tough fibers when released into the water.

A research team at Canada’s University of Guelph managed to harvest the slime from the fish, dissolve it in liquid, and then reassemble its structure by spinning it like silk. It’s an important first step in being able to process the hagfish slime into a useable material, according to Atsuko Negishi, a research assistant and lead author on the paper in this week’s journal Biomacromolecules.

“We’re trying to understand how they make these threads and how we can learn from that to make protein-based fibers that have excellent mechanical properties,” Negishi said. “The first step is can we harvest the threads. It turns out that is doable.”

. . .
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Old 2012-12-26, 03:09   #758
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Quote:
Originally Posted by cheesehead View Post
"Hagfish Slime Makes Super-Clothes"

http://news.discovery.com/tech/hagfi...es-121203.html
My favorite quote:

As for the slime itself, Negishi says it smells like dirty seawater and has the consistency of snot.

Wikipedia has this to say:
Quote:
Hagfish are long and vermiform, and can exude copious quantities of a slime or mucus (from which the typical species Myxine glutinosa was named) of unusual composition. When captured and held, e.g., by the tail, they secrete the microfibrous slime, which expands into up to 20 litres of gelatinous and sticky goo when combined with water.[4]
Up to 20 liters of slime? That's a whole lot of snot...which is eaten as a delicacy in one part of the world:
Quote:
Hagfish are usually not eaten owing to their repugnant looks, as well as their viscosity and unpleasant habits. However, a particular species, the inshore hagfish, found in the Northwest Pacific,[16] is valued as food in the Korean Peninsula. The hagfish is kept alive and irritated by rattling its container with a stick, prompting it to produce slime in large quantities. This slime is used in a similar manner as egg whites in various forms of cookery in the region.
More on the escape antics of the species:
Quote:
If they remain captured, they can tie themselves in an overhand knot which works its way from the head to the tail of the animal, scraping off the slime as it goes and freeing them from their captor, as well as the slime. It has been conjectured that this singular behavior assists them in extricating themselves from the jaws of predatory fish or from the interior of their own "prey", and that the "sliming" might act as a distraction to predators.

Recently it has been reported that the slime entrains water in its microfilaments, creating a slow-to-dissipate viscoelastic substance, rather than a simple gel, and it has been proposed that the primary protective effect of the slime is related to impairment of the function of a predator fish's gills.[5] It has been observed that most of the known predators of hagfish are varieties of birds or mammals; it has been proposed that the lack of marine predators can be explained by a "gill-clogging hypothesis", wherein one purpose of the slime is to impair the gill function of marine animals that attempt to prey on the hagfish. If true, it could be regarded as a highly successful evolutionary strategy against predatory fish.[6]

Free-swimming hagfish also "slime" when agitated and will later clear the mucus off by way of the same travelling-knot behavior.[7][8] The reported gill-clogging effect suggests that the travelling-knot behavior is useful or even necessary to restore the hagfish's own gill function after "sliming".
The traveling-knot escape trick (which is apparently used in reverse during feeding) is fascinating.
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Old 2012-12-31, 06:08   #759
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Not quite sure this counts for the thread, but I can't find the astronomy threads we're sure to have.

http://www.sciencerecorder.com/news/...y-astronomers/
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