Saturn's Hyperion: A Moon with Odd Craters (2009 Jan 18)

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Expand view Topic review: Saturn's Hyperion: A Moon with Odd Craters (2009 Jan 18)

Re: Saturn's Hyperion: A Moon with Odd Craters (2009 Jan 18)

by Alex » Mon May 04, 2009 3:13 pm

Chris Peterson wrote:
neufer wrote:What exactly do you mean by "Spent Comet" ...

Chris Peterson relplied:

There are "spent comets", and they are physically difficult to distinguish from asteroids. A "spent comet" is one which has traveled enough times through the inner system to lose all its volatile material (ices). Clearly, Hyperion does not meet this description. If it is going to be discussed as a captured icy body that has, in its history, made one or more trips near the Sun, some term other than "spent" should be adopted.
The term that came to mind when I first studied the Hyperion image is 'clinker' as in mass of vitrified material ejected from a volcano or fused non-combustible matter left over from burnt coal (such as I emptied from my dad's furnace back in the 1940's). Of course, the concept may just be a clinker as in a wrong note in a musical performance.

Alex

Re: Saturn's Hyperion: A Moon with Odd Craters (2009 Jan 18)

by Chris Peterson » Mon May 04, 2009 1:58 pm

neufer wrote:What exactly do you mean by "Spent Comet" ... an old non-functioning comet
that has trekked off to the cometary graveyard around Saturn to die?
I agree with you that this moon is far too large to be considered a "comet" by the usual definitions. That doesn't mean it can't be a captured body from the outer system, of course.

There are "spent comets", and they are physically difficult to distinguish from asteroids. A "spent comet" is one which has traveled enough times through the inner system to lose all its volatile material (ices). Clearly, Hyperion does not meet this description. If it is going to be discussed as a captured icy body that has, in its history, made one or more trips near the Sun, some term other than "spent" should be adopted.

Re: Saturn's Hyperion: A Moon with Odd Craters (2009 Jan 18)

by neufer » Mon May 04, 2009 4:18 am

Alex wrote:Re: Saturn's Hyperion: A Spent Comet?

Postby neufer on Wed Apr 29, 2009 2:41 pm
Two problems with Hyperion = captured cometary nuclei:
1) No known cometary nuclei looks like Hyperion.
2) Cometary nuclei (~ 10 km) are normally much smaller than Hyperion (360×280×225 km).

Response by Alex on Sunday May 3, 2009 10:45 pm
1) No spent comet nuclei have been cataloged to claim Hyperion is atypical.
2) EKO's (Edgeworth-Kuiper Belt objects) and Centaur comet sizes range to 200 km.
Well, I thought I WAS arguing that Phoebe & Hyperion were captured Centaurs;
however, I don't consider Centaurs to be "comets" in the normal sense.

What exactly do you mean by "Spent Comet" ... an old non-functioning comet
that has trekked off to the cometary graveyard around Saturn to die?

Re: Saturn's Hyperion: A Moon with Odd Craters (2009 Jan 18)

by Alex » Mon May 04, 2009 3:10 am

Re: Saturn's Hyperion: A Spent Comet?

Postby neufer on Wed Apr 29, 2009 2:41 pm
Two problems with Hyperion = captured cometary nuclei:
1) No known cometary nuclei looks like Hyperion.
2) Cometary nuclei (~ 10 km) are normally much smaller than Hyperion (360×280×225 km).

Response by Alex on Sunday May 3, 2009 10:45 pm
1) No spent comet nuclei have been cataloged to claim Hyperion is atypical.
2) EKO's (Edgeworth-Kuiper Belt objects) and Centaur comet sizes range to 200 km.

Reference: Comet Size Distributions and Distant Activity, Meech, Karen J.; Hainaut, Olivier R.; Marsden, Brian G., Minor Bodies in the Outer Solar System: Proceedings of the ESO Workshop Held at Garching, Germany, 2-5 November 1998, ESO ASTROPHYSICS SYMPOSIA. ISBN 3-540-41152-6. Edited by A. Fitzsimmons, D. Jewitt, and R.M. West. Springer-Verlag, 2000, p. 75

Re: Saturn's Hyperion: A Spent Comet?

by neufer » Wed Apr 29, 2009 7:41 pm

Alex wrote:RE: NASA APOD image of January 18, 2009 - Saturn's Hyperion: 'A Moon with Odd Craters' may be a spent comet. My conjecture is that Hyperion is the remnant of a comet captured by Saturn. The capture drew Hyperion into an orbit near Titan. Hyperion resembles a burnt-out clinker. The 'craters' of Hyperion suggest ebullient outgassing. Unlike typical impact craters, those on Hyperion are conical and exhibit a clear funnel-like shape. There's also evidence of a smaller compact spherical core deep inside Hyperion (just possibly an optical illusion). If there were two such denser cores, arranged like dumbbells, they could account for Hyperion's erratic rotation. Its very low density supports the notion that Hyperion is riddled with caverns and also my conjecture that it originally housed volatile matter that was heated and expelled during it's tenure as a sun-circling comet. In my Google search, I've not yet found a similar official explanation for Hyperion. I'm glad to see that APOD Forum participant Orin Stepanek on Sunday, January 18, 2009, and ‘Ruidh’ on Monday, October 03, 2005, agree with my theory: Orin wrote, “I think what were seeing is a captured comet.” Ruidh wrote, “It looks like a spent comet nucleus that was captured by Saturn.” A number of previous Forum participants dating back to 2005 agree with the ‘spent comet’ idea. It looks like NASA has an excellent spent comet specimen to examine in detail. The appearance of Hyperion can probably be duplicated in a laboratory to verify the spent comet clinker conjecture. Alex Vary
Two problems with Hyperion = captured cometary nuclei:
  • 1) No known cometary nuclei looks like Hyperion.
    2) Cometary nuclei (~ 10 km) are normally much smaller than Hyperion (360×280×225 km).
More likely Hyperion was a CENTAUR like 2060 Chiron:
-----------------------------------------------------------
http://en.wikipedia.org/wiki/2060_Chiron wrote:
<<2060 Chiron (Greek: Χείρων) is a planetoid in the outer Solar System. Discovered in 1977 by Charles T. Kowal (precovery images have been found as far back as 1895), it was the first known member of a new class of objects now known as centaurs, with an orbit between those of Saturn & Uranus. Although it was initially classified as an asteroid, it was later found to exhibit behaviour typical of a comet. Today it is classified as both, and accordingly it is also known by the cometary designation 95P/Chiron.

Data from the Spitzer Space Telescope in 2007 suggests that Chiron is 233 ± 14 km in diameter.

In February 1988, at 12 AU from the Sun, Chiron brightened by 75 percent. This is behaviour typical of comets but not asteroids. Further observations in April 1989 showed that Chiron had developed a cometary coma, and a tail was detected in 1993.

Chiron is officially designated as both a comet and an asteroid, an indication of the sometimes fuzzy dividing line between the two classes of object. The term proto-comet has also been used. Being at least 130 km in diameter, it is unusually large for a comet nucleus. Chiron differs from other comets in that water is not a major component of its coma, because it is too far from the sun for water to sublimate.

Chiron's orbit was found to be highly eccentric (0.37), with perihelion just inside the orbit of Saturn and aphelion just outside the perihelion of Uranus. According to the program Solex, Chiron's closest approach to Saturn in modern times was in May 720, at just under 30 Gm. During this passage Saturn's gravity caused Chiron's semi-major axis to decrease from 14.4AU to 13.7AU. Centaurs are not in stable orbits and over millions of years will eventually be removed by gravitational perturbation by the giant planets, moving to different orbits or leaving the solar system altogether. Chiron is probably a refugee from the Kuiper belt.>>
  • Hyperion: Titan associated with the sun
    Phoebe: Titan associated with the moon
http://antwrp.gsfc.nasa.gov/apod/ap040630.html wrote:
Explanation: <<Was Saturn's moon Phoebe once a comet? Images from the robotic Cassini spacecraft taken two years ago when entering the neighborhood of Saturn indicate that Phoebe may have originated in the outer Solar System. Phoebe's irregular surface, retrograde orbit, unusually dark surface, assortment of large and small craters, and low average density appear consistent with the hypothesis that Phoebe was once part of the Kuiper belt of icy comets beyond Neptune before being captured by Saturn. The image was taken from around 30,000 kilometers out from this 200-kilometer diameter moon.>>
http://antwrp.gsfc.nasa.gov/apod/ap040710.html
http://antwrp.gsfc.nasa.gov/apod/ap001103.html
http://en.wikipedia.org/wiki/Phoebe_(moon)

http://www.absoluteastronomy.com/topics/Phoebe_(moon) wrote:
<<Cassini-Huygens indicates that Phoebe's craters show a considerable variation in brightness, which indicate the presence of large quantities of ice below a relatively thin blanket of dark surface deposits some 300 to 500 metres (980 to 1,600 feet) thick. In addition, quantities of carbon dioxide have been detected on the surface, a finding which has never been replicated on an asteroid. It is estimated that Phoebe is about 50% rock, as opposed to the 35% or so that typifies Saturn's inner moons. For these reasons, scientists are coming to believe that Phoebe is in fact a captured Centaur (planetoid)>>

Saturn's Hyperion: A Spent Comet?

by Alex » Thu Mar 19, 2009 2:01 am

RE: NASA APOD image of January 18, 2009 - Saturn's Hyperion: 'A Moon with Odd Craters' may be a spent comet. My conjecture is that Hyperion is the remnant of a comet captured by Saturn. The capture drew Hyperion into an orbit near Titan. Hyperion resembles a burnt-out clinker. The 'craters' of Hyperion suggest ebullient outgassing. Unlike typical impact craters, those on Hyperion are conical and exhibit a clear funnel-like shape. There's also evidence of a smaller compact spherical core deep inside Hyperion (just possibly an optical illusion). If there were two such denser cores, arranged like dumbbells, they could account for Hyperion's erratic rotation. Its very low density supports the notion that Hyperion is riddled with caverns and also my conjecture that it originally housed volatile matter that was heated and expelled during it's tenure as a sun-circling comet. In my Google search, I've not yet found a similar official explanation for Hyperion. I'm glad to see that APOD Forum participant Orin Stepanek on Sunday, January 18, 2009, and ‘Ruidh’ on Monday, October 03, 2005, agree with my theory: Orin wrote, “I think what were seeing is a captured comet.” Ruidh wrote, “It looks like a spent comet nucleus that was captured by Saturn.” A number of previous Forum participants dating back to 2005 agree with the ‘spent comet’ idea. It looks like NASA has an excellent spent comet specimen to examine in detail. The appearance of Hyperion can probably be duplicated in a laboratory to verify the spent comet clinker conjecture. Alex Vary

Re: Saturn's Hyperion: A Moon with Odd Craters

by aristarchusinexile » Mon Jan 26, 2009 9:19 pm

neufer wrote:
aristarchusinexile wrote:Neufer, how canst thou knoweth so mucheth of so many different thingseth!?
Being old with internet access helps a lot.

But simply knowing does not not always equate with understanding.
It must be the internet access .. you have far too much energy to be old.

Re: Saturn's Hyperion: A Moon with Odd Craters

by neufer » Mon Jan 26, 2009 6:13 pm

aristarchusinexile wrote:Neufer, how canst thou knoweth so mucheth of so many different thingseth!?
Being old with internet access helps a lot.

But simply knowing does not not always equate with understanding.

Re: Saturn's Hyperion: A Moon with Odd Craters

by aristarchusinexile » Mon Jan 26, 2009 5:08 pm

neufer wrote:
aristarchusinexile wrote:I don't think the moon wasps are wasps ..
I think they're sweet little honeybees with stingers about 10 feet long.
http://simpsons.wikia.com/wiki/Bumblebee_Man

“¡Ay, ay, ay, no me gusta!”
“¡Ay, ay, ay, no es bueno!”
“¡Ay, Dios no me ama!”
Neufer, how canst thou knoweth so mucheth of so many different thingseth!?

Re: Saturn's Hyperion: A Moon with Odd Craters

by apodman » Sun Jan 25, 2009 5:12 pm

Troythius wrote:therum
Contribute after you achieve a degree of literacy.
Troythius wrote:Wasp nest? Get off the crack.
It was a joke. You're not going to make many friends with insults on your FIRST POST, junior.
Troythius wrote:incredible static charge
This should be a joke, but it looks like you are serious. Why don't you study science?

Re: Saturn's Hyperion: A Moon with Odd Craters

by Troythius » Sun Jan 25, 2009 6:52 am

Somebody wake up and smell the coffee! The proximity of Hyperion to Saturn and rings is close enough to generate an incredible static charge. Aren’t their any humanoids out there than can pull this therum together? This magnetic charge is creating an anti-gravitational erosion affect. In essence this moon with magnetic core of iron (solid or pieced), perhaps remnants of the chunk left by the last major impact which would have cleaned the slate (surface) at the time of impact anyway is interacting with Saturn's magnetosphere - ya like a generator. To over simplify; remember playing with magnets/motors and iron filings in 2nd grade. Wasp nest? Get off the crack. Captured comet? It would still be "burning" - that would look cool - but it's not! KISS

Re: Saturn's Hyperion: A Moon with Odd Craters

by neufer » Wed Jan 21, 2009 1:35 pm

hadashinogen wrote:Actually I have it on good authority that Hyperion was a nuclear test site used by a society now long gone. Hyperion was originally a satellite used for such tests. Eventually it became so radioactive that it had to be moved to it's present site. It is not certain whether any of the society responsible survived, or where they were.
http://en.wikipedia.org/wiki/Bikini_Atoll

<<Bikini Atoll (also known as Pikinni Atoll) is part of Republic of the Marshall Islands. It consists of 36 islands surrounding a 594.1 km2 lagoon. Bikini comes from Marshallese "Pik" meaning "surface" and "Ni" meaning "coconut." Between 1946 and 1958, twenty-three nuclear devices were detonated at Bikini Atoll.
----------------------------------------------
. The Cocoanuts (1929)
.
Hammer (Groucho Marx): I can see it now:
. you and the moon - wear a necktie so I'll know you.
----------------------------------------------
The March 1st, 1954 detonation codenamed Castle Bravo, was the first test of a practical hydrogen bomb. The largest nuclear explosion ever set off by the United States, it was much more powerful than predicted, and created widespread radioactive contamination. Among those contaminated were the 23 crewmembers of the Japanese fishing boat Lucky Dragon 5. The ensuing scandal in Japan was enormous, and ended up inspiring the 1954 film Godzilla, in which the 1954 U.S. nuclear test awakens and mutates the monster, who then attacks Japan before finally being vanquished by Japanese ingenuity.

The Micronesian inhabitants, who numbered about 200 before the United States relocated them after World War II, ate fish, shellfish, bananas, and coconuts. A large majority of the Bikinians were moved to a single island named Kili as part of their temporary homestead, but remain until today and receive compensation from the United States for their survival. In 1968 the United States declared Bikini habitable and started bringing a small group of Bikinians back to their homes in the early 1970s as a test. In 1978, however, the islanders were removed again when strontium-90 in their bodies reached dangerous levels after a French team of scientists did additional tests on the island. It was not uncommon for women to experience faulty pregnancies, miscarriages, stillbirths and damage to their offspring as a result of the nuclear testing on Bikini. The United States provided $150 million as a settlement for damages caused by the nuclear testing program.

Prior to the explosion of the first atomic bomb on the island, the lagoon at Bikini was designated as a ship graveyard during World War II by the US. Today the Bikini Lagoon is still home to a large number of vessels from the United States and other countries. The dangers of the radioactivity and limited services in the area led to divers staying away from one of the most remarkable potential diving sites in the Pacific for many years. Today a limited number of divers head for the lagoon at Bikini every year for an extensive tour of World War II naval vessels. The dive spot has become popular among divers in the last 10 years. The lagoon contains a larger amount of sea life than usual due to the lack of fishing, including sharks, increasing the fascination with the spot as a diver's adventure spot.

The special IAEA Bikini Advisory Group determined in 1997 that "It is safe to walk on all of the islands ... although the residual radioactivity on islands in Bikini Atoll is still higher than on other atolls in the Marshall islands, it is not hazardous to health at the levels measured ... The main radiation risk would be from the food: eating locally grown produce, such as fruit, could add significant radioactivity to the body...Eating coconuts or breadfruit from Bikini Island occasionally would be no cause for concern. But eating many over a long period of time without having taken remedial measures might result in radiation doses higher than internationally agreed safety levels."

It is because of these food risks that the group eventually did not recommend fully resettling the island.>>
----------------------------------------------

Re: Saturn's Hyperion: A Moon with Odd Craters

by hadashinogen » Wed Jan 21, 2009 5:44 am

Actually I have it on good authority that Hyperion was a nuclear test site used by a society now long gone. Hyperion was originally a satellite used for such tests. Eventually it became so radioactive that it had to be moved to it's present site. It is not certain whether any of the society responsible survived, or where they were. We have a similar site at
Latitude: 37deg, 3min, 36.84sec North; 116deg, 1min, 20.92 sec West.

Re: Saturn's Hyperion: A Moon with Odd Craters

by neufer » Wed Jan 21, 2009 1:39 am

Frenchy wrote:How do they determine the density of the gas giants?
Do they use just the volume of the planet, or the volume of the planets and their ring systems when making these calculations?
The period of any satellite (in minutes) determines the average density (in g/cm³)
in an imaginary spherical volume within that satellite's orbit:
...........................................................
Average Density = { [197 min./Orbital Period]^2 } g/cm³
--------------------------------------------------------------
The relative volume of the planet to the volume of the
imaginary sphere within that satellite orbit then scales up
this Average Density to determine the planet's actual density.
--------------------------------------------------------------
Density = { [197 min./Orbital Period]^2 } x { (semimajor axis)^3 / [(Polar radius)x(Equatorial radius)^2] } g/cm³
or Density = 5.5 g/cm³ x { [84 min./Period]^2 } x { (semimajor axis)^3 / [(Polar radius)x(Equatorial radius)^2] }
-------------------------------
Use Io's period to determine Jupiter's density:
...........................................
Io Period = 1.77 days = 2550 minutes
Io semimajor axis = 422,000 km.
Jupiter Polar radius = 67,000 km.
Jupiter Equatorial radius =71,500 km.
...........................................
Jupiter Density = 5.5 g/cm³ x { [84/2550]^2 } x { (422)^3 / [(67)x(71.5)^2] }
Jupiter Density = 5.5 g/cm³ x {.0011} x {219}
Jupiter Density = 1.32 g/cm³
-------------------------------
Use Titan's period to determine Saturn's density:
...........................................
Titan Orbital period = 15 days 22 hours = 22,900 minutes
Titan Semi-major axis 1,222,000 km.
Saturn Polar radius 54,400 km.
Saturn Equatorial radius 60,200 km.
...........................................
Saturn Density = 5.5 g/cm³ x { [84/23,000]^2 } x { (1222)^3 / [(54.4)x(60.2)^2] }
Saturn Density = 5.5 g/cm³ x {.0000135} x {9260}
Saturn Density = 0.69 g/cm³
--------------------------------------------------------------
Sun's galactic rotation period: 220 million years
...........................................
Milky Way Average Spherical Density ~ { [197 min./220 million years]^2 } g/cm³
Milky Way Average Spherical Density ~ 2.9 x 10^-24 g/cm³
Milky Way Average Spherical Density ~ 1 Sun every 11.5 lightyears
-------------------------------

Re: Saturn's Hyperion: A Moon with Odd Craters

by bystander » Wed Jan 21, 2009 1:32 am

Frenchy wrote:Speaking of density...I have a several questions.

How do they determine the density of the gas giants? Do they use just the volume of the planet, or the volume of the planets and their ring systems when making these calculations?

Can Saturn to have a bouyant shockwave that gives it a lower density than the other gas giants?

Lastly, is it possible to trace the outgassed material from Hyperion's surface?
I would expect that only the volume of the planet is used in calculating density as the ring system is not part of the planet proper.

I'm not sure what you mean bouyant shockwave, but Saturn is indeed the least dense of the gas giants.

If Hyperion is a captured cometary core, it was probably long dead before its capture. It was also probably captured long before there was sentient life on earth. Time alone would probably rule out the possibility of tracing the outgassed material.

Re: Saturn's Hyperion: A Moon with Odd Craters

by Frenchy » Tue Jan 20, 2009 11:30 pm

Speaking of density...I have a several questions.

How do they determine the density of the gas giants? Do they use just the volume of the planet, or the volume of the planets and their ring systems when making these calculations?

Can Saturn to have a bouyant shockwave that gives it a lower density than the other gas giants?

Lastly, is it possible to trace the outgassed material from Hyperion's surface?

Re: Saturn's Hyperion: A Moon with Odd Craters

by bystander » Tue Jan 20, 2009 1:31 pm

Frenchy wrote:How about a neutron star remnant with an embedded core?
If Hyperion was a neutron star, wouldn't Saturn be orbiting it? Now that would be strange.

To answer your question, Hyperion is low density and porous, not attributes of neutron stars.

Re: Saturn's Hyperion: A Moon with Odd Craters

by neufer » Tue Jan 20, 2009 12:59 pm

aristarchusinexile wrote:I don't think the moon wasps are wasps ..
I think they're sweet little honeybees with stingers about 10 feet long.
http://simpsons.wikia.com/wiki/Bumblebee_Man

“¡Ay, ay, ay, no me gusta!”
“¡Ay, ay, ay, no es bueno!”
“¡Ay, Dios no me ama!”

Re: Saturn's Hyperion: A Moon with Odd Craters

by Frenchy » Tue Jan 20, 2009 5:50 am

How about a neutron star remnant with an embedded core?

Re: Saturn's Hyperion: A Moon with Odd Craters

by aristarchusinexile » Mon Jan 19, 2009 7:51 pm

I don't think the moon wasps are wasps .. I think they're sweet little honeybees with stingers about 10 feet long.

Re: Saturn's Hyperion: A Moon with Odd Craters

by neufer » Mon Jan 19, 2009 3:54 am

rigelan wrote:Those space wasps would be huge!!!!! Worse than Jumanji.
Image
Say, its only a paper moon
Sailing over a cardboard sea
But it wouldn't be make-believe
If you believed in me

Yes, it's only a canvas sky
Hanging over a muslin tree
But it wouldn't be make-believe
If you believed in me
-------------------------------------------------
'Alien' Wasp Kills Whole Forests
Scientists Warn Now that Wasp Is Here and Poses Huge Risk to Pine Trees
ABC News, March 8, 2006 --

<<An invader has entered the United States and it could devastate pine trees across the country, especially throughout the lush forests of the Southeast.

Image

The wood wasp -- Sirex noctilio Fabricius -- has wiped out huge stands of trees in the Southern Hemisphere, killing 80 percent of the trees in affected forests in New Zealand, Australia, South America and South Africa. Scientists have dreaded the day when the alien wasp might make its way into the United States, but the wait is now over. It ended last year when Richard Hoebeke, an expert taxonomist at Cornell University, opened an insect trap in New York State. Inside the trap he identified the first Sirex woodwasp ever found in the wild in the United States. Since that discovery, entomologists have scattered out across New York, finding wasps over a wide area. And farther north, Canadian officials have found the wasp there, raising questions about just how widespread it already is. It's already too late to eradicate the wasp, Hoebeke says. "We are looking at long-term management and control," he says. "We've found the wasp in too many places."

Once the wasp penetrates a tree to lay eggs and produce the next generation, the tree begins to die. Not because of the wasps, or the resulting larvae, but because of a symbiotic fungus that the female wasp also introduces into the bark of the tree to provide food for the larvae to survive. The fungus attacks the tree, and it can kill it in less than a year. Government officials and the North American Plant Protection Organization recently issued dire warnings about the danger. The wasp likes all sorts of conifers, but it has a particular taste for pines. Death comes fairly quickly to the trees, although that may not be obvious at the time.

"When the wasp attacks a tree, the tree within that season will start to die," Hoebeke says. "You'll start seeing wilting of some of the upper branches, discoloration and yellowing, and eventually death." Beads of resin will trickle down the trunk from the tiny hole left for the exodus of the adult wasp, but that's about all.

Authorities think the wasp arrived in this country in wooden packing crates, or pallets, since that's precisely the kind of wood the wasp prefers. The larvae can live in the harvested wood, which is usually untreated, for more than a year, and that's plenty of time for the wood to be fabricated into containers and shipped into the United States. Hoebeke says he wasn't all that surprised when he found the first wasp. Considering the amount of cargo that moves into this country every day, much of it packaged in wood, it was only a matter of time.

So now it's here, but what can be done about it? There is some hope that the critter can be managed and kept to a tolerable level. Authorities in the southern hemisphere, particularly in New Zealand and Australia, have had considerable success using a natural bio-control agent. A particular parasitic worm, a nematode, has turned out to be a pretty good match for the wasp. The nematode is introduced into the forest, and it gets into the larvae of the wood wasp, leaving the eggs infertile. It's a tidy system in which the adult wasps pick up the nematodes and distribute them along with their larvae, forming sort of a search and destroy network. "In the Southern Hemisphere it has been a silver bullet," Hoebeke says. "It has kept the wasp population under control." That's a dramatic change from just a few years ago, when the wasp was destroying trees by the thousands.

But would the same strategy work here? Experts think it's promising, but the situation here is much more complex than it was to the south. Our forests are more diversified, as well as our wasp population, and no one wants to wipe out all wasps. After all, they eat many other harmful insects, and they provide food for a wide range of animals. There's always the concern that introducing a "bio-control agent," even a tiny nematode, could backfire. But at this point that's about the only thing that looks promising.

Hopefully, Hoebeke says, it's not already too late. The forests in this country are already under attack by beetles, fungus and all sorts of burrowing animals. In Alaska, for example, it is possible to drive for miles through dead spruce trees, killed by beetles that move across the landscape like an invisible plague. "We didn't need another invader," says Hoebeke.

But Sirex noctilio Fabricicus is here, none the less.>>
-----------------------------------

Re: Saturn's Hyperion: A Moon with Odd Craters

by rigelan » Sun Jan 18, 2009 9:50 pm

Those space wasps would be huge!!!!! Worse than Jumanji.

Re: Saturn's Hyperion: A Moon with Odd Craters

by orin stepanek » Sun Jan 18, 2009 7:32 pm

Re: Saturn's Hyperion: A Moon with Odd Craters

by neufer » Sun Jan 18, 2009 6:22 pm

astrolabe wrote:
hughhyatt wrote:Am I imagining it, or under most of the odd looking craters in this photo are there the remains of a huge crater covering something like two-thirds of Hyperion's visible surface?
It appears as if a "land" slide of sorts (for want of a better description) has occurred or a collapse of the large central area. It looks like it separated as a large layer and slid (fell?) radially into a pocket. Solar heating could be the trigger but, in any regard, the smoother areas around the edge appear to be newer exposed material mostly because of texture and color. Also the radial grooves around the perimeter could be a clue as well. Dirty snowball? The sharp edges around each crater could be a process of melting.

The captured comet idea is intriguing and I agree with it. For comet study nothing like having a captured audience for a laboratory, at least one wouldn't have to go a million miles as hour to hop on. Or would one?
OTOH, we've never seen a cometary nucleus quite like Hyperion.
http://en.wikipedia.org/wiki/Hyperion_(moon)

<<Hyperion is one of the largest highly irregular (non-spherical) bodies in the solar system (second to [Neptune's] Proteus). The largest crater on Hyperion is approximately 121.57 km in diameter and 10.2 km deep. A possible explanation for the irregular morphology is that Hyperion is a fragment of a larger body that was broken by a large impact in the distant past, an event which has been linked to the enigmatic darkening of Iapetus.

Hyperion is the only known moon in the solar system that rotates chaotically, but simulations suggest that other irregular satellites may have done so in the past. It is unique among the large moons in that it is very irregularly shaped, has a fairly eccentric orbit, and is near another large moon, Titan. These factors combine to restrict the set of conditions under which a stable rotation is possible. The 3:4 orbital resonance between Titan and Hyperion may also make a chaotic rotation more likely. The odd rotation probably accounts for the relative uniformity of Hyperion's surface, in contrast to many of Saturn's other moons which have contrastive trailing and leading hemispheres.>>
-----------------------------------------------------
HAMLET: Let me see. [Takes the skull]
Image
. Alas, poor Yorick! I knew him, Horatio: a fellow
. of infinite jest, of most excellent fancy: he hath
. borne me on his back a thousand times; and now,
. how abhorred in my imagination it is!

Re: Saturn's Hyperion: A Moon with Odd Craters

by bystander » Sun Jan 18, 2009 6:10 pm


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