Wednesday, August 13, 2008

World Biggest Freshwater Fish is the Giant Mekong catfish

                             mekong-catfish

What we see in the fish tank is not real....This the ever biggest freshwater fish found on earth. The dimensions of these catfish are very impressive, with the largest supposedly growing up to 10ft/3m and weighing up to 660lbs/300kg. This creature is 5 times bigger than the 'world record' catfish found in North America.

The biggest one ever captured and measured was caught in Thailand in May of 2005.

The fish in the photo below was captured by some fisherman where the species is considered endangered, but can still be caught with special permits. The fish was turned in to the Department of Fisheries where the eggs and sperm are collected from these rare giants and harvested for a captive breeding program to keep the species alive.

Scientists have recently discovered someting amazing about the Giant Mekong catfish; they live out part of their lives at sea. Most people have the impression of catfish as slow, lumbering bottom-feeders, but it turns out that the migration routes of these catfish rival those of the better known salmon. Scientists have recorded Pangasius gigas traveling as much as 600 miles (1000 km) inland from the south China sea up the Mekong River to spawn.

The waters of the Mekong River are very murky and make it difficult to track the movements of the fish. In order to determine where the Mekong catfish have been, scientists examined chemical markers called isotopes in bone and muscle tissue of catfish from the Khone Falls region of the Mekong. The team found evidence that the freshwater-dwelling fish had migrated recently from a marine habitat. Although this method of fish tracking is a highly regarded method, it appears that this is the first time it has been used to track the migration routes of river catfish species from a marine environment.

As big as the Giant Mekong catfish can get, there are rumored to be other species of freshwater fish whose dimensions rival those of the Mekong catfish. Among them are the Arapaima and huge freshwater stingrays, both found living in the Amazon River. The giant Chinese paddlefish is also a serious contender for world's biggest freshwater fish, but very little is known about this species that seems to be rapidly disappearing.

Thursday, August 7, 2008

Eris the largest known dwarf planet

 

                                      lilasmall

Eris, the largest dwarf planet known, was discovered in an ongoing survey at Palomar Observatory's Samuel Oschin telescope by astronomers Mike Brown (Caltech), Chad Trujillo (Gemini Observatory), and David Rabinowitz (Yale University).  We officially suggested the name on 6 September 2006, and it was accepted and announced on 13 September 2006. In Greek mythology, Eris is the goddess of  warfare and strife. She stirs up jealousy and envy to cause fighting and anger among men. At the wedding of Peleus and Thetis, the parents of the Greek hero Achilles, all the gods with the exception of Eris were invited, and, enraged at her exclusion, she spitefully caused a quarrel among the goddesses that led to the Trojan war.  In the astronomical world, Eris stirred up a great deal of trouble among the international astronomical community when the question of its proper designation led to a raucous meeting of the IAU in Prague. At the end of the conference, IAU members voted to demote Pluto and Eris to dwarf-planet status, leaving the solar system with only eight planets.

The satellite of Eris has received the offical name Dysnomia, who in Greek mythology is Eris' daughter and the demon spirit of lawlessness. As Dysnomia is a bit of a mouthful, we tend to simply call the satellite Dy, for short.

As promised for the past year, the name Xena (and satellite Gabrielle) were simply placeholders while awaiting the IAU's decision on how an official name was to be proposed. As that process dragged on, however, many people got to know Xena and Gabrielle as the real names of these objects and are sad to see them change. We admit to some sadness ourselves.We used the names for almost two years now and are having a hard time swtiching. But for those who miss Xena, look for the obvious nod in the new name of the moon of Eris.

What is it?

This new dwarf planet (see the now out of date "What makes a planet?" below) is the largest object found in orbit around the sun since the discovery of Neptune and its moon Triton in 1846. It is larger than Pluto, discovered in 1930. Like Pluto, the new dwarf planet is a member of the Kuiper belt, a swarm of icy bodies beyond Neptune in orbit around the sun. Until this discovery Pluto was frequently described as "the largest Kuiper belt object" in addition to being a dwarf planet. Pluto is now the second largest Kuiper belt object, while this is the largest currently known.

Where is it?

The dwarf planet is the most distant object ever seen in orbit around the sun, even more distant than Sedna, the planetoid discovered almost 2 years ago. It is almost 10 billion miles from the sun and more than 3 times more distant than the next closest planet, Pluto and takes more than twice as long to orbit the sun as Pluto.

 

                                        lonly

The dwarf planet can be seen using very high-end amateur equipment, but you need to know where to look. The best way to find precise coordinates (of this planet, or any other body in the solar system) is with JPL's horizons system. Click on "select target" and  then enter "2003 UB313" under small  bodies.

The orbit of the new dwarf planet is even more eccentric than that of Pluto. Pluto moves from 30 to 50 times the sun-earth distance over its 250 year orbit, while the new planet moves from 38 to 97 times the sun-earth distance over its 560 year orbit.

How big is it?

Usually when we first discover distant objects in the outer solar system we don't know for sure how large they are. Why not? Because all we see is a dot of light, like the picture at the top of the page. This dot of light is sunlight reflected off the surface of the planet (interestingly the sunlight takes almost a day to get out to the planet, reflect off of it, and get back to the earth!), but we don't know if the object is bright because it is large or if it is bright because it is highly reflective or both.

When an object is too far away to directly see how big it is, astronomers use an indirect method instead where they measure the heat coming from the object. If we wanted to measure the size of a fire, for example, we could do it by measuring the total amount of heat coming from the fire. The temperature of the flames in a match and a bonfire are essentially the same, but a bonfire emits much more heat because it is much bigger. The same is true of distant planets. Because we know how far away the planet is we have a pretty good idea of the surface temperature (a frosty 405 degrees below zero!), thus when we measure the total heat we can tell how big the object is. Unfortunately, the new planet is so far away and so cold that our first attempt at measuring the heat, using the Spitzer Space Telescope, could not detect the heat output. This fact tells us that the object must be smaller than about 3300 km.
In the meantime, observations have been made by a group from the University of Bonn from the 30-meter IRAM telescope. This telescope, like Spitzer, measures the heat output. IRAM measures the heat output in a region of the spectrum where much less heat is given off, but IRAM is a much larger telescope than Spitzer. The observations were successful in finally detecting the heat of Eris. From the amount of heat measured they determined that Eris has a diameter of 3000 +/- 400 km.  A very nice discussion of the measurement and what the uncertainties mean can be found  at the press release web page.
 

The newest size measurement comes from  the Hubble Space Telescope. While for most telescopes the planet is too small to be seen as anything other than a dot of light, HST can (just barely) directly measure how big across it is. The measurement is extremely hard, however, even for HST, because even HST distorts light a little bit as it goes through the telescope, and we needed to be sure that we were measuring the actual size of the planet, rather than being fooled by distortion. So we waited until Eris was very close to a star and then snapped a series of 28 pictures and carefully went back and forth comparing the star and the planet. In the end, we determined that Eris t is 2400 +/- 100 km across.

Wednesday, August 6, 2008

Oldest Creature in the world "Harriet" celebrates her 175th birthday on November 15th

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Harriet, a giant Galapagos Land tortoise celebrates her 175th birthday on November 15th. Just imagine lived 174 years in this world. Now don't you think we should respect them more than our grand parents? This creature came to this world 174 years before we born! The researchers came to know that she may live another 20 years...

She has traveled more than we have done. But she has came through a difficult period as a somewhat reluctant lesbian.

But this dear old lady has also known heartbreak - confusion over her gender has meant she has never known the love of a good tortoise nor had any offspring.

When Harriet was hatched  on one of Galapagos Islands, William IV was still on the throne and Victoria was a flighty teenager. When Harriet was just five and about the size of a dinner plate. She was discovered by Charles Darwin. Darwin was fascinated by the Galapagos tortoises, especially when he noticed that the different islands apparently contained distinct sub-species adapted to each island's particular conditions.

Why the great naturalist wasn't up to the task of sexing giant tortoises?

She had two friends.  Tom and Dick. They had miserable times. Freezing in winters and lucky sunshine sent them to state of virtual hibernation.

So in 1837 Tom, Dick and Harry were put back aboard the Beagle, this time bound for Australia. Five years later, the 12-year-old Harriet was donated to Brisbane Botanical Gardens in Queensland, where she began her new life. Sadly, Dick died in the late 1880s while Tom passed away in 1949.

And for the next 100 years, Harriet lived a confused, frustrated and unfulfilled life as a male tortoise called Harry because she was too heavy for anyone to take the time to flip her on to her back and check her gender.

For several unhappy decades, keepers tried in vain to mate "Harry" with female Galapagos land tortoises. Not surprisingly, Harriet was denied young of her own, and when she wasn't being coaxed into same-sex encounters with female tortoises, she gave piggyback rides to human children.

Harriet made her last journey in 1988 to Steve Irwin's Australia Zoo. This November 15, like every year, local schoolchildren will organize a birthday party for her. That's a amazing news. That's the respect that we should show to her. Because the humans are also creatures. she is the oldest and most experienced creature in the world since  she didn't have the technology and the brain like humans.

Saturday, August 2, 2008

THE CAMEL SPIDER IS NO JOKE

BIG  ENOUGH  TO  EAT  CATS  &  DOGS  &  KILL  COWS

           spidy     spider6

The photo above comes from a soldier, stationed in Baghdad, who was bitten by a Camel Spider that was hiding in his sleeping bag.  ....  The left photo shows two camel spiders attached together.  The right photo shows the two Camel Spiders along side a tape measure.  ....  Camel Spiders tend to seek out shade during the daytime, so it's not terribly unusual to have a Camel Spider come charging across the desert at you. .... They are BIG and FAST.  ( they can run up to 10 MPH )  Camel Spiders are also cannibalistic.  Looks like the bottom Spider is eating the top Spider.

A Camel Spider can live for 10-15 years.  Camel Spiders periodically shed their skin, increasing their size every time they do.  Seems that more and more Camel Spiders are living longer, and longer.  This means they are shedding more and more times, growing larger and larger.  If this trend continues, someday a Camel Spider may reach over 3 feet in length. 

A Camel Spider can run 10 mph and can jump over three feet.  A Camel Spider is nocturnal and only comes out at night.  ( or hides in the shade during the day - Now that's a comforting thought )  When a Camel Spider bites, it injects you with a Novocain type drug that instantly "numbs" your skin and the surrounding tissue.  You can't  even tell you've been bitten while you're sleeping.  When you wake up, you find part of your leg or arm severely chewed because the Camel Spider has been gnawing on it ...  all  night  long!

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Biggest Camel Spider fear is during the day.  If you move something that is shading a Camel Spider, when the sun makes contact with it, the Camel Spider will instantly 'jump' for "your" shadow!  If you run, it will chase you, giving out a terrible scream the whole time.  If you trip and fall, it will immediately burrow under you to get out of the sun.

Camels3  Camels4

CAMEL SPIDER  "EGGS"

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Unlike regular Spiders, which can lay thousands and thousands of Eggs,  Camel Spiders lay only about 12 Eggs per breeding.  Although the nests themselves can be over 3 feet in diameter, the Camel Spider Egg sack is a small mucus covered pouch.  The Egg Sack looks like a "sticky" marshmallow, with a dozen brownish Egg nodules inside.  Shown above is a rare sampling of Spider Eggs gathered from over 40 nests.  Both the male and  female Camel Spiders guard their nests, so collecting the Eggs is a highly dangerous event.  Most Human bites from Camel spiders occur while gathering the Camel Spider Eggs.  Many times large animals such as wild bore or lizards are found trapped in Camel Spider nests.  They become entangled in the multi-strand, twine-like "honey covered silk" which is similar to a very strong dental floss.  When the trapped animal tries to wrestle free, the strong silk cuts deeply into the struggling animals flesh.  When the guardian Camel Spider returns and find a nest invader trapped, they immediately set upon him and start chewing him to death.

The rare Eggs shown above were removed from their sticky egg sacks and carefully cleaned with mineral oil.  Only mineral oil can be used to clean Camel Spider Eggs because just like regular Spider Eggs, contact with water will cause the Eggs to hatch.  Because of this, all Camel Spiders hatch during the Spring rainy season.  It's the lack of rain in the eastern deserts that have kept the Camel Spider population in check for hundreds of years.  If Camel Spiders ever start moving north into rainy areas, the Camel Spider populations might explode.