Monday, September 28, 2009

Interesting capabilities of Crocodiles


• they can hold their breath underwater for up to one and a half hours

• they have a lingual gland at the back of the throat that removes salt from their body

• their brain is only the size of a walnut but it still allows enough 'processing' to take place to enable the animal to make a decision about whether to attack or not

• crocs replace their teeth by growing new ones inside old ones which eventually fall out

• the stomach of the crocodile is only about the size of a basketball and contrary to legends and 'old wives' tales', crocs do not store their food - they eat it right away

• of 23 species of crocodiles worldwide, Australian crocodile is considered the most aggressive

Wednesday, September 16, 2009

Facts on Spacesuits and Spacewalking:

1. Spacesuits help astronauts in several ways. Spacewalking astronauts face a wide variety of temperatures. In Earth orbit, conditions can be as cold as minus 250 degrees Fahrenheit. In the sunlight, they can be as hot as 250 degrees. A spacesuit protects astronauts from those extreme temperatures.
2. NASA's first spacesuits were made for the Mercury program. Mercury was the first time NASA astronauts flew into space. The Mercury suits were worn only inside the spacecraft.
3. NASA's first spacewalks took place during the Gemini program.
4. Spacesuits for the Apollo program had boots made to walk on rocky ground. The Apollo suits also had a life support system. The astronauts could go far away from the lunar lander because they weren't connected to it by a hose.
5. Spacesuits like the Apollo suits were used on the Skylab space station missions. Like the Gemini suits, these suits connected to Skylab with a hose.
6. Astronauts wear orange spacesuits called "launch and entry suits" during launch and landing of the space shuttle. In space, these suits can be worn only inside the shuttle.
7. An EVA is a spacewalk that takes place outside of a spacecraft. EVA stands for "extravehicular activity."
8. The first EVA (extravehicular activity, or spacewalk) took place on March 18, 1965, during the Soviet Union's Voskhod 2 orbital mission when cosmonaut Alexei Leonov first departed the spacecraft in Earth orbit to test the concept.
9. Edward H. White II performed the first EVA by an American on June 3, 1965, in Gemini IV.
10. The first EVA that was a moonwalk rather than a spacewalk was made by American astronaut Neil Armstrong on July 20, 1969, during Apollo 11.
11. Twelve men have walked on the moon, two each on six different Apollo missions.
12. Alan Shepard is the only person to hit a golf ball on the moon. During the Apollo 14 mission, he fitted an 8 iron head to the handle of a lunar sample collection device and launched three golf balls. They are still there!
13. The Apollo spacesuit was basically a one-piece suit, which astronauts entered from the back. Each suit was made to fit (custom-tailored to) each astronaut. Apollo 11 astronaut Buzz Aldrin stands on the surface of the moon on July 20, 1969. Apollo 11 Commander Neil Armstrong is seen reflected in Aldrin's helmet visor. Image Credit: NASA
14. Each Apollo mission required 15 suits to support the mission. For the main, or prime, three-man crew, each member had three suits: one for flight; one for training; and one as a flight backup in case something happened to the flight suit. Thus, the prime crew had a total of nine suits. The backup three-man crew each had two suits: one for flight and one for training.
15. Astronauts usually use tethers to keep them attached to the spacecraft while on a spacewalk. The first untethered spacewalk was by American astronaut Bruce McCandless II on Feb. 7, 1984, during Challenger mission STS-41-B.
16. The first woman to perform an EVA was cosmonaut Svetlana Savitskaya during Soyuz T-12 on July 17, 1984.
17. On Oct. 11, 1984, Katherine Sullivan became the first U.S. woman to walk in space.
18. The first and only three-person EVA was performed on May 13, 1992, as the third spacewalk of STS-49.
19. On Feb. 9, 1995, Bernard A. Harris Jr. became the first African-American to perform a spacewalk.
20. The longest EVA was 8 hours and 56 minutes, performed by Susan J. Helms and James S. Voss during STS-102 on March 11, 2001.
21. The first EVA where an astronaut performed an in-flight repair of the space shuttle orbiter was by American astronaut Steve Robinson on Aug. 3, 2005, during STS-114. Robinson removed two protruding gap fillers from space shuttle Discovery's heatshield while the shuttle was docked to the International Space Station.
22. Cosmonaut Anatoly Solovyev holds the record for the most spacewalks -- 16, with a total duration of 82 hours and 22 minutes.
23. Captain Michael Lopez-Alegria holds the American record for number of EVAs -- 10, with a total duration of 67 hours and 40 minutes.Space shuttle astronaut Bruce McCandless became the first astronaut to maneuver about in space untethered. He wore a jetpack-like device called the Manned Maneuvering Unit, or MMU. Image Credit: NASA
24. A spacesuit weighs approximately 280 pounds on the ground -- without the astronaut in it. In the microgravity environment of space, a spacesuit weighs nothing.
25. Putting on a spacesuit takes 45 minutes, including the time it takes to put on the special undergarments that help keep astronauts cool. After putting on the spacesuit, to adapt to the lower pressure maintained in the suit, the astronaut must spend a little more than an hour breathing pure oxygen before going outside the pressurized module.
26. The reason that spacesuits are white is because white reflects heat in space the same as it does here on Earth. Temperatures in direct sunlight in space can be more than 275 degrees Fahrenheit.
27. No difference exists in a male's or female's suit, though the female astronaut usually requires a smaller size.
28. The shuttle spacesuit was designed to be made of many interchangeable parts, to accommodate the large number of astronauts with widely varying body sizes. These parts (upper and lower torsos, arms, etc.) are made in different sizes.
29. The body measurements of each shuttle astronaut are taken and recorded. Then the measurements are plotted against the size ranges available for each spacesuit component. The suit components are then assembled. Training suits are usually assembled nine months prior to flight, and flight suits are usually assembled four months prior to flight.
30. Shuttle spacesuits are made by sewing and cementing various materials together, and then attaching metal parts that let the different components be joined together.
31. Shuttle spacesuit materials include ortho-fabric, aluminized mylar, neoprene-coated nylon, dacron, urethane-coated nylon, tricot, nylon/spandex, stainless steel, and high-strength composite materials.
32. Just before a shuttle mission, the suits designated for flight are tested, cleaned and packed at NASA's Johnson Space Center in Houston. Then they are flown to NASA's Kennedy Space Center in Florida and stowed on the shuttle orbiter. After each flight, the suits are returned to Johnson for postflight processing and reuse.
33. The Neutral Buoyancy Lab is a large indoor pool that is 202 feet in length, 102 feet in width, and 40 feet in depth (20 feet above ground level and 20 feet below). The pool holds 6.2 million gallons of water.
34. The Sonny Carter Training Facility including the Neutral Buoyancy Lab provides controlled neutral buoyancy operations to simulate the microgravity or weightless condition that is experienced by spacecraft and crew during spaceflight. For the astronaut, the facility provides important preflight training for extravehicular activities and with the dynamics of body motion under weightless conditions.Astronauts practice repairs to a Hubble Space Telescope model underwater at the Neutral Buoyancy Lab in Houston, Texas. Image Credit: NASA
35. Some astronauts train for spacewalks on the Precision Air Bearing Floor. The PABF is like a giant air hockey floor where jets of air allow massive objects to move with no friction. The floor is a metal surface 32 feet by 24 feet (10 meters by 7 meters). Moving something along on the floor gives an astronaut a sense of how an object might move in space with no force of gravity acting on it.
36. POGO is a device that uses cables connected to the ceiling to suspend an astronaut. POGO supports five-sixths of a person's weight; it mimics the one-sixth gravity of the moon. An astronaut walking around on POGO has the sensation of walking on the moon. POGO has been around since the Apollo days -- in fact, the device gets its name from the way Apollo astronauts tended to bounce when suspended from it. The real name for POGO is the Partial Gravity Simulator.
37. Astronauts use Lower Torso Assembly Donning Handles to pull the spacesuit pants up onto their bodies.
38. The spacesuit has two other sets of gloves that astronauts can use. Comfort Gloves are worn under the EVA glove and aid EVA glove donning, doffing and wicking away perspiration. They provide some additional thermal protection. Adjustable Thermal Mittens provide added protection in extreme temperature environments.
39. Thermofoil heaters are attached inside each of the fingertips in one of the layers of the glove. The heaters are located approximately over each of the crew member’s fingernails. The heaters have an on-off switch near each of the gloves' wrists.
40. EVA astronauts usually handle from 70 to 110 tools, tethers and associated equipment for a typical spacewalk.
41. Putting a spacesuit on is called "donning" the suit. Removing the suit is called "doffing."

Tuesday, September 08, 2009

Common characteristics of tiger

Tigers have historically lived in a wide variety of climates and habitats from Turkey east to China and from Siberia south to the Indonesian islands. They are the largest of the cats living on earth today.

After about 103 days of gestation, female tigers of all the subspecies produce a litter of between 1 and 5 cubs (2-3 is average). At 8 weeks, cubs start learning to hunt with their mother. By 6 months they have learned the basics of killing animal. It will be about 1 ½ years before they can really hunt and sustain themselves on their own.

Because these cats are so large, they require large species of prey animals. As you imagine, tigers naturally travel over large areas in search of prey. As the human population of the world and fragmentation of forests and wild lands continues, tigers are colliding with humans and losing the battle for wild places with enough large prey animals to sustain them. Tigers are also being killed for their spectacular fur coats and for Asian medicinal products.