For the first time, astronomers using NASA's Kepler space telescope have confirmed a roughly Earth-size planet orbiting a sun-like star in the so-called "Goldilocks" zone where water can exist in liquid form on the surface and conditions may be favorable for life as it is known on Earth.
Along with the confirmed extra-solar planet, one of 28 discovered so far by Kepler, researchers today also announced the discovery of 1,094 new exoplanet candidates, pushing the spacecraft's total so far to 2,326, including 10 candidate Earth-size worlds orbiting in the habitable zones of their parent stars.
Additional observations are required to tell if a candidate is, in fact, an actual world. But astronomers say a planet known as Kepler-22b, orbiting a star some 600 light years from Earth, is the real thing.
"Today I have the privilege of announcing the discovery of Kepler's first planet in the habitable zone of a sun-like star, Kepler-22b," Bill Borucki, the Kepler principal investigator at NASA's Ames Research Center, told reporters. "It's 2.4 times the size of the Earth, it's in an orbital period (or year) of 290 days, a little bit shorter than the Earth's, it's a little bit closer to its star than Earth is to the sun, 15 percent closer.
"But the star is a little bit dimmer, it's a little bit lower in temperature, a little bit smaller. That means that planet, Kepler-22b, has a rather similar temperature to that of the Earth...If the greenhouse warming were similar on this planet, its surface temperature would be something like 72 Fahrenheit, a very pleasant temperature here on Earth."
It is not yet known whether Kepler-22b is predominantly rocky, liquid, or gaseous in composition, but the finding confirms for the first time the long-held expectation that Earth-size planets do, in fact, orbit other suns in the habitable zones of their host stars.
That, in turn, greatly improves the odds for the existence of life, as it is commonly defined, beyond Earth's solar system.
"I think there are two things that are really exciting about Kepler-22b," said Natalie Batalha, the deputy science team lead at Ames. "One is that it's right in the middle of this habitable zone.
"The second thing that's really exciting is it's orbiting a star very, very similar to our own sun. This is a solar analogue, almost a solar twin, very similar to our own sun and you've got a planet 2.4 times the size of the Earth right smack in the habitable zone."
Equipped with a 95-megapixel digital camera, Kepler was launched from Cape Canaveral on March 6, 2009. The camera is aimed at a patch of sky in the constellation Cygnus that's the size of an outstretched hand that contains more than 4.5 million detectable stars.
Of that total, some 300,000 are believed to be the right age, have the right composition and the proper brightness to host Earth-like planets. More than 156,000 of those, ranging from 600 to 3,000 light years away, will be actively monitored by Kepler over the life of the mission.
To find candidate planets, the spacecraft's camera monitors the brightness of target stars in the instrument's wide field of view, on the lookout for subtle changes that might indicate a world passing between the star and the telescope. By studying the slight dimming--comparable to watching a flea creep across a car's headlight at night--and by timing repeated cycles, computers can identify potential extra-solar worlds even though the planets themselves cannot be seen.
But it's a challenging observation. For a planet like Earth passing in front of a star like the sun, the sun's light would dim by just 84 parts per million. To make sure an observation indicates the presence of a real planet and not some other phenomena, measurements over multiple orbits are required. For Earth-like planets in habitable-zone orbits, a full three years is needed to confirm an initial observation.
In June 2010, the Kepler team announced 312 planet candidates, most smaller than Neptune, in data collected over the first four months of the mission. In February 2011, based on 13 months of data, the number grew to 1,235 potential planets orbiting 997 stars.
The latest announcement pushes the total number of candidates to 2,326 possible planets orbiting 1,792 stars. Of that total, 367 stars--about 20 percent--show signs of multiple planet candidates.
Twenty-eight confirmed planets have been found in the Kepler data. Including Earth-based telescopes, more than 600 extrasolar planets have been found to date. But most of them are huge Jupiter-class worlds orbiting well outside the habitable zone.
With Kepler, "we're getting very close, we are really homing in on the true Earth-size habitable planets," Batalha said.
Also in the hunt: The SETI Institute, or the Search for Extraterrestrial Intelligence, in Mountain View, Calif.
Jill Tarter, director of the Center for SETI Research at the institute, said a radio telescope array that was looking for signs of radio signals in the Kepler field of stars that might indicate the presence of intelligent life is back in operation after a budget-driven hiatus earlier this year.
"I'm really pleased to announce as of 6:18 this morning, as the Kepler field rose over the observatory, the ATA (Allen Telescope Array) was back on the air, continuing the search for Earth analogues."
The Allen Telescope Array, originally funded by Microsoft co-founder Paul Allen, is being used to make systematic observations of stars in the Kepler field, on the lookout for any signs of artificial signals.
Citing a 1993 paper by Carl Sagan and four colleagues that used data from NASA's Jupiter-bound Galileo spacecraft as a test for detecting life on Earth, Tarter said "one of the strongest pieces of evidence for life, indeed intelligent life on Earth, was the presence of narrow-band pulse-amplitude-modulated radio transmissions."
"While there may be some uncertainty about how to define the habitable zone, an exoplanet that could be detected through the techno-signatures of its inhabitants would surely qualify as an Earth analogue," she said.
About William Hardwood
Bill Harwood has been covering the U.S. space program full-time since 1984, first as Cape Canaveral bureau chief for United Press International and now as a consultant for CBS News. He has covered more than 125 shuttle missions, every interplanetary flight since Voyager 2's flyby of Neptune, and scores of commercial and military launches. Based at the Kennedy Space Center in Florida, Harwood is a devoted amateur astronomer and co-author of "Comm Check: The Final Flight of Shuttle Columbia." You can follow his frequent status updates at the CBS News Space page
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Tuesday, July 26, 2011
Laboratory Apparatus And Their Uses
Lab apparatus is an important part of chemistry and science in general. In this page you will learn about lab equipment and its uses.
Name | Description | Picture |
---|---|---|
Beaker | Used to hold and heat liquids. Multipurpose and essential in the lab. | |
Bottle | Bottles can be ued for storage, for mixing and for displaying. | |
Bunsen Burner | Bunsen burners are used for heating and exposing items to flame. They have many more uses than a hot plate, but do not replace a hot plate. | |
Buret | The buret is used in titrations to measure precisely how much liquid is used. | |
Crucible | Crucibles are used to heat small quantities to very high temperatures. | |
Erlenmeyer Flask | The Erlenmeyer Flask is used to heat and store liquids. The advantage to the Erlenmeyer Flask is that the bottom is wider than the top so it will heat quicker because of the greater surface area exposed to the heat. | |
Evaporating Dish | The Evaporating Dish is used to heat and evaporate liquids. | |
Florence Flask | The Florence Flask is used for heating subtances that need to be heated evenly. The bulbed bottom allows the heat to distribute through the liquid more evenly. The Florence Flask is mostly used in distillation experiments. | |
Food Coloring | Food Coloring is used in many experiments to show color change and to make the experiment more exciting. | |
Funnel | The Funnel is a piece of eqipment that is used in the lab but is not confined to the lab. The funnel can be used to target liguids into any container so they will not be lost or spilled. | |
Microspatula | The Microspatula, commonly called a spatula, is used for moving small amounts of solid from place to place. | |
Mortar and Pestle | The Mortar and Pestle are used to crush solids into powders for experiments, usually to better dissolve the solids. | |
Paper Towels | Paper Towels are essential to the lab environment. They will be used in almost every lab. | |
Pipet | The pipet is used for moving small amounts of liquid from place to place. They are usually made of plastic and are disposable | |
Ring Stand | Ring stands are used to hold items being heated. Clamps or rings can be used so that items may be placed above the lab table for heating by bunsen burners or other items. | |
Stir Rod | The stir rods are used to stir things. They are usually made of glass. Stir Rods are very useful in the lab setting. | |
Stopper | Stoppers come in many different sizes. The sizes are from 0 to 8. Stoppers can have holes for thermometers and for other probes that may be used. | |
Test tube Brush | The test tube brush is used to easily clean the inside of a test tube. | |
Test tube Holder | The holder is used to hold test tubes when they are hot and untouchable. | |
Test tube Rack | The testtube rack is used to hold testtubes while reactions happen in them or while they are not needed. | |
Thermometer | The thermometer is used to take temperature of solids, liquids, and gases. They are usually in oC, but can also be in oF | |
Tongs | Tongs are used to hold many different things such as flasks, crucibles, and evaporating dishes when they are hot. | |
Triangle | The triangle is used to hold crucibles when they are being heated. They usually sit on a ring stand | |
Volumetric Flask | The Volumetric flask is used to measure one specific volume. They are mostly used in mixing solutions where a one liter or one half a liter is needed. | |
Watch Glass | The watch glass is used to hold solids when being weighed or transported. They should never be heated. |
COMPOUND MICROSCOPE PARTS
A high power or compound microscope achieves higher levels of magnification than a stereo or low power microscope. It is used to view smaller specimens such as cell structures which cannot be seen at lower levels of magnification.
Essentially, a compound microscope consists of structural and optical components. However, within these two basic systems, there are some essential components that every microscopist should know and understand.
These key microscope parts are illustrated and explained below.
STRUCTURAL COMPONENTS
The three basic structural components of a compound microscope are the head, base and arm.
- Head/Body houses the optical parts in the upper part of the microscope
- Base of the microscope supports the microscope and houses the illuminator
- Arm connects to the base and supports the microscope head. It is also used to carry the microscope.
When carrying a compound microscope always take care to lift it by both the arm and base, simultaneously.
OPTICAL COMPONENTS
There are two optical systems in a compound microscope: Eyepiece Lenses and Objective Lenses:
Eyepiece or Ocular is what you look through at the top of the microscope. Typically, standard eyepieces have a magnifying power of 10x. Optional eyepieces of varying powers are available, typically from 5x-30x.
Eyepiece tube holds the eyepieces in place above the objective lens. Binocular microscope heads typically incorporate a diopter adjustment ring that allows for the possible inconsistencies of our eyesight in one or both eyes. The monocular (single eye usage) microscope does not need a diopter. Binocular microscopes also swivel (Interpupillary Adjustment) to allow for different distances between the eyes of different individuals.
Objective Lenses are the primary optical lenses on a microscope. They range from 4x-100x and typically, include, three, four or five on lens on most microscopes. Objectives can be forward or rear-facing.
Nosepiece houses the objectives. The objectives are exposed and are mounted on a rotating turret so that different objectives can be conveniently selected. Standard objectives include 4x, 10x, 40x and 100x although different power objectives are available.
Coarse and Fine Focus knobs are used to focus the microscope. Increasingly, they are coaxial knobs - that is to say they are built on the same axis with the fine focus knob on the outside. Coaxial focus knobs are more convenient since the viewer does not have to grope for a different knob.
Stage is where the specimen to be viewed is placed. A mechanical stage is used when working at higher magnifications where delicate movements of the specimen slide are required.
Stage Clips are used when there is no mechanical stage. The viewer is required to move the slide manually to view different sections of the specimen.
Aperture is the hole in the stage through which the base (transmitted) light reaches the stage.
Illuminator is the light source for a microscope, typically located in the base of the microscope. Most light microscopes use low voltage, halogen bulbs with continuous variable lighting control located within the base.
Condenser is used to collect and focus the light from the illuminator on to the specimen. It is located under the stage often in conjunction with an iris diaphragm.
Iris Diaphragm controls the amount of light reaching the specimen. It is located above the condenser and below the stage. Most high quality microscopes include an Abbe condenser with an iris diaphragm. Combined, they control both the focus and quantity of light applied to the specimen.
Condenser Focus Knob moves the condenser up or down to control the lighting focus on the specimen.
Wednesday, May 18, 2011
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Wednesday, March 9, 2011
CONSTELLATION
Andromeda, the Chained Princess | Lepus, the Hare |
Aquarius, the Water Bearer | Libra, the Scales |
Aquila, the Eagle | Lyra, the Lyre |
Ara, the Altar | Boötes, the Bear Driver |
Aries, the Ram | Microscopium, the Microscope |
Auriga, the Charioteer | Monoceros, the Unicorn |
Camelopardalis, the Giraffe | Orion, the Hunter |
Canes Venatici, the Hunting Dogs | Pegasus, the Winged Horse |
Canis Major, the Great Dog | Perseus, the Hero |
Carina, The Keel | Pisces, the Fishes |
Cancer, the Crab | Canis Minor, the Lesser Dog |
Caelum, the Sculptor’s Cheasel | Pisces, the Fish |
Capricornus, the Sea Goat | Piscis Austrinus, the Southern Fish |
Cassiopeia, the Queen | Puppis, the Stern |
Cepheus, the King | Pyxis, the Compass |
Cetus, the Whale or Sea Monster | Sagitta, the Arrow |
Columba, the Dove | Sagittarius, the Archer |
Corona Borealis, the Crown | Scorpius, the Scorpion |
Cygnus, the Swan | Sculptor, the Sculptor |
Delphinus, the Dolphin | Scutum, the Shield |
Draco, the Dragon | Serpens Caput, the Serpent's Head |
Equuleus, the Little Horse | Taurus, the Bull |
Gemini, the Twins | Triangulum, the Triangle |
Hercules | Ursa Major, the Great Bear |
Lacerta, the Lizard | Ursa Minor, the Little Bear |
Leo Minor, the Little Lion | Vulpecula, the Fox |
Friday, February 25, 2011
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