Two planets orbiting a star 950 light-years from Earth are the smallest, most Earth-size alien worlds known, astronomers announced today (Dec. 20). One of the planets is actually smaller than Earth, scientists say.
These planets, while roughly the size of our planet Earth, are circling very close to their star, giving them fiery temperatures that are most likely too hot to support life, researchers said. The discovery, however, brings scientists one step closer to finding a true twin of Earth that may be habitable.
"We've crossed a threshold: For the first time, we've been able to detect planets smaller than the Earth around another star," lead researcher François Fressin of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., told SPACE.com. "We proved that Earth-size planets exist around other stars like the sun, and most importantly, we proved that humanity is able to detect them. It's the beginning of an era."
To discover the new planets, Fressin and his colleagues used NASA's Kepler space telescope, which noticed the tiny dips in the parent star's brightness when the planets passed in front of it, blocking some of its light (this is called the transit method). The researchers then used ground-based observatories to confirm that the planets actually exist by measuring minute wobbles in the star's position caused by gravitational tugs from its planets.
"These two new planets are the first genuinely Earth-sized worlds that have been found orbiting a sunlike star," University of California, Santa Cruz astronomer Greg Laughlin, who was not involved in the new study, said in an email to SPACE.com. "For the past two decades, it has been clear that astronomers would eventually reach this goal, and so it's fantastic to learn that the detection has now been achieved." [Gallery: Smallest Alien Planets Ever Seen]
Chances for life
The two Earth-size planets are among five alien worlds orbiting a star called Kepler-20 that is of the same class (G-type) as our sun, and is slightly cooler.
Two of the star system's planets, Kepler-20e and Kepler-20f, are 0.87 times and 1.03 times the width of Earth, respectively, making them the smallest exoplanets yet known. They also appear to be rocky, and have masses less than 1.7 and 3 times Earth's mass, respectively. Scientists think that they are composed mainly of silicates and iron, much like the Earth, though they lack our planet's atmsophere.
Kepler-20e makes a circle around its star once every 6.1 days at a distance of 4.7 million miles (7.6 million kilometers) — almost 20 times closer than Earth, which orbits the sun at around 93 million miles (150 million km).
The planet's sibling, Kepler-20f, makes a full orbit every 19.6 days, at a distance of 10.3 million miles (16.6 million km). Both planets circle closer to their star than Mercury does to the sun. [Infographic: Earth-Size Alien Planets Explained]
These snuggly orbits around their star give the newfound planets steamy temperatures of about 1,400 degrees Fahrenheit (760 degrees Celsius) and 800 degrees Fahrenheit (430 degrees Celsius) — way too warm to support liquid water, and probably life, researchers said.
Fressin said the chance of life on either of these planets is "negligible," though the researchers can't exclude the possibility that they used to be habitable in the past, when they might have been farther from their star. There is also a slim chance that there are habitable regions on the planets in spots between their day and night sides (the planets orbit with one half constantly facing their star and the other half always in dark). But astronomers aren't holding out hope.
"The chances of liquid water and life as we know it on Kepler-20e and f are zero," Laughlin said.
volving effort
Scientists say finding the smallest exoplanets yet represents a significant milestone in the fast-evolving effort to learn about planets beyond the solar system.
The first alien planet was discovered in 1996, and the first planet found through the transit method came just 11 years ago. Both of those planets were roughly the size of Jupiter.
"I think we're living in special times," Fressin said. "This was unfeasible 10 years ago, and just with the quality of detectors and the quality of the treatment is it possible now."
The total tally of known alien planets is above 700. Kepler alone has discovered 28 definite alien planets, and 2,326 planet candidates, since its launch in March 2009.
Earlier this month, the Kepler team announced another landmark find, the first planet known to occupy the habitable zone around its star where liquid water, and perhaps life, could exist.
That planet, called Kepler-22b, is about 2.4 times as wide as Earth.
The dream now is for astronomers to combine the two discoveries and find an Earth-size planet that's also orbiting its star in an Earth-like orbit that puts it in the habitable zone.
"The holy grail of the search for other worlds is to find an Earth analogue, a true Earth twin," Fressin said. "We just need to have these two pieces of the puzzle together."
While the newfound planets orbit with periods of 6.1 and 19.6 days, Fressin estimated the habitable zone around Kepler-20 begins at orbits that take roughly 100 days to make a circuit.
Astronomers think it's only a matter of time before they finally find one that's just right.
"These discoveries are a great technological step forward — to detect small planets, in size like Earth — but these planets are very hot and not in the habitable zone around their star," astronomer Lisa Kaltenegger of the Harvard-Smithsonian Center for Astrophysics wrote in an email. Kaltenegger, who studies the habitability of exoplanets, was not involved in the new study. "If we can already find these small planets with radii around Earth's now, some future ones could be in the habitable zone of their stars and THOSE future ones would be great targets to look for liquid water and signatures for life."
A paper detailing the discovery was published online in the journal Nature Dec. 20.
You can follow SPACE.com assistant managing editor Clara Moskowitz on Twitter @ClaraMoskowitz. Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.
Wednesday, December 21, 2011
Monday, November 7, 2011
NASA prepares for moon tourism
"Looting, that would be pretty bad," says archaeologist Beth O'Leary of New Mexico State University in Las Cruces. Looting is the bane of archaeological sites and O'Leary has spearheaded efforts to declare moon landing sites as historic preserves or national parks, seeking to head off similar depredations before before tourists leave Earth for the moon. "I put landing people on the moon up there with creating fire as a technological achievement."
From 1969 to 1972, NASA sent 6 manned space missions to the moon. Each one landed in a different spot, but in each case American astronauts left behind various artifacts. The first, Apollo 11, for instance, left things ranging from a "Camera, Lunar TV" to a "Urine Collection Assembly (Small)".
NASA isn't expecting the sites to generate the kind of traffic we see at national parks on Earth, but the prospect of future tourists could affect plans to inspect the sites and artifacts in the future. So, the space agency released guidelines this summer on protecting lunar landing sites and artifacts. They call for a 1,200 acre "no-fly" zone around the first Apollo 11 landing site, and final Apollo 17 one. Tourists could only walk within 82 yards of the Apollo 11 landing site where Neil Armstrong first took "One small step for man," on July 20, 1969, under the guidelines.
What's the rush? NASA had started to get questions from the two dozen or more teams competing for the $30 million Google Lunar X Prize for the "first privately funded teams to safely land a robot on the surface of the Moon." NASA officials suddenly had nightmares of private spaceships landing on top of Buzz Aldrin and Neil Armstrong's "Defecation Collection Device (4 bags)" left at the Apollo 11 site. Part of the prize involves driving a robot rover about a third of a mile on the moon, as well. And no one wants to see Armstrong's footprints obliterated by a robot tourist.
"This really is unprecedented," says NASA's Robert Kelso of the Johnson Space Center in Houston, who headed the guideline effort. "We went looking at NASA for guidelines on this (preservation), and we really didn't have anything."
Famous exploration sites have been looted before, such as the 1911 hut belonging toSouth Pole explorer Robert Falcon Scott, looted after its 1956 rediscovery. "What we don't want to happen is what happened in Antarctica at Scott's Hut," space historian Roger Launius of the National Air and Space Museum in Washington, D.C., told Science Magazine in September.
"We want to protect all the lunar sites, but the Apollo landing sites carry particularly important cultural, historical and heritage value," says Kelso. "They are key sites in Cold War history."
Apollo 17's recommended protection site is bigger than Apollo 11, because the lander mission featured a moon buggy, which is on the list of items that NASA might like inspected. The buggy allowed the astronauts to travel farther.
The guidelines aren't meant just to keep people out, but also to let researchers in selectively, Kelso adds, so that the space agency can learn how artifacts degrade on the moon. The only clues now come from 1969's Apollo 12 mission, which landed near the 1967 Surveyor 3 unmanned lander. The Apollo 12 landing about 500 feet away from Surveyor 3 scattered dust all over its landing site, to the surprise of scientists, according to Kelso, raising similar fears about astronaut footprints from historic missions being erased by Google Lunar X Prize contestants.
"We really could see little robots going in and assessing the sites. We just don't want them destroyed," Kelso says.
Space archeology at the Apollo sites has already started, O'Leary notes. NASA's Lunar Reconnaissance Orbiter mission flew over sites in 2009. And in September, the same orbiter dipped to within 15 miles of the lunar surface to take up-close images.
"One problem is that the moon is a bit of a legal gray area," O'Leary notes. NASA owns its artifacts, but nobody "owns" the moon, under the 1967 Outer Space Treaty, which doesn't even mention private visitors. "There are extraordinary Russian sites as well, that they would likely want to preserve," O'Leary says.
NASA has provided the guidelines to all its international space mission partners, including Russia's space agency, Kelso says. "We didn't want any of them hearing it first from somebody else."
Friday, March 26, 2010
The Big Bang
This experiment is based on the theory of the large big bang that took
place in universe billions billions ago...
YOU can get some information about this experiment .....
These are the facts about universe
The universe is 13.7 billion years old.
- All the matter in the universe used to be very close together (very dense)
- The universe used to be a very uniform cloud of energy/mass despite it being
- very clumpy today (galaxies being those clumps)
- Space began to expand and pushed matter apart
- The expansion of space is accelerating
- In the beginning the universe was so hot all the universal forces (gravitation, electromagnetism, etc.)
- were one force
- The accelerating expansion of the universe will one day spread galaxies so far apart we
- will not be
- able to see them because the light leaving them will constantly have new space created
- in front of it
The Big Bang theory says that the universe was very hot and concentrated in the distant past and, ever since then, space has been stretching and cooling. This is the only theory that successfully explains the observations made by astronomers.
The Big Bang was not an explosion.
The lightest chemical elements in the universe were made in nuclear fusion reactions when the universe was very hot and concentrated
The Big Bang theory is one of the most strongly supported theories in all of science. It explains the observed facts; it has made successful predictions; it has stood the test of time; and there is no alternate theory that the professional scientific community deems valid.
Astronomers see galaxies moving apart from one another: space in the universe is stretching.
The Big Bang theory explains the most basic observed properties of our universe
Some of the general Questions that might arise in ones mind..........
a) The Large Hadron Collider experiment is linked to the ‘Big Bang’ theory. What is this theory all about?
ANS-The creation of the Universe. ‘The Big Bang theory’ is a model used by physicists to explain the creation of the Universe. According to this theory, the Universe was created billions of years ago when matter and anti-matter collided creating a big bang. This theory was proposed by a Catholic priest named Lemaitre.
b)Which is the organisation responsible for conducting the Big Bang (LHC) experiment?
ANS-CERN. The Big Bang experiment is being conducted by the European Organization for Nuclear Research, CERN, which is located in Geneva. Interestingly the birth of the World Wide Web is said to have happened at CERN.
c)A popular term used in the Big Bang experiment is LHC. What does this stand for?
ANS- Large Hadron Collider. LHC stands for the Large Hadron Collider. This is a particle accelerator built by CERN for the Big Bang experiment. The collider is meant to be used to make hadrons or protons collide with each other. This collision is meant to recreate the conditions that happened after the original Big Bang. This is to enable scientists to understand more about the creation of the world.
d)The Big Bang experiment is being carried out to find out the ‘God particle’. By what name is this particle called?
ANS-Higgs boson particle. The Higgs boson particle is named after two scientists Jack Higgs and Satyendranath Bose. This particle is referred to as ‘God particle’. Scientists believe that the Big Bang created the Higgs boson particle, which in turn led to further events leading to the creation of the Universe. Scientists believe that the LHC experiment would produce the Higgs boson particle.
e)In which country did the Big Bang experiment start?
- . The LHC tunnel is located under the earth and spans two countries Switzerland and France. A major part of the LHC complex is located in France.
THE BIG BANG:
The Hubble Telescope's deepest view of the universe teaches us about the beginning
http://www.umich.edu/~gs265/bigbang.htm YOU CAN GO TO THIS LINK TO GET REALLY VERY INTERESTING INFORMATION ABOUT BIG BANG......
Thursday, March 25, 2010
For Football Fans............
FOOTBALLLL
How did football start?????
Guess where football originally came from? Thought it over?
Well, guess what? It originally came from the eastern
United States. Now you may be thinking,"When did football start?
And was it always played like it is today?" Well, let's find out...
This Is The History... if well said THE BEGINING
Football began to develop in the 1800s. Football was originally a combination of soccer and rugby. In 1874, the first game resembling present-day football was played. The game was between Harvard and McGill College. As we said, at this time, they played football like soccer and rugby. Harvard wanted to play the game like soccer, and McGill wanted to play the game like rugby. So you can see there was a lot of confusion. They decided to play two games. One game was played like rugby and the other game was played like soccer. After the two games, Harvard agreed that McGill's way (like rugby) was better. They liked it so much that they decided to introduce the sport to other Eastern colleges. And that was how college football began. The first NFL (National Football League) game was played on August 31, 1895 between a team from Latrobe, PA and a team from Jeannette. Jeannette lost 12-0. It wasn't really until the 1950s though that the NFL earned its popularity. CONDITIONS FOR PENALTIES
SOME IMPORTANT TERMS ABOUT FOOTBALL..
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Saturday, March 20, 2010
How airplanes fly - the basic principles of flight
The basic principles of why and how airplanes fly apply to all airplanes, from the Wright Brothers' first machine to a modern Stealth Bomber, and it's actually not difficult to understand how airplanes get, and stay, airborne.
Aerodynamic forces
Essentially there are 4 aerodynamic forces that act on an airplane in flight; these are lift, drag, thrust and gravity (or weight).
In simple terms, drag is the resistance of air (the backward force), thrust is the power of the airplane's engine (the forward force), lift is the upward force and gravity is the downward force. So for airplanes to fly, the thrust must be greater than the drag and the lift must be greater than the gravity (so as you can see, drag opposes thrust and lift opposes gravity).
This is certainly the case when an airplane takes off or climbs. However, when it is in straight and level flight the opposing forces of lift and gravity are balanced. During a descent, gravity exceeds lift and to slow an airplane drag has to overcome thrust.
The picture below shows how these 4 forces act on an airplane in flight:
The thrust is generated by the airplane's engine (propeller or jet), gravity is anatural force acting upon the airplane and drag comes from friction as the plane moves through air molecules. Drag is also a reaction to lift, and this lift must be generated by the airplane in flight. This is done by the wing of the airplane...
How wings generate lift
The generation of lift is a widely discussed and sometimes disputed theory, but there are some key factors that nobody argues. A cross section of a typical airplane wing will show the top surface to be more curved than the bottom surface. This shaped profile is called an 'airfoil' (or 'aerofoil').
During flight air naturally flows over and beneath the wing. Any given 'parcel' of air gets split in two as it hits the leading edge of the wing, and both halves of that parcel actually meet up again at the same moment as they come off the trailing edge of the wing. So because the air moving over the top of the wing has more distance to cover (because of the curvature it is forced to follow) in the same amount of time as the air passing below the wing, it has to move faster.
If you're having trouble following that, look at the picture below showing a parcel of air hitting a wing. Arrows A and B is air getting split at the same moment, and meeting up again at the same moment.
Faster moving air is less dense than slower moving air, so this speed difference results in a lower air pressure on top of the wing, and a higher air pressure below the wing. The result of this pressure gradient is that the wing, and hence the plane, is pushed upwards by the higher pressure.
One of the argued theories of lift generation is that some of the air that passes beneath the wing is deflected downwards. This causes an opposite upward force in accordance with Newton's 3rd Law of Action & Reaction that acts upon the underside of the wing, effectively pushing it upwards. It's widely agreed that this upward force also occurs because the air that comes over the top surface of the wing moves downwards as it flows off the trailing edge, hence forcing the upwards reaction.
If you want to generate some lift yourself, try holding a sheet of paper in front of your face and blowing hard over its top surface. Your breath moves the air molecules above the sheet, thus reducing the pressure while the pressure below the sheet remains the same, and so becomes relatively higher pushing the paper upwards...
The faster a wing moves through the air, so the actions are exaggerated and more lift is generated.
However, a direct reaction to lift is drag and this too increases with airspeed. So airfoils need to be designed in a way that maximizes lift but minimizes drag, in order to be efficient.
A crucial factor of lift generation is the Angle of Attack - this is the angle at which the wing sits in relation to the horizontal airflow over it. As the angle of attack increases, so more lift is generated - but only up to a point until the smooth airflow over the wing is broken up and so the generation of lift cannot be sustained. When this happens, the sudden loss of lift will result in the airplane entering into a stall, where the weight of the airplane cannot be supported any longer.
Airplane control surfaces
For an airplane to be controllable, control surfaces are necessary. The 4 main surfaces are ailerons, elevator, rudder and flaps as shown below:
To understand how each works upon the airplane, imagine 3 lines (axis - the blue dashed lines in the picture above) running through the plane. One runs through the center of the fuselage from nose to tail (longitudinal axis), one runs from side to side (lateral axis) and the other runs vertically (vertical axis). All 3 axis pass through the Center of Gravity (CG), the airplane's crucial point of balance.
When the airplane is in forward flight, it will rotate around each axis when movement to any control surface is made by the pilot. The table below shows the appropriate actions...
Action: Axis: Controlled by: Roll Longitudinal Ailerons Pitch Lateral Elevators Yaw Vertical Rudder
The following sections explain how each control surface effects the airplane...
Ailerons
Located on the trailing edge (rear) of the wing, the ailerons control the airplane's roll about its longitudinal axis. Each aileron moves at the same time but in opposite directions ie when the left aileron moves up, the right aileron moves down and vice versa.
This movement causes a slight decrease in lift on the wingtip with the upward moving aileron, while the opposite wingtip experiences a slight increase in lift. Because of this subtle change in lift, the airplane is forced to roll in the appropriate direction ie when the pilot moves the stick left, the left aileron will rise and the airplane will roll left in response to the change in lift on each wing.
The ailerons are controlled by a left/right movement of the control stick, or 'yoke'.
Rudder
The rudder is located on the back edge of the vertical stabilizer, or fin, and is controlled by 2 pedals at the pilot's feet. When the pilot pushes the left pedal, the rudder moves to the left. The air flowing over the fin now pushes harder against the left side of the rudder, forcing the nose of the airplane to yaw round to the left.
Elevators
The elevators are located on the rear half of the tailplane, or horizontal stabilizer. Like the ailerons, they cause a subtle change in lift when movement is applied which raises or lowers the tail surface accordingly. In addition, air hitting deflected elevators does so in the same way as it hits the rudder ie with exaggerated effect that forces the airplane to tilt upwards or downwards.
Moving the elevator up (pulling back on the yoke) will cause the airplane to pitch its nose up and climb, while moving them down (pushing forward on the yoke) will cause the airplane to pitch the nose down and dive. Elevators are linked directly to each other, so work in unison unlike ailerons.
Flaps
Flaps are located on the trailing edge of each wing, between the fuselage and the ailerons, and extend outward and downward from the wing when put into use.
The purpose of the flaps is to generate more lift at slower airspeed, which enables the airplane to fly at a greatly reduced speed with a lower risk of stalling. When extended further flaps also generate more drag which slows the airplane down much faster than just reducing throttle power.
Although the risk of stalling is always present, an airplane has to be flying veryslowly to stall when flaps are in use at, for example, 10 degrees deflection.
So all these factors are why and how airplanes fly. Radio control model airplanes can of course be more simple - for example, just have rudder and elevator control or perhaps just rudder and motor control. But the same fundamental principles always apply to all airplanes, regardless of size, shape and design.
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