Gliese 581g: The Most Earth-Like Planet Discovered

US astronomers say they have discovered an Earth-sized planet that they think might be habitable, orbiting a nearby star, and believe there could be many more planets like it in space.

An artist's impression of Gliese 581g, which astronomers say is near Earth - relatively speaking - at 120 trillion miles. Photo: Zina Deretsky/National Science Foundation
A team of planet hunters led by astronomers at the University of California, Santa Cruz, and the Carnegie Institution of Washington has announced the discovery of an Earth-sized planet (three times the mass of Earth.)
The new planet, called Gliese 581g, is orbiting a nearby star at a distance that places it squarely in the middle of the star’s “habitable zone,” where liquid water could exist on the planet’s surface.
If confirmed, this would be the most Earth-like exoplanet yet discovered and the first strong case for a potentially habitable one.
To astronomers, a “potentially habitable” planet is one that could sustain life, not necessarily one that humans would consider a nice place to live. Habitability depends on many factors, but liquid water and an atmosphere are among the most important.
“Our findings offer a very compelling case for a potentially habitable planet,” said Steven Vogt, professor of astronomy and astrophysics at UCSanta Cruz . “The fact that we were able to detect this planet so quickly and so nearby tells us that planets like this must be really common.”
The findings are based on 11 years of observations at the W. M. Keck Observatory in Hawaii. “Advanced techniques combined with old-fashioned ground-based telescopes continue to lead the exoplanet revolution,” said Paul Butler of the Carnegie Institution. “Our ability to find potentially habitable worlds is now limited only by our telescope time.” Vogt and Butler lead the Lick-Carnegie Exoplanet Survey. The team’s new findings are reported in a paper to be published in the Astrophysical Journal and posted Online at arXiv.org.
Coauthors include associate research scientist Eugenio Rivera of UC Santa Cruz; associate astronomer Nader Haghighipour of the University of Hawaii-Manoa; and research scientists Gregory Henry and Michael Williamson of Tennessee State University.
The paper reports the discovery of two new planets around the nearby red dwarf star Gliese 581. This brings the total number of known planets around this star to six, the most yet discovered in a planetary system other than our own solar system. Like our solar system, the planets around Gliese 581 have nearly circular orbits.
The most interesting of the two new planets is Gliese 581g, with a mass three to four times that of the Earth and an orbital period of just under 37 days. Its mass indicates that it is probably a rocky planet with a definite surface and that it has enough gravity to hold on to an atmosphere, according to Vogt.
Gliese 581, located 20 light years away from Earth in the constellation Libra, has a somewhat checkered history of habitable-planet claims. Two previously detected planets in the system lie at the edges of the habitable zone, one on the hot side (planet c) and one on the cold side (planet d).
While some astronomers still think planet d may be habitable if it has a thick atmosphere with a strong greenhouse effect to warm it up, others are skeptical. The newly discovered planet g, however, lies right in the middle of the habitable zone. “We had planets on both sides of the habitable zone–one too hot and one too cold–and now we have one in the middle that’s just right,” Vogt said.
The planet is tidally locked to the star, meaning that one side is always facing the star and basking in perpetual daylight, while the side facing away from the star is in perpetual darkness. One effect of this is to stabilize the planet’s surface climates, according to Vogt.
The most habitable zone on the planet’s surface would be the line between shadow and light (known as the “terminator”), with surface temperatures decreasing toward the dark side and increasing toward the light side. “Any emerging life forms would have a wide range of stable climates to choose from and to evolve around, depending on their longitude,” Vogt said.
The researchers estimate that the average surface temperature of the planet is between -24 and 10 degrees Fahrenheit (-31 to -12 degrees Celsius). Actual temperatures would range from blazing hot on the side facing the star to freezing cold on the dark side.
If Gliese 581g has a rocky composition similar to the Earth’s, its diameter would be about 1.2 to 1.4 times that of the Earth. The surface gravity would be about the same or slightly higher than Earth’s, so that a person could easily walk upright on the planet, Vogt said.
The new findings are based on 11 years of observations of Gliese 581 using the HIRES spectrometer (designed by Vogt) on the Keck I Telescope at the W. M. Keck Observatory in Hawaii. The spectrometer allows precise measurements of a star’s radial velocity (its motion along the line of sight from Earth), which can reveal the presence of planets.
The gravitational tug of an orbiting planet causes periodic changes in the radial velocity of the host star. Multiple planets induce complex wobbles in the star’s motion, and astronomers use sophisticated analyses to detect planets and determine their orbits and masses.
“It’s really hard to detect a planet like this,” Vogt said. “Every time we measure the radial velocity, that’s an evening on the telescope, and it took more than 200 observations with a precision of about 1.6 meters per second to detect this planet.”
To get that many radial velocity measurements (238 in total), Vogt’s team combined their HIRES observations with published data from another group led by the Geneva Observatory (HARPS, the High Accuracy Radial velocity Planetary Search project).
In addition to the radial velocity observations, coauthors Henry and Williamson made precise night-to-night brightness measurements of the star with one of Tennessee StateUniversity’s robotic telescopes.
“Our brightness measurements verify that the radial velocity variations are caused by the new orbiting planet and not by any process within the star itself,” Henry said.
The researchers also explored the implications of this discovery with respect to the number of stars that are likely to have at least one potentially habitable planet. Given the relatively small number of stars that have been carefully monitored by planet hunters, this discovery has come surprisingly soon.
“If these are rare, we shouldn’t have found one so quickly and so nearby,” Vogt said. “The number of systems with potentially habitable planets is probably on the order of 10 or 20 percent, and when you multiply that by the hundreds of billions of stars in the Milky Way, that’s a large number. There could be tens of billions of these systems in our galaxy.”

Set up parental controls
Step 1.

In Windows 7, click the Start button , click Control Panel, and then, under User Accounts and Family Safety, click Set up parental controls for any user.
If you're prompted for an administrator password or confirmation, type the password or provide confirmation.
Step 2.

Click the standard user account for which you want to set Parental Controls. If the standard user account hasn’t been created yet, click Create a new user account to set up a new account.
Step 3. Under Parental Controls, click On, enforce current settings.

Manage programs, games, and time limits

After you've turned on Parental Controls for your child's standard user account, you can adjust any of the following individual settings that you want to control:
Time limits:

You can set time limits to control when children are allowed to log on to the computer. Time limits prevent children from logging on during the specified hours. You can set different logon hours for every day of the week. If they're logged on when their allotted time ends, they'll be automatically logged off. For more information, see Control when children can use the computer.
Games: You can control access to games, choose an age-rating level, choose the types of content you want to block, and decide whether you want to allow or block unrated or specific games. For more information, see Choose which games children can play.
Allow or block specific programs: You can prevent children from running programs that you don't want them to run. For more information, see Prevent children from using specific programs.

Aurora

Northern lights is the name of a light phenomenon often seen in the northern regions. The lights have been around since Earth formed an atmosphere -the dinosaurs saw it, early humans saw it and our descendants will se it. The scientific name for the phenomenon is “Aurora Borealis”, aurora for short.

An aurora (plural aurorae/auroras) is an electro-static phenomenon, characterised by a bright glow and caused by the collision of charged particles in the magnetosphere with atoms in the Earth’s upper atmosphere. An aurora is usually observed in the night sky, particularly in the polar zone. For this latter reason, some scientists call it a “polar aurora” (or “aurora polaris”). In northern latitudes, it is known as the aurora borealis, which is named after the Roman goddess of the dawn, Aurora, and the Greek name for north wind, Boreas. Especially in Europe, it often appears as a reddish glow on the northern horizon, as if the sun were rising from an unusual direction. The aurora borealis is also called the northern lights since it is only visible in the North sky from the Northern Hemisphere. The aurora borealis most often occurs from September to October and from March to April. Its southern counterpart, aurora australis, has similar properties. Australis is the Latin word for “of the South”.

Aurora (astronomy) - Coloured light in the night sky near the Earth’s magnetic poles, called aurora borealis (‘northern lights’) in the northern hemisphere and aurora australis (‘southern lights’) in the southern hemisphere. Although auroras are usually restricted to the polar skies, fluctuations in the solar wind occasionally cause them to be visible at lower latitudes. An aurora is usually in the form of a luminous arch with its apex towards the magnetic pole, followed by arcs, bands, rays, curtains, and coronae, usually green but often showing shades of blue and red, and sometimes yellow or white. Auroras are caused at heights of over 100 km/60 mi by a fast stream of charged particles from solar flares and low-density ‘holes’ in the Sun’s corona. These are guided by the Earth’s magnetic field towards the north and south magnetic poles, where they enter the upper atmosphere and bombard the gases in the atmosphere, causing them to emit visible light.

An aurora is a sporadic, generally faint, atmospheric phenomenon usually seen in the night sky from locations at high latitudes. More commonly known as the “northern lights,” it may first appear as a faint, milky glow low in the north, too dim for the human eye to detect any color but bright enough to silhouette clouds near the horizon. It may develop into steady greenish arcs or form scintillating, swirling curtains of yellow-green light. During the most dramatic displays visible from regions at middle latitudes, such as central Europe and the United States, a crimson glow fills much of the sky. It was this form that inspired European scientists of the 1600s to call the phenomenon aurora borealis, literally “northern dawn,” but it also occurs at high southern latitudes, where it is formally called aurora australis, “southern dawn.” The same processes are at work in both hemispheres — not just on Earth, but on other planets as well — and today, scientists simply refer to this phenomenon as an aurora. The ghostly forms of an aurora include quiescent patches, veils, and arcs, and rapidly moving rays and curtains.

Many historical accounts of the northern lights from areas far south of its usual location exist. An early Chinese record describes it as a “red cloud spreading all over the sky.” The Roman philosopher Seneca wrote that an aurora in a.d. 37 tricked the emperor into sending troops to aid what he thought was the burning seaport of Ostia, “when the glowing of the sky lasted through a great part of the night, shining dimly like a vast and smoking fire.” In 1583, similar “fires in the air” mobilized thousands of French pilgrims, who prayed to avert the wrath of God. On September 15, 1839, an intense aurora dispatched firefighters throughout London.

Aurorae occur in two great luminous ovals centered on Earth’s north and south magnetic poles. Collisions between atmospheric gases and showers of electrons and protons guided by Earth’s magnetic field set the ovals aglow, typically between heights of 62 and 155 miles (100 to 250 kilometers). Each gas gives out a characteristic color when bombarded. Excited oxygen atoms give off yellow-green light, the color most commonly observed. Ionized molecular nitrogen emits blue and violet light, colors to which the human eye is less sensitive. At lower altitudes, excited molecules of nitrogen and oxygen glow with a vivid red. These three primary colors together produce the myriad hues of a typical aurora.

What causes the showers of charged particles that create the northern lights? Ultimately, the source lies in the solar wind, a fast-moving stream of particles constantly flowing from the Sun that carries the Sun’s magnetic field out into space. The solar wind, typically moving at 250 miles (400 kilometers) per second, flows past Earth’s magnetic field and molds it into an elongated bubble or cavity, compressing its sunward side and stretching its night side far beyond the Moon’s orbit. Under certain conditions, the solar wind’s magnetic field can merge with Earth’s, creating electrical currents that drive protons and electrons into the polar atmosphere. Powerful events occurring on the Sun can drive enormous changes in the solar wind, increasing both its speed and density and enhancing its effect on Earth.

Understanding just how Earth’s magnetic field responds to such events is now a focus of much solar and space research. We are increasingly dependent on technologies that are extremely sensitive to changes in the space environment, changes often collectively referred to as “space weather.” The story of Galaxy 4, a heavily used communications satellite, serves as a good example. At 22h UT on May 19, 1998, while in geostationary orbit above the central United States, Galaxy 4 lost its primary and backup attitude control systems. At the time, Galaxy 4 handled about 80 percent of all U.S. pager traffic. Controllers could no longer maintain a stable link between the satellite and Earth, resulting in a loss of pager service to an estimated 45 million customers. Researchers believe the incident occurred because a sequence of solar events about two weeks prior to the failure created an extremely energetic cloud of electrons that wreaked havoc with the satellite.

Transient events on the Sun can generate fast-moving clouds of particles that greatly intensify the solar wind’s impact on Earth. Solar flares may blast material from the Sun’s surface for hours. Areas called coronal holes generate broad torrents of solar wind and may last for many months. But the most dramatic space-weather effects arise when enormous clouds of material erupt from the solar atmosphere and race to Earth. Scientists call these eruptions coronal mass ejections, or CMEs. Somehow, a portion of the Sun’s magnetic field undergoes a sudden disruption, stretching and twisting like a rubber band until it snaps. When it does, as much as one billion tons of matter blast away from the Sun at speeds up to 1,250 miles (2,000 km) a second. When a CME slams into Earth’s magnetic bubble, it pushes the sunward side closer to Earth and triggers other sudden changes. The result is a surge of particles into Earth’s atmosphere — a geomagnetic storm. Sometimes a fast CME will overtake and merge with one or more CMEs already on their way, resulting in a “cannibal” CME that can have an especially dramatic effect. Particularly powerful storms cause the auroral ovals to expand and move southward from their normal locations, bringing the northern lights to skywatchers at far lower latitudes than normal.

One of the most important spacecraft in the fleet now dedicated to monitoring the Sun is the Solar and Heliospheric Observatory (SOHO), a joint mission between NASA and ESA. Launched in December 1995, it was placed in an orbit around a dynamically stable point 932,000 miles (1.5 million km) sunward of Earth. From here, it has an uninterrupted view of the Sun.

“Two instruments on SOHO have proved to be especially valuable for continuous real-time monitoring of solar storms that affect space weather,” says Paal Brekke, a SOHO project scientist. These are the Extreme ultraviolet Imaging Telescope (EIT) — which provides images of the solar surface at far ultraviolet wavelengths that are blocked by Earth’s atmosphere — and the Large Angle and Spectrometric Coronagraph (LASCO) — which looks for the enormous bubbles of charged particles and entrained magnetic field that represent a CME. Before SOHO was operational, only 27 percent of major magnetic storms were forecast correctly, and most forecasts were false alarms. Between 1996 and 1997, SOHO detected more than two dozen CMEs. “Over 85 percent [of these CMEs] caused major magnetic storms,” Brekke says, “and only 15 percent of such storms were not predicted.” Because geomagnetic storms can affect radio communications and navigation signals — and even introduce errors in positions determined by the Global Positioning Satellite network — advance notice is increasingly important as our reliance on such technology grows.

Coronal mass ejections, solar flares, and coronal holes tend to be more frequent on the active side of the Sun’s 11-year sunspot cycle. This cycle peaked in 2000, with a secondary maximum in 2002, which means solar activity is now on the downswing and will continue to decline until sometime between 2005 and 2006, when the next solar cycle begins. Activity will then slowly rise as the Sun powers up for its next maximum early in or after 2010.

Overall, the chances of seeing an aurora are not all that bad — especially in Canada and the United States. Because the north magnetic pole lies in North America, the auroral oval generally reaches farther south there. This means observers at a given latitude in North America have a better chance of seeing an aurora than those at the same latitude in Europe or Asia. Both Rome and Chicago lie at a latitude of 42°, for example, but Rome averages one aurora per decade while Chicago could see about ten each year.

The atmospheric activity responsible for the northern lights occasionally has a profound effect on everyday life. “During the aurora of September 2, 1859,” wrote American researcher Elias Loomis (1811-1889), “the currents of electricity on the telegraph wires were so steady and powerful that, on several lines, the operators succeeded in using them for telegraphic purposes as a substitute for the battery.” For a time, messages were transmitted solely on auroral currents.

A rapidly shifting and expanding auroral oval can induce electrical currents in other long conductors as well. An example that has become legend in the space-weather community occurred in March 1989, when an extremely active solar region broke records held for more than 30 years: Auroral activity was seen as far south as Jamaica. In Quebec, Canada, aurora-induced currents flowed through seven 100-ton capacitors operated by the Hydro-Quebec Power Authority, causing their protective relays to detect an overload condition. When the relays kicked in and took the devices off-line, about half of Quebec’s available electrical power went with them. Less than one minute later, the entire power-distribution system collapsed, leaving some 6 million people without electricity for more than 9 hours.

And the blackout could have expanded farther. “The power pools that served the entire northeastern United States were uncomfortably close to a cascading system collapse,” says Paal Brekke. Beyond power problems, induced currents also can weaken welds in oil pipelines and create damaging electrical surges in telecommunications cables.

A bright aurora is a feast for the eyes, but it is also a reminder of the powerful forces and tremendous energies routinely at work just a few miles above our heads.

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Micromax Q7 Price

Micromax announced its new upcoming Micromax Q7 Dual SIM GSM, full QWERTY keypad mobile phone in India with attractive features & price. Micromax Q7 featuring with latest technology like Wi-Fi wireless LAN, Integrated Facebook applications, Multi messenger, 2MP camera, music player and FM radio. Let’s discuss complete about Micromax Q7 price, features & specifications.

Micromax Q7 Features & Technical Specifications are:

Brand: Micromax
Model: Q7
Model Type: Mobile phone
Network /Band: EDGE/GSM 900/1800MHz
Display: 262K Color QVGA Screen 5.6 cms)
Trackball Navigation with Full QWERTY keypad

Camera: 2 Mega-pixel

Multi Media: Video Player (AVI/3GP/MP4), Facebook Integrated,
Multi Format Music Player (MP3 / AMR / MIDI / WAV),
Built in Yamaha Audio Amplifier

Internal Phone Memory: 78MB
Memory Card: MIcroSD, expandable upto 4GB
Email/JAVA/EGPRS/WAP/MMS
3.5mm Jack
WI-FI
Opera Mini
Stereo FM Radio
Bluetooth(A2DP)
Battery Li-ion 800mAh
Talk Time: Up to 4.5 hours*
Dimensions: 110mm*59mm*10.7mm
Standby Time: Up to 6 days *
Weight: 100 grams

Micromax Q7 Price in India

The new Micromax Q7 will be available in India very soon, price of Q7 is not revealed yet, It will cost around Rs.5,500/- (Price in India)