Earth's "twin," roughly the same direction as Vega (famous in "Contact"), is 600 light-years away, and perhaps covered in water, say the Kepler team.
About 2-and-1/2 times the size of Earth, and not quite so far from its own very Earth-like sun, which is located in the direction of Cygnus (the "Northern Cross," visible in the night sky from the Northern Hemisphere during the summer), Kepler 22-B is located in the direction the fictional aliens hailed from in the film "Contact" (1997, based on the book by Carl Sagan), just south of the North Pole.
Kepler 22-B orbits its sun with a 290-or-so day Earth-like year. It orbits however at about 600 light-years from Earth, roughly 24 times the distance of the advanced civilization in "Contact," which came from somewhere near the hot blue star Vega.
Kepler 22-B's average temperature is believed to be around 72 degrees fahrenheit. Since it's bigger than Earth, there's no reason its gravity won't hold both water and rocks.
Although NASA won't be able to get more data till the Northern Cross is visible at night next summer, NASA is sure it has found a planet, based on observations it made beginning May 12, 2009, and ending March 14, 2011, according to the report submitted by Borucki et. al.
First "Earth Twin" Discovered?
This is the first Earth-like planet found to date, and one of 54 planets in the "life zone" (where liquid water is possible) supposedly found by Kepler. Other habitable planets have been found previously by other means, beginning with Gliese 876-B and Gliese 876-C both orbiting the star Gliese 876 about 15 light-years away in the direction of Aquarius. These were discovered in 1998 and 2001 respectively. Gliese 589-D (orbiting the star Gliese 581) is perhaps the first terrestrial mass planet in or near the habitable zone. Like the fictional aliens in "Contact," it's just over 20 light-years away, but in the direction of Libra, quite a different direction than Kepler 22-B. All three of these planets have much shorter years than does Earth, whereas Kepler 22-B's year is about the same length as Earth's. Except that it is slightly larger than Earth, Kepler 22-B seems to be truly a "twin."
Information about Gliese 589-D was revised to include it in or near the habitable zone in 2009. Of the thousands of "planet candidates" it has surveyed, the Kepler telescope mission has, to date, confirmed about 33 (three more were confirmed by the Kepler team on the ground).
Messages to the Stars?
According to Wikipedia's information on Gliese 581-D, in 2008 the website Bebo beamed a message to Gliese 581-D which will (hopefully) arrive in 2029. Kepler 22-B, however, is apparently too far from Earth for it to receive our messages with current transmitters, according to Katherine Noyes (Dec. 5, 2011).
SETI, with new funds from both the web and the U.S. Air Force, will nevertheless direct its searches for signals so as to include the newly discovered Kepler 22-B. One possible option might be to send messages, albeit not people, to star regions near or far via "wormholes" (tunnel-like paths through space) such as the one used by the heroine of "Contact" for her eighteen-hour round trip to Vega. However no one has suggested sending either by wormhole yet. In any case, it might be more difficult to send people than signals this writer speculates: according to physicists Ford and Roman (January, 2000), who have studied quantum mechanics and black hole physics for a number of years, for a wormhole to be stable enough for travel through it, it would have to have a throat with a radius no greater than the "Planck length," the distance at which waves start to behave like particles.
How Kepler Works
The Kepler Space Telescope, launched in March of 2009, has a lens diameter of just under a meter, trained on the Milky Way in the direction of Cygnus and Lyra (a location chosen for its many stars). It locates planets' transits of their suns (the star a planet orbits is dimmed slightly when it transits, and measuring the tiny change in its luminosity is something akin perhaps to finding a "needle in a haystack"). The Kepler observatory orbits the sun a bit beyond the earth, with a 371-day orbital period.
Cost and Funding
Kepler's cost is relatively low at around 600 million U.S. dollars total. This cost includes 3.5 years of operation. (Each year of operation costs about 20 million U.S. dollars.) Funding is slated to run out in less than a year, in November of 2012. Its advocates hope to extend funding through 2016.
Other Space Telescopes: the Webb
The much more powerful 6.5 meter Webb Space Telescope, the official Hubble successor (the Hubble will "retire" in 2013), which won't be ready till 2018 if then, is expected to cost around 8 billion U.S. dollars, if it stays within budget. Of course the Webb may be able to see into the darkest reaches of the universe yet and get a real look at some planets we've "seen" only through their effects on other celestial bodies. The Webb is slated to get about $529 million in funds for 2012 according to John Matson (Nov. 17, 2011).
Like the European Space Agency's Herschel, the Webb will orbit about one-and-a-half million kilometers from Earth, at a point where both Earth and sun pull on it equally. Its lens diameter is slated to be about twice that of the Herschel (meaning it will gather around three or four times as much light) and three times that of the Hubble (gathering about seven times as much light). Both the Herschel and Webb are designed to operate primarily at infrared wavelengths, but the Webb will operate at a slightly higher wavelength, with its focus on receding stars and distant galaxies. The Webb is expected to create 2000 jobs, many in Maryland.
Telescopes: Advantages From Space
Telescopes see better than people because their wide lenses capture more light than the human eye. The advantage of having telescopes in space is that they orbit above the atmosphere's interference, which tends to cause light coming across it to "flicker;" and also above the interference of background light (glare) on Earth. For an idea of how much interference from light on Earth there is, see NASA's "Lighting Up the Ecosphere." In spite of its being in space, the Kepler observatory has encountered a great deal of variation in the light it has received, much more than expected.
Infrared and Ultraviolet Observation
Observations of space in the infrared radiation bands are virtually impossible from Earth. Both space dust, which is heated by hot gasses, and distant galaxies, which tend to be receding from Earth at high speeds so that their light is red-shifted, emit radiation in the infrared bands. This radiation is used by astronomers to look back into the earlier days of the universe, and to get an idea of how much total matter there is including dust and "dark matter." Like infrared radiation, most ultraviolet and gamma radiation is absorbed by the atmosphere and cannot be easily observed from Earth either. Much ordinary stellar variation occurs at these wavelengths but planetary transits tend to cause more variation in the visible spectrum.
The Hubble, which makes use of the popular "Cassegrain" reflector, currently captures light at visible, infrared, and ultraviolet wavelengths, but not all at once. It orbits at the top of Earth's atmosphere almost 600 km above Earth. The Webb is planned to orbit 1.5 million miles away from Earth, around both Earth and Sun. Kepler trails Earth's orbit around the sun.
Communications satellites normally operate at 35,000 km above Earth ("geosynchronous orbit;" this is the orbit at which a satellite's orbit follows that of the Earth so that the orbit is "stationary" above Earth). Weather satellites operate at about 1000 to 6000 km above Earth. Spy satellites may operate lower still, in "low earth orbit," where the International Space Station operates, or slightly below that. The Chandra X-ray observatory operates a third of the way to the moon.
Servicing Space Telescopes In Orbit
Space telescopes have to be serviced remotely, in space, or else abandoned. The Hubble, in low-earth orbit, was serviced a number of times, the first when it had lens troubles. They also must initially fit into a rocket, and thus tend to have folding mirrors. (For more about the various space telescopes in operation, see the article at Historic Spacecraft, "Space Telescopes.")