Kepler Finds Evidence of Habitable Earth-Size Planets in Milky Way

Is our Milky Way galaxy home to other planets the size of Earth? Are Earth-sized planets common or rare? NASA scientists seeking answers to those questions recently revealed their discovery.

"We went from zero to 68 Earth-sized planet candidates and zero to 54 candidates in the habitable zone -- a region where liquid water could exist on a planet's surface. Some candidates could even have moons with liquid water," said William Borucki of NASA's Ames Research Center, Moffett Field, Calif., and the Kepler Mission's science principal investigator. "Five of the planetary candidates are both near Earth-size and orbit in the habitable zone of their parent stars."

Planet candidates require follow-up observations to verify they are actual planets.

"We have found over twelve hundred candidate planets -- that's more than all the people have found so far in history," said Borucki. "Now, these are candidates, but most of them, I'm convinced, will be confirmed as planets in the coming months and years."

The findings increase the number of planet candidates identified by Kepler to-date to 1,235. Of these, 68 are approximately Earth-size; 288 are super-Earth-size; 662 are Neptune-size; 165 are the size of Jupiter and 19 are larger than Jupiter. Of the 54 new planet candidates found in the habitable zone, five are near Earth-sized. The remaining 49 habitable zone candidates range from super-Earth size -- up to twice the size of Earth -- to larger than Jupiter. The findings are based on the results of observations conducted May 12 to Sept. 17, 2009 of more than 156,000 stars in Kepler's field of view, which covers approximately 1/400 of the sky.

"The fact that we've found so many planet candidates in such a tiny fraction of the sky suggests there are countless planets orbiting stars like our sun in our galaxy," said Borucki. "Kepler can find only a small fraction of the planets around the stars it looks at because the orbits aren't aligned properly. If you account for those two factors, our results indicate there must be millions of planets orbiting the stars that surround our sun."

"We're about half-way through Kepler's scheduled mission," said Roger Hunter, the Kepler project manager. "Today's announcement is very exciting and portends many discoveries to come. It's looking like the galaxy may be littered with many planets."

Among the stars with planetary candidates, 170 show evidence of multiple planetary candidates, including one, Kepler-11, that scientists have been able to confirm that has no fewer than six planets.

"Another exciting discovery has been the tremendous variations in the structure of the confirmed planets -- some have the density of Styrofoam and others are denser than iron. The Earth's density is in between."

"The historic milestones Kepler makes with each new discovery will determine the course of every exoplanet mission to follow," said Douglas Hudgins, Kepler program scientist at NASA Headquarters in Washington.

Kepler, a space telescope, looks for planet signatures by measuring tiny decreases in the brightness of stars caused by planets crossing in front of them -- this is known as a transit.

Since transits of planets in the habitable zone of sun-like stars occur about once a year and require three transits for verification, it is expected to take three years to locate and verify Earth-size planets orbiting sun-like stars.

The Kepler science team uses ground-based telescope and the Spitzer Space Telescope to perform follow-up observations on planetary candidates and other objects of interest found with the spacecraft. The star field that Kepler observes in the constellations Cygnus and Lyra can only be seen from ground-based observatories in spring through early fall. The data from these other observations helps determine which of the candidates can be validated as planets.

"The first four months of data have given us an enormous amount of interesting information for the science community to explore and to find the planets among the candidates that we have found," said Borucki. "Keep in mind, in the future, we'll have even more data for small planets in and near the habitable zone for everyone to look at."

Kepler will continue conducting science operations until at least November 2012, searching for planets as small as Earth, including those that orbit stars in a warm habitable zone where liquid water could exist on the surface of the planet. Since transits of planets in the habitable zone of solar-like stars occur about once a year and require three transits for verification, it is expected to take three years to locate and verify Earth-size planets orbiting sun-like stars.

Borucki predicted that the search using the Kepler spacecraft's continuous and long-duration capability will significantly enhance scientists' ability to determine the distributions of planet size and orbital period in the future.

"In the coming years, Kepler's capabilities will allow us to find Earth-size planets in the habitable zone of other stars," Borucki said. "Future missions will be developed to study the composition of planetary atmospheres to determine if they are compatible with the presence of life. The design for these missions depends of Kepler finding whether Earth-size planets in the habitable zone are common or rare."

The Kepler Mission team has discovered a total of 15 exoplanets, including the smallest known exoplanet, Kepler-10b.

"Kepler is providing data 100 times better than anyone has ever done before," said Borucki. "It's exploring a new part of phase space, a new part of the universe that could not be explored without this kind of precision, so it's producing absolutely beautiful data. We're seeing the variability of stars like no one has ever seen before. We're finding planets smaller than anyone has ever seen before, because the data quality is extremely good."

"In one generation we have gone from extraterrestrial planets being a mainstay of science fiction, to the present, where Kepler has helped turn science fiction into today's reality," said NASA Administrator Charles Bolden. "These discoveries underscore the importance of NASA's science missions, which consistently increase understanding of our place in the cosmos."

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Global data storage calculated at 295 exabytes !!

Mankind's capacity to store the colossal amount of information in the world has been measured by scientists.

The study, published in the journal Science, calculates the amount of data stored in the world by 2007 as 295 exabytes.

That is the equivalent of 1.2 billion average hard drives.

The researchers calculated the figure by estimating the amount of data held on 60 technologies from PCs and and DVDs to paper adverts and books.

"If we were to take all that information and store it in books, we could cover the entire area of the US or China in 13 layers of books," Dr Martin Hilbert of the University of Southern California told the BBC's Science in Action.
Information revolution
Digital audio tape By 2007, 94% of stored information was kept digitally

Computer storage has traditionally been measured in kilobytes, then megabytes, and now usually gigabytes. After that comes terabytes, petabytes, then exabytes. One exabyte is a billion gigabytes.

The same information stored digitally on CDs would create a stack of discs that would reach beyond the moon, according to the researchers.

Scientists calculated the figure by estimating the amount of data held on 60 analogue and digital technologies during the period from 1986 to 2007. They considered everything from computer hard drives to obsolete floppy discs, and x-ray films to microchips on credit cards.

The survey covers a period known as the "information revolution" as human societies transition to a digital age. It shows that in 2000 75% of stored information was in an analogue format such as video cassettes, but that by 2007, 94% of it was digital.

"There have been other revolutions before." Dr Hilbert told the BBC's Science in Action programme.

"The car changed society completely, or electricity. Every 40, 50 or 60 years something grows faster than anything else, and right now it's information.

"Basically what you can do with information is transmit it through space, and we call that communication. You can transmit it through time; we call that storage. Or you can transform it, manipulate it, change the meaning of it, and we call that computation."

Other results from the global survey show that we broadcast around two zettabytes of data (a zettabyte is 1000 exabytes). That's the equivalent of 175 newspapers per person, per day.

The fastest growing area of information manipulation has been computation. During the two decades the survey covers, global computing capacity increased by 58% per year.

These numbers may sound large, but they are still dwarfed by the information processing and storage capacity of nature.

"The Human DNA in one single body can store around 300 times more information than we store in all our technological devices" according to Dr Hilbert.

This study looked at the world as a whole, but the scientists say that it does show that the "digital divide" between rich and poor countries is growing. Despite the spread of computers and mobile phones, the capacity to process information is becoming more unequal.

In 2002 people in the developed world could communicate eight times more information than people in the developing world. Just five years later, in 2007, that gap has nearly doubled, and people in richer countries have 15 times more information carrying capacity.

Source:- Global data storage calculated at 295 exabytes