Finding another planet like ours – another Earth – has been the stuff of science fiction works of the past decades. Planetary colonization, as it is commonly called, has been a recurring theme of sci-fi literature and visual arts. Films and television programs have exposed most of us about outer space and planets different from our own. Star Trek, Star Wars, Hitchhiker’s Guide to the Galaxy and many other films have brought our awareness about life in outer space, interplanetary and faster-than-light travel and discovery and possible colonization of planets. But finding another Earth didn’t just stop at being a concept or theme of sci-fi works. Scientists from around the globe have been taking keen interest and concrete steps in discovering habitable and Earth-like planets outside of our solar system or our galaxy.

The universe is a very wide expanse that contains of countless other galaxies and still much more planets and star systems that make them up. Thus, there is a probability of finding a planet with the same habitable condition such as our planet Earth. The thought of looking for another habitable planet wasn’t just born out of fancy or whim, but more likely born out of scientific curiosity and precaution. Most of us may have been curious if there is life out there in the universe other than ours, or if there are other life forms that inhabit other planets. On the side of precaution, scientists have considered the possibility of exhausting our natural resources, overpopulation or catastrophic events that might permanently alter the habitability of Earth, which necessitates the effort to look for a planet or planets that have the same conditions as Earth and can support human life.

Fortunately, after years of effort in scouring the galaxies and finding possible second Earth candidates, scientists have found major breakthroughs. One promising candidate is the planet named Kepler-452b.

1400 light-years away from our Earth and also within the Milky way, Kepler-452b can be considered our stellar neighbor. The planet’s designation came from NASA’s Kepler Mission, using the Kepler Space Telescope, which aimed to discover Earth-like planets outside of our solar system. Its mass is at least 5 times that of Earth, and is within the habitable zone of its parent star, designated as Kepler 452. Certain conditions of this planet such as comparable temperature to our earth, an almost identical star to our Sun, and a slightly longer orbit time has lead it to be nicknamed Earth 2.0 and Earth’s Cousin. Because of its considerable bigger size, it is also considered a super-Earth.

Kepler-452b isn’t just the only heavy contender for the 2nd Earth category. There are also recent discoveries by NASA of nearly Earth-sized planets which have the potential to hold life. These are Kepler-438b, Kepler-186f, TRAPPIST-1, Proxima b among others.

All these discoveries are still at the infancy stage of the hunt for the 2nd Earth. Scientists have warned the public to not get too excited and jump into conclusions with these planetary discoveries. Planets found in the habitable zones of their stars do not mean they are habitable for humans. The atmosphere of these planets, their gravitational fields, their surface temperature and their composition are just several of the many things to consider for a planet to be considered habitable for us. Also, there is the problem of the technology for space travel, as these planets are thousands or hundreds of light-years away. Scientists all over the world are looking into the possible solutions to these challenges. In any way, there are still many reasons to celebrate and be happy about the current developments in finding potentially habitable planets among the countless stars in our galaxy. The road to Earth 2.0 might be challenging for now, but I know we’ll get there someday.

That was the consensus of a panel on the search for life in the universe held at NASA headquarters Monday in Washington. The discussion focused not only on the philosophical question of whether we’re alone in the universe but also on the technological advances made in an effort to answer that question.

“We believe we’re very, very close in terms of technology and science to actually finding the other Earth and our chance to find signs of life on another world,” said Sara Seager, a MacArthur Fellow and professor of planetary science and physics at the Massachusetts Institute of Technology.

“Finding Earth’s twin, that’s kind of the holy grail,” said John Grunsfeld, an astronaut who helped repair the Hubble Space Telescope in 2009 and is now an associate administrator at NASA.

Strides in the search for life

NASA: 'Close' to finding life on planets

NASA: ‘Close’ to finding life on planets 03:10

Imagine finding Earth 2.0

Imagine finding Earth 2.0 02:12

NASA: Kepler planet may be habitable

NASA: Kepler planet may be habitable 00:32

Scientists have made stellar strides in the past few years alone.

“We already know that our galaxy has at least 100 billion planets, and we didn’t know that five years ago,” said Matt Mountain, director of the Space Telescope Science Institute in Maryland.

He credited the work of the Kepler Space Telescope for these new discoveries. The planet-hunting Kepler probe, launched in 2009, finds planets by looking for dips in the brightness of a star as a planet transits, or crosses, in front of that star.

Kepler also found the first Earth-size planet that orbits in a star’s habitable zone, the area around a star where a planet could exist with liquid water on its surface.

The Kepler mission builds upon the stalwart Hubble Space Telescope, which launched in 1990 and was the first of its kind to be placed in space. As Hubble orbits the Earth, it allows scientists to peer back in time, into distant galaxies, and yields stunning images of the cosmos.

Hubble has helped shape our awareness of our planet’s place in an ever-changing universe.

The Earth, though 4.5 billion years old, is a newcomer, said John Mather, senior project scientist on NASA’s next-generation James Webb Space Telescope. It’s only about one-third of the age of the universe.

And our galaxy is ever-evolving, with “about five or 10 new stars being born per year in our Milky Way,” Mather said.

Planet hunters

Hubble’s astounding views come from a vantage point only 353 miles above our Earth.

The Kepler Space Telescope, launched in 2009, finds planets by looking for dips in the brightness of stars as a planet crosses in front.

The Kepler Space Telescope, launched in 2009, finds planets by looking for dips in the brightness of stars as a planet crosses in front.

In comparison, the James Webb telescope will be a whopping 930,000 miles from our planet. That’s close to four times the distance between the Earth and the moon.

Webb is set to launch in 2018.

Mountain, who is the telescope scientist for Webb, said scientists now know where every single star is within 200 light years of the Sun.

NASA’s assembled panelists said, if they follow this map of stars, they’re certain to find a multitude of new planets.

“Every star in the sky is a sun, and if our sun has planets, we naturally expect those other stars to have planets also, and they do,” said Seager. She said if someone looked up at a starry sky and wondered how many of the stars have planets, the answer would be “basically every single one.”

An artist's depiction of what the James Webb Space Telescope will look like.

An artist’s depiction of what the James Webb Space Telescope will look like.

Some of a star’s light will shine through the atmosphere, said Seager, and the Webb telescope should be able to pick up gases from the planet that are imprinted on the atmosphere. While the Webb telescope wasn’t designed to find signs of life on another planet, it can spot biosignature gases — gases in the atmosphere produced by life.

Seager said, with the James Webb telescope, “we have our first chance, our first capability of finding signs of life on another planet. Now nature just has to provide for us.”

Spotting Earths

Finding small planets, ones the size of Earth, is challenging, in part because they produce fainter signals, said Dave Gallagher, director for astronomy and physics at NASA’s Jet Propulsion Laboratory, who likened it to spotting a firefly beside a searchlight.

That difficulty doesn’t dull the hunt for another Earth or signs of life.

NASA administrator Charles Bolden said he counts himself among the people who “are probably convinced that it’s highly improbable in the limitless vastness of the universe that we humans stand alone.”


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