The search for other Earth-like planets

Billions of stars. Billions of galaxies. A thousand years just to count all of the stars in our galaxy and then another thousand to count the galaxies in the universe.

The Odds of Intelligent Alien Life

Could there be intelligent life on other planets? This question has piqued imagination and curiosity for decades. Explore the answer with the Drake Equation — a mathematical formula that calculates the possibility of undiscovered life.

2012: A Banner Year in the Hunt for Exoplanets

The search for worlds outside our solar system has come a long way since the first exoplanets were confirmed in the early 1990s. Since then, the average rate of alien-world discoveries has shot from about three per year to between fifty and a hundred per year in the last five years. As of the end of 2012, with the tally standing at 854 newfound worlds and reports of new detections being announced nearly every week, thanks in large measure to NASA’s Kepler space telescope, astronomers are calling this the golden age of exoplanet discovery.

Now the race is on to find Earth’s twin, the elusive Earth-size planet in the habitable, or “Goldilocks,” zone around a star where liquid water can exist—and experts believe we may hit the cosmic jackpot soon.

In 2012 astronomers came closer than ever to zeroing in on an earthly doppelganger, or at the very least a planet considered potentially habitable.

However, we are far from confirming the habitability of any of these planets until we have the capability to observe their atmosphere, but that will take many years. The big goal now is to find an Earth-size planet in its star’s habitable zone—something more similar to Earth.

To learn about five of the most interesting exoplanetary discoveries of this past year like Gliese 667Cc, Alpha Centauri Bb and Tau Ceti e and f - go here.

Sugar Found In Space: A Sign of Life?

Astronomers have made a sweet discovery: simple sugar molecules floating in the gas around a star some 400 light-years away, suggesting the possibility of life on other planets.

The discovery doesn’t prove that life has developed elsewhere in the universe—but it implies that there is no reason it could not. It shows that the carbon-rich molecules that are the building blocks of life can be present even before planets have begun forming.

Scientists use the term “sugar” to loosely refer to organic molecules known as carbohydrates, which are made up of carbon, hydrogen, and oxygen.

The molecules that the team detected in space are the simplest form of sugar, called glycoaldehyde. Learn more here.

A needle in countless haystacks: Finding habitable worlds

Out of billions of galaxies and billions of stars, how do we find Earth-like habitable worlds? What is essential to support life as we know it?

Planet Found in Nearest Star System to Earth

Meeting the neighbours is normally easier than this. After years of searching, astronomers have finally spotted an Earth-mass planet in Alpha Centauri, the nearest star system to our own. Although the planet orbits too close to its parent star to host life, its discovery ups the chance of the system also hosting hospitable worlds.

Alpha Centauri looks like a single point of light from Earth, but it contains two bright stars that share a relatively close binary orbit, including one that looks a lot like our sun. This binary pair is in our cosmic backyard, about 4.3 light years away, spurring great interest in its ability to host planets.

If you’re hoping to visit the neighbours, though, you may want to pack a few books for the trip. Even with the current record holders for the world’s fastest spacecraft, the Helios sun probes, the journey to Alpha Centauri would take 19,000 years – and that’s assuming you travel at top speed for the whole journey, which is unlikely. Learn more here, here, here or here.

Researchers discover ‘waterworld’

An astronaut attempting to visit recently discovered planet GJ1214b would land in hot water – literally.

Researchers said they have identified an entirely new kind of planet, dominated not by rock, gas or other common materials, but water. The planet is “a waterworld enshrouded by a thick, steamy atmosphere.

GJ1214b was discovered in 2009 by the ground-based MEarth Project. Described as a “super-Earth,” it is about 2.7 times Earth’s diameter and weighs almost 7 times as much.

Further studies in 2010 led to scientists suspecting that the planet, where the temperature is some 232 degrees Celsius, was largely covered in water. This was confirmed by using Hubble to study the planet when it crossed in front of its host star.

The light of the star, filtered through the planet’s atmosphere, gave clues to the mix of gasses, backing up the water vapor theory. Learn more here or here.

Two Earth-Size Planets Found Around Sunlike Star

Astronomers using NASA’s Kepler mission have detected two Earth-sized planets orbiting a distant star. This discovery marks a milestone in the hunt for alien worlds, since it brings scientists one step closer to their ultimate goal of finding a twin Earth.

The two planets, dubbed Kepler-20e and 20f, are the smallest planets found to date. They have diameters of 6,900 miles and 8,200 miles – equivalent to 0.87 times Earth (slightly smaller than Venus) and 1.03 times Earth. These worlds are expected to have rocky compositions, so their masses should be less than 1.7 and 3 times Earth’s.

Both worlds circle Kepler-20: a G-type star slightly cooler than the Sun and located 950 light-years from Earth. Kepler-20e orbits every 6.1 days at a distance of 4.7 million miles. Kepler-20f orbits every 19.6 days at a distance of 10.3 million miles. Due to their tight orbits, they are heated to temperatures of 1,400 degrees Fahrenheit (760 °C)and 800 degrees F (430 °C).

In addition to the two Earth-sized worlds, the Kepler-20 system contains three larger planets. All five have orbits closer than Mercury in our solar system. They also show an unexpected arrangement. In our solar system small, rocky worlds orbit close to the Sun and large, gas giant worlds orbit farther out. In contrast, the planets of Kepler-20 are organized in alternating size: big, little, big, little, big. Learn more here, here, here, here or here.

Earthlike planet found in the habitable zone

Astronomers have found a planet smack in the middle of the habitable zone of its sunlike star, where temperatures are good for life. If this planet has a surface, it would have a very nice temperature of about 20°C (70° F).

Unfortunately, the true nature of the planet, named Kepler-22b, remains unknown. It is 2.4 times the size of Earth, but its mass, and hence its composition, has not yet been determined.

The Kepler telescope has been staring at more than 150,000 stars between the constellations Cygnus and Lyra for the past 1000 days. The Kepler team has now found more than 2300 candidate exoplanets, about 1000 more than it reported in February. Ten of those span no more than about twice Earth’s width. Learn more here, here, here or here.

Massive lakes could lie beneath Jupiter moon

Hidden inside the thick, icy crust of Jupiter’s moon Europa may be a giant saltwater body. Lying about 1.9 miles (3 kilometers) from the surface, the ice-trapped lake may represent the newest potentially habitable environment in the solar system—and one of the best prospects for the search for life beyond Earth.

For decades scientists have thought Europa was a likely place for life, but now they have specific, exciting regions on the icy moon to focus their future studies. It’s possible for lake water to be only a few tens of meters of depth under the moon’s surface, meaning that there may be great opportunities to land and sample remnants of the salty ocean with relative ease. Learn more here or here.