Stargazing: Are there Earth-like planets out there?

December 17, 2011 at 09:11 AM

It is truly a fascinating time in which to live as the night sky continues to reveal its secrets to scientists pushing deeper into the cosmos.

This past week two areas of astronomical research have extended the limits of our knowledge.

The spacecraft Voyager, launched in 1977 to explore the outer planets, continues to sail beyond the very limits of the solar system.

Thirty-five years and billions of miles later, Voyager keeps making observations and streaming data home.

Recently, voyager picked up a signal from hydrogen atoms deep in the Milky Way Galaxy called Lyman-alpha radiation.

This shows up as a specific wavelength of ultraviolet light that astronomers suspect will tell a great deal about star formation in the galaxy.

Lyman-alpha radiation from the Milky Way has not been detected from Earth or even in space close to Earth because it is scattered by hydrogen atoms packed around the inner solar system.

Meanwhile, NASA’s Kepler spacecraft continues to make amazing discoveries of planets orbiting far-off stars.

As the science advances, with improvement in technique and instrumentation - as well as the longer time spent in space - explorers are finding smaller and smaller worlds that are more likely to be Earth-like.

Scientists are seeking planets within the so-called Goldilocks zone, where a planet is not too hot and not too cold, and where liquid water could exist.

After a long series of observations to confirm its orbit, NASA announced finding such a planet only 2.4 times the size of Earth where the average temperature would be just below freezing.

If an atmosphere is present, the greenhouse effect could offer “shirt sleeve” temperatures.

The planet is dubbed Kepler 22-b, and circles its star in 290 days.

The star is in the constellation Cygnus the Swan, about 600 light years away.

It was detected by tracking the dip in the starlight as the planet crosses (transits) the face the star from our line-of-sight.

Of course a lot more factors are needed for life as we know it to exits.

As you read the reports sent back from Voyager and Kepler, remember that Earth is an amazing place.

We are fortunate that Earth’s axis has just the right tilt.

Earth also has a protective magnetic field, a large moon that guards us from many meteor impacts, an active geology, thick atmosphere, a stable star (the sun) and other benefits we quickly take for granted.

Enjoy your next time out under the stars, and keep looking up!