Planet hunting for another earth


The search for another earth is getting closer

Regan Meloche

For many people the field of astronomy is mind-blowing. Tales about another earth-like planet smashing into earth and possibly forming the moon, the universe being over 13 billion years old, or how there is a supermassive black hole at the center of the galaxy astonish the minds and capture the imagination of many people.

What is even more astounding than these discoveries, however, is the fact that they can actually be discovered in the first place. Brilliant new finds in astronomy are nothing new.

Before the telescope was invented the ancient Greeks used astronomy to accurately estimate the size of the earth and found methods of measuring astronomical distances. This tradition of using clever techniques to study the cosmos is still carried out by astronomers today. One of the most exciting recent developments in the field of astronomy is the constant discovery of more earth-like exoplanets. Last week, astronomers discovered a planet almost identical to earth.

An exoplanet, or extrasolar planet, is a planet outside our solar system. The first exoplanet orbiting a sun-like star was discovered in 1995. Since then, scientists have identified over 750 confirmed planets and over 2,300 more potential candidates. This large number of ‘potential candidates’ is largely attributable to the Kepler space telescope launched in 2009. Kepler’s sole purpose is seeking out earth-like planets around sun-like stars.

A number of things make it difficult to spot planets, regarldess of how large they acutally are. For example, planets are trillions of kilometers away, and are often overwhelmed in the brightness of their parent star.  Things like this make planet hunting difficult, but to an astronomer equipped with the right instruments, overcoming these obstacles is all in a day’s work.

There are many methods used to detect exoplanets, but two techniques in particular have proven to be the most useful.

The first is the transit method. There comes a point, as a planet orbits its parent star, where the planet will pass in front of the parent star. This is somewhat similar to the recent transit of Venus that occurred this year. When this happens, the planet blocks some of the light coming from the star, causing it to dim ever so slightly. Very precise instruments can measure this periodic dimming, and astronomers can infer the existence of an exoplanet.

The other main technique is called the radial velocity method and makes use of gravity. As a planet orbits its parent star, the planet’s gravity causes the star to slightly wobble, causing a small change in the motion of the parent star. This change is measured by analyzing the light spectrum emitted from the star, and may be a sign of another world.

Combining these two techniques and others can give scientists a good idea of when they have found a new exoplanet. Note that these are all detection methods, meaning they can only detect the existence of a planet, and not actually observe it. But, researchers are hopeful that in a matter of time, observing the planet will also be a reality.

The primary goal of planet hunting is to find an earth-like planet that could potentially support life. While we have already discovered over 750 exoplanets, astronomers are particularly interested in planets in the ‘habitable zone’. The habitable zone is the region around any parent star where temperatures would allow liquid water to exist on the surface. The planet cannot be too far away from the star, where the water would freeze, or  too close to the star, where the water would evaporate. With that being said, how close are researchers to finding a planet with the right conditions for life?

There are many candidates that show some potential for being habitable. The red dwarf Gliese 581 has an impressive planetary system sitting 22 light-years from earth. Another one of the planets, Gliese 581g disovered in 2010, showed lots of promise as well.The planet is tidally locked to its parent star, meaning one side is always facing the star and the other is always facing away.  If life was to be estiblished on this planet,  humans would have to live along the perpetual day-night border, where the sun would always be setting in the crimson sky. Astrobiologists hypothesize that the red color of the star would also change the photosynthetic properties of the plants on Gliese 581g, causing them to be completely black.

Most recently, astronomers discovered a new exoplanet on Oct. 16 – Alpha Centauri Bb. While this planet is not quite in the habitable zone as it is too close to the parent star and would cause any water to evaporate, the discovery is very important, nonetheless. Alpha Centauri Bb is potentially the smallest exoplanet detected so far, which would prove that current techniques could allow the detection of other planets of similar size.

Philosophers and scientists have long debated about whether or not  planet earth is alone in its ability to support life. With emerging insturments and continued research, this debate may one day be settled.

Gizmos & Gadgets: Your weekly dose of science and technology

Microsoft Surface: Microsoft’s new tablet, the Surface, goes on sale in Canada on Oct. 26. Some are calling it a bold move for Microsoft since they traditionally make software, rather than hardware. But then again, they were successful with the X-Box.

Long-distance Teamwork: the Mars Curiosity Rover discovered an out-of-place white speck while taking soil samples off the red planet. The rover had previously found out-of-place material, which turned out to  be a piece of debris from when the spacecraft landed. Meanwhile on Earth, Alberta scientists are studying a meteorite from Mars that landed in Morocco 14 months ago. The space rock matches  some samples collected from Mars over 30 years ago, and could tell us more about the composition of the planet.

Ocean Fertilization: The Haida Salmon Restoration project controversially dumped 100 tones of iron sulfate into the Pacific Ocean last week. The project leaders argue that doing so will encourage plankton growth, helping to bring back the salmon population. Ocean fertilization may also be a possible method of combating global warming, since the plankton are capable of absorbing carbon dioxide, but the debate is ongoing.

Rocket Penguins: Canadian photographer Paul Nicklen won the coveted Veolia Environmental Wildlife Photographer of the Year award for his stunning underwater shot of a group of emperor penguins charging out of the Ross Sea in Antarctica.

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