08/03/2009

PLANETS, PLANETS EVERYWHERE. BUT NOT A DROP TO DRINK!

The search for extra solar planets has boomed in the last decade with over 340 confirmed exoplanets discovered to date. The vast majority of these are gas giants and ice giants with several hot super earths also having been found. These are mostly large Jupiter sized planets somewhat similar to the outer planets of our solar system. They are unlikely to be able to support life. They are also missing one very important factor for supporting life, water. More specifically liquid water, in order for a planet to contain a substantial amount of liquid water it needs to orbit a relatively thin band of space around a star, often called the goldilocks zone for some obscure scientific reason that I could explain but you probably wouldn´t understand anyway. Within this “zone” it´s cold enough so all water isn´t lost to space during formation and hot enough its not frozen.

The search for planets has focused on these larger varieties due to the limitations of earth based astronomy such as atmospheric turbulence and thermal noise. In order to detect terrestrial planets, similar to our inner planets, rocky, metallic cores and earth sized, greater accuracy is required. Which is why NASA´s Kepler space telescope was successfully launched at 10.49pm EST or 03.49am GMT on March 6/7 from Cape Canaveral Air Force Station. It specifically aims to find earth sized, terrestrial exoplanets with possible liquid surface water, i.e. habitable.

Kepler will take up residence at a point in space for the next 3.5 years facing away from the sun allowing a continuous view of its target area of space in the Cygnus and Lyra constellations. Keplers large field of View(FOV) plus the large number of Sun like stars, roughly 100,000, in this area increases the likely hood of observing earth-like planetary transits.

Planetary transits is the method Kepler will use to detect new planets. When a planet moves between its star and the observer, its said to transit it, and a dip in the brightness can be measured. From this and the stars data the characteristics of the planet can be deduced such as mass, orbital period and approximate temperature. Appropriately the orbital period is calculated using Keplers third law of planetary motion. Johannes Kepler being the famous 17th century astronomer who defined the three laws of planetary motion and for which the telescope is named. This information can then tell us if surface water is possible and thus if life is possible. A long step from knowing but a step in the right direction considering the existence of extra solar planets was still debatable in recent history.

The telescope is a Schmidt design with a 0.95 meter aperture and a 109 square degree FOV, this is roughly your hand held at arms length (assuming you don´t have freakishly large hands). This feeds the photometer which is composed of an array of 42 CCD´s(Charged Coupled Devices, like in your digital camera). Each one being 50x25mm and 2200x1024 pixels. The satellite then stores the data and transmits to earth once a month.
The mission is very optimistic, hoping to discover over 800 gas giants with small periods and over 600 hundred terrestrial planets depending on characteristics of planets. Either way the vast amount of data obtained will go along way to increasing our knowledge of planetary systems throughout our galaxy. The characteristics they exhibit and the properties of stars harboring planetary systems. This is the real value of the mission, knowing how common place or unique our solar system is. I like feeling special but I really like ET so the more the merrier. Peace out

By Ronan O'Neill

4 comments:

Lono said...

Good work man keep searching for liquid water

Anonymous said...

You think i wouldn't understand? how condescending. Some day i will have my vengance.

Unknown said...

"for some obscure scientific reason that I could explain but you probably wouldn´t understand anyway"

"the likely hood"

all very dodgy business.

but anyway, are you turning into some sort of weird streetwise patrick moore-like nerd-a-lot?
good work.

Glazz Magazine said...

I'll give you likely hood. But I claim artistic licence on the horrific structure of that sentence. Unless its punctuation you're talking about, then I don't have a clue.
Ronan