Yuri Alexyevich Gagarin, "Columbus of the Cosmos"

Yuri Alexyevich Gagarin was a Soviet cosmonaut.  He was the first human in space and is often referred to as "the Columbus of the Cosmos".   His spacecraft Vostok-1 orbited the Earth on April 12, 1961 for the duration of 108 minutes.   Yuri's Night, usually celebrated on April 12^th celebrates this historic first flight.

Yuri's Night also celebrates another April 12^th anniversary notable in the annals of space travel.  Twenty years after Yuri Gagarin's historic flight, the first NASA space shuttle flight, STS-1 was launched into space.  STS is short for Space Transportation System.  NASA names each flight STS with the chronological number after it.  STS-1 was launched on April 12, 1981; the shuttle orbited the earth 37 times during a 54.5 hour mission.

Since 1961, our interest in space and the exploration of its depths has magnified.  Recently NASA launched the Kepler mission.  On March 7^th, 2009, the Kepler Mission successfully launched from Cape Canaveral, Florida.  Kepler, which is a specialized telescope, was designed to find the first Earth-size planets orbiting stars within a "habitable zone". A habitable zone is an orbit around a star that would enable a planet to formulate and upkeep an atmosphere and the ability for water to form in pools on the planet's surface.  Liquid water is believed to be essential for the formation of life.  Thus from the nascent flight of orbiting our own Earth, space travels has evolved to look amongst other start.  This progress is certainly something worthy of celebration!

An exhibit on the Kepler Mission along with other NASA initiatives like SOFIA, LCROSS and NLSI fascinated guests last Thursday night.  For one guest, meeting Buzz Aldrin in person was the highlight of his night.   My favorite aspect of the evening was a 3-D rendered tour of the moon and neighboring space.  I am anxious to see what will be the new annal of space exploration when April 12^th and Yuri's Night comes around again in 2010.

The main method for detecting exoplanets is by spectroscopically observing a tiny "wobble" in a star caused by the gravitational tug of a massive planet in orbit. Only Jupiter-sized planets have enough pull to produce a wobble in their star that we can detect—and the closer they are to their star, the shorter their orbital period and the more wobbles we can measure in a given period of time. The gravity of an Earth-sized planet is too feeble for this and planets at Earth-like distance orbit only once in many months.

But NASA is about to launch a new spacecraft, Kepler, whose mission is to detect Earth-sized planets at Earth-like distances from their stars. Kepler will launch on March 5th, and will eventually move into an orbit around the Sun. In essence, Kepler is a giant space camera designed to "stare" at a chosen patch of the sky continuously for years to come.

So what exactly is Kepler looking for in its unblinking stare contest with the stars in its vision? Kepler won’t be looking for microwobbles in those stars. Kepler will detect planets through the transit method. A transit is when a planet crosses in front of its star, blocking off a tiny amount of the star's light for a time.

A number of the hot Jupiters have been detected by their transits across their stars: a large planet can block a measurable amount of their star's light. But the drop in a star's brightness caused by an Earth-sized planet is far smaller—and if that planet only orbits its star every year or so, with its infrequent transit lasting only a few hours, an observer would have to stare long and hard to notice it.

Kepler will be based in space, and will be able to observe its target patch of sky continuously, uninterrupted by the cycles of day and night on Earth. Also by virtue of being in space, Kepler won't be hampered by Earth's turbulent and obscuring atmosphere—so there will be far less "noise" in the starlight, noise that can hide a minute drop in brightness. Finally, Kepler's sensitive digital camera system is an array of 42 CCD chips positioned at the focus of a 0.95 meter telescope, which will image an area of the sky about 12 degrees in diameter—equivalent to the area of sky you can cover with your open hand at arm's length.

Kepler will stare at a patch of sky near the constellation Cygnus, constantly monitoring about 150,000 stars for the next few years, looking for minute drops in brightness that may be the passage of Earth-sized planets.

Kepler won't reveal the composition or atmospheres of Earth-sized planets, or any telltale signs of life. Perhaps more importantly at this stage of our exploration of space, Kepler should give us an idea of how numerous Earth-sized planets are out there—whether or not they are as commonplace as depicted on Star Trek…

Good luck, Kepler, and stare on!

Artistic rendition of exoplanet Gilese 436 b, created in Celestia

Once astronomers have found an extrasolar planet, also called an exoplanet, they look to see if it is in the Goldilocks zone. This is an area of space in which a planet is just the right distance from its' parent star so that the surface is neither too hot nor too cold. A habitable temperature means that the planet could possibly host liquid water, an ingredient for life.

A number of exoplanet findings have come from astronomy teams in Switzerland and near San Jose at Lick Observatory. Astronomers at Lick made news in the fall of 2007 when they discovered 55 Cancri. The discovery of the five-planet system came after nearly 20 years of observations. Also in 2007, astronomers with the Geneva Extrasolar Planet Search Program discovered the most earth-like planet ever found. Gilese 581 c lies in the Goldilocks Zone, it's surface temperature ranges from an estimated 32 degrees Fahrenheit to 102 degrees Fahrenheit. The research team that discovered the new planet believes it may have a developed atmosphere and be covered with oceans.

Curious to see how astronomers hunt for extrasolar planets, I took the trip up the long, windy road to the top of Mt. Hamilton. It is a beautiful drive up to the observatory and it's wise to take your time so that you can enjoy the ideal California landscape of rolling hills dotted with oak trees and wildflowers. The 365 sharp curves along the 19 mile road will also slow you down.

At the top of Mt. Hamilton are several white domes dotting the 4,200-foot crestline. From Lick Observatory you can see forever– not just across the vast northern California landscape but out into our own galaxy and beyond. By coincidence, the night I was there astronomer Debra Fischer confirmed five new planets outside our solar system. The discovery was the culmination of five years of watching these specific planets from Lick's 3-meter Shane Telescope. Fischer and her colleague Geoff Marcy will publish their findings soon. These two astronomers are obsessed with looking for exoplanets, they just returned from the Andes mountains in Chile, where they spent day and night for several weeks hunting for planets. But Fischer and Marcy are not the only ones who have caught the exoplanet bug.

Scientists at NASA are nearly ready to launch a bus-sized telescope into space. NASA's Kepler Telescope which will orbit our sun, will be trained on a hundred thousand stars at a time. It may be our best chance yet for finding new life in outer space. The telescope is scheduled to launch in February. Kepler will find planets by looking for tiny dips in the brightness of a star caused by planetary transits.

Make sure to check out our photo set on Flickr which includes: photos of Lick Observatory; the Kepler testbed at NASA Ames in Mountain View; the Kepler spacecraft assembly in Boulder, Colorado; and artists' renditions of exoplanets discussed in this report.You can also hear our radio story on the search for exoplanets, watch the Planet Hunters TV story online and find additional links and resources.