Kepler satellite searches for new Earth

by Diana Crofts-Pelayo

Courtesy of NASA
Courtesy of NASA

Professors at San Diego State have been working with NASA on the Kepler Mission since 2009, but recent discoveries have them excited.

Jerome Orosz, William Welsh and Donald Short, former dean of the College of Sciences, are part of the team that is analyzing data from the Kepler Mission.

The Kepler Mission was launched to survey a portion of the Milky Way to find terrestrial planets in the habitable zone with their stars. Scientists analyze which planets are the right size and temperature for sustaining life.

According to Orosz and Welsh, the most interesting finding has been the recent discovery of Kepler-11. It is a system about 2,000 light-years from Earth and is the most tightly packed planetary system yet discovered. All six of its confirmed planets have orbits smaller than Venus’.

All of the planets orbiting Kepler-11 are larger than Earth and are a mixture of rock and gases, possibly even water.
It is the largest group of transiting planets orbiting a single star discovered outside our solar system.

“Kepler-11 is one of about 1,200 stars that have good planet candidates,” Welsh said.

The Kepler-11 system is unique, in comparison to Earth.

“Kepler-11’s planets are bigger than Earth, but not by much,” Orosz said. “There is probably no life because the surface temperature is too hot; there are no oceans.”
Scientists can detect these planets by viewing images that the Kepler telescope takes of the galaxy.

“(The Kepler telescope) is on a heliocentric orbit so Earth never gets in the way of the images,” Orosz said. “Kepler is farther away than the moon.”
When a terrestrial planet crosses in front of its star it produces a very small change in a star’s brightness.

“Imagine an ant walks over the headlight of a car at night,” Welsh said. “The car is parked several miles away and you need to detect that subtle difference in the light, that’s what it’s like to detect these stars.”

Knowing the temperature of a planet is key because only moderate temperatures are habitable for life similar to those found on Earth.

After discovering Kepler-11, Orosz and Welsh remain optimistic about finding planets within the hospitable zone.

“Any life we know of requires a liquid; water is the best,” Welsh said. “It is likely there are planets in the universe with water.”
Since Feb. 1, Kepler has identified 1,235 planet candidates.

“The mission has only been up for two years, but we have found good results,” Welsh said.

“We will be working with the Kepler mission until it is over,” Welsh said. “We just don’t know how long it will be funded. It could last many more years or could end in one year.”

According to Welsh, since the telescope is drifting slower than Earth around the sun, eventually it will distance itself so much that reading data will be difficult. After it orbits the sun in about 70 to 80 years, Kepler will come close enough to Earth again to be ale to examine data.