The Kepler telescope has identified more than 5100 possible exoplanets and verified more than 2500 as bona fide planets.
Of these, a dozen are Earth-like in size and orbit in their stars' habitable zones.
These rocky worlds are known as ''terrestrial planets'' and, as they are outside this solar system, called exoplanets.
Like Earth and its sun, to sustain water, and therefore the possibility of life, the planet has to be the right distance from its home star so its surface is neither too hot nor too cold.
Kepler cannot find life itself, just where conditions might be right for it to thrive.
Earlier this year astrophysicists were over the moon when another programme, Nasa's Spitzer Space Telescope, revealed seven Earth-size planets around a single star, a record for habitable-zone planets outside this solar system.
They are about 40 light-years (235 trillion miles) from Earth, so relatively close in space terms, and in the constellation Aquarius.
The researchers detected the planets by monitoring the star for variations in its movement that could have been caused by a planet's gravitational pull.
Batalha's work extends to the new James Webb Space Telescope due to launch in October 2018.
Today, she leads the effort to understand planet populations in the galaxy.
She participates on numerous scientific advisory panels to chart the future of Nasa's astrophysics research to find life beyond the solar system and answer the question: are we alone?
Also a guest of the Northland Astronomical Society, she will deliver a public lecture sponsored by the Royal Astronomical Society of New Zealand's Lecture Trust tonight, at Tikipunga High School Hall, 7pm.
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