An era of planet discovery is dawning that will see thousands of new worlds identified in the next few years, some of which may harbour life, say scientists.
British astronomers are in the vanguard of the search, which could transform humanity's view of its place in the universe.
More than 400 "exoplanets" orbiting stars beyond the Sun have been catalogued so far since the first were discovered in 1991.
A report from the Institute of Physics today predicted that in the coming years "the number will rise to thousands".
To date, most of the planets identified have been the size of gas and ice giants such as Jupiter and Neptune. But new advances may soon allow scientists to image Earth-like worlds which could sustain life.
The report, Exoplanets - The Search for Planets Beyond Our Solar System, said: "Future generations of instruments and observatories may enable researchers to image directly small, rocky planets like earth orbiting distant Sun-like stars, and analyse their atmospheres for tell-tale signs of life.
"Such searches represent the next frontier for scientific exploration - following in the footsteps of Galileo and Darwin in past centuries."
British astronomers and other scientists are already pioneering many of these developments.
In particular, UK researchers have been heavily involved in a new "adaptive" optics system called the Gemini Plant Imager which will allow far more sensitive searches to be made of fainter planets in close orbits.
Finding such small rocky planets is a key step on the way to discovering a second earth, said the report.
Scientists believe our galaxy, the Milky Way, is teeming with planets. It is estimated that more than 10 billion of its 100 billion stars could host planetary systems. At least one in 10 stars that are similar to the Sun may be orbited by planets.
In future more sophisticated methods may be used in place of or together with these techniques.
Some of the projects British scientists are already involved in include:
- The Anglo-Australian Planet Search: An ongoing survey of 250 nearby stars started in 1998 that has so far found 35 exoplanets.
- The Wide Angle Search for Planets (SuperWASP): A robotic system of wide-angle cameras monitoring millions of stars for transit events. Since 2004, it has already uncovered evidence for up to 30 new exoplanets.
- The WFCAM Transit Survey: Another transit search based at the UK Infra-Red Telescope in Hawaii, focusing on dim "red dwarf" stars.
- Gaia: A European Space Agency mission due to be launched next year with the aim of identifying planets within 650 light years of the Sun.
- Genie: A "nulling interferometry" system to be used with the Very Large Telescope multiple telescope array in Chile. The technology combines star light received by interacting telescopes in such a way that their waves cancel out, removing the glare that would otherwise obscure an orbiting planet.
- The James Webb Space Telescope: The Hubble Space Telescope's successor, due to be launched by the American space agency Nasa in 2014, will provide images of exoplanets and forming planetary systems.
- The European Extremely Large Telescope: Scheduled to start operations in 2018, this will be the world's biggest telescope, with an "eye" measuring 42 metres across. It will track down earth-like planets in habitable zones.
Robert Kirby-Harris, chief executive at the Institute of Physics, said: "This report outlines exciting developments in detecting planets which might - just might - be able to support life in distant solar systems.