NASA today played up an artist's illustration showing what it says how common planets are around the stars in the Milky Way. "The planets, their orbits and their host stars are all vastly magnified compared to their real separations. A six-year search that surveyed millions of stars using the microlensing technique concluded that planets around stars are the rule rather than the exception. The average number of planets per star is greater than one. This means that there is likely to be a minimum of 1,500 planets within just 50 light-years of Earth," NASA said.
More: Fabulous space photos from NASA's Hubble telescope
Microlensing takes advantage of the random motions of stars, which are generally too small to be noticed. If one star passes precisely in front of another star, the gravity of the foreground star bends the light from the background star, according to NASA. This means that the foreground star acts like a giant lens amplifying the light from the background star. A planetary companion around the foreground star can produce additional brightening of the background star. This additional brightening reveals the planet, which is otherwise too faint to be seen by telescopes. Using the microlensing technique, astronomers can determine a planet's mass. This method, however, does not reveal any clues about the world's composition, astronomers say.
The billion number comes from observations taken over six years by Probing Lensing Anomalies NETwork or PLANET study that found there are far more Earth-sized planets than bloated Jupiter-sized worlds. This notion is based on calibrating a planetary mass function that shows the number of planets increases for lower mass worlds. A rough estimate from this survey would point to the existence of more than 10 billion terrestrial planets across our galaxy, NASA said.
Follow Michael Cooney on Twitter: nwwlayer8 and on Facebook
Layer 8 Extra
Check out these other hot stories:
Federal courts scuffle in face of digital information overload
FBI: Investment scams, Black Hole exploit kit lead cybercrime wave
DARPA building test bed for virtual satellite clusters
Hypersonic test aircraft peeled apart after 3 minutes of sustained Mach 20 speed
Massively controversial revenge site IsAnyoneup.com shuttered
One busy fraudster - Man charged with hacking securities accounts for $1M; IRS fraud scheme
DARPA exploring miniature, atomic sensor systems as alternative to GPS
Intellectual property worth over 27 million jobs, $5.6 trillion to US economy
Creepy: FBI wants to advance the science of interrogation
Expect a flood of competitions as US tries to spur public inventions
US offers $12M to develop wireless charging stations for electric vehicles