Beyond the Milky Way
Danish researchers are part of an effort to identify planets outside of our own galaxy, including in the Andromeda galaxy some 2.5 million light years away.
Astronomers have identified nearly 2,000 planets outside of our own solar system – but still inside our own galaxy – meaning that there could potentially be something like 100 billion planets in the Milky Way.
But a research group affiliated with the Niels Bohr Institute in Copenhagen is looking even deeper into space.
“We will try to detect planets in other galaxies, including the Andromeda Galaxy,” Uffe Gråe Jørgensen, an associate professor and astrophysicist at the Niels Bohr Institute who heads up the research group Mind Step, told Berlingske newspaper.
Although it is almost certain that there are planets in other galaxies, the immense distances of space has made proof of there existence impossible up until now.
Almost all of the planets that have been discovered so far are located within a distance of a few hundred light years from Earth.
In January 2006, Jørgensen used a Danish telescope in Chile to identify a planet inside our galaxy about 25,000 light years away, which remains the most distant planet documented thus far.
A giant magnifying glass
Even today's powerful telescopes and high resolution cameras cannot do much better. Jørgensen and his team plan to use a natural phenomenon called ‘gravitational lenses’ – a kind of natural magnifying glass – to see further than has ever been possible before.
The effect occurs when two objects in the universe are aligned relative to Earth. If the nearest object is very heavy – like a big star or a black hole – it bends space and thus the light around it, creating a magnifying lens effect.
“In theory, the magnification is infinite. In reality, magnifications of 500-600 times are entirely possible,” said Jørgensen.
The professor said that the magnification would make it is possible to detect planets in completely different galaxies, including in Andromeda, our nearest large neighbouring galaxy.
Patience is important
The search will require patience. Stars and galaxies are in perpetual motion, so it could take millions of years for an object to appear to create the magnifying effect on a planet millions of light years away, and then there is only a window of a few weeks to take advantage of the magnification.
“We can not be absolutely sure that we will be able to discover a planet in another galaxy,” said Jørgensen. “But we have discovered planets in our own galaxy by using this technique, so we have high hopes.”