In recent years, many planets have been discovered that are outside our solar system, so-called exoplanets. Now I wondered if those are all planets that are in ‘our’ Milky Way galaxy. Or have people already reached the point where they can also start looking for planets in other galaxies?
Answer
The known exoplanets are indeed all located in our galaxy, most even in the fairly close (everything is relative!) environment of the Sun.
The detection of exoplanets is a high-precision task, and you need a lot of signal for that. Individual stars in other galaxies are too dim from Earth to achieve a sufficient signal-to-noise ratio to detect planets.
The only technique that makes it possible to find exoplanets at fairly large distances is that of so-called ‘gravitational microlensing’. It cannot be ruled out that this technique will provide clues to exoplanets in the Large Magellanic Cloud, a small system close to our own, in the near future.
Anyway, there is no reason to suppose that the picture of planets looks completely different in other systems. The only expected difference is in the chemical composition of other systems. In systems with less heavy elements (like the Large Magellanic Cloud by the way) you expect fewer planets.
Answered by
Prof. dr. Christopher Waelkens
Astronomy
Old Market 13 3000 Leuven
https://www.kuleuven.be/
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