Strange flashes are coming out of the Moon – and scientists do not know why.

Parts of the surface are lighting up multiple times per week, sometimes with quick flashes and sometimes for hours. At other times, parts of the surface mysteriously go dark.

Scientists have not been able to work out why the strange changes in light are happening. That is despite them being observed for decades, and being catalogued in scientific papers as far back as the 1950s.

Scientists refer to them as "transient lunar phenomena". One paper in 1970 described how the "emitted light is usually described as reddish or pinkish, sometimes with a 'sparkling' or 'flowing' appearance", noting that they stretched for miles across the surface and usually lasted for 20 minutes but could go on for hours.

They have suggested various explanations, such as the Moon being hit by meteors or the solar wind hitting moon dust, or movement of the Moon's surface that lets out gases that reflect sunlight back at the Earth. But no decisive explanation of the behaviour has been offered.

Now they hope to finally understand what is causing the strange flashes on the surface.

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Doing so will mean watching the surface systematically and over the long-term, to try and establish what makes the flashes happen.

One attempt to do so is being led by Hakan Kayal, professor of space technology at Julius-Maximilians-Universität Würzburg (JMU) in Germany.

His team have built a telescope in Spain, which went into operation earlier this year and can be controlled from JMU's campus. It uses two cameras to watch the moon after night, and when they both see one of the flashes, the telescope captures photos and videos and alerts Professor Kayal's team for further observation.

The team then hope to share those results with the European Space Agency, with the aim of cataloguing the events and trying to understand what seems to be making them happen.

Learning about the Moon's surface in this way could prove key as countries including the US, China and India all hope to head to the Moon and stay there. "Anyone who wants to build a lunar base at some point must of course be familiar with the local conditions," sad Professor Kayal in a statement.