Australasian Science: Australia's authority on science since 1938

Lunar Craters Revealed

By Stephen Luntz

It might be thought that 400 years of telescope observations, not to mention numerous manned and robotic missions, would have revealed every decent-sized crater on the near side of the Moon. However, Curtin University has turned up evidence for 280 previously unidentified lunar craters, many on the near side.

The discoveries were made using gravitational mapping techniques used on Earth to identify possible mineral bodies. These were then compared with topographic information to see if there might be a crater obscured under other features. Of these, 66 appeared visible on both tests, while topographic data were inconclusive for the rest.

“They’re not that distinct,” explains Prof Will Featherstone. “Some people have suggested some of these might be there, but we needed gravitational anomalies for corroboration.

“The best analogy is that it is like turning down the base and turning up the treble on speakers,” Featherstone says. “On the far side of the Moon there is a huge basin which our technique removes, so we can see more detailed features.”

While most lunar craters are caused by meteor strikes, some may be of volcanic origin. Featherstone says that nothing is known about the origins of the newly discovered objects. The largest crater was 300 km in diameter, while the smallest were around 100 km.

Satellites on the far side of the Moon cannot be tracked directly from Earth, so the small wobbles in height caused by passing over territory of greater or lesser gravity went undetected until a relay satellite placed near the Moon allowed real-time recording of what occurred as probes explored the far side.

The International Astronomical Union (IAU) will have the task of deciding which of these craters are certain enough to deserve names, and then allocating monikers to them. However, since the IAU’s rules that astronomers can only be honoured in this way after they are dead, Featherstone says he is very keen not to have any named after him.