It seems as if the more we try to find out about the moon, the less we know about it. Even after centuries, our only satellite continues to surprise mankind. For example, findings of water on the moon were regarded as the greatest discovery ever made, but now there is fresh evidence that may topple that—since the satellite is more alive than it appears to be.

Similar to a science fiction story from the early ’50s, scientists have discovered that our moon is shrinking—but not in an outlandish or strange way. On the contrary, it is quite normal and expected. But what wasn’t expected, and caught the scientists off-guard, was the rate at which it was shrinking.

In its early days, the moon was a molten piece of mass which was regularly bombarded with asteroids and meteorites, and continued to be in a molten form for a while. During this time, as it cooled, it also shrank in size and, according to Nasa’s Lunar Reconnaissance Observer (LRO) website, the mantle and surface crust began to adjust to the changes, forming thrust faults. This geological formation occurs when a layer of the moon's surface slides over another layer. This shrinkage is normal and expected of any celestial body in its early days. Such formations are common in other ‘worlds’ in our solar system. Planets like Mercury have larger structures of thrust faults most of which cover hundreds of miles and can reach up to a mile in height.

What surprises scientists is the fact that the shrinkage of the moon continued and can be traced back to as early as 100 million years in the past. In human terms, this seems a lot of time, but in geographical terms it is miniscule. It is during this time, it is estimated, that the moon has shrunk some 300 feet.

"We estimate these cliffs (which are actually fault lines), called Lobate scarps, formed less than a billion years ago, and they could be as young as a hundred million years," explained Dr Thomas Watters of the Centre for Earth and Planetary Studies at the Smithsonian's National Air and Space Museum, Washington, as quoted on the Nasa LRO website. In human terms, it is less than 25 per cent of the moon's current age of more than four billion years. "Based on the size of the scarps, we estimate the distance between the moon's centre and its surface shrank by about 300 feet," added Watters.

Nasa believes that this activity is fresh, and that our satellite could have begun reducing only recently. During the Apollo manned missions, astronauts planted several seismometers, instruments used to detect quakes, on the lunar surface. These seismometers have lately detected moonquakes. And although the quakes can be attributed to meteorite strikes, Earth’s gravitational pull and temperature changes, there is also a remote possibility that these moonquakes are associated with ongoing scarp formations.

This recent discovery was confirmed by the LRO, the satellite partially responsible for the discovery of water on the moon. But how exactly did the LRO discover that the moon was shrinking?

The satellite discovered ridges, cliffs and fault lines, similar to what we find on Earth, on the surface of the moon. These fault lines—which are known as Lobate scarps—were also discovered by the manned Apollo missions, but those missions mapped only 20 per cent of the moon’s surface, compared to the LRO which has a much more detailed observation.

In coming years, Nasa and its team hopes to utilise the LRO’s multitude of tools and cameras to build up a highly detailed map of the moon. By mapping the distribution and determining the size of all lunar surface activity, tectonic and thermal history of the moon can be reconstructed over the past billion years. A much more complete lunar map could be drawn up to reflect new changes and formations which are due in particular to the Earth's gravitational pull.

Eventually, man plans to make our moon a home away from home. Therefore, it’s imperative to understand the changing ‘moonscape’. Every little bit of information helps, and for that there are many exciting missions planned by many nations in the very near future.