Mercury is SHRINKING! Stunning new images reveal planet is getting smaller due to tectonic activity

  • Nasa's Messenger spacecraft has spotted a series of small 'fault scarps'
  • These are cliff-like formations, and their size indicates they are young 
  • They formed as Mercury's interior slowly cools and the planet contracts

A series of cliff-like landforms discovered on the surface of Mercury suggest it is tectonically active, shrinking as the planet’s interior slowly cools.

While Earth was previously thought to be the only planet which currently hosts these processes, scientists are now saying this is not the case.

Images captured by Nasa’s Messenger spacecraft have revealed a number of ‘fault scarps’ much smaller than those seen in earlier observations, suggesting these structures are geologically young.

In the image above, the narrow linear troughs known as 'graben' have been found associated with small fault scarps (indicated with the white arrows). These form as the interior cools and the planet contracts, causing the crust to break and thrust upward

In the image above, the narrow linear troughs known as 'graben' have been found associated with small fault scarps (indicated with the white arrows). These form as the interior cools and the planet contracts, causing the crust to break and thrust upward

WHAT THEY FOUND  

The newly discovered scarps spotted during Messenger's low-altitude approach, are smaller than previously found formations, indicating they are much younger.

Fault scarps are cliff-like structures that resemble stair steps.

The researchers say the young scarps detected in the low-altitude images must be young in order to have survived a barrage of meteoroids and comets.

The new images were taken in the last 18 months of Mercury Surface, Space Environment, Geochemistry, and Ranging (Messenger) mission, during which the spacecraft lowered to an altitude that allowed for a much better look at the planet’s surface.

Fault scarps, cliff-like structures that resemble stair steps, have been found on the planet before.

But, the structures previously discovered during the flybys of Mariner 10 in the mid-70s and later confirmed by Messenger were massive, with some cliffs up to a hundred miles long, and some more than a mile high.

According to astronomers, these formed as the interior cooled and the planet contracted, causing the crust to break and thrust upward.

The newly discovered scarps, however, are smaller, indicating they are much younger.

‘The young age of the small scarps means that Mercury joins Earth as a tectonically active planet, with new faults likely forming today as Mercury’s interior continues to cool and the planet contacts,’ said lead author Tom Watters, Smithsonian senior scientist at the National Air and Space Museum in Washington DC.

A series of cliff-like landforms discovered on the surface of Mercury suggest it is tectonically active, shrinking as the planet’s interior slowly cools. While Earth was previously thought to be the only planet which currently hosts these processes, scientists now say this is not the case

A series of cliff-like landforms discovered on the surface of Mercury suggest it is tectonically active, shrinking as the planet’s interior slowly cools. While Earth was previously thought to be the only planet which currently hosts these processes, scientists now say this is not the case

The researchers say the young scarps detected in the low-altitude images must be young in order to have survived a barrage of meteoroids and comets.

As Mercury joins Earth as a tectonically active planet, researchers say the findings support recent studies which have shown that the planet’s magnetic field has existed for billions of years, and that the outer core is still hot – but slowly cooling.

‘This is why we explore,’ said Jim Green, Nasa Planetary Science Director.

‘For years, scientists believed that Mercury’s tectonic activity was in the distant past. It’s exciting to consider that this small planet – not much larger than Earth’s moon – is active even today.’

The small scarps on Mercury are similar in size to those seen on Earth’s moon, which also indicate shrinking may be underway.

Astronomers say that along with its contraction, the planet may also experience ‘Mercury-quakes, which could one day be confirmed with seismometers.

 

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