Moon’s tilt changed by volcanic activity over three billion years ago

https://www.theguardian.com/science/2016/mar/23/moons-tilt-changed-by-volcanic-activity-over-three-billion-years-ago?google_editors_picks=true

Huge volcanic activity over three billion years ago appears to have altered the tilt of the Moon, according to new research.

Scientists concluded that the celestial body may have once spun on a different axis after studying its north and south poles, and finding that lunar ice was deposited in unexpected locations.

“The discovery of ice on the poles of the moon was probably one of the most significant discoveries in lunar science ever,” says Dr Ian Garrick-Bethell from the University of California, who was not involved in the study. “This goes one step further.”

The researchers concluded that the moon’s axis of rotation is now 5.5 degrees different from what it once was as a result of volcanic activity, which stemmed from a region of hot rock lurking deep beneath its surface.

Orbiting the Earth at an average distance of 385,000km, the moon boasts some of the coldest spots in the solar system, with temperatures at its poles reaching below -240 C.

The revelation came after a US and Japanese research team took a fresh look at data collected by the Lunar Prospector neutron spectrometer in the late 1990s. Such data had previously been used to map the presence of hydrogen deposits on the lunar surface and, because water is rich in hydrogen, had led scientists to conclude that they were made of ice.

But scientists had been puzzled by that fact that deposits of hydrogen didn’t tally with what would be expected from current lunar temperatures.

The latest research suggests two of these deposits are not only offset from the moon’s current axis by around 5.5degrees each, but are diametrically opposite to each other. That, the authors of the new study conclude, suggests that these deposits mark “palaeopoles” – former north and south poles where ice formed billions of years ago.

This change in lunar tilt, the researchers suggest, could have been triggered by change in volcanic activity more than 3.5 billion years ago – a period when a region on the near-side of the moon known as the PKT erupted with the lava flows that formed the large, dark expanses of basalt visible from Earth.

As the mantle deep within the moon heated up, it expanded and decreased in density. According to models created by the authors of the new study, that could have been enough to change the moon’s tilt. “It is like taking a football and removing a chunk out of one side – that would change how the football would spin in the air,” said Keane.

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i blame global warming..

“This change in lunar tilt, the researchers suggest, could have been triggered by change in volcanic activity more than 3.5 billion years ago – a period when a region on the near-side of the moon known as the PKT erupted with the lava flows that formed the large, dark expanses of basalt visible from Earth.”

3.5 billion years ago eh?

401

~ by seeker401 on March 31, 2016.

3 Responses to “Moon’s tilt changed by volcanic activity over three billion years ago”

  1. Hello seeker.

    The Moon can be quite a surprise, despite being our nearest celestial neighbour. It seems reasonable-ish that the two ice deposits might have once been the location of ancient poles.

    As to what caused the shift (if in fact there was a shift, of course), it might have been the volcanic flooding of basalt lavas onto the lunar surface, from the lunar interior, geological ages ago. These basalt lavas are the dark splotches on the lunar surface, and that type of rock is more dense/heavier than the lighter rocks that make up the rest of the lunar surface. This redistribution of mass onto the lunar surface might have done something to alter the moon’s axial tilt…maybe.

    The change in axial tilt might also have come about from a massive impact. A suitably huge impact, such as the one that caused the huge South Pole-Aitken Basin might have done it. That impact basin is just about the largest impact crater in the solar system, and it appears to be very ancient.

    Anyway, who knows?

    All the best.

    Andrew Farquharson.

  2. I thought only an external force could do this since an internal force would have an equal and opposite effect – but I am maybe just showing off my knowledge of the cosmos with my secondary level 4 “o” level “c ” grade pass in science .

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