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