The Rings Of Saturn And It’s Moon, Enceladus.

For comparison purposes

Stunning, trippy 1970s NASA concept art for future space colony designs. Available (plus many more) in super hi-res here (and copyright free), for all your desktop wallpaper and/or prog-rock album cover needs. (via io9)

Curiosity descends

Where did the Moon come from?

The Moon is about 40 to 140 million years younger than the Earth and its geology offers broad hints that it was formed in an impact. This is called the giant impact hypothesis.

Nobody can be sure what actually happened, but computer simulations provide some clues. In one simulation, the newly-formed Earth suffers an impact with another planet (called Theia, a little larger than Mars). Theia is torn apart, its core dragged down through Earth’s interior to merge with the Earth’s core. Much of Theia’s mantle is absorbed into Earth’s mantle, and the side of Theia furthest away from the impact is hurled into space. About half the material ejected by the collision is lost and the rest accretes to form the Moon.

The Earth’s axis is tilted, and it is left spinning faster than it does today. A day lasts about ten hours. Months are much shorter too, as the new Moon orbits the Earth much faster. It is also much closer. Had there been anyone on Earth to observe it, they would have glimpsed a Moon twice the present size in the Earth’s primitive sky.

The Moon has since slowed the Earth’s spin, and it is moving away from us at a rate of almost 4 centimetres a year.

You can learn more about the birth of our Moon via Origins: The Scientific Story of Creation by Jim Baggott, or by following #BaggottOrigins across social media.

Image: Moon, by Yutaka Tsutano. CC-BY-2.0 via Flickr.

A solar eclipse (left) happens when the moon gets in the way of the sun’s light and casts its shadow on Earth. During a lunar eclipse (right), Earth gets in the way of the sun’s light hitting the moon.

Toute la nuit sous la lune ronde à faire le tour de l'étang

Bashô / © Pascal Picco, Pleine lune du mercredi 8 avril 2020

https://player.vimeo.com/video/11386048?title=0&byline=0&portrait=0&app_id=122963

Jennifer Daniel

Vote for Place of the Year 2015

Was 2015 the year of Pluto? Or does its exit from the Eurozone make Greece Place of the Year? Now is the time to vote and tell us which place made the most history this year.

In the meantime, reflect on 2014 Place of the Year, Scotland.

Image: Public Domain via Wikimedia Commons.