Duncan Steel

Duncan Steel is a space scientist based in Nelson. He has worked in scientific research for over forty years, with times spent with NASA, ESA, various universities and observatories, and also running his own company. Duncan is the author of four books, over a hundred research papers, and more than a thousand articles for newspapers and magazines. He has also appeared in hundreds of radio and TV programmes. Minor planet/ asteroid (4713) Steel is named for him, as is a lunar-roving robot in one of Arthur C. Clarke's SciFi novels.

And so this is Christmas… - Out of Space

Dec 19, 2018

[avatar user=”duncansteel” size=”thumbnail” align=”right” /] The date of Christmas is a matter many find confusing, and yet the adopted anniversary is easy to understand if you follow through the history, astronomy and human biology that are involved.  Why is the Nativity commemorated on December 25th, when it is clear Jesus was not actually born on that date? And how can a year be termed “Before Christ” if he was born in that year? This is a topic that crops up often in the media and online discussions as the holiday (‘holy day’) season approaches… and yet I have never seen a correct explanation being given. The answers are a mixture of science (astronomy and physiology), religious observances and historical contingencies, but if one follows it through step by step it’s all quite simple. Before going further I should make clear … Read More

Skywatching southerners have chance to see selenelion this Saturday morning - Out of Space

Jul 26, 2018

A few minutes after 8am this Saturday those further south in New Zealand will have a once-in-a-lifetime chance to witness a rare celestial event: a selenelion (or selenehelion). What is that? It’s when the eclipsed Moon can be seen on one horizon, whilst the rising Sun can also be observed near the opposite horizon. One might think this to be impossible – because an eclipse occurs when the Sun, Earth and Moon are in a straight line, and so if the Moon is above the horizon then the Sun must surely be below it. But the bending (refraction) of the rays of light caused by our atmosphere makes it feasible to see both the eclipsed Moon and the Sun at the same time — so long as you are in the right place. The areas of our … Read More