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.

The day the Sun stood still - Out of Space

Jun 25, 2019

[avatar user=”duncansteel” size=”thumbnail” align=”right” /] We have just passed the solstice, the shortest day of the year in the southern hemisphere. From now on, the hours of daylight will get longer through until the December solstice. Here I discuss why the June solstice occurs a few days before the Feast Day of St John the Baptist, the traditional time of ‘midsummer’ in the northern hemisphere (and the reason for the festivities depicted by Shakespeare in the comedy whose title includes that word). There is also a serious side to this: few people (including many climatologists) seem to realise that the durations of the seasons are varying, and this might be a significant factor to encompass in climate change studies; quite apart from that, analysis of historical climate records should take into account the fact that the seasonal cycle was, until … Read More

Murchison and geology - Out of Space

Jun 19, 2019

[avatar user=”duncansteel” size=”thumbnail” align=”right” /] There are many places, both in New Zealand and elsewhere around the globe, that are named for the nineteenth-century Scottish geologist Sir Roderick Impey Murchison. It seems astonishing how many of these are connected in some way with events of geological significance, or are otherwise of scientific importance.  One of my predilections is writing blog posts prompted by the occurrence of some sort of anniversary. In recent weeks I have noted the centenary of the total solar eclipse of 1919, which demonstrated the veracity of Einstein’s General Theory of Relativity; the 250th anniversary of the observation of the transit of Venus by James Cook and his accompanying scientists from Tahiti; and the annual recurrence of Bloomsday. This week I have, however, missed the 90th anniversary of the Murchison earthquake of 17th … Read More

Astronomy on Bloomsday - Out of Space

Jun 16, 2019

[avatar user=”duncansteel” size=”thumbnail” align=”right” /] The name of Michael Faraday is well-known in science, for his pioneering work in both chemistry and physics (in particular electricity and magnetism; hence the name of the SI unit of capacitance, the farad). As a postgraduate student at the University of Canterbury I spent many hours working on experimental radio receivers sat inside a large metallic box known as a Faraday cage,the function of which was the exclusion of extraneous radio signals. Quite apart from his scientific discoveries, there is something else that has been passed down to me from Faraday. He was a renowned public speaker, and one of his cardinal rules for giving a lecture was this: Never begin a talk with an apology. How true that imperative is. Many, many times I have sat in an audience and … Read More

Connecting comets and rubber - Out of Space

Jun 11, 2019

[avatar user=”duncansteel” size=”thumbnail” align=”right” /] Comet Grigg-Skjellerup was one of the first such celestial bodies to be visited by a spacecraft, the Giotto probe which was sent on to encounter it in mid-1992 after having first visited the famous Comet Halley in 1986. Comet Grigg-Skjellerup was discovered about a century ago, independently by a New Zealander (John Grigg) and an Australian (Frank Skjellerup). The younger brother of the latter (George Skellerup) moved to New Zealand in 1902, and established the iconic NZ rubber company.  It being my birthday, I thought that the occasion should be marked with a blog post. But about what? My quandary was solved when my partner Jan presented me with a splendid pair of gumboots. And here they are:   Now, perhaps (like the BBC) the Science Media Centre might eschew any … Read More

The problem of knowing when a lunar year begins and ends - Out of Space

Jun 05, 2019

[avatar user=”duncansteel” size=”thumbnail” align=”right” /] The Islamic fast of Ramadan has come to an end, marking the beginning of the tenth month of the religion’s twelve-lunation year and therefore Eid al-Fidr, the ‘Festival of Breaking the Fast’. How the decision is made when each of those months begins and ends depends upon the actual sighting of the crescent new moon in the sky, a highly-complicated matter that is briefly explained here.  Most of us are habituated to the use of a calendar based on how long it takes the Earth to orbit the Sun (for present purposes, a ‘solar year’), and it is such a system that is used as the global standard in all but a few places (such as North Korea) for ease of international communications. Very often people refer to this as the ‘Gregorian calendar’, but it … Read More

The 250th anniversary of Cook’s observation of the transit of Venus - Out of Space

Jun 02, 2019

[avatar user=”duncansteel” size=”thumbnail” align=”right” /] On June 3rd occurs the 250th anniversary of the transit of Venus across the face of the Sun, the observation of which was the prime purpose behind the expedition of HM Bark Endeavour to the South Pacific, under the command of Lieutenant James Cook. Following the measurements of the transit made by Cook and the mission’s scientists in Tahiti, the Endeavour sailed west, leading to the claiming of New Zealand and then eastern Australia by the British.  It happens that I have a particular – some would say peculiar – interest in calendars. This manifests itself in various ways, one of which is finding an excuse to have a celebratory drink on just about any day of the year. Last week I wrote about why 29th May is a special date, last Wednesday … Read More

The Great Eclipse of 1919 - Out of Space

May 29, 2019

[avatar user=”duncansteel” size=”thumbnail” align=”right” /] Measurements of photographs obtained during the total solar eclipse of 29th May 1919 were pivotal in demonstrating the veracity of Einstein’s General Theory of Relativity, turning him into a household name. The centenary of that event is now upon us, and well worthy of being remembered.  As I sit here typing on my keyboard, my favourite photo showing myself and my two sons aged 6 and 4 is beside me on the desk. I can tell you precisely where the photograph was taken: we were fossicking for crabs and shrimps in rockpools at St Michael’s Mount in Cornwall, England. I can also tell you the precise date: it was the tenth of August, 1999 – almost two decades ago. The reason I can recall the date so easily is that the times of total solar … Read More

A new crater on the Moon - Out of Space

May 21, 2019

[avatar user=”duncansteel” size=”thumbnail” align=”right” /] The scar on the lunar surface produced when the Israeli space probe ‘Beresheet’ slammed into the Moon on April 11 has just been spotted using an orbiting NASA satellite.  Three nations have so far landed spacecraft on the Moon: the USA, the Soviet Union/Russia, and China. A fourth nation, Israel, has attempted to join this club, but its probe (named Beresheet) made a hard rather than a soft landing six weeks ago. Now detailed images of the lunar surface obtained using NASA’s Lunar Reconnaissance Orbiter (LRO) have been scoured and the crash site identified. Beresheet (Hebrew for ‘In the beginning’, the first words in the biblical Book of Genesis) was built and operated by Israel Aerospace Industries on behalf of SpaceIL, a non-profit organisation founded in 2011 with the specific aim of landing a … Read More

Talking satellites and space in Washington - Out of Space

May 16, 2019

[avatar user=”duncansteel” size=”thumbnail” align=”right” /] The annual beanfeast for the US satellite industry — featuring major participation from European nations and companies in particular — is the SATELLITE congress held at the Washington Convention Center, a few blocks from the White House. It was an amazing event to attend, compared to the sort of low-key conferences we have in New Zealand.  Now I’m back in NZ and almost recovered from the jetlag, a few pieces of information about the SATELLITE 2019 convention that I attended last week in Washington DC. Starting at the beginning, the keynote talk on the opening day was by the Vice-President, Mike Pence. I decided I could miss that, as he would not be saying anything not known already, and the security-check lines were long. Yes, the US will be proceeding with the development of … Read More

Imagine an asteroid impact due in 2027: How would you tackle it?   - Out of Space

May 09, 2019

[avatar user=”duncansteel” size=”thumbnail” align=”right” /] It’s now scientifically possible to predict potential asteroid impacts years in advance. But knowing that such a calamitous event is going to occur, due to the clockwork of the heavens, presents its own problems. Can we divert it, and if so, how? Similarly, if the impact is inevitable, can we model what is going to happen far ahead of time, and so plan better for this rude intrusion into global affairs?   In my preceding blog post I described the Planetary Defense [sic] Conference (PDC) that I was attending at the University of Maryland: a biennial meeting about the hazard posed to humankind by asteroids and comets, which we know strike the Earth from time to time with calamitous consequences. Just ask the dinosaurs. Smaller objects than the 10 km leviathan that saw … Read More