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.

Lunar landing by Indian space probe - Out of Space

Sep 06, 2019

All being well, the Indian space probe Chandrayaan-2 now in orbit around the Moon will drop its lander safely and softly onto the surface on Saturday morning. The lander (named Vikram) will then roll out its rover (Pragyan), which it is hoped will prowl around for the next two weeks before the cold of the lunar night closes it down. The parent orbiter should continue to function for the next year, mapping the lunar surface and making other measurements of the space environment.  Life-off for Chandrayaan-2 on July 22nd. Photo: ISRO. Following its launch on July 22nd (above), the Chandrayaan-2 mission (a follow-up to Chandrayaan-1, which flew to the Moon a decade ago) has been following a path that many would find peculiar. For a direct path to the Moon, a vast amount of energy is needed. Read More

An invitation to name a star and a planet - Out of Space

Sep 04, 2019

The International Astronomical Union (IAU) — the global organisation of professional astronomers — is marking its centenary this year by inviting different nations to propose names for both a distant star, and a planet found to orbit it (a so-called exoplanet). Anyone can suggested a moniker, for the star, for the planet, or both. So: calling all New Zealanders to suggest names suitable for ‘our’ celestial pair! Let me begin by saying that I will not be proposing names myself, as I’ve had the privilege already of labelling many minor planets (usually called asteroids, but the IAU prefers the ‘minor planet’ terminology). My sons (5263 Arrius and 6828 Elbsteel) are spoilt, as are my parents, siblings, and the little town where I was born, amongst others. It is not the done thing to suggest one of … Read More

The fires in Brazil in satellite imagery: Part 1 - Out of Space

Aug 31, 2019

The numerous fires now burning in Brazil have been much-discussed of late, with world leaders complaining that the nation’s authorities allowing such clearing of land is highly detrimental to international efforts to limit the release of more carbon dioxide into the atmosphere, with the potential to exacerbate anthropogenic global warming/climate change. In this post I illustrate how such fires may be identified, and analyses conducted of the areas that have been (or are being) burnt, using freely-available satellite imagery collected at various wavelengths across the visible, near-infrared and shortwave-infrared parts of the spectrum.  Over the past couple of weeks there has been intense media coverage of the widespread fires burning in Brazil. Last Friday (August 22nd) I was asked by the good people at the NZ Science Media Centre to provide comments on the utility of satellite imagery in … Read More

Remembering Apollo 11 - Out of Space

Jul 18, 2019

There are lots of ways of remembering the Apollo project, which resulted in a dozen men walking on the lunar surface (and some of them even driving around in their lunar buggies). Here I show a few of them, dear to my heart.  You may not have heard, but this weekend marks the 50th anniversary of Apollo 11, when we humans first walked on the Moon. That happened on July 20th Universal or U.S. Time, though it was already July 21st over this side of the International Date Line. Earlier today (Thursday 18th) I was delighted to go to the Nelson Provincial Museum to film a short clip for the forthcoming Kura Pounamu exhibition, which runs for two months from August 24th, and an associated My Taonga social media campaign. I was asked to show something special to … Read More

Apollo 11 and the Real Dish - Out of Space

Jul 16, 2019

The TV pictures of Neil Armstrong clambering down the ladder of the Apollo 11 Lunar Excursion Module and taking the first steps by a human on the Moon’s surface are rightly iconic, though rather fuzzy. Most people seem to think that those images were received by the radio telescope at Parkes in New South Wales, largely because that was what was depicted in a popular Australian movie entitled ‘The Dish’. The truth, however, is that those pictures were grainy in part because they were actually received using a rather smaller antenna, located at a tracking station close to Canberra that few people have heard about: Honeysuckle Creek.  Whenever a movie appears on TV and it starts with a statement that it is “Based on a True Story”, I switch it off (or at least leave the room, so as to … Read More

The Equation of Time - Out of Space

Jul 14, 2019

The solstice on June 22nd marked the shortest duration of sunlight (or day length) during this year. One might have expected that from that date sunrise would have started getting earlier; and prior to that date sunset to have been consistently getting earlier (as the daylight duration was shortening). In fact the latest sunrise did not occur until almost a fortnight after the solstice, whereas the earliest sunset happened around a week before the solstice and so began progressing later before the solstice was reached. The reason for these surprising facts are all tied up with the equation of time, a graph of which is shown on many good sundials. But what causes these apparent discrepancies, to which we are largely oblivious?  It had been my intention to write this blog post on July 5th, for reasons that will become … Read More

Orbits of the satellites launched by Rocket Lab three days ago - Out of Space

Jul 02, 2019

On Saturday June 29th Rocket Lab launched another cluster of seven satellites into low-Earth orbit from the Mahia Peninsula in New Zealand’s North Island. In this blog post I illustrate the orbital paths of the ten resultant tracked items now in orbit.  In a blog post last week (June 27th) I showed the orbits of the various satellites launched by Rocket Lab through to that date. Following the launch last Saturday I added a note to that post, as follows: Update (June 30th): Congratulations to Rocket Lab on another successful launch yesterday. I will post here graphics and a movie of the orbits of the seven deployed satellites as soon as possible (perhaps a few days). The present post fulfills that promise (or maybe it was a threat…). The June 29th launch was given the name Make It Rain. Information … Read More

Asteroid Day… and what may follow - Out of Space

Jun 30, 2019

The Tunguska explosion in 1908 was due to the arrival of a small (perhaps 50 metre) cosmic object, quite likely a fragment of a known comet. Astronomers are now wondering whether siblings of that projectile might pass close by the Earth over the next week or so.  I write tonight on Asteroid Day, which occurs on June 30th each year: the anniversary of the Tunguska event in 1908. All around the globe there are meetings, talks, TV and radio shows, and newspaper articles, discussing the hazard that asteroids and comets pose to our civilisations. All around the globe, perhaps, but with little happening in New Zealand. Here on the Sciblogs website I have published two items of late concerning what we are doing about this surprising risk: Defending the planet from asteroids and Imagine an asteroid impact due … Read More

Tracking satellites launched from NZ - Out of Space

Jun 27, 2019

With so many thousand satellites now in orbit, and tens of thousands of other tracked items, one might think that it is difficult keeping tabs on them, simply as an interested person. In fact it is quite straightforward, with long lists of orbital elements freely available for all except the few satellites deemed by the US Government to require secrecy, and of course one might find information about those in other ways. There are also many applications available to peruse what might be passing overhead at any time, plus sophisticated software tools that are free and make use of the very best algorithms for following how the various orbits alter over weeks and months.  In a press release issued yesterday the NZ Space Agency has announced that it has partnered with US company LeoLabs on a “project which … Read More

The day the Sun stood still - Out of Space

Jun 25, 2019

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 about 70/80 years ago, apparently … Read More