Archive | Talks RSS for this section

Ziggy Stardust and the Spiders from Mars – David Bowie was right! Part II

Today we have a guest post by Planet Four volunteer Peter Jalowiczor.

As a Planet Four contributor for a number of years this blog is a description of a presentation I recently gave at my local Astronomical society. It was based, of course, on my P4 work and included a preliminary discussion on Mars before starting on the focus of the talk – this project.  About two months earlier I had given a talk based on material provided by Meg so everyone was already familiar with the project as well as everyone involved. Here is how the second talk was structured.

Introduction to P4

P4 is a citizen science project designed to help planetary scientists identify and measure features on the surface of Mars, the images on the site are around the Southern polar region, an area of Mars that we know little about and the majority of which have never before been seen by human eyes!

Mars throughout the Ages

Following the introduction came a brief discussion of the history of observation from the first observations of planetary motion by Kepler and the first telescopic observations of Mars by Galileo, to maps (of Mars) by Christiaan Huygens, Giovanni Cassini on to Beer & Madler, Richard Proctor, Schiaparelli, Camille Flammarion and of course Percival Lowell and his famous Martian Canals. But, how was this all relevant to P4? The answer was that the HiRISE experiment on the MRO spacecraft was mapping areas around the South Pole…

Mars in the Solar System

How does Mars compare as a planet within the terrestrial group? Following a comparative overview of the five terrestrial bodies (including the Moon) in the inner Solar System.  In this group, Mars is intermediate in its properties. For example, compared to the largest body (the Earth) and the smallest (the Moon) it displays features on its surface, which are Earth-like: evidence of river valleys, lakes and the likelihood of an ancient Ocean in the Northern hemisphere. Whereas in the Southern hemisphere, the landscape is more primitive and cratered, more Moon-like. A discussion into why this was so and the importance of the surface area to volume ratio and its effect on planetary evolution across the terrestrial group. Mars’ properties in its own right was briefed.

The Planet Four Project

A detailed description of the project starting with the HiRISE experiment. From an altitude of 200 to 400 kilometers above Mars, surface images are acquired containing individual, basketball-size (30 to 60 centimeters) pixels, allowing features 1.2m to 2.4m across to be resolved. Large swaths of the surface are imaged: 20,000 x 126,000 pixels and the image is broken up into individual P4 tiles.


Citizen scientists mark dark fans and dark blotches that appear and disappear during Spring/ Summer around the South Pole of Mars. The dark fans and blotches appear in the Southern spring when the ice cap begins to thaw and sublimate back into the atmosphere. The fans and blotches then disappear at the end of the summer when there is no more ice left. How do these fans form, how they repeat from Spring to Spring? What does this tell us about the surface winds on the South Pole?  How would these features enable scientists to build-up a global map of wind-directions on Mars.

30 images (tiles) were shown from categories such as: #spiders, #fans, #blotches, #yardangs, #dendritic features, #Mars-has-the-blues…


Results of work carried out by myself. Occasionally, during classification, the #measurement tag was used by myself to measure various features within the tile. This started out as no more than an intention to log the size of features. After a few years a few hundred measurements had accumulated.

I found that:

  • This was biased towards the measuring of blotches.
  • 31-40m was the modal, or most commonly occurring size of blotch within the tile.
  • 10m-90m – fan sizes were grouped in this region.
  • Where the blotch, spider or fan went outside the range, an attempt was made to estimate its size.
  • The images of the tiles here ranged from ~150m x 200m to 366m x 475m.

However, the constraints of the tile parameters mean that the sizes may not be a true reflection of reality; and this was a simple experiment in science, The  results could be improved with a larger sample size (more measurements) particularly if measurements taken outside the tiles.


This image was taken with the Sun about 0 deg above the horizon and started a lot of discussions how these channels looked like ridges. Particularly with such a low Sun angle.


Linear venting. What evidence was there for cracking in the Martian surface? One member asked before this image came up and was discussed!


My favourite spider…


This is based on questions/ discussions, which came up both during and after the lecture.  Some I answered such as the linear venting (to the question below) as it was asked before the relevant slide came up! For some of the other questions I gave partial answers and we agreed that this should be forwarded on to Meg, and the Planet Four Science Team is going to answer these in a following blog post.

  • What evidence is there for cracking (of the ice) in the Martian surface?
  • Was there certainty that the channels were not ridges? (Yes, this is an optical illusion!)
  • Where does the blue colour come from?
  • Is the North Polar region of Mars going to be investigated in the same way as the South polar region?
  • What height are the geysers?
  • Is there an imaging dataset, perhaps an experiment on a satellite, which could enable these heights to be measured more accurately?
  • How often do we return to each of the imaged areas? Surely there must be some follow-up to see how the features have developed.

And finally!

The talk started with the good news of a certain Sagan Medal recipient and ended with the news that there was now an alternative to Mars bars with Martian cake, however this had to be refrigerated at Martian polar temperatures…

Ziggy Stardust and the Spiders from Mars – David Bowie was right!

Today we have a guest post by Planet Four volunteer Peter Jalowiczor.

Why Ziggy Stardust and the Spiders from Mars? As we know Ziggy Stardust is David Bowie’s alter ego, a rock star who acts as a messenger for extraterrestrial beings. Unfortunately, no extraterrestrial beings have been found on Mars (at the time of writing, at least!). But spiders have definitely been discovered…

From this then, as a Planet Four contributor for a number of years now, I recently put together a talk about the P4 Project to be given at my local Astronomical Society: the MSAS (Mexborough and Swinton Astronomical Society). The society is based about 20km from Sheffield (pop. 570,000), England and was founded in 1978. Every Thursday evening is a social occasion centered around a talk.  Members, such as myself are encouraged to give talks on different subjects. Usually once a month, an academic visits the society to lecture on an aspect of Astronomy. In March this year the MSAS held a ‘Back to Basics Workshop’ in conjunction with the BAA (British Astronomical Association).

Back to the talk: my initial presentation was to be a preliminary discussion about Mars in general, before focusing on the results (images) from the HiRISE (High Resolution Imaging Science Experiment).

After letting Meg know of my P4 talk, I was very kindly sent lecture materials over from Hawaii. and on June 1st did my best to interpret and present one of Meg’s lectures: ‘Exploring Mars with 150,000 Earthlings’. This was Meg’s lecture at the ‘Imiloa Astronomy Center of Hawaii  from February. It was an introduction to the Planet Four Project and collaboration with over 150,000 citizen scientist volunteers worldwide. Describing how, by the power of the internet, volunteers map the fans and other surface features formed by carbon dioxide jets helping planetary scientists characterize surface features on Mars. There was also a discussion of the other Mars projects: Terrains and Ridges and how people can get involved in exploring Mars from the comfort of their own home.


Photo courtesy: Jeremy Robinson, MSAS Member.

Photo courtesy: Jeremy Robinson, MSAS Member.

Photos from just before start of the lecture are included here. On an evening where I was competing against the British weather – but this time it was a very beautiful, warm sunny evening (something to be cherished in the UK) so the turnout wasn’t that bad. The society was very interested in the research carried out by the team and is grateful to Meg for the material.

A Zoominar

Greetings from Oxford, UK where the spires are looking lovely in the Autumn weather. I’ve been on a bit of a Planet Four talk tour this 2 weeks between WIRED2015 and the Bash Symposium. I’m spending a few days at the Oxford Zooniverse HQ before heading back to Taiwan. I’ll be spending some time working on a few projects while I’m here in Oxford including Planet Four and  especially on the next steps for Planet Four: Terrains data analysis.  I got asked to give a short Zoominar (the Oxford Zooniverse group’s seminar series) to introduce the motivations behind Planet Four and a quick status report of where we are with the project for the Zooniverse core team in Oxford and other interested folks. I thought I’d share my slides. The slide show below is adapted from my talk.

This slideshow requires JavaScript.