Happy Christmas and New Year – better late then never!

“We saw his star when it rose and have come to worship him.” Matthew 2:2 (NIV)

I’ve posted on the star of Bethlehem before (see here), but I’ve just come across some interesting thoughts by Greg Boyd that I’d like to share.  In my previous post I laid out three possible astronomical explanations for the ‘star’ of Bethlehem (1. a conjunction of Jupiter and Saturn, 2. a comet, 3. a supernova); at the time I concluded that none of them really fit the biblical account which says “… the star … stopped over the place where the child was.” (Matthew 2:9).  However, Greg Boyd explains that this is just a turn of phrase, like we might say “oh look at the moon over the mountains” – obviously the moon isn’t really stopped over those particular mountains!  He then goes on to summarise Molnar’s hypothesis (option 1 above) as being interesting and worthy of consideration.  Check out the short video:

Late, I know, for some reason was never published two years ago!!!

Best Films: Argo, Intouchables, Skyfall

Best TV Series: Call the Midwife, The Bridge, Sherlock (season 2)

Best Music: (Haven’t got to listen to as much music this year as I normally do) Lonerism by Tame Impala, An Awesome wave by Alt-J,

Major Events: New job as Assistant Professor at Trinity Western University, buying a house,

Best Drink: Ten Fidy by Oscar Blues

A large ice island has broken off the Petermann Glacier in northern Greenland.

NASA satellite image (MODIS).

This iceberg is about twice the size of Manhattan but approximately half the size of the previous recent break-off in 2010 (blog post here).  Unlike the 2010 event the current ice has broke off further up glacier and marks a retreat of the calving front of the glacier.  The crack and rift that led to this break off has been known and observed for some time and so this event was expected in this regards.  However, the question is still being asked as to how unusual these large calving events are and whether they were caused by climate change.  Certainly we can say that these changes have not been seen for at least a 150 years (see previous post and this discussion article).  However, we can’t say for certain that these two massive calving event are a direct result of climate change.  An interesting discussion on these questions is provided in this BBC article.

The Guardian has a little interactive page where you can watch the iceberg break off in context (click here).

Glaciologist Tim Creyts provides an insightful radio interview here.

The artist Gabo Guzzo has a new art project called The Geological Turn this project explores the Anthropocene and involves several contributors (most notably Paul Crutzen (Nobel prize winning Chemist) and Jan Zalasiewicz (Geologist and author)).  The residency was at Banner Repeater (which according to the Guardian is one of the best arts venues in north London) and the project continues to be hosted on the blog:

http://thegeologicalturn.tumblr.com/

My own contribution/response shown on the project blog is reproduced below.

The formula in the picture is a standard conservation of mass equation describing landscape evolution, essentially all Earth surface changes in one equation, e.g. uplift, erosion, sediment flux, etc [1].  These natural geomorphic processes operate over geological time periods shaping the landscape – mountain ranges etc.  However, humans have now become the leading geomorphic agents of landscape change [2].  For example, the current rate of sediment transport by humans ellipses that of glaciers and rivers combined.  This simple picture endeavors to capture this concept.  Humankind has literally bulldozed its way into a new geological era, the Anthropocene.

[1] W. E. Dietrich and J. T. Perron, The search for a topographic signature of life, Nature, 439, 411-418, 2006.

[2] R. LeB. Hooke, On the history of humans as geomorphic agents, Geology, 28, 843-846, 2000.

The sinking bubbles in Guinness and stouts in general have intrigued drinkers and scientists alike.  Research into this phenomena has been highlighted before on this blog (post linked here).  The latest research published in arxiv (academic paper linked here) demonstrates the importance of the shape of the glass in generating the fluid circulation necessary for the creation of the sinking bubbles.  Numerical simulations and experimentation show that the standard pint glass which has a narrower base cause the falling bubble effect whereas a glass that has a larger base does not i.e. results in rising bubbles.  Essentially the small (nitrogen, as opposed to carbon dioxide used in most beers) bubbles are being carried along by the local fluid motion in the glass and the shape of the glass influences the circulation of the beer as it is poured determining a sinking or rising bubble effect.  More explanation is provided in a BBC news article here.

What are climate models?  The UK Met. Office explains:

Here is our wonderful planet (or the northern hemisphere part at least!). Images taken from the Russian Elcctro-L satellite every 30 minutes are stitched together to make this video.

The geostationary weather satellite takes the highest resolution images of our planet, they are single shot photos. The images consist of visible and near-infrared wavelengths (e.g. vegetation is red not as the human eye sees it).

More details are provided here.