What is a Galaxy (QI style)?

I'm a big fan of QI, so it was fun when Brian Cox was on it recently and the whole show was peppered with astronomy.

I was amused to find them mention the interesting paper by Duncan Forbes and Pavel Kroupa in which they consider what the definition of a galaxy is. Luckily someone posted the segment on You Tube:



Earlier this year when they posted the discussion on the arxiv, Duncan and Pavel opened it up for a vote - in good "citizen science" style. Of course this caught my "Galaxy Zoo" eye so I blogged about it last Feb (2011).

It's on my mind tonight as I prepare to talk about "What is a Galaxy?" tomorrow night as part of the Intech Science Centre Adult Only Evening.

Comments

Post a Comment

Popular posts from this blog

Visiting Jodrell Bank as part of the UK National Astronomy Meeting

Image
I'm in Manchester this week at the UK National Astronomy Meeting . As part of this, yesterday evening I went on a visit to the Jodrell Bank Observatory, with 120 other astronomers. NAM Astronomers at JBO It was a gorgeous spring evening, and the disk looked lovely as a contrast to the beauty of spring around it. Jodrell Bank and a sheep The Sun through the dish Jodrell Bank and some daffodils Jodell Bank and spring blossom Jodrell Bank and a hedge of forsythia We got to walk under the dish too. Here we are crossing the track which the telescope uses to rotate in azimuth. Jodrell Bank azimuth track And we stood under the dead centre of the dish. Looking up at the base of Jodrell Bank That's me directly under the centre of the dish The sky was clear, and the crescent Moon was prominent, see if you can spot it through the dish below. Required picture of me with the dish We also got a tour of the control room - and the set of BBC Stargazing LIVE of course.  And we're astronomer...
Read more

What is Hoag's Object?

Image
Perhaps one of the most striking looking galaxies I know of is "Hoag's Object" (seen below by the Hubble Space Telescope;  NED information , Wikipedia article ,  lookUP information ). The wikipedia article talks of it as an object which fascinates both amateur and professional astronomers.  I am really curious to know how it might look through an amateur telescope, and I'd love to see it for myself some day (RA=15 17 14, Dec=+21 35 08 in the Serpens constellation), Astrometry.net can help give an idea - see Hoag's Object images on Flickr  found by the service. HST Image of Hoag's Object. Credit: NASA. Through HST as you can see the object appears to be made up of a red spheroidal core, surrounded by a blue ring of star formation (with a gap between the two). The ring shows some spiral structure. In my opinion, one of the most fun things about the object is the more distance ring galaxy which can be seen through the gap (just to the right of 12 o'clock)...
Read more

Modelling Data - Example using A-level Physics Gender Trends

Image
Love this blog post: " Brent and Levenberg-Marquardt: the bread and butter algorithms for postgrads " which uses data I collected as an example for modelling trends. I collected these data to include in an article I was invited to write for Astronomy&Geophysics on " Women of the future in the RAS ". In that article I conclude: "Fitting a straight line to this 60-year trend and dangerously extrapolating the poor linear fit into the future, we find that we can't expect gender equality in physics A-level until 2163." The data is not cheerful, and a linear increase model does not fit it well. In fact according Val Aslanyan 's best fit model, recent years show a decline in the fraction of A-level physicsists who are women.  Credit to Val Aslanyan (http://improbablematter.blogspot.com/2016/12/brent-and-levenberg-marquardt-bread-and.html) for this version of this plot.
Read more