AstroInformatics II: From public outreach to public engagement June 28, 2010
Posted by sarah in: science . 1 comment so far
Outreach and education are two areas that stand to gain from developments in semantic astronomy and an increased scientific presence on the web. Big changes have already taken place, driven by a community eager to connect and communicate about the research we do every day. As part of a panel at the AstroInformatics 2010 conference last week, I gave a talk on aspects of science communication and education that are benefiting from the semantic web.
The internet these days is a cacophony of conversations, opinions, visual information (and porn). Many scientists and science enthusiasts write about the stuff that inspires or excites them in blogs, like I do here, which allow them to connect to people they would never have encountered, let alone talked with, in real life. This has led to some great scientific content generated entirely by the science community itself, without intermediate brokerage by communication or media professionals. But in this symphony of chaos, how do we increase the signal to noise? How do we ensure that the best content is heard?
The Big Bang Debate June 12, 2010
Posted by sarah in: reviews, science, women . 5comments
A few days ago, I posted this poll about the show The Big Bang Theory, asking the question if it was bad for science (and women). I closed the poll last night, the votes are in, you people have spoken. Here’s the final results from 58 votes – and thanks for voting, polls are fun!
Most of you don’t seem to take sitcoms all that seriously, and that’s probably a sensible attitude. Also, quite a few of you think I should get a life. That’s probably also a fair statement. Beyond that, there’s about twice the number of BBT-lovers as there are BBT-haters, with a smattering of on-the-fencers. Well, you already know where I stand, but before I return back to the life that I do in fact have, let me elaborate.
Dear Fuzzies, Why So Green? May 21, 2010
Posted by sarah in: new astronomy . 3comments
Green fuzzies (Cyganowski et al, 2008 & De Buizer & Vacca, 2010)
Amongst all the excitement over the first results from Herschel, it’s easy to forget about its comparatively tiny American cousin Spitzer. Launched in 2003 with its 3 instruments IRAC, IRS and MIPS, Spitzer covers the infrared wavelengths from around 3 to 150 microns – a region that from Earth is either totally inaccessible or severely hampered by atmospheric absorption. With its 85-cm diameter primary mirror, it’s easy to dismiss Spitzer as belonging to a former era. But new science is coming out of Spitzer data every day, and vast quantities of data remain unpublished in the archives. The big legacy surveys in particular, such as c2d (Cores to Disks) and the galactic plane surveys GLIMPSE and MIPSGAL, have released a wealth of data into the public domain, throwing light on old problems and unveiling new mysteries to solve.
One interesting phenomenon witnessed on the images from the GLIMPSE survey was a curious population on extended green objects (EGOs). Catalogued by Cyganowski et al in 2008, these “green fuzzies” appear to be associated with regions of massive star formation – many of them lie in or very near to infrared dark clouds, known to harbour the earliest forms of massive star birth, or are associated with methanol masers, strong radio emission caused by excitation of methanol molecules by infrared radiation from dust. Their green colour is in a sense incidental, arising from the way we construct 3-colour images from the Spitzer camera IRAC. IRAC takes images in 4 channels, at 3.6, 4.5, 5.8 and 8 microns, and typically an red-green-blue image uses the 8, 4.5 and 3.6 micron data, respectively. In this picture, “green” indicates that the object has an unusually high flux in the 4.5 micron band.
A blast from a black hole’s past May 2, 2010
Posted by sarah in: new astronomy, science . 1 comment so far
A superluminal X-ray echo travelling through the Galactic Centre molecular clouds (Ponti et al, 2010)
For over a decade, through the ingenious tracking of stellar orbits in the galactic centre, we’ve known that a supermassive black hole weighing the equivalent of several million solar masses is lurking at the centre of our galaxy. But this discovery, while offering us the tantalising opportunity to study these enigmatic objects in our own back yard, raises many more questions.
One persisting puzzle has been the low luminosity of the black hole. The balance of inward and outward forces around an accreting object place a limit on its luminosity (the Eddington luminosity). As the SgrA* black hole is located in a densely populated part of our galaxy, we’d expect it to be accreting actively and therefore pretty bright. Instead, its luminosity is just 0.000001% of the Eddington limit – a factor of 10^8 lower. Yusef-Zadeh & Wardle give a good discussion of this phenomenon in this recent paper.
This has led astronomers to wonder: has our black hole always been this dim, or are we just seeing it in an unusually quiet phase, or are we missing something more fundamental? With some very cool X-ray observations stretching over almost a decade, Gabriele Ponti and colleagues have been able to uncover evidence of a very strong flare in SgrA*’s past, several hundred years ago.
Spreading Galaxies Gospel on Facebook April 11, 2010
Posted by sarah in: astro 2.0 . 7comments
Galaxy rotation curves: NOT flat (Noordermeer et al, 2007)
Paolo Salucci has a bone to pick with the community. The Trieste-based astronomer is fed up with his colleagues’ misconceptions about galaxy rotation curves and has decided to Do Something About It. In his short paper posted to astro-ph last Friday, he describes the experiment he’s set up to convince the world that galaxy rotation curves are not flat (oh sorry, that’s: NOT flat) – he has set up a Facebook group with plots, background, links and discussion, to orchestrate a change in the hearts and minds of astronomers around the world, to stamp out once and for all the damaging “hoax” of flat galaxy rotation curves.
Rotation curves describe how the rotation velocity in galaxies changes with increasing distance from the galactic centre. For spiral galaxies these curves are useful for learning about the galaxies’ matter distribution and, importantly, the presence of dark matter. But I’m not going to talk about rotation curves – it’s not my field and I’m happy to accept that they’re not flat.
