Here’s a very nice movie showing the stars in the Solar neighbourhood (defined to be within 100 parsecs of the Sun) with positions and colours mapped by the European Space Agency’s Gaia mission.
P.S. The video is timed to coincide with Gaia’s third data release: for more information about DR3 see here.
Follow @telescoperIt’s time I shared another one of those interesting cosmology talks on the Youtube channel curated by Shaun Hotchkiss. This channel features technical talks rather than popular expositions so it won’t be everyone’s cup of tea but for those seriously interested in cosmology at a research level they should prove interesting.
In this video, Eiichiro Komatsu and Yuto Minami talk about their recent work, first devising a way to extract a parity violating signature in the cosmic microwave background, as manifested by a form of birefringence. If the universe is birefringent then E-mode polarization would change into B-mode as electromagnetic radiation travels through space, so there would be a non-zero correlation between the two measured modes. They try to measure this correlation using the Planck 2018 data, getting a 2.4 sigma `hint’ of a result.
A problem with the measurement is that systematic errors, such as imperfectly calibrated detector angles, could mimic the signal. Yuto and Eiichiro’s idea was to measure the detector angle by looking at the E-B correlation in the foregrounds, where light hasn’t travelled far enough to be affected by any potential birefringence in the universe. They argue that this allows them to distinguish between the two types of measured E-B correlation. However, this is only the case if there is no intrinsic correlation between the E-mode and B-mode polarization in the foregrounds, which may not be the case, but which they are testing. The method can be applied to any of the plethora of CMB experiments currently underway so there will probably be more results soon that may shed further light on this issue.
Incidentally this reminds me of Cardiff days when work was going on about the same affect using the Quad instrument. I wasn’t involved with Quad but I do remember having interesting chats about the theory behind the measurement or upper limit as it was (which is reported here). Looking at the paper I realize that paper involved researchers from the Department of Experimental Physics at Maynooth University.
P. S. The paper that accompanies this talk can be found here.
Follow @telescoperI posted recently about the decision to close the iconic radio telescope at Arecibo. Well it seems the end has come more quickly than anticipated.
The instrument platform (which weighed 820 tonnes), normally suspended at a height of 150m, has crashed down into the dish causing catastrophic destruction.
Fortunately nobody was hurt. The telescope is however a goner.
P. S. For bonus marks, calculate the energy released by the collapse.
Follow @telescoperIt’s 1st December 2020 which means that it’s now been three whole years since I started my job as Professor of Theoretical Physics in the Department of Theoretical Physics at Maynooth University, in County Kildare in the Irish Republic.
Until the Summer of 2018 I was working part-time at Cardiff and part-time in Maynooth, which required a lot of flying to and from between Wales and Ireland. That situation would have been impossible to sustain during the pandemic for reasons of quarantine and also because FlyBe went bust. The timing of my move to Maynooth was providential in many ways apart from that.
I didn’t think it would take me the best part of three years to buy a house in Ireland, but owing to a combination of circumstances it took until the end of this summer to do that. Still, all’s well that ends well and I’m very happy with my home.
When I first arrived in Maynooth I stayed in St Patrick’s House (above), part of the Roman Catholic seminary on Maynooth University’s South Campus. I took this picture of the corridor I was on the night I arrived because it reminded me of The Shining:
The arrival of the Covid-19 Pandemic earlier this year has been another completely unexpected development. I wonder what fate has next in store?
In the Dark 