I’ve had a very busy day today and am now about to dash off again so I’ll just post this picture to see if anyone can guess what the mystery object is..
Answers through the Comments Box please!
Follow @telescoperResults from the Event Horizon Telescope
Posted in Astrohype, The Universe and Stuff with tags black hole, Event Horizon, Event Horizon Telescope on April 10, 2019 by telescoper
Following yesterday’s little teaser, let me point out that there is a press conference taking place today (at 2pm Irish Summer Time, that’s 3pm Brussels) to announce a new result from the Event Horizon Telescope. The announcement will be streamed live here.
Sadly, I’m teaching at the time of the press conference so I won’t be able to watch, but that doesn’t mean that you shouldn’t!
I’ll post pictures and comments when I get back. Watch this space. Or you could watch this video..
UPDATE: Well, there we are. Here is the image of the `shadow’ of the event horizon around the black hole in M87:
The image is about 42 micro arcseconds across. I guess to people brought up on science fiction movies with fancy special effects the image is probably a little underwhelming, but it really is an excellent achievement to get that resolution. Above all, it’s a great example of scientific cooperation – 8 different telescopes all round the world. The sizeable European involvement received a substantial injection of funding from the European Union too!
Other parameters are here:
The accompanying EU press release is here. Further information can be found here. The six publications relating to this result can be found here:
- Paper I: The Shadow of the Supermassive Black Hole
- Paper II: Array and Instrumentation
- Paper III: Data processing and Calibration
- Paper IV: Imaging the Central Supermassive Black Hole
- Paper V: Physical Origin of the Asymmetric Ring
- Paper VI: The Shadow and Mass of the Central Black Hole
The Shadow of an Event Horizon
Posted in The Universe and Stuff with tags arXiv:1311.1841, black holes, Event Horizon, Gravitational Lensing, M87, Messier 87 on April 9, 2019 by telescoper
There is a paper on the arXiv written about 5 years ago called Towards the event horizon – the supermassive black hole in the Galactic Center by Falcke and Markoff, the abstract of which reads:
The center of our Galaxy hosts the best constrained supermassive black hole in the universe, Sagittarius A* (Sgr A*). Its mass and distance have been accurately determined from stellar orbits and proper motion studies, respectively, and its high-frequency radio, and highly variable near-infrared and X-ray emission originate from within a few Schwarzschild radii of the event horizon. The theory of general relativity (GR) predicts the appearance of a black hole shadow, which is a lensed image of the event horizon. This shadow can be resolved by very long baseline radio interferometry and test basic predictions of GR and alternatives thereof. In this paper we review our current understanding of the physical properties of Sgr A*, with a particular emphasis on the radio properties, the black hole shadow, and models for the emission and appearance of the source. We argue that the Galactic Center holds enormous potential for experimental tests of black hole accretion and theories of gravitation in their strong limits.
Please note that the black hole in the centre of the giant elliptical galaxy M87 is about 1000 times further away from us than the black hole in the centre of the Milky Way but is also about 1000 times more massive, so its Schwarzschild radius is 1000 times larger. The observational challenge of imaging the event horizon is therefore similar in the two cases.
You may find this useful if, by sheer coincidence, there is some big announcement tomorrow..
Follow @telescoperGravitational Wave Flash!
Posted in The Universe and Stuff with tags Advanced LIGO, Binary Black Holes, gravitational waves, LIGO, S190408an on April 9, 2019 by telescoperThe third observing run for Advanced LIGO – O3 – started on April 1 2019, after 19 months upgrading the detectors. Last night, April 8, saw the first new detection of a candidate gravitational wave source, apparently another black hole binary, dubbed S190408an.
It is anticipated that sources like this will be discovered at a rate of roughly one per week for the (planned) year-long run. Given the likely rate of events the policy of LIGO is now to make data publicly available directly without writing papers first. You can find the data entry for this event here, including this map of its position.
Whether the LIGO Scientific Collaboration will release sufficient data for others to perform a full analysis of the signal remains to be seen, but if the predicted detection rate matches reality, the field is going to move very rapidly from studies of individual events to statistical analysis of large populations. Such is the way of science!
Follow @telescoperThis is not an Animation…
Posted in Art with tags optical illusion, Yurii Peripedia on April 8, 2019 by telescoper
To find out more about this optical illusion, which was created by Yurii Peripedia using nothing more complicated than Adobe Illustrator, see here.
Follow @telescoperThe Arthritic Cosmological Principle
Posted in Biographical with tags arthritis, knees on April 7, 2019 by telescoperWhen I attended a meeting recently quite a few people expressed concern about my health given that I turned up with a walking-stick. I’ve actually been using one on occasions for quite a few months now, and it may well become a regular accessory, so to avoid anyone else I meet wondering what’s going on I thought I’d post a brief explanation.
Over the past six months or so I’ve had an increasing problem with swelling and stiffness in my knees. This is worst in the morning when I’ve just got out of bed, in which situation my knees are invariably bright red.
You can see what I mean in the picture here (viewer discretion advised). The stiffness sometimes makes me a bit wobbly on my pins and makes it a bit tricky dealing with stairs. I use the stick more for balance than anything else, and once I get going I can walk quite comfortably. I spent most of a day walking around Copenhagen without ill effects when I visited there in February.
I’ve been to the doctor several times about this and, although I’m still waiting for various test results, it’s clear that I have some form of arthritis. For the time being I’m just taking an anti-inflammatory drug which is quite effective at reducing the swelling. In due course I may be put on other medication, possibly involving a course of injections, and maybe even surgery. I’ll just have to wait and see about that.
The important thing is that, although I’m not exactly thrilled to have arthritis, I’m not in any real pain. It’s just a bit uncomfortable, that’s all, though that does make it hard to concentrate sometimes and it has impacted on my capacity to work long hours. I am sorry that I have missed some deadlines as a result.
You may or may not know that I used to run a lot when I was younger, including a few marathons and half-marathons. This has caused me some problems with my knees before, and I had minor surgery (arthroscopy) about 15 years ago to help with this. That procedure went pretty well, but I was warned that I was a relatively high risk for arthritis. It looks like the doctor wasn’t wrong! My running days are well and truly over, that’s for sure.
One other thing worth mentioning is that this condition does seem to be highly temperature-dependent. This last week the weather suddenly turned a lot colder and the arthritis definitely got worse. Perhaps in future I could learn to use the colour of my knees as some kind of forecasting method?
Follow @telescoperDer Englische Patient
Posted in Politics with tags BrExit, Der Englische Patient, Jürgen Tomicek on April 7, 2019 by telescoper
A challenge in the dark
Posted in Uncategorized on April 6, 2019 by telescoper
Cherokee – Clifford Brown
Posted in Jazz with tags Art Blakey, Blue Note, Cherokee, Clifford Brown, Jazz on April 6, 2019 by telescoperWell, I’ve been on duty all day so far at the Open Day I mentioned yesterday and am about to knock off and go home for a rest but first I thought I’d share this wonderful version of Cherokee, a tune that because of its complex chord changes is generally regarded as a test piece for jazz musicians. You’d never guess that from the ease that Clifford Brown shows as he tackles the 64-bar harmonic labyrinth at a breakneck tempo. If you want an example of jazz as a white knuckle ride, this is it!
Clifford Brown was a phenomenal virtuoso on the trumpet and it’s so sad that he died so young, at the age of 25, in a car accident. This performance was recorded in August 1953 and features an extended solo by Clifford Brown followed by a series of four-bar exchanges with the great drummer Art Blakey. Other principals are Percy Heath on bass and John Lewis on piano; Gigi Gryce (alto) and Charlie Rouse (tenor) also participate on the intro and outro. Enjoy!
Follow @telescoperTheoretical Physics at Maynooth University Open Day!
Posted in Education, Maynooth with tags Maynooth University, theoretical physics on April 5, 2019 by telescoperWell, tomorrow (Saturday 6th April) is an Open Day at Maynooth University. If you want to find out more about it you can look here where you will find this video which has some nice views of the campus:
I used to give Open Day talks quite frequently in a previous existence as Head of School of Mathematical and Physical Sciences at the University of Sussex and now I’m at it again, giving a talk on behalf of the Department of Theoretical Physics this Open Day. If you come along, please come along to my talk (at 14.10 on Saturday)!
We also have a stall in the Iontas Building from 10.30, where you can meet staff and students and talk to them about the course, or anything else vaguely related to Theoretical Physics. There are other stalls, of course, but the Theoretical Physics one is obviously way more interesting than the others!
Looking for fun pictures to put in my talk I stumbled across this:
I think that’s the only one I need, really!
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In the Dark 
