Archive for the Uncategorized Category

LIGO: Live Reaction Blog

Posted in Uncategorized on February 11, 2021 by telescoper

I don’t usually reblog my own posts, but this is just to mark the fact that the first discovery of gravitational waves by Advanced LIGO was announced on this day in 2016.

Can that really have been 5 years ago?

In the Dark

So the eagerly awaited press conference happened this afternoon. It started in unequivocal fashion.

“We detected gravitational gravitational waves. We did it!”

As rumoured, the signal corresponds to the coalescence of two black holes, of masses 29 and 36 times the mass of the Sun.

The signal arrived in September 2015, very shortly after Advanced LIGO was switched on. There’s synchronicity for you! The LIGO collaboration have done wondrous things getting their sensitivity down to such a level that they can measure such a tiny effect, but there still has to be an event producing a signal to measure. Collisions of two such massive black holes are probably extremely rare so it’s a bit of good fortune that one happened just at the right time. Actually it was during an engineering test!

Here are the key results:

LIGO

Excellent signal to noise! I’m convinced! Many congratulations to everyone involved…

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Armchair Critic

Posted in Uncategorized on January 29, 2021 by telescoper

Following the success of yesterday’s post, which has received several hits, I have decided to become an armchair critic.

Take this one for example:

I quite like the shape, but the upholstery is awful.

Stay tuned for further reviews.

The Song of the Dunnock

Posted in Uncategorized with tags , on December 6, 2020 by telescoper

It’s very cold and foggy today and there was a hard frost overnight, all of which wintriness made me go out and replenish the bird feeders. No sooner had I refilled and replaced the one that holds peanuts when I had a visitation from starlings, blue tits and even a jackdaw. There was a blackbird too, but that remained at ground level pecking at the frozen earth.

I was hoping to see my favourite garden visitor, whom I last saw a few days ago. This is the Dunnock (sometimes called a hedge sparrow, though it’s not a member of the sparrow family).

The Dunnock is a fairly drab-looking bird easily mistaken at for a House Sparrow at a quick glance. A quick glance is all you’re likely to get, in fact, because, although they’re not at all uncommon in Ireland, they are very shy. The one – I think it’s the same one – that visits my garden darts out from a hedge from time to time, grabs something from the lawn (presumably a bug of some sort), then darts back again and vanishes. It probably pays to be wary when you’re a bird that feeds on the ground. I’ve never seen it on any of the bird feeders, which contain seeds and nuts.

Anyway, I do enjoy seeing this critter when it makes an appearance. Although I don’t it very often I know it’s around as I hear its song very often. For a small bird it’s very loud indeed, and very distinctive. Here’s a recording:

That rapid-fire jumble of notes is very different from the song of a House Sparrow which is much simpler, consisting of a series of single notes at the same pitch.

Wrens are even smaller but are also very loud. As far as I know I haven’t had one of those in my garden yet.

The Arecibo collapse as it happened…

Posted in Uncategorized with tags on December 3, 2020 by telescoper

The Arecibo Observatory has released this dramatic footage of the recent collapse of the instrument platform on the telescope. Credit: Arecibo Observatory and the National Science Foundation.

The Arecibo Telescope is 57 years old. It suddenly occurred to me that so am I…

Arecibo Collapse

Posted in Uncategorized with tags on December 1, 2020 by telescoper

I 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.

Pictures from a Mediaeval Bestiary, No. 78 – The Snail

Posted in Uncategorized on October 17, 2020 by telescoper

Bird 100: Bird of Paradise

Posted in Uncategorized with tags , , on August 29, 2020 by telescoper

And so we come to the final post of the day in honour of the centenary of the birth of Charlie Parker, also known as `Bird’. I know a lot of people don’t really `get’ Bird’s way of playing, but for me he created some of the most beautiful and exciting sounds not only in jazz, but in any musical genre. Here is a piece called Bird of Paradise (a thinly disguised version of the Jerome Kern standard All The Things You Are) recorded in 1947 for the Dial label with a quintet that included a young (21 year-old) Miles Davis on trumpet. Miles Davis was still finding his way musically at the time of the Dial sessions, but Bird had already established himself as a powerful creative force and his solo on this number is absolutely exquisite.

Anyway, that’s it for Bird 100 from me. I hope you enjoyed the posts. Normal service will be resumed tomorrow!

Lá Saoire i mí Lúnasa

Posted in Uncategorized on August 3, 2020 by telescoper

Today being the first Monday in August it is a Bank Holiday in Ireland. This holiday was created by the Bank Holiday Act of 1871 when Ireland was under British rule. While the holiday was subsequently moved to the end of August in England and Wales it has remained at the start of August in Ireland.

I was leafing through my diary yesterday, looking at all the deadlines coming up and wondering whether I could actually take today off*, when I got to thinking more generally about matters calendrical.

In the Northern hemisphere, from an astronomical point of view, the solar year is defined by the two solstices (summer, around June 21st, and winter around December 21st) and the equinoxes (spring, around March 21st, and Autumn, around September 21st). These four events divide the year into four roughly equal parts each of about 13 weeks.

Now, if you divide each of these intervals in two you divide the year into eight pieces of six and a bit weeks each. The dates midway between the astronomical events mentioned above are (roughly) :

  • 1st February: Imbolc (Candlemas)
  • 1st May: Beltane (Mayday)
  • 1st August: Lughnasadh (Lammas)
  • 1st November: Samhain (All Saints Day)

The names I’ve added are taken from the Celtic/neo-Pagan (and Christian terms) for these cross-quarter days. These timings are rough because the dates of the equinoxes and solstices vary from year to year. Imbolc is often taken to be the 2nd of February (Groundhog Day) and Samhain is sometimes taken to be October 31st, Halloween. But hopefully you get the point.

Incidentally, the last three of these also coincide closely with Bank Holidays in Ireland, though these are always on Mondays so often happen a few days away.

Anyway, it is interesting (to me) that the academic year here in Ireland is defined by these dates.

Usually the first semester of the academic year starts on or around September 21st (Autumnal Equinox) and finishes on or Around December 21st (Winter Solstice). Half term (study week) thus includes the Halloween Bank Holiday.

After a break for Christmas and a three-week mid-year exam period Semester Two starts on or around 1st February (Imbolc). Half-term is then around March 21st (Vernal Equinox) and teaching ends around May 1st. More exams and end of year business take us to the Summer Solstice and the (hypothetical) vacation.

So we’re basically operating on a pagan calendar.

The exception is, of course, the date of Easter, which is fixed by a mixture of solar and lunar considerations: Easter is celebrated on the first Sunday following the full Moon that occurs on or just after the spring equinox. This date moves about between March and April, which is very messy and inconvenient and should, in my opinion, be reconsidered.

*I decided on “yes”.

New Publication at the Open Journal of Astrophysics!

Posted in Uncategorized with tags , , , , on July 29, 2020 by telescoper

To celebrate yesterday’s news, I have great pleasure today in publishing another paper in The Open Journal of Astrophysics.

A reason to be especially pleased with this article is that this is our first publication in the Solar and Stellar Astrophysics category of astro-ph. It’s good to be spreading out beyond cosmology and extragalactic astrophysics which is where most of our papers appear.

The intriguing title of the latest paper is The one that got away: a unique eclipse in the young brown dwarf Roque 12. There’s also a blog post by one of the authors that tells the fascinating behind-the-scenes story of this paper.

The authors of the paper are Aleks Scholz (University of St Andrews, UK), Dirk Froebrich (University of Kent, Canterbury, UK); Koraljka Muzic (University of Lisbon, Portugal) and Jochen Eislöffel (TLS Tautenburg, Germany).

Here is a screen grab of the overlay:

You might notice that we now have the volume number appearing on the overlay, a change we requested recently from Scholastica.

You can find the arXiv version of the paper here.

God’s Little Cow

Posted in Uncategorized with tags , on June 8, 2020 by telescoper

The other day I discovered that Ladybird in Irish is Bóín Dé which means, literally, “Little Cow of God”. I thought it a strange name for this critter, then a friend told me (via Facebook) that the Welsh is buwch goch gota which means “short red cow”. A little googling then told me that the Russian is Bozhya korovka which is in literal translation the same as the Irish, God’s Little Cow.

The more general connection with God seen in Irish and Russian is presumably to do with the Ladybird being either cute or beneficial (or both): if you’re a gardener you will certainly appreciate the help that Ladybirds offer in eliminating aphids and other garden pests. They may look cute but they are voracious predators.

I am told that the `cow’ part of the name probably comes from the spots on a Ladybird, which resemble the black patches on the hides of certain breeds of cow.

I have known for a while that the Lady in the English Ladybird refers not just to any lady but to the Virgin Mary, allegedly because the most common type of Ladybird has seven spots and the number 7 is associated with Mary, as is the colour red. The original English term was “Our Lady’s Bird” which turned into Ladybird (or Ladybug in the United States).

The connection with the Virgin Mary is more explicit in the Danish Mariehøne (Mary’s Hen). I assume the Hen is because the Ladybird would have to be a bird that can fly but not all that well. In German the word for Ladybird is Marienkäfer (Mary’s Beetle). In Spanish it is Mariquita, which I assume also has a connection with the Virgin Mary though there is another term: Vaca de San Antón , which brings us back to cows again (Vaca is Spanish for cow).

The Italian word for Ladybird is Coccinella (from the Latin Coccineus, scarlet) which is also the scientific name; the family is Coccinellidae. The standard French for a Ladybird is Coccinelle, but older terms found in dictionaries include vache à Dieu (Cow of God again) and bête à bon Dieu.

I know Ladybirds are very widespread and, to a lesser extent, so are my readers, so I’d be very interested to hear what a Ladybird is in other languages (alongside a literal translation).