The Future of Extragalactic Observations from the Past

Posted in Biographical, The Universe and Stuff with tags , , , , , , , , , on December 27, 2021 by telescoper

The launch of the James Webb Space Telescope on Christmas Day triggered a memory that twenty years ago, in July 2001, I was an invited speaker at a Conference in Cape Town entitled The Early Universe and Cosmological Observations: a Critical Review. That meeting was preceded by the 16th International Conference on General Relativity and Gravitation in Durban which I also attended, but did not speak at. For the Cape Town meeting I was asked to give a talk about some of the things coming up in the future to do with observational extragalactic astronomy, though I was told to avoid the cosmic microwave background and galaxy redshift surveys as other speakers were covering those areas. At the time I was serving on the Astronomy Advisory Panel for the (now defunct) Particle Physics and Astronomy Research Council so I was keeping up with developments fairly well then.

Anyway, I wrote up my talk and it was published in 2002 in a special issue of Classical and Quantum Gravity, along with the other talks (which were more theoretical, as opposed to hypothetical). I never bothered to put in on the arXiv so if you want a copy you’ll have to get it from the publisher.

I’m not claiming it is a particularly insightful article – and I did refrain from giving specific timescales – but, looking back at it, it is interesting which projects I mentioned in the abstract actually did get completed in the following twenty years.

The European X-ray mission XEUS was never completed. It was proposed for a while to merge it with a rival US mission Constellation-X in the International X-ray Observatory (IXO), but that was cancelled in 2011/12 owing to budget constraints at NASA. An ESA X-ray mission, called ATHENA (Advanced Telescope for High ENergy Astrophysics, based to some extent on the XEUS concept, is pencilled in for launch in 2034.

At the time of writing the article, JWST was called the Next Generation Space Telescope (NGST) and was envisaged to be an 8m class telescope, though I did suggest in the article would probably be “de-scoped” to involve a smaller mirror “perhaps 6m or thereabouts”. As we now know, it was finally launched on December 25 2021 and has a mirror of diameter 6.5m.

GAIA was developed and launched in 2013 and will operate until next year; it has been a tremendous success.

The Overwhelming Large (OWL) Telescope was planned to be a huge ground-based telescope, with a 100m diameter mirror and a target timescale of around 2015, to be built by the European Southern Observatory in Chile. I remember in informal discussions we used to call it the FLT. It was eventually decided that was not technically feasible and it was downgraded to a merely Extremely Large Telescope, which has a 39m mirror, underwhelming in comparison. Construction is in progress and it should see first light in 2027.

As well as the ELT there are now also the Thirty Metre Telescope and the Giant Magellan Telescope, which will come into operation on a similar timescale.

The Atacama Large Millimetre Array (ALMA) consisting of 66 telescopes working as an interferometer was completed and has been fully operational since 2013. That too has been a great success.

The Square Kilometre Array (SKA) also had its share of cost overruns and technical delays and although initial construction plans have been developed it is not expected to be operational until 2027.

Probably the most notable omission from my list is the Large Synoptic Survey Telescope (LSST) now called the Vera Rubin Observatory. That wasn’t really within my horizon in 2001, although its planning phase had started then. It really got under way around 2008 and is now nearing completion. I certainly would have mentioned it had I known more about it at the time!

P.S. In case you’re wondering, the Euclid Mission due to be launched in early 2023 was very far from the drawing board in 2001 so I don’t apologize for not mentioning it!

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On Nominal

Posted in The Universe and Stuff with tags , on December 26, 2021 by telescoper

Yesterday’s launch of the James Webb Space Telescope reminded me of something I blogged about many years ago. At regular intervals during the launch we heard staff at Mission Control in Kourou saying that everything was “nominal”. As always when wondering about the meaning of words, I searched in the One True Chambers Dictionary, where I found:

nominal, adj relating to or of the nature of a name or noun; of names; by name; only in name; so-called, but not in reality; inconsiderable, small, minor, in comparison with the real value, hardly more than a matter of form…

So was the so-called launch of JWST only in name, but not in reality? Was it faked? Is the telescope real?

That reminds me that years and years ago I had an idea for a crime novel with a plot that revolves around the murder of a prominent cosmologist just as some important scientific discovery is about to be announced. Suspicion gathers that the whole thing is an enormous hoax and the discovery bogus. But the experiment is shrouded in secrecy, and was so expensive that it can’t easily be repeated, so  who can tell, and how?

I wouldn’t put it past some conspiracy theorist to argue that the data from JWST (assuming there is some) is manufactured.

It’s very difficult to know for sure whether any scientific discoveries are genuine or not, even if the data and analysis procedures are made public. There’s always the possibility that everything might have been fabricated or simulated, but in most cases the experiment can be repeated at a later date and the fraud eventually exposed, such as in the Schön Scandal.  In Big Science, this may not be practicable. However, Big Science requires big teams of people and the chances are someone would blow the whistle, or try to…

Anyway, I know that there are people out there who take everything I write on this blog absurdly literally so I’ll spell it out that I am in no way suggesting that the James Webb Space Telescope is a fraud. Or predicting that there’ll be a murder just before the first observations are released. Any similarity purely coincidental and all that. And I’ve never had time to write the book anyway – perhaps a publisher might read this and offer me an advance as an incentive?

Moreover, going back to the Chambers Dictionary, I note the final definition given there and omitted above i

…according to plan (space flight)

So that’s that. Nothing sinister. I’m not sure how “nominal” acquired that meaning, mind you, but that’s another story…

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Merry JWSTmas!

Posted in The Universe and Stuff with tags , , , , on December 25, 2021 by telescoper

Well it’s 10.20am on Christmas Day and I’ve got up specially early in order to be ready for the launch at 12.20pm today (Irish Time) of the James Webb Space Telescope from Kourou in French Guiana. The JWST project has been almost thirty years in the making and it is great that it is finally going to be heading into space. The launch however is just the start – JWST has a very complicated journey in front of it – as demonstrated by the following little video.

In particular, JWST should separate from the Ariane 5 launcher at about 27 minutes after takeoff so look out for that.

I have no direct personal involvement with JWST but I am still feeling a bit nervous. I can’t imagine how it must feel to have spent decades working on it. I know a great many astronomers around the world who are waiting anxiously and hoping all goes well. Fingers crossed!

If you want to watch the launch live you can do so on Youtube here:

You can find alternative viewing options here.

The launch window opens at 12.20 UTC and lasts for 31 minutes but I understand they’re going to launch as early as possible within that so it looks like we’re in for a launch before lunch rather than the other way round.

I’ll update with any news as the day goes on.

UPDATE: 12.28pm Launched right on time, everything nominal as JWST leaves Earth’s atmosphere propelled by Stage One of the Ariane 5.

UPDATE: 12.31pm Stage One jettisoned, Stage 2 ignition. All still nominal.

UPDATE: 12.48pm JWST has separated from the launch vehicle and is on its way. The solar panel is deployed and is working. The spectacular onboard video showing the separation of JWST from the Ariane 5 launch vehicle and the deployment of the solar panels was supplied by Irish company Réaltra.

P.S. I still think JWST should have had a different name.

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Reasons to be cheerful?

Posted in Biographical, Covid-19 on December 24, 2021 by telescoper

We’ve all been bracing for the arrival of the omicron storm here in Ireland. I has been like waiting for a tsunami know is coming and praying that the flood defences are strong enough to hold.

The wave now seems to be here, with 11,182 new cases reported today. That is by far the highest figure reported during the entire pandemic so far and it has dragged the 7-day average up to 6776.4 from yesterday’s figure of 5697.3.

I think it’s probably true to say the worst is yet to come. So far, though, the number of hospitalizations and deaths has not increased hugely; the former has, if anything been falling, and the latter is only rising slowly:

The number of Covid-19 related deaths reported in the last week was 55, which is an average of about 7.9 per day. We won’t know until the New Year whether the latest surge will drive these curves up.

There is some good news in that the omicron variant may be less likely to lead to severe illness than the delta variant. This is non-trivial to assess because one has to allow for factors other than the infecting variant (such as age, underlying health and vaccination status)  before one can see the true effect of this one variable. Comparing sickness and mortality rates now with earlier stages of the pandemic is virtually impossible for this reason. However, because the UK has allowed very large case numbers of both delta and omicron to occur for several weeks, there is enough data to see some difference between omicron and delta in hospitalization rates.

It also seems that while a booster seems to be needed to prevent infection by omicron, a standard two-dose vaccination still seems to be effective at preventing serious illness.

There are grounds for optimism, then. The problem as I see it is that if the number of people infected with omicron goes through the roof then there will still be lots of very sick people around, some of whom will die. Say a combination of vaccination and less severe variant reduces the mortality rate per case to 10% of what it was last January, which seems reasonable. If there are ten times as many cases, the number of deaths will be similar to last January so we’re still in for a terrible New Year.

We’ll just have to wait and see. I recommend staying as drunk as possible over the next week or ten days so as to avoid thinking about it.

 

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A Christmas Scene

Posted in Uncategorized on December 24, 2021 by telescoper

There were disturbing scenes in Maynooth today as concerned passers-by and farm animals gathered around a small child mysteriously injured by being hit on the head by a gold Frisbee.

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Bird Life

Posted in Biographical, Uncategorized on December 23, 2021 by telescoper

This morning, while I was waiting for my extra special Christmas veggie box to arrive, I was watching the birds in the garden through my kitchen window. For the last several days I’ve been putting out several full feeders only to see them emptied within minutes by a sundry collection of starlings, sparrows, tits, finches, wood pigeons, a dove, and a couple of jackdaws. A rook which on several occasions tried to demolish one of the feeders (ti being too clumsy to get any food by conventional methods) seems now to have given up and merely watches angrily from a tree.

The dove (a collared dove to be precise) is a new arrival in my garden (though not at all a rare bird). It seems rather shy and quiet in behaviour, usually to be found sitting in a tree while all the smaller birds flutter and chatter around. It does seem to like the seed, but also eats the berries on the hedges. It’s a very interesting bird to look at, its grey feathers making it look rather ghostly. The wood pigeons (which are much bigger) are quite noisy but I haven’t heard the dove make any sound yet.

A number of robins also visit the garden. They’re not agile enough to use the feeders but instead patrol around at ground level collecting bits and pieces that have fallen down. One of them however has realized that my stash of food is in the shed and that my entering the shed is a prelude to good being available. The other day as soon as I went in, one particular robin followed me right inside and jumped onto the bench where I was spooning out the seed. I had spilled some, which he/she tucked into, and I gave him/her a bit more. Now the little critter is there every day waiting in the VIP lane. Whenever I open the back door to go into the garden all the other birds scatter in all directions, except the robin who doesn’t seem to be at all intimidated.

With the eventual arrival of my veggie box I have got just about everything I need for a self-indulgent holiday. The amount of food and wine I’ve laid up for myself is probably enough for a month and I thought that this afternoon’s trip to the fishmonger to collect six oysters for Christmas Eve would be my last trip to the shops before Christmas Day, but I think I’ll make one more trip to buy bird food. At the rate they’re scoffing it I’ll be out of supplies by Boxing* Day!

*”Boxing Day” isn’t really used in Ireland; the usual term is “St Stephen’s Day”

 

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R.I.P. Thomas Kinsella

Posted in Poetry on December 22, 2021 by telescoper

The renowned Irish Poet Thomas Kinsella has passed away at the age of 93. By way of a small tribute I thought I would post again a poem by him that I first posted about 7 years ago when I had no inkling that I would move to Ireland. Probably his most famous and definitely his most anthologised work Mirror in February gives us a reflection (in more ways than one) on the inexorable and irreversible process of ageing. Kinsella actually wrote this in May 1962 when he would have been just 34 years old and probably had no idea he would live almost another sixty years. Apart from everything else this poem confirms my opinion that shaving is to be avoided…

The day dawns with scent of must and rain,
Of opened soil, dark trees, dry bedroom air.
Under the fading lamp, half dressed – my brain
Idling on some compulsive fantasy-
I towel my shaven jaw and stop, and stare,
Riveted by a dark exhausted eye,
A dry downturning mouth.

It seems again that it is time to learn,
In this untiring, crumbling place of growth
To which, for the time being, I return.
Now plainly in the mirror of my soul
I read that I have looked my last on youth
And little more; for they are not made whole
That reach the age of Christ.

Below my window the awakening trees,
Hacked clean for better bearing, stand defaced
Suffering their brute necessities,
And how should the flesh not quail that span for span
Is mutilated more? In slow distaste
I fold my towel with what grace I can,
Not young and not renewable, but man.

by Thomas Kinsella (1928-2021)

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The Future of Publishing

Posted in Open Access with tags , , on December 22, 2021 by telescoper
Citations to papers in the Open Journal of Astrophysics

I’ve long thought that The Open Journal of Astrophysics is ahead of its time, but when I checked the citation record via NASA/ADS the other day I found corroborating evidence in the form of citations from papers published in 2022! It’s very futuristic to be cited by papers that haven’t been published yet.

I’ve actually noticed this sort of thing before. Some journals announce publications and lodge metadata well in advance of the official publication date so the citations get tracked. At the Open Journal of Astrophysics we usually publish papers within a day or two of acceptance so this doesn’t really happen to papers cited from our articles.

Notice also there are citations going back to 2014. This might surprise you since our first papers were not published until 2016. The reason is that some papers were hanging around on the arXiv accumulating citations before we officially published them.a

That deals with the Ghosts of Citations Past and Citations Yet to Come so I feel I should mention the Present situation. According to ADS, as of today (22nd December 2021), papers in the Open Journal of Astrophysics have garnered 992 citations. That’s an average of just over 20 per paper. We might just get to a thousand before the end of the year. Now that would be a nice Christmas Present!

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The Winter Solstice 2021

Posted in The Universe and Stuff with tags , , , on December 21, 2021 by telescoper

So it comes around again. The winter solstice in the Northern hemisphere happens today, Tuesday 21st December, at 15.59 Irish Time. Among other things, this means that tomorrow is the shortest day of the year in the Northern hemisphere. Days will get steadily longer from then until the Summer Solstice next June.  The  the shortest day – defined by the interval between sunrise and sunset – is today. Tomorrow will be two whole seconds longer. Make the most of it!

This does not, however,  mean that sunrise will happen earlier tomorrow than it did this morning.  Actually, sunrise will carry on getting later until the new year, the length of the day nevertheless increasing because sunset occurs even later. Sunrise yesterday morning (20th December) was at 08.37 Dublin Time while today it was 08.38; the latest sunrise will be on 29th December (08.40). Sunset last night was at 16.07 and tonight it will be at 16.08. The earliest sunset this year was actually on 13th December (16:06).

These complications arise because there is a difference between mean solar time (measured by clocks) and apparent solar time (defined by the position of the Sun in the sky), so that a solar day does not always last exactly 24 hours. A description of apparent and mean time was given by Nevil Maskelyne in the Nautical Almanac for 1767:

Apparent Time is that deduced immediately from the Sun, whether from the Observation of his passing the Meridian, or from his observed Rising or Setting. This Time is different from that shewn by Clocks and Watches well regulated at Land, which is called equated or mean Time.

The discrepancy between mean time and apparent time arises because of the Earth’s axial tilt and the fact that it travels around the Sun in an elliptical orbit in which its orbital speed varies with time of year (being faster at perihelion than at aphelion).

In fact if you plot the position of the Sun in the sky at a fixed time each day from a fixed location on the Earth you get a thing called an analemma, which is a sort of figure-of-eight shape whose shape depends on the observer’s latitude. Here’s a photographic version taken in Edmonton, with photographs of the Sun’s position taken from the same position at the same time on different days over the course of a year:

maxresdefault

The winter solstice is the lowermost point on this curve and the summer solstice is at the top. These two turning points define the time of the solstices much more precisely that the “shortest day” or  “longest night”.

Anyway, the north–south component of the analemma is the Sun’s declination, and the east–west component arises from the  equation of time which quantifies the difference between mean solar time and apparent solar time. This curve can be used to calculate the earliest and/or latest sunrise and/or sunset.

Using a more rapid calculational tool (Google), I found a table of the local mean times of sunrise and sunset for Dublin around the 2020  winter solstice. This shows that today is indeed the shortest day (with a time between sunrise and sunset of 7 hours 29 minutes and 57 seconds).

P.S. As usual, crowds gathered at the spectacular neolithic monument at Newgrange in County Meath to observe the sunrise at the Solstice. As usual it was cloudy.

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Carúl Inis Córthaidh

Posted in Irish Language, Music on December 20, 2021 by telescoper

The Wexford Carol is a traditional Christmas song whose origin is obscure. It is often said to date from the 12th Century, or even earlier, but music historians consider it more likely to be from the 15th or 16th Century. Whatever its provenance, it’s a fascinating folk melody with a haunting, timeless quality to it.

The song is associated with Enniscorthy in County Wexford so is called in the Irish Language Carúl Inis Córthaidh or Carúl Loch Garman, Wexford being one of those towns in Ireland with an Irish name (Loch Garman) that bears no phonetic relationship whatsoever to its English name. Anyway the song is very well known and there are a lots of versions floating around, but is usually sung in English so I thought I’d post a version in Irish. Altogether now “Ó, tagaigí uile is adhraigí …”

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