Archive for the ‘Science’ Category

Nova Musca update (and another one)

January 20, 2018

It’s been several days since the nova in Musca was found by Rob Kaufman. The alert notice was sent out by AAVSO on January 16.

Below is the green filter channel of a DSLR image I took around midnight on January 17. The nova is shown via red markers with a faint satellite trail at upper right. Compare this with the narrow field Stellarium screenshot in my last post.

img-g13-cropped-annotated

That was one of 20 images used for photometry of the nova that night. I’ve repeated this on two other nights since submitting untransformed green (visual wavelength), blue and red band observations.

My visual band (binocular and DSLR photometry) observations are shown below in purple alongside visual band contributions from others:

NovaMusca2018Jan20

A polynomial fit makes the emerging pattern a little more obvious (if exaggerated in parts); up and down from night to night as is common with novae.

NovaMusca2018

This morning another southern nova was discovered in the constellation Circinus (near Alpha Centauri) by John Seach in NSW at magnitude 9.1. John also discovered a bright nova in Centaurus in 2013. I have not been able to observe this yet due to cloudy conditions tonight.

Here’s a Stellarium screenshot of this latest nova’s location:

Nova Circinus 2018

The AAVSO finder chart I will be using initially is this:

Nova near Southern Cross

January 15, 2018

Rob Kaufman in Victoria discovered a possible nova (PNV J11261220-6531086) near the Southern Cross (Crux) in the constellation of Musca on January 14 2018. All novae start out having the designation PNV or possible nova.

Rob’s discovery visual estimate was magnitude 7. I estimated it tonight with 7×50 binoculars at magnitude 6.7 relative to magnitude 6.4 and 7.1 comparison stars.

This context screenshot from Stellarium shows the nova’s location (cross-hairs at upper middle of image) relative to familiar stellar sign posts, including Crux and Alpha Muscae at 10pm Adelaide time (AEDT).
PNV J11261220-6531086 wide

The next shows a narrower field of view with the nova at right of the helpful triangular, A-shaped asterism.

PNV J11261220-6531086 narrow

Here’s a 10º finder chart from AAVSO
X22594EOand an 8º finder chart with the orientation closer to that of the sky around tonight’s observation time. The two comparison stars I used are circled in red.

X22594EI

After submitting my observation tonight to AAVSO I noticed that since Rob’s discovery observation, only two have been submitted other than mine:

  • another visual estimate by Sebastian Otero in Argentina (6.85);
  • and a tri-colour green DSLR observation (6.72) by David Blane in South Africa.

What I love about such transients, is their spectacular brightness rise and unpredictability.

Initial spectroscopy by Rob indicates a classical nova. I’d expect to see more amateur spectroscopy of this object in the near future.

Will it become visible to the naked eye like the similarly southern and close-to-Crux V1369 Cen did in 2013 (peaking at around magnitude 3.4)? One never knows with these things but it’s worth noting, as per the CBAT transient report page, ASAS-SN observations suggest the nova may actually have started in the first few days of January. If so, perhaps we’re a little too far down the track to expect naked eye visibility. All we can do is to observe it and see!

Being such a southerly object, it will not be as well observed as novae in the northern hemisphere, but it’s in a great location, so have a go if you can! I’ll be out every clear night observing it when I can in the days to come, visually and possibly via DSLR.

Mr & Mrs JW: I have some questions…

October 3, 2017

In recent months, I’ve noticed more of you in pairs with portable pamphlet displays, congregating mostly around public transport interchanges, train stations, busy street corners, and near the occasional university in Adelaide.

Are we special or is the picture more or less the same elsewhere?

Is the Apocalypse impending? Wasn’t it supposed to happen in the mid-70s? Where’s the evidence that it will ever happen? Please don’t say “it’s in the Bible”. That doesn’t count as evidence. Telling me to “have faith” doesn’t help either. I prefer not to pretend to know things I don’t know, especially for no apparent reason and certainly not about things that could profoundly affect my life, in spite of Pascal’s Wager.

Why do you think it’s reasonable that Joseph Rutherford in the early 1930s declared that only 144,000 would make it to heaven once the total number of JWs exceeded that number?

Isn’t that just a little bit convenient?

Do you think you’re one of those 144,000?

If not, what makes you OK with the idea that millions of you will be resurrected bodily, zombie-like (from Jehovah’s Witness to Jehovah’s Zombie) to live in “paradise” (no, not Paradise, the Adelaide suburb, although there is a major bus interchange there) built upon the 7 billion human corpses of the Apocalypse, assuming the rest of us haven’t become followers by then?

But that’s your mission now, isn’t it? To get yourself and the rest of us through the Apocalypse and into this paradise on earth depicted by the Watch Tower publications you hand out.

Isn’t that at least a little bit creepy?

What will happen in Paradise? What will the newly resurrected bodies be sustained by?

Will we get to worship your genocidal god for eternity? If so, we’ll need to be sustained for eternity so we’ll need food for eternity.

Will dead animals be bodily resurrected too just so they can be consumed again in an infinite cycle? Or will animals be outside of the Apocalypse loop yet still be consumed?

I hope we find strong evidence for life on other worlds. Not because we will be able to communicate within reasonable timeframes, but so that the Copernican revolution continues on its logical trajectory toward deposing us from our delusion of central importance in the universe. We can be important to one another and create meaning in our lives without being favoured by gods. Watch Pale Blue Dot! It always comes back to that.

How is it that you don’t see that in the marketplace of religions, yours is just as manufactured as the rest?

We create gods in our own image not the other way around!

What evidence do you have that around 1915, your religion was “selected” by Jesus to be the one true religion? Has no-one else declared such a status for their religion?

And don’t get me started on shunning, your theological allergy to blood transfusions, or allegations of child sexual abuse in your chosen church? It’s not just the Catholics and Anglicans anymore who are under the spotlight.

I’ve engaged in civil conversation with JWs when they’ve knocked on our door, especially when a child has been in attendance, so they at least hear a different viewpoint. But door knocks are infrequent and I feel the need to engage in street epistemology with JWs (or Mormons or …) where I find them.

I don’t particularly enjoy debate or conflict, but I like dogmatic thinking less.

I wrote this post after hearing a compelling interview with Lloyd Evans, an ex Jehovah’s Witness, on The Thinking Atheist podcast.

Alto creator Charles P. Thacker dies

June 23, 2017

The influential American engineer Charles P. Thacker died on June 19, aged 74.

Thacker designed the Alto personal computer at Xerox PARC in the 1970s which influenced development of the Mac after Steve Jobs saw it during a visit to PARC.

He also contributed to the development of Ethernet, Tablet PCs, and laser printers.

The computer scientist Butler Lampson, one of Thacker’s colleagues at Xerox PARC and later at Microsoft has spoken about his ability to see what was important and his breadth of coverage:

He could do everything from circuit design all the way through hardware architecture and programming and user-interface design.

The Association for Computing Machinery and IEEE Computer Society recently honoured Charles P. Thacker with the Eckert-Mauchly Award.

HD 148703

June 12, 2017

A request for observations by astronomers at the University of Wroclaw in Poland was announced by AAVSO on June 8.

The bright (magnitude 4.23 V) long period eclipsing binary HD 148703 (aka N Sco, HR 6143) is expected to undergo primary and secondary eclipses on June 11 and 14 each lasting around 20 hours.

The brightness and requested precision of 0.01 or better makes this an ideal candidate for wide field DSLR photometry.

I’ve taken pre-eclipse images but cloud prevented me from imaging the primary eclipse. I’ll take further images over the next few days, hoping to record the secondary eclipse.

The Arrival, linguistic determinism, and programming languages

January 1, 2017

My son and I recently saw The Arrival, a movie that at first reminded me of Arthur C. Clarke’s Childhood’s End. The trailer suggested more action than was delivered, not a bad thing; the impact was primarily psychological.

Spacecraft arrive in several locations, hovering just above the ground. As you might guess, each country’s military forces quickly take control. The focus is on the US contingent (of course), although Australia, China and other countries are initially in frequent communication to collectively figure out what’s going on.

A sliding “door” periodically opens in the underside of each craft and personnel enter to try to make contact. Artificial gravity inside the atrium in which the humans stand makes things a little easier. A mostly opaque rectangular window separates them from the aliens and their atmosphere. The military personnel quickly realise that they need outside help so they enlist a linguist and a physicist. Apparently only America has competent linguists and physicists. 🙂

1

I won’t say more about the plot because I want to focus on one aspect and head off on a tangent. After a lot of puzzling by the main protagonists over the strange circle-based language in which the aliens try to communicate, the linguist eventually understands, with the help of a close encounter, why they have come. Nothing sinister as it turns out.

Along the way, the linguist talks to her physicist colleague and friend about the now somewhat outmoded Whorf-Sapir hypothesis (or just Whorfianism) of language or in which the structure of language is thought to affect the world view or cognition of its speakers. The weak form of this, linguistic relativity, says that a language merely influences thought, whereas the strong form, known as linguistic determinism, suggests that language determines what can be thought.

As the philosopher Ludwig Wittgenstein put it in his Tractatus Logico Philosophicus:

The limits of my language mean the limits of my world.

and

About what one cannot speak, one must remain silent.

The Arrival adds an interesting twist to this by allowing the linguist, who understands and internalises the alien language, to experience the world in a way that is, shall we say: temporally flexible.

The tangent has almost arrived; just a couple more paragraphs… 🙂

There is research suggesting that languages with names for particular colour shades make it easier for its speakers to remember those shades. This is an example of the weak form. However, we know that it is possible to perceive and describe shades, even if we have no explicit names for them, evidence against the strong form of the hypothesis.

Another example of the weak form would seem to be the fact that the Greek language has a different words for love: for God, friendship, the love of a parent for a child, and love between intimate partners.

I have not researched this enough to know whether there really are plausibly deterministic examples in natural languages, but I’d be interested in seeing some.

EDIT: It occurred to me today that I had heard of and recently read (here) about a culture whose language has only the number words one and two with many being the catch-all for other quantities. This most definitely places constraints upon the worldview of its people. In particular: the ability to count to specific numbers beyond two. It may be that in such a culture, this is all that’s required for enumeration in daily life, but it’s difficult to argue that growth is not limited by this, in particular: the discovery and use of mathematics. This is an example of linguistic determinism in natural languages.

Now finally, the tangent…

This all got me thinking about linguistic relativism and determinism in programming languages. To what extent does a programming language influence or determine what a programmer can think or limit his/her world view?

Whereas a language like assembly, C or C++ gives complete access to the hardware of a computer, Virtual Machine based languages like Java don’t, so too for explicit memory de-allocation vs garbage collection and other “unsafe” operations.

For example, not being able to express the thought in code: “write 42 to memory address 673416” limits what can be thought (programmed) in that language, an example of the strong form, so linguistic determinism.

There are of course many applications for which it is completely unnecessary (and dangerous) to be able to express such thoughts, so type systems that rule out whole classes of dangerous “code thoughts”, do us a great service, but at the cost of limiting our world and forcing us to be silent about certain things, as Wittgenstein might say, and possibly but not necessarily at the cost of performance.

Similarly, a language with even simple intrinsic data structures such as lists and maps permits more complex code with less effort. So long as suitable language constructs exist, i.e. pointers and dynamic memory allocation, such data structures (and algorithms to operate over them) can be created by the programmer, albeit at a greater cost and cognitive effort, and made available as libraries for use by others. Here we are closer to linguistic relativity I think. It was not uncommon to find myself, especially in the 90s, writing custom list data structures and search or sort algorithms from scratch when coding in the C programming language.

Perhaps the strongest encounter I had with the idea of language-as-influencer-of-thought was when learning Perl 20 years ago while working for a dial-up era Internet provider. The combination of regular expressions, lists, and maps in particular provided new ways to think about text processing, beyond simple character-by-character or sub-string comparisons.

If you had asked me 15 years ago which languages I could “think fastest” in, I would have said Perl and Java. Before them, the answer would have been C. The Perl experience translated to similar scripting languages all of which have been only incrementally better or worse, including Python.

At University I had studied and taught programming paradigms,  written a couple of compilers (e.g. ACE), engaged in some language design; I spent a lot of time in the 90s and early 2000s on the latter two.

The impact of object-oriented languages like Java and C++ (in fact, embodying multiple paradigms) was longer-lasting than most, especially with respect to the design and maintenance of large code bases. In recent years I’ve had increasing sympathy with the functional programming paradigm and strongly statically typed languages that limit the set of “legal” programs (for my own good).

As I have said in a different post, all programming languages are crude approximations of some Platonic ideal of a coming together of minds, artificial and natural, and there are very few languages yet that make communion with the machine or, just as important, with other programmers, a beautiful experience.

The idea of a programming language that doesn’t just place limits on my world, but one that radically changes the way I think about the world, as the alien language did for the linguist in The Arrival, is alluring.

I remain in search of such a language (and its ecosystem of libraries and tools), one that of course can only ever be asymptotically approached.

Writing this has scratched an itch that has been irritating me for a long time. Perhaps I’ll have more to say about particular languages and how they live up to the “ideal” in future posts.

Update on novae in Sagittarius

December 11, 2016

It’s been a month since my last update on ASASSN-16ma and  TCP J18102829-2729590, mostly due to family commitments; my wife was out of town with her sick father, and looking after her mother, so I was busy keeping things going on the home front.

As can be seen below, both novae have been in decline for most of that time.

tcp-j18102829-2729590

asassn-16ma

ASASSN-16ma declining?

November 11, 2016

Poor weather prevented any observations last night but tonight the sky cleared after a late afternoon storm and I estimated the nova at magnitude 6.3.

asassn-16manov11

So, it’s been gradually declining for 3 days, but whether that continues remains to be seen.

ASASSN-16ma: easy binocular object

November 8, 2016

Last night’s observation of ASASSN-16ma was with 7×50 binoculars rather than my Meade LX-90 8″ SCT. The nova is now on the verge of naked eye visibility!

asassn-16ma

I estimated the nova at magnitude 5.5 last night with one before mine at 5.4 and two subsequent observations of 5.8 and another at 5.9. Mine are highlighted in purple as usual.

Here’s the section of Sagittarius of interest as it currently appears from Adelaide, low in the south-western sky at around 9pm:

sgr

The nova is just west of the circled star HIP 90012, the 6.2 (labeled 62) magnitude star near the middle of this AAVSO finder chart:

x16923acn

If you rotate this chart 90 degrees to the right, it will have roughly the same orientation as the Stellarium sky scene.

Alnasl is the star labeled 30 (magnitude 3.0) at bottom right of the finder chart. Kaus Media corresponds to the label 27 and Kaus Borealis with the star labeled 28. Kaus Australis and Φ Sagittarii do not appear on the finder chart, but would be off to the left of the unrotated chart.

As I write this, the sky here in Adelaide is quite overcast, so there may be no observation from me tonight.

 

Update on two novae in Sagittarius

November 7, 2016

Poor weather then being away for work for three days last week has kept me away from variable star observing since October 29. Last night (November 6) I observed TCP J18102829-2729590 and ASASSN-16ma again.

While the first is on the decline currently (around magnitude 9):

tcp-j18102829-2729590-lc-nov-7

On the other hand, I caught ASASSN-16ma on the rise. My October 29 observation gave a visual magnitude of 10.3 whereas last night it was 7.3. Several hours later others were recording it at around 6.5:

asassn-16manov-7

So, ASASSN-16ma has exceeded TCP J18102829-2729590’s maximum (so far) by around one magnitude. If this rate of increase continues, who knows, maybe it will reach naked eye visibility. Here’s hoping!