Archive for February 4, 2014

A Matter of Life and Death

Posted in Film, Poetry with tags , , , , on February 4, 2014 by telescoper

One for the file marked “they don’t make films like this any more”. Here is a clip from very near the beginning of the extraordinarily imaginative romantic fantasy A Matter of Life and Death. It’s not quite the opening sequence as titled, though: there’s an astronomically themed preamble before the sequence shown in the clip.

Directed by Michael Powell and Emeric Pressberger and released in 1946, A Matter of Life and Death has remained in most film critics’ lists of top British movies for almost seventy years. If you really want to know why then you’ll have to watch the whole film, but this is a memorable opening to a film if ever there was one.

Incidentally, the splendid poem by Sir Walter Raleigh from which Peter Carter character (played by David Niven) quotes is called The Passionate Man’s Pilgrimage. Here it is in full:

GIVE me my scallop-shell of quiet,

My staff of faith to walk upon,
My scrip of joy, immortal diet,
My bottle of salvation,
My gown of glory, hope’s true gage;
And thus I’ll take my pilgrimage.

Blood must be my body’s balmer,
No other balm will there be given;
Whilst my soul, like a quiet palmer,
Travelleth towards the land of heaven;
Over the silver mountains,
Where spring the nectar fountains:
There will I kiss
The bowl of bliss;
And drink mine everlasting fill
Upon every milken hill:
My soul will be a-dry before;
But after, it will thirst no more.
Then by that happy blestful day,
More peaceful pilgrims I shall see,
That have cast off their rags of clay,
And walk apparelled fresh like me.
I’ll take them first
To quench their thirst,
And taste of nectar suckets,
At those clear wells
Where sweetness dwells
Drawn up by saints in crystal buckets.

And when our bottles and all we
Are filled with immortality,
Then the blessed paths we’ll travel,
Strowed with rubies thick as gravel;
Ceilings of diamonds, sapphire floors,
High walls of coral, and pearly bowers.
From thence to heavens’s bribeless hall,
Where no corrupted voices brawl;
No conscience molten into gold,
No forged accuser bought or sold,
No cause deferred, nor vain-spent journey ;
For there Christ is the King’s Attorney,
Who pleads for all without degrees,
And he hath angels, but no fees.
And when the grand twelve-million jury
Of our sins, with direful fury,
‘Gainst our souls black verdicts give,
Christ pleads his death, and then we live.

Be thou my speaker, taintless pleader,
Unblotted lawyer, true proceeder!
Thou giv’st salvation even for alms ;
Not with a bribèd lawyer’s palms.
And this is my eternal plea
To him that made heaven, earth, and sea,
That, since my flesh must die so soon,
And want a head to dine next noon,
Just at the stroke, when my veins start and spread,
Set on my soul an everlasting head.
Then am I ready, like a palmer fit;
To tread those blest paths which before I writ.

Big Trouble with Big G

Posted in The Universe and Stuff with tags , , on February 4, 2014 by telescoper

An Antonymous email correspondent this morning drew my attention to an interesting article in the latest Physics World about the trials and tribulations of groups of physicists trying to measure Newton’s Gravitational Constant,  G. This is probably the first physical constant that most of us encounter when we’re learning the subject so it might seem strange that it’s the one which is known to the lowest accuracy. That’s not for want of trying to make the measurements more precise, just that gravity is such a very weak force that it’s very difficult to eliminate systematic effects down to the necessary level.

Just how difficult it is to measure Big G is demonstrated by the following graphic which shows the latest measurements:


Here’s the caption, so you can identify the various groups responsible for the various measurements:

Disagreeing over “big G” This chart shows wildly differing values of the gravitational constant, G, as measured by various high-profile research groups (blue). The values do not agree even within their error bars. Also shown are two values of G adopted by the Committee on Data for Science and Technology (CODATA) as international standards (red). The groups are based at the National Institute of Standards and Technology (NIST), the University of Washington (UWASH), the International Bureau of Weights and Measures (BIPM), the Measurement Standards Laboratory of New Zealand (MSL), the University of Zurich (UZURICH), the Huazhong University of Science and Technology (HUST) and the Joint Institute for Astrophysics (JILA).

Clearly there’s quite a lot of disagreement between recent results, with some a long way outside each other’s error bars. They can’t all be right, but who’s most likely to be wrong? Answers on a postcard.

I’m by no means an expert on experimental gravity so I won’t attempt to suggest who is right and who is wrong. What I will say is that although this kind of research is clearly extremely important it is clearly also fiendishly difficult. I’m not really surprised that the pieces of the puzzle haven’t fallen into place yet. The dedicated teams who have been tackling this problem for many decades deserve the deep admiration as well as the continued support of the physics community. Theoretical physics is generally perceived to be more glamorous and exciting than its experimental counterpart, but the subject as a whole is nothing without its empirical foundations. That said, I’m glad it’s not my job to measure Big G. I have neither the practical skill nor the patience to cope with so many frustrations!