Friday, November 18, 2016

The American Astronomical Society reaffirms its commitment to discrimination

The President of the American Astronomical Society (AAS), Christine Jones, released a letter today (18 November 2016) on behalf of the AAS Council, titled “Reaffirming Our Commitment to Inclusiveness”. While purporting to support inclusiveness, this letter calls for bigotry to be tolerated and indulges in victim-blaming and gaslighting of those who feel threatened by Trump's election.

The tone of the letter becomes obvious in the first paragraph, which states that “it is the responsibility of each of us to treat every member of our Society -- and every member of society more generally -- with respect and dignity, regardless of … political opinions.” As we have seen recently, the spectrum of political opinions in the US includes fervent opposition to inclusiveness in all of its forms. This is an unacceptable call to tolerate racism, misogyny, homophobia, xenophobia, and other oppressive behaviours.

Later in the same paragraph, the letter talks about “cruel incidents” – a euphemism, it would seem, for hate crimes and violence, and one which serves to minimise the impact of these acts. These are blamed on “a polarizing national election”, implying that there was blame on both sides. That was not the case – on one side, Trump and his supporters were actively provoking intolerance, while on the other side groups who have suffered historic and ongoing oppression were asking to be treated equally as human beings. This false equivalence boils down to saying that the victims of Trump's rhetoric are partly to blame for the violence aimed at them. This is an unacceptable act of victim-blaming.

The second paragraph of the letter starts promisingly, with a call for everyone to “be committed to ensuring an astronomy community that is safe and welcoming for all people, especially those who are currently underrepresented in our science and/or marginalized by society at large.” But the idea of how to do this appears to be limited to a call to AAS members “to be mindful of how we treat each other and to support students and colleagues”. There is a complete lack of any commitment, or even notice of intent, from the AAS to actually stand up for its members who might be threatened by proposed actions of the Trump administration – everything is to be done by members being nice to one another (including, let us not forget, being nice to the bigots, misogynists, racists, homophobes, etc.). There appears to be a deliberate ignorance of the fact that the freedom of AAS members to practice astronomy is threatened not just be the violence of Trump supporters but by the campaign promises he himself made and the stated opinions of those he has nominated to serve in his administration.

The second paragraph goes on to talk about “those who may now feel threatened or frightened by recently reported acts” – minimising the violence as merely “reported”, a word that implies by its inclusion that the violence might not actually be happening, and insinuating that people are merely frightened of reports, thus dismissing the possibility that they could have actually been victims themselves. Indeed, nowhere in the letter does it actually acknowledge that any violent acts or hate crimes have actually taken place. This is classic gaslighting.

There no mention in the letter of the fact that Trump and his supporters deliberately provoked the rise of hate and intolerance, let alone any condemnation of this. Nor is there any recognition that people in the targeted groups might be threatened or frightened by the President-elect and his spokespeople having encouraged intolerance of them and engendered an environment where violence, both physical and psychological, is seen as socially acceptable.

Overall, the message of this letter is that the AAS are willing to appease and tolerate oppression. My take home from this, as an immigrant myself, is that when they come for me, I shouldn't expect the AAS to speak. There is one light on the horizon, however – the AAS Council elections are coming up, and a number of the candidates are known as supporters of diversity who might move the society towards representing all of its members.


Text of the AAS letter:

Reaffirming Our Commitment to Inclusiveness

As President of the American Astronomical Society, I wish to remind members and other stakeholders of the Society's resolute commitment to promote inclusiveness. In keeping with the AAS Council's recent adoption of a comprehensive code of ethics, it is the responsibility of each of us to treat every member of our Society -- and every member of society more generally -- with respect and dignity, regardless of race, ethnicity, skin color, national origin, age, disability, religion, faith, gender identity, gender expression, sexual orientation, socioeconomic status, or political opinions. I expressed similar sentiments in my last President's Column, but they bear repeating in the aftermath of a polarizing national election that has been followed by a growing number of cruel incidents.

We must all be committed to ensuring an astronomy community that is safe and welcoming for all people, especially those who are currently underrepresented in our science and/or marginalized by society at large. I urge all AAS members to be mindful of how we treat each other and to support students and colleagues, especially those who may now feel threatened or frightened by recently reported acts of harassment, intimidation, and violence against people of color, women of all backgrounds, immigrants of all statuses, Jews, Muslims, people with disabilities, LGBTQIA+ persons, and those at the intersections of these axes. I am especially troubled by hateful acts occurring on the campuses of educational institutions.

Finally, as our colleagues in the American Geophysical Union (AGU) frequently point out, science plays a central role in America's security, economy, and well-being. Let's do our part to ensure that science continues to make our country more secure, more prosperous, and more comfortable -- for everyone.

-- President Christine Jones for the AAS Council

Sunday, August 14, 2016

Double Prime Meridian – why is the Greenwich Prime Meridian 102m west of the GPS zero meridian?

If you visit the Royal Greenwich Observatory and stand across the Prime Meridian of the World, your GPS will tell you that you are are at 0.00147°W (or 0°0.09′W or 0°0′5.3″W, depending on how your system displays coordinates), the GPS zero meridian (properly called the International Terrestrial Reference Frame zero meridian) is 102m further east. A recent article on, Moving the Earth's Prime Meridian, says that this is due to "improving technology" and "increased accuracy" in the measurements. This seemed unlikely, as the error sounds well above the level of accuracy achievable with the Airy Transit Circle, so I clicked through to the scientific article by Malys et al. that they were reporting on, and found that had completely misunderstood it. The actual reason is completely different, and far more interesting.*
* Well, to me anyway

GPS on the Greenwich Prime Meridian, showing 0.00149W
This GPS unit reads 0.00149°W on the Prime Meridian at Greenwich (Source: J. Cohen/Wikimedia Commons)
Airy defined the Prime Meridian using astronomical measurements of the stars. His instrument was surveyed carefully into position. He measured the horizontal with a bowl of mercury (don't do this at home, kids!), which was used to define the vertical. There was nothing wrong with his astronomical measurements – it was his measurement of the vertical that caused the position of the Prime Meridian to be 'wrong'.

What could possibly be wrong with that though? When we think of vertical we think of 'straight down' – the direction in which things fall, which is what Airy measured. However, this is not what is used for vertical when defining the Earth's coordinate system nowadays. For the coordinate system, a vertical line is one joining where we are on the Earth's surface to the centre of mass of the Earth. Globally this works, but locally on the Earth's surface there are deflections caused by mountains, ocean trenches, and other lumps and bumps. The mass of a mountain pulls the local vertical towards it, while the missing mass of a trench means the local vertical is pulled away from it.

Here at Arecibo Observatory we are just south of the Puerto Rico Trench – the deepest spot in the Atlantic. This causes a significant 'deflection of the vertical', as it is termed. The astronomical latitude of the Observatory, based on the vertical defined by the local gravity, is 18°21′13.7″N, but the geodetic latitude, based on the vertical passing through the Earth's centre of mass, is 18°20′36.6″N. That's a shift of 37.1 arcseconds, corresponding to over a kilometre! This is caused by the 'missing mass' of the Puerto Rico Trench, meaning the local 'straight down' is pulled south by the mass of Puerto Rico, shifting 'straight up' northwards. The stars that pass directly overhead are 37.1 arcseconds further north than our geodetic coordinates would indicate – we have to use astronomical coordinates, based on our local vertical, in order to point our telescope correctly.

The 102m shift at Greenwich is due to the deflection of the vertical in exactly the same way as the shift at Arecibo. Malys et al. used a model for the Earth's gravitational field to estimate the deflection of the vertical at Greenwich, and found that it was 5.5 seconds of longitude (and about 2.2 arcseconds in latitude, which isn't important here). This makes the astronomical longitude of the Greenwich Prime Meridian 0°00′00.19″ ± 0.47″. In other words, completely consistent with it being at zero longitude, as originally defined. This means that a line passing through the centre of mass of the Earth and the GPS zero meridian 102m east of Greenwich is parallel with a locally vertical line passing through the Greenwich Prime Meridian: they point to the same place in the sky. However, a locally vertical line on the GPS zero meridian would point about 5 seconds of longitude (3.3 arcseconds at that latitude) east on the sky, meaning a transit there would take place about 0.35 seconds earlier than predicted.
A line joining zero longitude on the celestial sphere to the centre of mass of the Earth passes through the GPS zero meridian, but zero longitude on the celestial sphere appears 'straight up' on the Greenwich Prime Meridian (which is how zero longitude on the celestial sphere was originally defined). As the celestial sphere is effectively at an infinite distance, the line from the Earth's centre of mass to zero on the celestial sphere and the line from Greenwich to zero on the celestial sphere are essentially parallel in reality, but that would require an infinitely large figure to show!
So, where does the "improving technology" come in? Satellite measurements force the vertical to be towards the Earth's centre of mass – which is what the satellites are orbiting. Furthermore, we now want a single system that will cover the entire globe – it is much easier to get a match between astronomical and geodetic coordinates when trying to only map a single continent. In North America, the ellipsoid (approximation to the shape of the Earth) worked out by Alexander Clarke in 1866 is generally off from the true shape of the Earth (i.e. sea level) by less than 10m, while the ellipsoid used for the GPS coordinate system is always off by at least 15m and often more. But the North American ellipsoid, and the 1901/1927 North American Datum coordinate system based on it, would fail dismally if extended over the entire world, while the GPS system works approximately equally badly everywhere.[1] This is why GPS heights are often significantly off from heights measured from sea level – the difference is about 60m in Arecibo.

In summary: The Greenwich Prime Meridian is the line of zero longitude defined astronomically, with vertical defined by local gravity. The GPS zero meridian is the line of zero longitude defined geodetically, with vertical passing through the centre of mass of the Earth. If you calculate a point on the sky that will be overhead at zero longitude at a certain time, it will be overhead on the Greenwich Prime Meridian, not the GPS zero meridian. Airy wasn't wrong, he was simply using a different definition of 'vertical'.

Sunday, January 31, 2016

Rhodes Should Fall

Outside of Oriel College, Oxford, in a second floor niche above a doorway stands a statue of the British colonialist and architect of apartheid, Cecil Rhodes. On a nearby building, also part of the College, there is a plaque erected “in recognition of the great services rendered by Cecil Rhodes to his country”.
The autumn of 2015 saw protests by students at Oxford calling for removal of both of these. A petition was handed in to Oriel on 3 November, and they responded on 17 December. The College said they would be seeking consent to remove the plaque, adding: “This plaque was erected in 1906 by a private individual. Its wording is a political tribute, and the College believes its continuing display on Oriel property is inconsistent with our principles.”
The issue of the statue was deemed to be more complex, which Oriel said “cannot be resolved quickly”, although they recognised that “In the absence of any context or explanation, it can be seen as an uncritical celebration of a controversial figure, and the colonialism and the oppression of black communities he represents”. But a way ahead was proposed: “the College has decided to launch a structured six-month listening exercise on the statue, running from early February 2016, seeking the views and ideas of students and staff of the College and the wider University, alumni, heritage bodies, Oxford City Council, residents of Oxford, and other members of the public, as we seek a positive way forward. This is a commitment to seek views in as inclusive a way as possible on how controversial associations and bequests, including that of Rhodes to Oriel, and the record of them in the built environment, can be dealt with appropriately.”
Both of these commitments, on statue and plaque, would be broken.
In late January, 2016, before the consultation on the statue's future had even begun, the College announced that they were reneging on their promises. The plaque would stay and the consultation on the statue would not be happening. The decision that could not be made quickly could, as it turned out, be made in a matter of weeks without any of the promised inclusive listening.
The Daily Telegraph, a right wing British paper that favoured keeping the statue, revealed how such a difficult decision could suddenly become so easy: the College faced losing donations from alumni – presumably worried about what history would have to say about their legacies. Oriel’s principles, that six weeks earlier had said the plaque must go, were swiftly forgotten. They were, quite simply, bought.
Besides money, the intellectual arguments that have been made for keeping the statue are (i) that it is better to remember history than to forget it and (ii) that Rhodes was a man of his time.
To the first, I would simply say that a statue, in our society, will always appear as celebration of a person. There is no getting around this: we put up statues of the “great and good”, not of those we would rather forget given the opportunity. The context of the statue, above the doorway looking down on everyone entering and leaving the College, is completely out of keeping with any idea that the statue will remind people of Rhodes’ evil. While for historians it might be possible to view the statue as history, for black students in Oxford today it is the present.
The second is more complex. Historical figures are never perfect; William Wilberforce, the famous anti-slavery campaigner, opposed granting equal rights to Catholics, for example. But an important point here is that we don't commemorate Wilberforce for his anti-Catholic position, we commentate him for his part in the campaign to end slavery. With Rhodes, the statue commemorates the money he left Oriel, which he had accumulated as a direct result of “the colonialism and the oppression of black communities he represents”.
Furthermore, it is far from clear that Rhodes truly was a “man of his time”. In 1876, while Rhodes was an undergraduate at Oxford, Fourah Bay College in Sierra Leone became affiliated to Durham University in England. The Durham University Journal printed the following:
“In reflecting upon the origin and growth of the Fourah Bay College, it must be borne in mind that it was at the first purely experimental. There were many who considered that the children of Ham could not be taught, and that they were decidedly inferior to the average of Europeans. But the chill of heathendom and slavery had frozen them. In the genial warmth of Christianity their faculties expanded, and it was soon discovered, as the universal testimony of those who have taught them shows, that this low estimate of their capabilities was a delusion, and that the African under favourable circumstances can effectually receive the highest education.”
Durham, which only a decade earlier had become the last university in Britain to open its degrees to non-Anglicans, was hardly a hotbed of liberalism. It was still strongly tied to the Anglican church: the head of the University was the Dean of Durham Cathedral, and the canons of the Cathedral formed its governing body. The affiliation of Fourah Bay to Durham helped maintain the colonial structure, putting an end to the campaign for it to become a locally-run independent university.
However, it does demonstrate that in England, at the time Rhodes was himself being educated, people knew there was nothing inherently inferior about Africans. The first Durham BA at Fourah Bay was Nathaniel Davis in 1878, with an external examiner from Oxford ensuring the degree was equal to the one Rhodes himself took in 1881.
Davis was the first but by no means the last. By the time Rhodes returned to Africa, it was clear that African students could compete alongside English students for English university degrees. The idea of African inferiority was exploded: “this low estimate of their capabilities was a delusion”. Rhodes revived the concept in South Africa and Rhodesia in order to justify his exploitation of the native people. He was, by the standards of his own time, a vicious racist.
The Oxford Union (the posh debating society, not the Students’ Union, whose £248 membership fee ensures it’s anything but a bastion of radicalism) debated the issue and voted to take the statue down. Yet Oriel came to a different conclusion, choosing not only to keep the statue up without the promised consultation, but also to preserve the plaque, even after saying this went against their principles. It is hard to escape the conclusion that Oriel, and by extension Oxford University’s Committee to Review Donations, have allowed money to talk louder than addressing institutional racism. The statue of Rhodes, representing “colonialism and the oppression of black communities”, will continue to stand proud; Oriel and Oxford should hang their heads in shame.