On the International Day of Light, remembering darkness

Today is the International Day of Light. According to a UNESCO note:

The International Day of Light is celebrated on 16 May each year, the anniversary of the first successful operation of the laser in 1960 by physicist and engineer, Theodore Maiman. This day is a call to strengthen scientific cooperation and harness its potential to foster peace and sustainable development.

While there are natural lasers, the advent of the laser in Maiman’s hands portended an age of manipulating light to make big advances in a variety of fields. Some applications that come immediately to mind are communications, laser-guided missiles, laser cooling and astronomy. I’m not sure why “the first successful operation of the laser” came to be commemorated as a ‘day of light’, but since it has, its association with astronomy is interesting.

Astronomers have found themselves collecting to protest the launch and operation of satellite constellations, notably SpaceX’s Starlink and Amazon’s upcoming Project Kuiper, after the first few Starlink satellites interfered with astronomical observations. SpaceX has since acknowledged the problem and said it will reduce the reflectance of the satellites it launches, but I don’t think the problem has been resolved. Further, the constellation isn’t complete: thousands of additional satellites will be launched in the coming years, and will be joined by other constellations as well, and the full magnitude of the problem may only become apparent then.

Nonetheless, astronomers’ opposition to such projects brought the idea of the night sky as a shared commons into the public spotlight. Just like arid lands, butterfly colonies and dense jungles are part of our ecological commons, and plateaus, shelves and valleys make up our geological commons, and so on – all from which the human species draws many benefits, an obstructed view of the night sky and the cosmic objects embedded therein characterise the night sky as a commons. And as we draw tangible health and environmental benefits from terrestrial commons, the view of the night sky has, over millennia, offered humans many cultural benefits as well.

However, this conflict between SpaceX, etc. on one hand and the community of astronomers on the other operates at a higher level, so to speak: its resolution in favour of astronomers, for example, still only means – for example – operating fewer satellites or satellites at a higher altitude, avoiding major telescopes’ fields of view, painting the underside with a light-absorbing substance, etc. The dispute is unlikely to have implications for the night sky as a commons of significant cultural value. If it is indeed to be relevant, the issue needs to become deep enough to accommodate, and continue to draw the attention and support of academics and corporations for, the non-rivalrous enjoyment of the night sky with the naked eye, for nothing other than to write better poems, have moonlight dinners and marvel at the stars.

As our fight to preserve our ecological commons has hardened in the face of a state bent on destroying them to line the pockets of its capital cronies, I think we have also started to focus on the economic and other tangible benefits this commons offers us – at the cost of downplaying a transcendental right to their sensual enjoyment. Similarly, we shouldn’t have to justify the importance of the night sky as a commons beyond saying we need to be able to enjoy it.

Of course such an argument is bound to be accused of being disconnected from reality, that the internet coverage Starlink offers will be useful for people living in as-yet unconnected or poorly connected areas – and I agree. We can’t afford to fight all our battles at once if we also expect to reap meaningful rewards in a reasonably short span of time, so let me invoke a reminder that the night sky is an environmental resource as well: “Let us be reminded, as we light the world to suit our needs and whims,” a 2005 book wrote, “that doing so may come at the expense of other living beings, some of whom detect subtle gradations of light to which we are blind, and for whom the night is home.”

More relevant to our original point, of the International Day of Light, astronomy and the night sky as a commons, a study published in 2016 reported the following data:

According to the study paper (emphasis added):

The sky brightness levels are those used in the tables and indicate the following: up to 1% above the natural light (0 to 1.7 μcd/m2; black); from 1 to 8% above the natural light (1.7 to 14 μcd/m2; blue); from 8 to 50% above natural nighttime brightness (14 to 87 μcd/m2; green); from 50% above natural to the level of light under which the Milky Way is no longer visible (87 to 688 μcd/m2; yellow); from Milky Way loss to estimated cone stimulation (688 to 3000 μcd/m2; red); and very high nighttime light intensities, with no dark adaption for human eyes (>3000 μcd/m2; white).

That is, in India, ‘only’ a fifth of the population experiences a level of light pollution that obscures the faintest view of the Milky Way – but in Saudi Arabia, at the other end of the spectrum, nearly 92% of the population is correspondingly unfortunate (not that I presume they care).

DOI: 10.1126/sciadv.1600377
DOI: 10.1126/sciadv.1600377

While India has a few red dots, it is green almost nearly everywhere and blue nearly everywhere, lest we get carried away. Why, in March this year, Dorje Angchuk, an engineer at the Indian Astronomical Observatory in Hanle who has come to be celebrated for his beautiful photographs of the night sky over Ladakh, tweeted the following images that demonstrate how even highly localised light pollution, which may not be well-represented on global maps, can affect the forms and hues in which the night sky is available to us.

The distribution of colours also reinforces our understanding of cities as economic engines – where more lights shine brighter and, although this map doesn’t show it, more pollutants hang in the air. The red dots over India coincide roughly with the country’s major urban centres: New Delhi, Mumbai, Kolkata, Guwahati, Hyderabad, Bangalore and Chennai. Photographs of winter mornings in New Delhi show the sky as an orange-brown mass through which even the Sun is barely visible; other stars are out of the question, even after astronomical twilight.

But again, we’re not going to have much luck if our demands to reduce urban emissions are premised on our inability to have an unobstructed view of the night sky. At the same time we must achieve this victory: there’s no reason our street lamps and other public lighting facilities need to throw light upwards, that our billboards need to be visible from above, etc., and perhaps every reason for human settlements – even if they aren’t erected around or near optical telescopes – to turn off as many lights as they can between 10 pm and 6 am. The regulation of light needs to be part of our governance. And the International Day of Light should be a reminder that our light isn’t the only light we need, that darkness is a virtue as well.

Curious Bends – a rabid burden, two caverns of oil, the death of universal marriage and more

1. Over 35% of the world’s rabies burden is borne by India

“A global report on rabies has found India accounts for more than one-third of all deaths due to dog bite worldwide. Worse, the report says, most victims die at home because hospitalization provides little palliative care and death is inevitable. … According to one study, only 70% of the people in India have ever heard of rabies, only 30% know to wash the wounds after animal bites and, of those who get bitten, only 60% receive a modern cell-culture-derived vaccine.” (3 min read, timesofindia.com)

2. Pollution is ruining many iconic monuments in India, not just the Taj Mahal

“In Delhi, the white-marbled Lotus Temple, an architectural triumph and pride of the Bahai faith, is wilting under the onslaught of pollution. The temple was built in 1986 and attracts 400,000 visitors every month. But the pristine marble has been fading, despite regular maintenance. So badly, in fact, that the entire temple may look grey in a matter of years, according to the National Green Tribunal, an arm of the Indian parliament that focuses on environmental issues.” (4 min read, qz.com)

3. A new solar installation will produce electricity for cheaper than coal or natural gas – a first

“In January 2015, Saudi Arabian company ACWA Power surprised industry analysts when it won a bid to build a 200-megawatt solar power plant in Dubai that will be able to produce electricity for 6 cents per kilowatt-hour. The price was less than the cost of electricity from natural gas or coal power plants, a first for a solar installation. Electricity from new natural gas and coal plants would cost an estimated 6.4 cents and 9.6 cents per kilowatt-hour, respectively, according to the U.S. Energy Information Agency.” (9 min read, ensia.com)

4. Thanks to a slump in oil prices, India is filling two caverns with $800 million’s worth of it

“Taking advantage of weak global crude prices, down about 42.5% since July 2014, the government is spending about Rs 4,948 crore to shore up what are called strategic oil reserves, which can be used in emergencies, if crude imports are disrupted. Apart from the natural caverns, concrete tanks are being built at Vishakhapatnam port. Both underground facilities can together hold 1.33 metric tonnes of crude—the equivalent of 1,29,221 truck-tanker loads.” (4 min read, indiaspend.com)

5. Why you can ignore India’s dark monsoon forecast

“While the IMD allows for a wide margin of error of 5% above or below its April predictions, it still rarely gets it right. Even within that 10 percentage point margin of error, its early prediction has been right in only six of the last 21 years.” Simultaneously, “Economists say even if India is hit by another weak monsoon, it is unlikely the country’s grain output will take a huge hit. India’s biggest grain-producing states are more productive than ever and don’t depend on the monsoon anymore.” (3 min read, wsj.com)

Chart of the Week

“The roots of the current [marriage] squeeze go back a generation. Sex-selective abortions became common in China in the 1990s as a result of the country’s strict (now somewhat laxer) one-child-per-couple policy and a traditional preference for sons. A few years later they became increasingly common in India, also because of a preference for sons and helped by the growing availability of prenatal tests to determine sex. In 2010-15, according to the UN Population Division, China’s sex ratio at birth was 116 boys to 100 girls; in India the figure was 111. Though these ratios have fallen a little since their peaks, they are still far above the natural rate, which is 105 to 100. As a result, enormous numbers of girls and women are “missing”—absent, that is, compared with what would have happened if there had not been sex selection.” (11 min read, economist.com)