Astronomy – Close Read

Science’s humankind shield

We need to reconsider where the notion that “science benefits all humans” comes from and whether it is really beneficial.

I was prompted to this after coming upon a short article in Sky & Telescope about the Holmdel Horn antenna in New Jersey being threatened by a local redevelopment plan. In the 1960s, Arno Penzias and Robert Wilson used the Holmdel Horn to record the first observational evidence of the cosmic microwave background, which is radiation leftover from – and therefore favourable evidence for – the Big Bang event. In a manner of speaking, then, the Holmdel Horn is an important part of the story of humans’ awareness of their place in the universe.

The US government designated the site of the antenna a ‘National Historic Landmark’ in 1989. On November 22, 2022, the Holmdel Township Committee nonetheless petitioned the planning board to consider redeveloping the locality where the antenna is located. According to the Sky & Telescope article, “If the town permits development of the site, most likely to build high-end residences, the Horn could be removed or even destroyed. The fact that it is a National Historic Landmark does not protect it. The horn is on private property and receives no Federal funds for its upkeep.” Some people have responded to the threat by suggesting that the Holmdel Horn be moved to the sprawling Green Bank Telescope premises in Virginia. This would separate it from the piece of land that can then be put to other use.

Overall, based on posts on Twitter, the prevailing sentiment appears to be that the Holmdel Horn antenna is a historic site worthy of preservation. One commenter, an amateur astronomer, wrote under the article:

“The Holmdel Horn Antenna changed humanity’s understanding of our place in the universe. The antenna belongs to all of humanity. The owners of the property, Holmdel Township, and Monmouth County have a historic responsibility to preserve the antenna so future generations can see and appreciate it.”

(I think the commenter meant “humankind” instead of “humanity”.)

The history of astronomy involved, and involves, thousands of antennae and observatories around the world. Even with an arbitrarily high threshold to define the ‘most significant’ discoveries, there are likely to be hundreds (if not more) of facilities that made them and could thus be deemed to be worthy of preservation. But should we really preserve all of them?

Astronomers, perhaps among all scientists, are likelier to be most keenly aware of the importance of land to the scientific enterprise. Land is a finite resource that is crucial to most, if not all, realms of the human enterprise. Astronomers experienced this firsthand when the Indigenous peoples of Hawai’i protested the construction of the Thirty Meter Telescope on Mauna Kea, leading to a long-overdue reckoning with the legacy of telescopes on this and other landmarks that are culturally significant to the locals, but whose access to these sites has come to be mediated by the needs of astronomers. In 2020, Nithyanand Rao wrote an informative article about how “astronomy and colonialism have a shared history”, with land and access to clear skies as the resources at its heart.

Also read:

One argument that astronomers arguing in favour of building or retaining these controversial telescopes have used is to claim that the fruits of science “belong to all of humankind”, including to the locals. This is dubious in at least two ways.

First, are the fruits really accessible to everyone? This doesn’t just mean the papers that astronomers publish based on work using these telescopes are openly and freely available. It also requires that the topics that astronomers work on need to be based on the consensus of all stakeholders, not just the astronomers. Also, who does and doesn’t get observation time on the telescope? What does the local government expect the telescope to achieve? What are the sorts of studies the telescope can and can’t support? Are the ground facilities equally accessible to everyone? There are more questions to ask, but I think you get the idea that claiming the fruits of scientific labour – at least astronomic labour – are available to everyone is disingenuous simply because there are many axes of exclusion in the instrument’s construction and operation.

Second, who wants a telescope? More specifically, what are the terms on which it might be fair for a small group of people to decide what “all of humankind” wants? Sure, what I’m proposing sounds comical – a global consensus mechanism just to make a seemingly harmless statement like “science benefits everyone” – but the converse seems equally comical: to presume benefits for everyone when in fact they really accrue to a small group and to rely on self-fulfilling prophecies to stake claims to favourable outcomes.

Given enough time and funds, any reasonably designed international enterprise, like housing development or climate financing, is likely to benefit humankind. Scientists have advanced similar arguments when advocating for building particle supercolliders: that the extant Large Hadron Collider (LHC) in Europe has led to advances in medical diagnostics, distributed computing and materials science, apart from confirming the existence of the Higgs boson. All these advances are secondary goals, at best, and justify neither the LHC nor its significant construction and operational costs. Also, who’s to say we wouldn’t have made these advances by following any other trajectory?

Scientists, or even just the limited group of astronomers, often advance the idea that their work is for everyone’s good – elevating it to a universally desirable thing, propping it up like a shield in the face of questions about whether we really need an expensive new experiment – whereas on the ground its profits are disseminated along crisscrossing gradients, limited by borders.

I’m inclined to harbour a similar sentiment towards the Holmdel Horn antenna in the US: it doesn’t belong to all of humanity, and if you (astronomers in the US, e.g.) wish to preserve it, don’t do it in my name. I’m indifferent to the fate of the Horn because I recognise that what we do and don’t seek to preserve is influenced by its significance as an instrument of science (in this case) as much as by ideas of national prestige and self-perception – and this is a project in which I have never had any part. A plaque installed on the Horn reads: “This site possesses national significance in commemorating the history of the United States of America.”

I also recognise the value of land and, thus, must acknowledge the significance of my ignorance of the history of the territory that the Horn currently occupies as well as the importance of reclaiming it for newer use. (I am, however, opposed in principle to the Horn being threatened by the prospect of “high-end residences” rather than affordable housing for more people.) Obviously others – most others, even – might feel differently, but I’m curious if a) scientists anywhere, other than astronomers, have ever systematically dealt with push-back along this line, and b) the other ways in which they defend their work at large when they can’t or won’t use the “benefits everyone” tack.

They’re trying to build a telescope

If a telescope like the TMT and a big physics experiment like the INO are being stalled for failing to account for the interests and sensibilities of the people already living at or near their planned sites, what should scientists do when they set out to plan for the next big observatory or similar installation at a new site? A new paper published by Nature on August 18, by a bunch of researchers from China, describes in great detail their efforts to qualify a new “astronomical observing site”. “On Earth’s surface,” their paper begins, “there are only a handful of high-quality astronomical sites that meet the requirements for very large next-generation facilities. In the context of scientific opportunities in time-domain astronomy, a good site on the Tibetan Plateau will bridge the longitudinal gap between the known best sites (all in the Western Hemisphere). The Tibetan Plateau is the highest plateau on Earth, with an average elevation of over 4,000 metres, and thus potentially provides very good opportunities for astronomy and particle astrophysics.” In the paper, the researchers explain their estimates of the available observing time; seeing with a differential image motion monitor; and air stability and turbulence and water vapour over the site – near a town named Lenghu in the Qinghai province (central China).

Such exhaustive detail may be common when it comes to qualifying one astronomical observing spot over another, but information about the mountain, the town, the people who live there, how they use the land, the cultural significance of their natural surroundings and – given that Qinghao is on the Tibetan plateau – if the installation of a telescope, if and when that happens, will be perceived as yet another form of colonialism by the Chinese state are all conspicuous by absence. I’m sure most readers of this blog are familiar with the TMT – short for Thirty-Meter Telescope – story: residents of Mauna Kea, where the observatory is to be built, protested and stopped its construction in 2014. Work resumed only in 2019 after a series of interventions, one outcome of which was that the international astronomy community had to reckon with its colonial history and present. Let me quote at length from an article Nithyanand Rao wrote for The Wire Science in 2020, about the “shared history” of astronomy and colonialism:

[Leandra] Swanner finds that for native Hawaiians, “science has effectively become an agent of colonisation”, “fundamentally indistinguishable from earlier colonisation activities”. This puts astronomers in a difficult position. They see the economic benefits astronomy brings to Hawai’i – over a thousand jobs, business for local firms and services and, once the TMT comes online, a promise to pay $1 million in annual lease rent — and their own work as a noble pursuit of knowledge. However, they encounter opposition that has charged them with environmental and cultural destruction.
“Unfortunately for the astronomers involved in the TMT debate,” writes Swanner, “whether they identify as indigenous allies or neocolonialists ultimately matters less than whether they are perceived as practicing neocolonialist science” (emphasis in the original).
Astronomers have attempted a counter-narrative, linking the contemporary practice of astronomy to ancient Polynesian explorers and astronomers who navigated using the stars. A concrete outcome and centrepiece of this effort was a science education centre and planetarium that “links to early Polynesian navigation history and knowledge of the night skies, and today’s renaissance of Hawaiian culture and wayfinding with parallel growth of astronomy and scientific developments on Hawaii island.”
Swanner notes the unequal relationship – the centre “merely grafts Native Hawaiian culture onto the dominant culture of Western science … Astronomers do not look to traditional knowledge to carry out their observing runs, after all, but the observatories studding the summit physically deny access to sites of sacred importance.”

The story of the India-based Neutrino Observatory is equally cynical, and equally problematic in a different way. When I commissioned Rao, and Virat Markandeya, to investigate the INO’s ‘situation’ in 2016, some four years after the Indian government had permitted its constriction, for The Wire, I assumed that it was being held back by bureaucratic inefficiency, as is so common in India, and a mulch of pseudoscience and regional politics in Tamil Nadu. But when they were pursuing the story, I learnt of a small but interesting detail: since 2010, India has required any agency that prepares an environmental impact assessment report (for a project that might damage the environment) to be accredited by the Quality Council of India. The INO collaboration’s report had been prepared by an unaccredited body, and this presented a stumbling block. Members of the collaboration – physicists – thought this was okay, just a minor detail, but to the people protesting the project, it was one thorn among many that they’d come to identify with numerous projects that governments have approved in India and which have overlooked the rights of the people living near those projects. And in the INO’s case, the principal offenders have been the Department of Atomic Energy and the Tamil Nadu Pollution Control Board, helped along of late by the Ministry of Environment, Forests and Climate Change. It struck me that people overlooking the little things was, for many of those at the receiving end of the new India’s ‘acche din’, a perfectly legitimate reason to suspect something was up. I’m bummed that the INO isn’t being built (and in fact could be cancelled, if the state’s new chief minister M.K. Stalin has his way – although I was confused when he expressed his opposition to the INO but his government had, a month or so ago, allowed the embattled Sterlite copper-smelting unit in Thoothukudi to reopen) but I wouldn’t have the project’s still being stalled any other way.

The problem is what counts as due process, and who gets to decide. As Swanner has noted, a bunch of astronomers “grafting” one idea onto another was for them the right way to go – but it’s of little use to the people in Hawai’i who are afraid of losing access to what is to them a culturally and spiritually significant location, in exchange for something originally conceived to benefit other people. (It was also quite ironic when astronomers were pissed after SpaceX’s Starlink constellation satellites began to obstruct astronomical observations of the night sky, and began to complain that the sky is a global commons, etc. It’s perhaps a greater irony that India – which contributes to 10% of the TMT collaboration – wants the telescope to be shifted away from Mauna Kea, to a different site, because of the threat of future protests – the same India that has almost amended all the country’s environmental laws to include a ‘pay and pollute’ clause.) The INO outreach team has insisted that it conducted regular and effective outreach among the people of Theni, the district in which the INO’s site is located, but they may have overlooked the wider environment of cynicism and bureaucratic dishonesty in which their efforts, and the public perception of those efforts, was couched.

Environmental activist and writer (and my former teacher) Nityanand Jayaraman told me sometime between 2016 and 2020 that at no time did the governments of India and Tamil Nadu nor the INO collaboration give themselves or the people of Theni opposed to the project the option of moving the experiment to a different location. When the latter group did demand that the project be moved away, members of the INO collaboration and other scientists that Rao and Markandeya spoke to countered that the protestors’ reasons were pseudoscientific (most of them were pseudoscientific) – but this was hardly the point. The protestors had no need to be scientific any more than they had to be guaranteed their rights and other entitlements. (It nags me that ‘solving’ the latter is a much larger problem than the proponents of one project could accommodate, but I don’t know what else I’d advocate.)

And now, astronomers in China have published a paper expressing their excitement about having spotted a new location at which to mount a telescope, themselves overlooking considerations of whether the people who are already there might be okay with it. As a result they may have effectively shut one option out. This is an important factor because, as Rao has written (see excerpt below), many people seem to think that Hawaiians’ resistance to the TMT and others of its kind on the islands is fairly recent; this is not true. They expressed their opposition how they could; the rest of us didn’t pay attention. From Rao’s article:

For a historically informed understanding of the conflict, we have to go back much further, to Hawaii’s annexation by the US in 1898, following which land was ceded to the US government.
In 1959, these lands – including Mauna Kea – were in turn ceded by the US government to the State of Hawai’i, which held them “in trust” for native Hawaiians. The next year, a tsunami laid waste to the city of Hilo in Hawai’i, prompting its chamber of commerce to write to universities in the US and Japan suggesting that Mauna Kea might be useful for astronomical observatories. This event coincided with US astronomers’ interest in Hawai’i as well.
And so the conflict between native Hawaiians and the American astronomy community began in the 1960s, when the first of the 13 observatories was constructed on the mountain that the former consider to be “a place revered as a house of worship, an ancestor, and an elder sibling in the mo’okū’auhau (or genealogical succession) of all Hawaiians.”
At the time, writes [Iokepa] Casumbal-Salazar, “there was no public consultation, no clear management process and little governmental oversight.” Environmentalists soon began opposing further construction on the mountain, arguing that the existing telescopes had contaminated local aquifers and destroyed the habitat of a rare bug found only on the mountain’s summit. …
Contrary to the narrative that native Hawaiians did not oppose the first telescopes on Mauna Kea in the 1960s and 1970s, Casumbal-Salazar shows how they did indeed express their dissent “in the few public forums available, by writing newspaper editorials, publishing opinion pieces and speaking out at public events” while also fighting other battles, such as those to reclaim their rights to land, resources, cultural practices — even the right to teach their children in the Hawaiian language.
They were also fighting evictions and resettlements in the name of tourism development and decades of the US Navy’s use of an island as target practice for its bombs. At the same time, the state’s dependence on tourism and militarism resulted in income inequalities and emigration. …
Similarly, native communities and environmentalists opposed the Kitt Peak National Observatory in Arizona, concerned about the ecology and “spiritual integrity” of the mountain. At the time the new observatory was proposed, Kitt Peak was already host to two dozen telescopes.

Today, moving the TMT or any of the other observatories away will be no small feat: they draw hundreds of thousands of dollars in grants and investments every year, not to mention setting them up took decades of work. To echo Jayaraman, not having any observatories here is no longer an option. And this is the same future the new Chinese Nature paper seems to augur: pick a spot, plan a telescope, and then ask the locals if they’re okay with it. If they’re not, tough luck. To borrow a few words from the abstract of Casumbal-Salazar’s thesis, it will become another push for a telescope “realised through law and rationalised by science”.

(I’m not sure if a lot of people got the headline – a play on the name of a song by System of a Down.)

Rupavardhini B.R. read a draft of this post before it was published.

‘World class’ optical telescope – India’s largest – to be activated near Nainital

Update: This article was written before the telescope was activated yesterday. Here’s the PIB announcement.

India’s largest ground-based optical telescope, in Devasthal in Uttarakhand, is set to be switched on on March 30 by the Prime Ministers of India and Belgium from Brussels, during Narendra Modi’s day-long visit to the country. The telescope is the product of an Indo-Belgian collaboration, assisted by the Russian Academy of Sciences, that was kicked off in 2007. It is going to be operated by the Aryabhatta Research Institute of Observational Sciences (ARIES), an autonomous research body under the Department of Science and Technology.

The instrument is part of a widening foray into observational research in astronomy that India has undertaken since the 1960s, and bolstered with the successful launch of its first multi-wavelength satellite (ASTROSAT) in September 2015. And apart from the merits it will accord Indian astronomy, the Devasthal optical telescope will also be Asia’s largest ground-based optical telescope, succeeding the Vainu Bappu Observatory in Kavalur, Tamil Nadu.

A scan of the sketch of the 3.6-m optical telescope. Credit: ARIES

Its defining feature will be a 3.6-metre-wide primary mirror, which will collect light from its field of view and focus it onto a 0.9-m secondary mirror, which in turn will divert it into various detectors for analysis. This arrangement, called the Ritchey-Chrétien design, is also what ASTROSAT employs – but with a 30-cm-wide primary mirror. In fact, by contrast, the mirrors and six instruments of ASTROSAT all weigh 1,500 kg while the Devasthal telescope’s primary mirror alone weighs 4,000 kg.

A better comparison would be the Hubble space telescope. It manages to capture the stunning cosmic panoramas it does with a primary mirror that’s 2.4 m wide. However, Hubble’s clarity is much better because it is situated in space, where Earth’s atmosphere can’t interfere with what it sees.

Nonetheless, the Devasthal telescope is located in a relatively advantageous position for itself – atop a peak 2.5 km high, 50 km west of Nainital. A policy review published in June 2007 notes that the location was chosen following “extensive surveys in the central Himalayas” from 1980 to 2001. These surveys check for local temperature and humidity variations, the amount of atmospheric blurring and the availability of dark nights (meeting some rigorous conditions) for observations. As the author of the paper writes, “The site … has a unique advantage of the geographical location conducive for astronomical observations of those optical transient and variable sources which require 24 h continuous observations and can not be observed from [the] east, in Australia, or [the] west, in La Palma, due to day light.”

From this perch, the telescope will be able to log the physical and chemical properties of stars and star clusters; high-energy radiation emanating from sources like blackholes; and the formation and properties of exoplanets. The data will be analysed using three attendant detectors:

High-resolution Spectrograph, developed by the Indian Institute of Astrophysics, Bengaluru
Near Infrared Imaging Camera, developed by the Tata Institute of Fundamental Research, Mumbai
Low-resolution Spectroscopic Camera

“India has collaborated with a Belgian company called AMOS to produce this [telescope], which is the first of its kind in the whole of Asia,” said Vikas Swarup, spokesperson of the Ministry of External Affairs, in a statement. AMOS, an acronym for Advanced Mechanical and Optical Systems, was contracted in 2007 to build and install the mirrors.

When Modi and Michel complete the so-called ‘technical activation’ to turn the Devasthal instrument on, it will join a cluster of scopes at the Indian astronomical research community’s disposal to continue surveying the skies. Some of these other scopes are the Giant Metre-wave Radio Telescope, Pune; Multi Application Solar Telescope, Udaipur; MACE gamma-ray telescope, Hanle; Indian Astronomical Observatory, Leh; Pachmarhi Array of Cherenkov Telescopes, Pachmarhi; and the Ooty Radio Telescope, Udhagamandalam.

In fact, over the last few years, the Indian research community has positioned itself as an active player in international Big Astronomy. In 2009, it pitched to host a third advanced gravitational-waves observatory, following the installation of two in the US, and received governmental approval for it in February 2016. Second: in December 2014, India decided to become a full partner with the Thirty Meter Telescope (TMT) collaboration, a bid to construct an optical telescope with a primary mirror 30 metres wide. After facing resistance from the people living around the venerated mountain Mauna Kea, in Hawaii, atop which it was set to be built, there are talks of setting it up in Hanle. Third: in January 2015, the central government gave the go-ahead to build a neutrino observatory (INO) in Theni, Tamil Nadu. This project has since stalled for want of various state-level environmental clearances.

All three projects are at the cutting edge of modern astronomy, incorporating techniques that have originated in this decade, techniques that take a marked break from the conventions in use since the days of Galileo. That Modi has okayed the gravitational waves observatory is worth celebrating – but the choices various officials will make concerning the INO and the TMT are still far from clear.

The Wire
March 30, 2016

Rocky exoplanets only get so big before they get gassy

By the time the NASA Kepler mission failed in 2013, it had gathered evidence that there were at least 962 exoplanets in 76 stellar systems, not to mention the final word is awaited on 2,900 more. In the four years it had operated it far surpassed its envisioned science goals. The 12 gigabytes of data it had transmitted home contained a wealth of information on different kinds of planets, big and small, hot and cold, orbiting a similar variety of stars.

Sifting through it, scientists have found many insightful patterns, many of which evade a scientific explanation and keep the cosmos as wonderful as it has been. In the most recent instance of this, astronomers from Harvard, Berkeley and Honolulu have unearthed a connection between some exoplanets’ size, density and prevalence.

They have found that most exoplanets with radii 1.5 times more than Earth’s are not rocky. Around or below this cut-off, they were rocky and could hypothetically support human life. Larger exoplanets – analogous to Neptune and heavier – have rocky cores surrounded by thick gaseous envelopes with atmospheric pressures too high for human survival.

“We do not know why rocky planetary cores begin to support thick gaseous layers at about 1.5 Earth radii as opposed to 1.2 or 1.8 Earth radii, and as the community answers this question, we will learn something about planet formation,” said Lauren Weiss, a third year graduate student at UC Berkeley.

She is the second author on the group’s paper published in Proceedings of the National Academy of Sciences on May 26. The first author is Geoff Marcy the “planet hunter”, who holds the Watson and Marilyn Alberts Chair for SETI at UC Berkeley.

Not necessarily the bigger the heavier

The planets of the Solar System. Image: Lsmpascal

The group analyzed the masses and radii of more than 60 exoplanets, 33 of which were discussed in the paper. “Many of the planets our study straddle the transition between rocky planets and planets with gaseous envelopes,” Weiss explained. The analysis was narrowed down to planets with orbital periods of five to 100 days, which correspond to orbital distances of 0.05 to 0.42 astronomical units. One astronomical unit (AU) is the distance between Earth and the Sun.

Fully 26.2% of such planets, which orbit Sun-like stars, have radii 1 to 1.41 times that of Earth, denoted as R_⊕, and have an orbital distance of around 0.4 AU. Accounting for planets with radii up to 4R_⊕, their prevalence jumps to more than half. In other words, one in every two planets orbiting a Sun-like star was bound to be just as wide to eight times as wide as Earth.

And in this set, the connection between exoplanet density and radius showed itself. The astronomers found that the masses of Earth-sized exoplanets steadily increased until their radii touched 1.5R_⊕, and then dropped off after. In fact, this relationship was so consistent with their data that Weiss & co. were able to tease out a relation between density and radius for 0-1.5R_⊕ exoplanets – one they found held with Mercury Venus and Earth, too.

Density = 2.32 + 3.19R/R_⊕

So, the astronomers were able to calculate an Earth-like planet’s density from its radius, and vice versa, using this equation. Beyond 1.5R_⊕, however, the density dropped off as the planet accrued more hydrogen, helium and water vapor. At 1.5R_⊕, they found the maximum density to be around 7.6 g/cm³, against Earth’s 5.5 g/cm³.

The question of density plays a role in understanding where life could arise in the universe. While it could form on any planet orbiting any kind of star, we can’t also forget that Earth is the only planet on which life has been found to date. It forms an exemplary case.

There’s nothing inbetween

Figuring out how many Earth-like planets, possibly around Sun-like stars, there could be in the galaxy could therefore help us understand what the chances are like to find life outside the Solar System.

And because Earth leads the way, we think “humans would best be able to explore planets with rocky surfaces.” In the same way, Weiss added, “we would better be able to explore, or colonize, the rocky planets smaller than 1.5 Earth radii.”

This is where the astronomers hit another stumbling block. While data from Kepler showed that most exoplanets were small and in fact topped off at 4R_⊕, the Solar System doesn’t have any such planets. That is, there is no planet orbiting the Sun which is heavier than Earth but lighter than Neptune.

“It beats all of us,” Weiss said. “We don’t know why our Solar System didn’t make sub-Neptunes.” The Kepler mission is also responsible for not providing information on this front. “At four years, it lasted less time than a single orbit of Jupiter, 11 years, and so it can’t answer questions about the frequency of Jupiter, Saturn, Uranus, or Neptune analogs,” Weiss explained.

It seems the cosmos has lived up to its millennia-old promise, then, as more discoveries trickle in on the back of yet more questions. We will have to keep looking skyward for answers.

A brief description of galactic clusters and their detection

The oldest galaxies are observed today as elliptical, and to be found in clusters. These clusters are the remnants of older protoclusters that dominated the landscape of outer space in the universe’s early years, years that witnessed the formation of the first stars and, subsequently, the first galaxies. In regions of space where the population density of stars is low and the closest cluster farther away from the closest star, more recently formed galaxies may be found. These relatively emptier regions are called ‘general fields’.

A galaxy takes hundreds of millions of years to form fully, and involves processes quite complex; imagine, the simplest among them are nuclear transmutations! At the same time, the phenomenology of the entire sequence – the first steps taken, the interaction of matter and radiation at large scales, the influence of the rest of the universe on the galaxy’s formation itself – can be understood by peering into history through some of Earth’s most powerful telescopes. The farther through their lenses we look, the deeper into the universe’s history we are gazing. And so, looking hard enough, we may observe a protocluster in its formative years, and glean from the spectacle the various forces at play!

That is what two astronomers and their team from the National Astronomical Observatory of Japan (NAOJ) have done. Using the Multi-object Infrared Camera and Spectrograph (MOIRCS – mounted on the Subaru Telescope), Drs. Masao Hayashi and Tadayuki Kodama identified a highly dense and active protocluster 11 billion light-years from Earth (announced September 20, 2012). In other words, the cluster they are looking at exists 11 billion years in our past, at a time when the universe was only 2.75 billion years old! Needless to say, it makes for an excellent laboratory, one that need only be carefully observed to answer our burning questions.

The first among them is why galaxies “choose” to cluster themselves. The protocluster, as usual named inelegantly as USS1558-003, actually consists of three large closely-spaced clusters of galaxies, with an astral density as much as 15 times that of the general fields in the same cosmic period and a star-formation rate equivalent to a whopping 10,000 Suns/year. These numbers effectively leave such clusters peerless in their formative libido, as well as naked in the eyes of infrared telescopes such as the MOIRCS, without with such bristling cosmic laboratories could not have been found.

Because of the higher star-formation rate, a lot of energy is traded between different bits of matter. However, there is an evident problem of plenty: what do the telescopes look for? Surely, they must somehow be able to measure the amount of energy riding on each exchange. However, the frequency of the associated radiation is not confined to any one bracket of the electromagnetic spectrum – even if only thermal or visible radiation is being tracked. What exactly do the telescopes look for, then?

Leave alone the quintillions of kilometers; the answer to this question lies in the angstroms, within the confines of hydrogen atoms. Have a look at the image below.

The galaxies marked by green circles are emitting radiation with a wavelength of 656 nm, also called H-alpha radiation. It falls within what is called the Balmer series of hydrogen’s emission spectrum, named for Johann Balmer, who discovered the formula for the eponymous series of emission-frequencies in 1885. The presence of an H-alpha line in the emitted radiation is an unmistakable sign of the presence of hydrogen: Radiation is emitted at precisely 656 nm (in the form of a photon of that wavelength) when excited electrons in the hydrogen atom drop from the third to the second energy levels.

The Balmer series, and the H-α line, are important tools used in astronomical spectroscopy: It is not just that they indicate the presence of hydrogen, but where and in what quantities, too. Those values throw light on which stages of formation the stars of that galaxy are in, the influence of the reactive region’s neighborhood, and where and how star-formation is initiated. In fact, by detecting and measuring the said properties of hydrogen, Kodama et al have already found that, in a cluster, star-formation begins at the core – just where the density of extant stars is already high – and gradually spreads outward to its periphery. In the present-day, this finding contrasts with the shape and structure of elliptical galaxies, which have a different mass distribution from what an in-to-out star-formation pattern suggests.

These are only the early stages of Kodama’s and his team’s research. As they sum it up,

We are now at the stage when we are using various new instruments to show in detail the internal structures of galaxies in formation so that we can identify the physical mechanisms that control and determine the properties of galaxies.

Not that it needs utterance, but: This is important research. Astronomy and astrophysics are costly affairs when the genre is experimental and the scale quite big, rendering finds such as that of USS1558-003 very providential as well as insightful. We may have just spotted the Higgs boson, we may just have begun on a long journey to find the smallest thing in the universe. However, as it stands, of the largest things in the universe we have very little to say, too.