高中生英文通识精读样刊

NASA’s Hubble Space Telescope just revealed a mystery in our cosmic neighborhood. In a paper published Monday in The Astrophysical Journal, researchers using Hubble studied 37 nearby dwarf galaxies — small galaxies containing a few thousand to hundreds of millions of stars — and found that much of the oxygen they expected to see is missing.

Simulations predict that significantly more oxygen, a tracer of a wider set of heavy elements, should reside in these galaxies. So where did it go?

“Oxygen is produced by stars, which are inside of galaxies. We know that the oxygen had to be inside of the galaxies at some point in the past, so the oxygen must have been ejected,” said co-investigator Grace Telford, assistant professor in the Department of Physics and Astronomy at the University of Utah. “And to do that, you need energy from massive stars and supernova explosions to drive material out of the host galaxies and into the space between galaxies.”

Galactic winds unleashed by supernovae are apparently more effective at removing oxygen from low-mass galaxies than current models predict, according to the new study. The findings show that dwarf galaxies can hold onto only a small fraction of the oxygen made by stars.

In the Galaxies Losing Oxygen via Winds (GLOW) project, funded by NASA and the National Science Foundation, scientists traced the oxygen to understand how it is distributed inside stars, in the gas between stars, and in the space between galaxies. But, of all the elements in the galaxies, why study oxygen?

Oxygen, the most abundant element after hydrogen and helium, is relatively easy to detect and measure, and its production is well understood — making it a reliable indicator of how chemical elements are distributed in a galaxy.

“So, it's really for practical reasons that we've chosen oxygen,” said Kristen Wingfield McQuinn, GLOW principal investigator and mission head of the Science Operations Center for NASA’s newly launched, panoramic Nancy Grace Roman Space Telescope at the Space Telescope Science Institute in Baltimore, Maryland. She also is an associate professor at Rutgers University in New Brunswick, New Jersey.

“Oxygen is one of the primary elements formed by stars. Being able to trace how much oxygen gets made, and then how much is distributed inside and outside of galaxies, helps us understand galaxy evolution,” said McQuinn. “It also helps us learn where and how much galaxies are enriching the space between galaxies, called the intergalactic medium.”

The study used archival optical imaging data from Hubble to resolve stellar populations and determine star-formation histories and compositions. Along with data from NASA’s retired Spitzer Space Telescope as well as the ground-based Very Large Array and Australian Telescope Compact Array, the researchers analyzed 37 nearby dwarf galaxies to trace oxygen atoms produced by stars.

The team wanted to understand how oxygen is distributed across the stars, gas, and dust in the galaxies. These dwarf galaxies were selected because their masses fall in the range where simulations and theory predict that an increasing amount of their oxygen will be expelled from the galaxies via supernovae explosions. These 37 galaxies also are all close enough for Hubble to resolve their individual stars.

That's not true for the vast majority of known dwarf galaxies, which are too far away for this kind of study.

Although astronomers already suspected that galaxies expel a large fraction of oxygen and other heavy elements, an open question has been where these metals end up. A previous study from 2014 addressed this question for Milky Way-like, star-forming galaxies, finding that these galaxies lost a large fraction of their oxygen, some of which is found in the diffuse haloes of gas surrounding galaxies outside their disks, called the circumgalactic medium.

In the GLOW study, McQuinn and her team extended this research to low-mass galaxies across a wide range of masses and environments. While previous teams have measured oxygen in the circumgalactic medium of dwarf galaxies, it is still unclear if most of the missing oxygen is in this region, or if it has been completely ejected from the galaxy’s surroundings.

In his 1910 collection Optimos, the American poet Horace Traubel ventriloquized an auctioneer, selling off a dead poet’s “wares”: his dreams, hopes, promises. There are few takers:

No one to bid where so much may be bought? / You would not buy this man in his life — I thought you would buy him in his death. / No? Well the judges somewhere judge — I do not: / I check off all these effects for heaven — let them ascend with their owner : / Those would have made you free.

It was barely a metaphor. For the last twenty years, Traubel had been serving as the literary executor of Walt Whitman, and had been his amanuensis for almost twenty years before that. He put out editions of Leaves of Grass; founded a socialistic Whitman journal, The Conservator; published a Bosworthesque nine-volume memoir titled With Whitman in Camden. In short, he tried desperately to keep the older man’s memory alive.

For Traubel, Whitman was not just a poet but — as the poem above implies — a seer, a font of wisdom, a source of knowledge on life and death.

Nowhere is this conviction clearer than in The Book of Heavenly Death, from 1905. In this short work, Traubel compiled choice excerpts from Leaves of Grass that spoke to Whitman’s conception of immortality. An opening preface adds context from the two’s conversations: “What Spinoza said concerning God, ‘to reason about God is to deny him,’ Whitman said about immortality, to reason about immortality is to deny it” (xvii).

According to scholar Harold Aspiz, Whitman, like his contemporaries Ralph Waldo Emerson and William James, believed immortality to be real because there is an (almost universal) human instinct that it is. For the transcendentalists, immortality was a matter of faith, but available to those who would simply look. Traubel again:

With him immortality was not an argument. It was a vision. Life does not answer the questions of reason. It answers the questions of sight. There was no because or therefore in Whitman’s revelation. Everything about Whitman was this: See. See life. See love. See the soul. See the continuance of identity. See the past. See the future. See the sympathies. See. See.

The phrase “heavenly death” was one of Whitman’s; it appears several times in the poems collected here. Yet Traubel must have been thinking most particularly of number 86, which ends:

I do not doubt that wrecks at sea, no matter what the horrors of them, no matter whose wife, child, husband, father, lover, has gone down, are provided for, to the minutest points, / I do not doubt that whatever can possibly happen anywhere at any time, is provided for in the inherences of things, / I do not think Life provides for all and for Time and Space, but I believe Heavenly Death provides for all.

Traubel had been friends with Whitman since he was a teenager, when he had joined the circle of young men that gravitated around the poet after his move to Camden, New Jersey. Reading the foreword to The Book of Heavenly Death, one still feels the endurance of that youthful admiration, even as he built a career of his own in socialism and journalism.

(In the introduction to a 1912 edition of Leaves of Grass, he wrote of Whitman that “my small boy wonder is having my man’s confirmations”.)

Perhaps that explains the resolute esotericism of this collection: Traubel’s own conviction about Whitman’s stated ideals, coupled with a refusal to see Whitman’s human frailty.

Aspiz points out that in compiling the collection, Traubel left out those of Whitman’s poems about death’s relationship to war or to sex — and perhaps most incriminatingly, “nearly every passage in which death is associated with violence, terror, and pain.” For Aspiz, Traubel was attempting to make Whitman a saint, and there is certainly something of that in Traubel’s description of Whitman’s 1892 demise:

When the Bristol Channel flooded on January 30, 1607, pamphlets describing it as God’s warning to a wayward people likewise flooded out of London’s booming presses. Rare weather events of all sorts are ironically commonplace in seventeenth-century news — a century otherwise tempestuous in its frequent, often literal, chopping and changing in church and state. In fact, the two are reflections of each other.

True, British weather was consistently inconsistent during the Little Ice Age, a period of prolonged cold and wet that would not end for another two centuries. But the headlines reporting “prodigious” thunderstorms, “miraculous” apparitions, and “terrible” earthquakes were often followed by interpretations of them as moral weathervanes — divine providence, a sign to repent and return to the proverbial straight and narrow.

It is perhaps little surprise, then, that the pamphleteer William Jones rushed to the presses when a storm surge inundated 518 square kilometres surrounding the Bristol Channel. Present scholarship counts 2,000 recorded deaths, making it one of Britain’s worst natural disasters and, according to Jones, a judgement from God.

It is difficult to know how much credence a contemporary reader placed in these reports. But that there was wariness of spurious news is evidenced, if anything, by the lengths to which their writers went to assert their credibility.

Some are, granted, no more than lip service: the author of the “tragi-comical” accounts above simply says they include “none but those that are true”. While a third account of the Bristol flood, entitled Lamentable Newes Out of Monmouthshire (1607), makes a more concerted effort, the author saying they initially refused to write on the disaster because “of the usual unfaithfulness of men ordinarily in reporting of such accidents”. More strident authors list the names and addresses of eyewitnesses.

To prove his account of a miraculous rain shower of wheat, the author William Averell lists, among others, a clothier “Master William Geffreyes dwelling in Ipswich” and “John Bull, servant to Justice Germaye”. A True Relation of the Wonderful Apparition of a Cross in the Moon name-drops none other than the Lord Chancellor of Ireland. Generally, the higher up the social ladder a witness was, the more credible they were thought to be.

The pamphlets were immensely popular, questions about their veracity notwithstanding. Overall, the sixteenth and seventeenth centuries witnessed an “early modern vogue for the preternatural”, to quote historian of science Lorraine Daston, a passion for anything whiffing of oddities, the occult, witchcraft, or exotic news from beyond the horizon. The skies above Britain were no different.

This fascination was partly academic: unusual natural phenomena of all sorts stood out in the prevailing scientific paradigm of Francis Bacon as providing a better window into the natural world than simply observing its smooth, quotidian ticking over. But there was also a millenarian culture of moral crisis — tensions between Catholics and Protestants, Roundheads and Cavaliers, Puritans and everyone — that left the public searching for omens.

The apogee of the pamphlet and broadside, “true” and “certain” reports of marvels, wonders, and prodigies of all sorts flooded the market, sold from shops around St Paul’s Cathedral, London, huckstered outside of theatres and alehouses, or carried by peddlers into the countryside.

Not all prodigies, however, were immediately accepted as true signs from on high. Jones argues for the providential nature of the flood in Gods Warning by underscoring its preternatural quality — how animals that would usually fight like cats and dogs did not “express their natural envy”. But other pamphleteers employ historical analogy or theological argumentation to assert that the lightning, hail, or winds they report are more than just bad weather.

The author of A True Report, for example, pairs his description with an account of a flood that happened in 1570, “that comparing the one with the other, God’s justice and mercy may both be seen”. A similar approach is taken by Averell in his report of the rain shower of wheat, prefacing a laundry list of sundry omens, ranging from “the noise and sound of trumpets from the skies” to “showers of blood.” In Lamentable Newes, readers eager to learn about the “great many” who were “utterly undone” advertised on the title page may have been disappointed to first wade through eleven pages of theological exegesis on God’s power, tracking from Adam and Eve through to Noah and the flood.

Separating the showers of wheat from the showers of chaff had real importance at a time when there was widespread acceptance of omens as a true sign of divine judgement. The church and state, as those primarily responsible for upholding a moral society, faced roundabout critique in claims that God was signalling displeasure.

A typical response to poor weather, throughout the period, was to order penitent self-humiliation, prayer, and fasting in church and at home as a plea for divine mercy. But the politics of weather could be particularly pointed when they correlated with specific events, as when a violent thunderstorm shook London immediately after the coronation of Charles II.

Breaking an extended period of consistently pleasant weather, the storm’s timing was striking enough for the diarist Samuel Pepys, otherwise a sceptic of omens, to admit that it was “strange”. In a case of seventeenth-century spin, Charles’ supporters tried to frame the storm as celebratory. Prodigious storms seem to have been more likely to confirm existing biases than lead to groundswells in public sentiment or piety.