I’ve already reported on some of the big themes that the researchers were obsessing over at the recent meeting of the American Astronomical Society – the self-proclaimed “Woodstock of astronomy.” But one big theme I haven’t discussed yet is data mining, extracting significant findings from huge, unwieldy archives of information. In that spirit, I’ve data mined the meeting itself, looking and listening for the recurring terms that define the hottest areas of research about the universe and our place within it. Dark is a ubiquitous word in astronomy and cosmology today. It is also highly unnerving, because everything we know about the universe comes from detectable radiation or particles. Anything truly dark is, then, undetectable and mysterious. “Dark matter” is material that cannot be seen but is
The cluster Cygnus OB2, about 5,000 light years from Earth, is a hotbed of star formation. This composite image combines optical, X-ray, and infrared views. (Credit: NASA/CXC/SAO/J.Drake et al; Univ. of Hertfordshire/INT/IPHAS; NASA/JPL-Caltech) only inferred from its gravitational tug. “Dark energy” is a putative repulsive force that permeates the universe, speeding up the cosmic expansion that began with the Big Bang. Both of these terms were used so often and so loosely at the astronomy conference that it is easy to forget just how bizarre they are. The structure and the dynamics of the universe are dominated by two “dark” things that we know absolutely nothing about. Cosmic Dawn, in contrast, is every bit as hopeful as it sounds. Very early in cosmic history, the universe was an opaque fog of amorphous gas (or so the theoretical models show). Then at some point—within a few hundred million years—the first ultramassive stars formed, flooding the universe with radiation and stripping electrons off of atoms, rendering the universe transparent. This era, which also gave rise to the first protogalaxies and early black holes, is the earliest observable stage of the modern universe. Mapping out what was happening then is one of the key jobs for the upcoming James Webb Space Telescope (see below). Transients are a catch-all term for anything that goes blink in the night. That includes exotic objects such as pulsars (fast-spinning stellar remnants), supernova explosions, gamma ray bursts, flares around black holes, and microlensing events—in which the gravity of one object temporarily magnifies the light of another one lying farther away. Traditional observatories were geared toward making long, sensitive images of the sky and so were terrible at finding things that change quickly. But California’s Palomar Observatory, once the very definition of old-school astronomy, is now home to the Palomar Transient Factory. True to its name, it produced nine different papers at the astronomy conference, including the discovery of catastrophically colliding pairs of white dwarf stars in the Andromeda Galaxy. Python might seem like a surprising obsession for astronomers, and yet there was a day-long session devoted to it. Python is actually a programming language (named, in true computer-geek style, after Monty Python) that provides a flexible, economical way to analyze large scientific datasets. Such as the cost of success. Astronomers have become expert at building detectors that collect vast amounts of digital data. Now much of their work consists of expert number crunching. Actually looking through a telescope is purely an amateur sport at this point. Exoplanet, also known as “extrasolar planet”: This word does not even exist in the Merriam-Webster dictionary but it is on everybody’s lips in astronomy today—so much so that it has crossed over from scientific jargon into mainstream news coverage. An exoplanet is any planet circling a star other than our sun (“exo” is “outside” and “planet” is “wanderer” in ancient Greek). The word is everywhere because exoplanets are everywhere, too. Science fiction writers used to assume that other worlds were plentiful in the universe and now we know they were right: There are probably hundreds of billions of planets in our galaxy alone, apparently including water worlds, iron worlds, diamond worlds, comet worlds, backwards worlds, and—increasingly likely—truly earthlike worlds. Migration explains how many of those planets came to be. Once upon a time (by which I mean 1995, the year that astronomers found the first planets around other sunlike stars), people used to think that our solar system formed in an orderly way, with each planet born pretty much in its present location. Now we know that the planets “migrated,” or moved into different orbits, during those early days. Around other stars the process was much more extreme, sending Jupiter-like worlds spiraling inward to searing-hot, star-grazing orbits. Do other planets get consumed entirely? Did our own solar system contain an earlier generation of lost worlds? What makes a planet careen 99% the way in toward its star but then stop short? Those kinds of questions are energizing researchers now. Decadal Survey is not a study but rather a report—a hugely influential, 324-page report put together by the National Research Council—that identifies the top scientific priorities in astronomy over the next 10 years. As such it has a tremendous influence on what projects get funded and what kind of research actually happens. Not surprisingly, the latest version the survey (formally, Astro2010: The Astronomy and Astrophysics Decadal Survey) has generated as much grumbling as plaudits. Even in a collaborative field like astronomy there are lots of competing interests, and some researcher muttered that politics, not science, explained why the survey provides so little support for the further study of exoplanets. JWST. Any time you get scientists together the acronyms flow like keg beer at a frat party. You can ignore most of them but this one matters. It is the James Webb Space Telescope, NASA’s sort-of successor to the Hubble Space Telescope. It will peer even deeper into space and provide our best shot yet at catching a glimpse of what was happening at Cosmic Dawn after its launch in 2018. It is also the most expensive telescope ever lofted into space, so its success has come at the cost of other projects. ALMA is the Atacama Large Millimeter/submillimeter Array, an innovative network of radio telescopes now under construction in northern Chile. It will provide extremely detailed observations of the kinds of radiation emitted by infant stars before they begin to shine. That should lead to a much better understanding of how stars and planets are born in nearby gas clouds, and also of how entire galaxies come together from their raw materials. WFIRST, the Wide-Field Infrared Space Telescope, is the #1 big-ticket priority according to the Decadal Survey. It is a kind of Swiss-Army Watch of a mission, capable of observing distant galaxies, structures within our galaxy, supernova explosions, and exoplanets as they pass in front of other stars. LSST, the Large Synoptic Survey Telescope, is another Decadal Survey top pick—this one the #1 priority among ground-based projects. LSST’s neat trick is that is more movie camera than telescope, mapping the whole sky over and over again in nearly real time. That makes it a great tool for finding strange transient phenomena. And like WFIRST, it’s an all-purpose machine that can keep a lot of different kinds of research going during a period of fiscal austerity. Color kept coming up in conversation at the Astronomical Society meeting, but not in a celestial context. There was a surprising amount of funky hair color at the meeting, including one dramatic pink spiked mohawk. A sign of social change in the once-sedate field of astronomy. LGBTIQ/WGLE provide another sign of change. Those letters have nothing to do with a telescope or research project; they stand for Lesbian/Gay/Bisexual/Transgender/Intersexed/Questioning, and the Working Group on LGBTIQ Equality. Their meetings have become much more visible and, I’m glad to say, seemed to be greeted in a very matter-of-fact way. (You will notice that the second acronym is an acronym of an acronym—astronomers just cannot resist.) More research is required. And some things just do not change at all. Nearly every major presentation ended with some variation on the classic scientist’s plea. --
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