Tag: cosmology
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Early quasar illuminates a Universe without metals
The moments after the Big Bang left the Universe very hot and dense. In that violent environment, the first nuclei came to be: hydrogen, helium, and lithium…but nothing heavier. The elements more massive than helium (which astronomers perversely refer to as “metals”) were forged by stars and spread through the Universe as those stars died.…
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Tracking dark energy using galaxy clusters
I write articles and posts on a lot of different topics, both for my own blog and at Ars Technica. Many of those subjects drift pretty far from my putative area of expertise, but occasionally I get to write about something I know pretty well. To wit: last week, a group of researchers using the…
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Halo star haze helps hidden galaxies look huge
(Not fully alliterative, but it’s the best I can do after driving 6 hours today.) The halos of galaxies are best known for harboring dark matter, but they also contain stars. Only a tiny fraction of the total stars in a galaxy are in the halo, so usually they’re hard to spot, but astronomers are…
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You may hate me, but don’t spread your lies to children
I take it personally when idiot politicians call me and my fellow scientists evil liars. My latest post at Galileo’s Pendulum explains why: Broun and his compatriots obviously think very bad things about me, my friends, and the work we do. They don’t just disagree or think we’re wrong, they think we’re literally in league…
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Could quasars be standard candles?
Quasars are some of the brightest objects in the Universe—powerful jets emanating from supermassive black holes as they gorge on gas. However, their light is irregular, both varying in brightness between different quasars and fluctuating in time. A new analysis may have found regularities within those fluctuations, which might allow them to be used as…
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The galaxy from the dawn of time
The first galaxies in the Universe probably played a major part in reionization—the event in which primordial gas was turned into a plasma. However, observations of this era are very hard: we’re looking back in time to when the first stars formed, over 95% of the total age of the Universe. As a result, the…
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The Dark Energy Camera takes its first images
I had the privilege of visiting Fermilab in May, as part of my research for my book-in-progress. While I was there, I got to see the test rig for the Dark Energy Camera (DECam), which looks like something from Stargate or the wormhole entrance from Contact. Unfortunately for me, the camera itself had already been…
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