Tracing Dark Matter with Ripples in the Whirlpool Galaxy

A new paper presented at this week’s American Astronomical Society conference promises to shine some light, so to speak, on the pursuit of dark matter in individual galaxies. The current model of cold dark matter in the Universe is extremely successful when it comes to mapping the mysterious substance on large scales, but not on galactic and sub-galactic scales. Earlier today, Dr. Sukanya Chakrabarti of Florida Atlantic University described a new way to map dark matter by observing ripples in the hydrogen disks of large galaxies. Her work may finally allow astronomers to use their observations of ordinary matter to probe the distribution of dark matter on smaller scales.
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Unlocking Cosmology With Type 1a Supernovae

Let's face it, cosmologists catch a lot of flack. It's easy to see why. These are people who routinely publish papers that claim to ever more finely constrain the size of the visible Universe, the rate of its breakneck expansion, and the distance to galaxies that lie closer and closer to the edges of both time and space. Many skeptics scoff at scientists who seem to draw such grand conclusions without being able to directly measure the unbelievable cosmic distances involved. Well, it turns out cosmologists are a creative bunch. Enter our star (ha, ha): the Type 1a Supernova. These stellar fireballs are one of the main tools astronomers use in order to make such fantastic discoveries about our Universe. But how exactly do they do it?
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Testing the Multiverse... Observationally!

The multiverse theory is famous for its striking imagery. Just imagine our own Universe, drifting among a veritable sea of spontaneously inflating “bubble universes”, each a self-contained and causally separate pocket of higher-dimensional spacetime. It’s quite an arresting picture. However, the theory is also famous for being one of the most criticized in all of cosmology. Why? For one, the idea is remarkably difficult, if not downright impossible, to test experimentally. But now, a team of British and Canadian scientists believe they may have found a way.
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Ancient Galaxies Fed On Gas, Not Collisions

The traditional picture of galaxy growth is not pretty. In fact, it’s a kind of cosmic cannibalism: two galaxies are caught in ominous tango, eventually melding together in a fiery collision, thus spurring on an intense but short-lived bout of star formation. Now, new research suggests that most galaxies in the early Universe increased their stellar populations in a considerably less violent way, simply by burning through their own gas over long periods of time.
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Most Distant Quasar Opens Window Into Early Universe

Astronomers have uncovered yet another clue in their quest to understand the Universe’s early life: the most distant quasar ever observed. At a redshift of 7.1, it is a relic from when the cosmos was just 770 million years old – just 5% of its age today.
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Cosmology in the Year One Trillion

Much of what is known today about the birth of the cosmos comes from astronomical observations at high redshifts. Due to the accelerated expansion of the Universe, however, astronomers of the future will be unable to use the same methods. In a trillion years or so, our own Milky Way galaxy will have merged with the Andromeda galaxy, creating a new galaxy that has been quaintly termed “Milkomeda.” All of our other galactic neighbors will have long disappeared beyond our cosmological horizon. Even the CMB will have been stretched into invisibility. So how will future Milkomedans study cosmology? How will they figure out where the Universe came from?
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Full story at Universe Today.