The Universe Throws Yet Another Solveable Mystery at Us

So many cool science stories, so little time! Against the backdrop of the ongoing saga of Rosetta at Comet 67P (and cool results are starting to flow from the Philae lander, which I’ll talk about in another entry), the rest of the universe has been ticking merrily away, providing a constant stream of fascinating information.

Artist’s concept of the large-scale structure of the universe. Courtesy European Southern Observatory.

For example, here’s a story to get your thinking, It involves the large-scale structure of the universe and a curious property of quasars. You know what a quasar is, right? It’s an active supermassive black hole at the center of a galaxy. There are countless numbers of these eerily bright objects scattered throughout the universe. These incredibly massive black holes are usually surrounded by dense, hot disks funneling material into the black hole. This action produces tremendous jets of superheated material threaded with strong magnetic fields. These jets extend out across many light-years of space.

These objects, called quasars (short for quasi-stellar radio sources) are incredibly bright in radio frequencies, as well as visible light. Astronomers studying quasars measure various characteristics in order to understand what they’re doing and what effects they have on their galaxies. One such characteristic is the spin of a quasar — its spin rate and its spin axis.

A research team using the European Southern Observatory’s Very Large telescope has been studying light polarized light streaming from 93 of these quasars spread out across billions of light-years, as they appeared when the universe was about one-third of its current age. (Polarized light can give hints about the accretion disk and its spin direction.) To their surprise, the observers have found that the rotation axes of those quasars are parallel to each other.

This video shows that if you back off a little and look at the distribution of galaxies across billions and billions of light-years, you see them fall into a graceful cosmic web of filaments and clumps outlining huge voids where there are few galaxies. This is called the “large-scale structure of the universe”. When the astronomers superimposed the quasars in their study over a map of the large-scale structure, they found that nearly all of the rotation axes of the quasars pointed along the filaments they existed in at that time. (If you want to know the details of how the astronomers found this amazing alignment, check out this press release from ESO.)

This arrangement is not just by chance. There’s a physical reason WHY this is happening — perhaps due to the influence of nearby dark matter? It’s not clear yet why these early quasars are spinning away in parallel across vast distances in the early cosmos. This finding will certainly be added to cosmologist’s working models of the early universe!

Comet 67: the Gift that Keeps on Giving

OSIRIS spots the Philae lander "skipping" across the surface during its landing last week.  Courtesy: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

OSIRIS spots the Philae lander “skipping” across the surface during its landing last week. Courtesy: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Okay, I’ve just seen two “wow!!!” images today that I have to share with you.  The first is a sequence of images taken by the Rosetta mission’s OSIRIS imaging system that shows the Philae lander making its first “bounce” on the surface of Comet 67P/Churyumov-Gerasimenko, and then lifting off and traversing up to a kilometer above the surface before bounding again and then finally landing partially shadowed by a cliff. It’s an amazing feat of imaging ability. Keep in mind that the comet is more than 513 million kilometers away from Earth moving at a speed of 18.5 kilometers per second!  So, all this is being done long distance, via an orbiter that is itself busy mapping and studying the comet.

The Philae lander is, as you have probably heard, in hibernation now. It had a good day or so of data gathering after its spectacular landing last week. By early Saturday (central European time, early evening U.S. time), its batteries had gotten very depleted  and the solar panels weren’t getting enough sunlight to keep up with the electrical demand. The mission teams ordered it to send back all the data, and now they’re poring over that information to learn more about it. Then, with people around the world watching (via Twitter and other social media), the lander said good night and went to sleep. It may be awakened early next spring when the amount of sunlight it receives should be higher.

I studied comets back in grad school, and this mission has had a special significance for me. It now shows me what we all imagined comets MIGHT look like if one could get “up close and personal”. I’ll be following this mission as it progresses, and I encourage you to do the same at the Rosetta blog. 

Now, let’s look at our second image of the day.

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