The Great Attractor

The Great Attractor

   Sounds ominous, doesn't it, as if a label straight out of Hollywood or a campaign ad from an aspiring politician.  But no, this is something much larger than a societal or cultural trend; in fact, this is larger than our entire planet, our solar system, and even our entire galaxy.  It's tentatively named, Laniakea, a native Hawaiian term for "immeasurable heaven."  And it is one object just recently discovered in space.

   So how big IS this single cosmic discovery?  It's much too large to fathom in today's world, but basically it is large enough to swallow 100,000 galaxies the size of our Milky Way (or put another way, about 100 quadrillion --that's a billion million-- times the mass of our sun).  It all appeared in an article in Discover, an article by Corey Powell about our place in space.  And did I mention, our Milky Way Galaxy is in this huge mass?

   The article highlights the work of catographer, Brent Tully, who works in Hawaii and treats distant galaxies more as points on a map, markers if you will, each providing a path to a more distant point.  But he noticed that something had such a strong gravitational pull that despite our Big Bang and its force outward, entire galaxies were being drawn into this path "downtown," as he puts it.  Over a century ago, astronomer Harlow Shapley showed that we were pretty much located on the edge of our Milky Way galaxy.  Our Milky Way belongs to a meager gathering of about 54 galaxies called the Local Group, explains the article.  The Local Group lies on the outskirts of a much greater clumping of galaxies called the Local Supercluster, which collectively are on the fringes of Laniakea.  If the Great Attractor is downtown, we are truly in the cosmic boondocks.

   This came to mind (that of how remote we are and how seemingly safe we tend to feel) as I again watched Hyperspace, a BBC series attempting to simply explain some of the dazzling wonders of our known universe.  In one episode on black holes, it was pointed out that a massive black hole, over 4 million times the mass of our sun, exists at the center of our Milky Way.  Should gravitational fields ever vary too much, such a black hole would easily gobble up planets such as ours (even the much larger Jupiter) and eventually our own sun.  Yet when a gas cloud called G2 recently neared this black hole, instead of scientists seeing the cloud pulled apart like taffy, the scientists saw little if any action.  Was this because the black hole didn't exist (indeed, there has emerged a growing field of scientists who are disputing the existence of black holes as told in another article in Discover by the same author).  Or was it because rather than being a gas cloud it was really a massive star hidden within a gas cloud? 

   Okay, keep in mind that again, a) this is a blog and not subject to fact checking (although I do try my best to stay accurate and provide links for further study), and b) I am not an astronomer or astrophysicist or even close to being one .  But here's what I found interesting in my lay readings.  Our earth wobbles, just slightly but enough to make GPS satellites have to adjust their calibrations 38-millionths of a second each day!  The wobble is steady, and cycles every 25,700 years.  Add to this, an orbital shift which occurs every 109,000 years and another one which happens every 405,000 years, and scientists were suddenly aware that they'd have to begin adjusting their instruments to this shifting perspective...in one case, the star 61 Cygni was 1/100,000 of a degree off at different times of viewing (it's "an effect known as parallax," says the article in Discover).  But what's even more interesting is that that discovery was made in 1838.  By the 1960s, physicist Irwin Shapiro showed that the gravity of our sun would delay a radar signal bounced off of Mercury (once when the planet was closest to the sun and the other when it was furthest away) by 2/100,000,000 of a second.  Today's instruments show "that at just 1 foot higher in elevation, a clock ticks four-hundred quadrillionths faster per second."
  
   If it all seems far too much to take in, just imagine the new calculations with going on with the Great Attractor, a gravitational pull apparently strong enough to lure entire galaxies in line.  The Hubble Space Telescope celebrated 25 years in space last month (showing what appeared to be black holes was among its first discoveries;  two years later, it would appear to find dark matter).  Click on the NASA link previous and you'll find that what we see, and what we measure, is estimated to make up just about 5% of our known universe; the rest in invisible to us.  Some scientists speculate that black holes pull everything in, even light, and possibly shoot it out the other side, creating its own Big Bang...multi-verses, or universes beyond our understanding, much as we are discovering now with such massive objects as Laniakea.

   The Atlantic had an interesting side piece titled Mystery Killers by health writer, Jeremy N. Smith.  In the piece about tracking health records, the author opens with: Considering we live in the age of big data, we know astonishingly little about why people die.  Each year, more than 50 million deaths occur around the globe—and for all but a fraction, the actual cause goes unrecorded.  That’s a major obstacle to improving public health: How can we save lives if we don’t understand what threatens them?

   It was indeed ironic that in a time when we can measure time and things to the quadrillionth power, we are losing so many people without notice.  So it was a double entendre of sorts when I read about the Laniakea discovery:  Laniakea is measurable, said the article, and with this latest discovery, researchers have come closer than ever to defining humanity's true place within the heavens.  Perhaps we have on one end; but it seems that we apparently still have an unimaginable ways to go on another.