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Saturday, July 30, 2016

WHERE IS PLANET EARTH IN OUR UNIVERSE?

The simple answer is that experts don't know where we are in our Universe.  According to one report, there is no center of the universe and no edge.  According to another, the observable Universe is 46 billion light years across.  How incredibly precise, when we seem not to know much.

All this is certainly confusing to me, for, if the Big Bang occurred 13.8 billion years ago, the fastest the edge can be moving away from that bang can't be more than 13.8 billion light years, so how can the edge of what we see be further away than 13.8 BLY( billion light years) x 2, or 27.6 BLY?

Sure, I know that our Universe is growing at an accelerated rate, but light can't go faster than the speed of light...or can it?  Apparently, yes, it can.  In any case, if you were not aware of what smart elementary school students know, in one second light travels a distance 7.5 times around our planet, which in one year, or one light year (LY), is nearly 6 trillion miles.  The three stars closest to us, in the Alpha Centauri system, are 25 trillion miles away.

Can you believe that our best minds, even with the Hubble and other high tech tools, aren't sure of the shape of our Universe?  (That omega symbol represents the critical density of the cosmos.)


Worse, according to these scientists, we can see and measure only 4.6% of what exists:

No one knows what dark matter and dark energy are.  Even something so out there as black holes....you want to guess how many are just in our galaxy?  100 million, and, of course, the one in the middle of our disk.  Has anyone ever photographed a black hole?  Nope.

Einstein predicted this phenomenon exactly a hundred years ago.  Today, a team is in the planning stages of combining the capabilities of 50 radio telescopes, to be named the Event Horizon Telescope, and point this system to the middle of our galaxy and hope to succeed in making the first photograph.  Wait, a minute, if black holes are at the middle of any galaxy and we can see many of them, why hasn't anyone ever taken a photo of one?  Even if they are invisible, just the absence of everything should be a good a shot as any.  Anyway, these are three speculations.


Beginning with all the above, it is remarkable what we do know. Most of us, when we look into a clear sky at night, even with binoculars, only see space and twinkles.  I still marvel at how Galileo Galilei 400 years ago detected planet Neptune (below). I  have difficulty with Saturn and its rings, and I have a Celestron.  Galileo, incidentally, while being harassed by the Roman Inquisition, lived to the age of 77 when the life expectancy in those days was in the lower 40's.


In any case, astronomers know exactly where Planet Earth is in our Milky Way Galaxy.  So what are you seeing to the right?  Click on it if you can't read the fine print, but towards the bottom is our Sun.  To appreciate the vastness of space, the time it would take for light to travel from one end of our galaxy to the other is 100,000 years.  Jesus Christ, for Heaven's sake, was only 2,000 years ago.

Our Milky Way is in an assemblage of 54 galaxies, mostly dwarfs, called The Local Group, seen to the left.  The diameter of TLG is 10 million light years.

As a helpful aside, the closest real galaxy to ours is Andromeda (right--certainly looks like ours), 2.5 million light years away, which you can  actually barely see as a tiny fuzzy blur if you know where to look.  Here is something frightening:  in four billion years, our two galaxies will collide.  Actually, not so scary, because the space between each star is so vast that they will all co-exist within a larger galaxy.


We are all then in the Virgo Cluster of 300 Local Groups (up to 2000 galaxies--and each has from 100 billion to a trillion stars), around 110 light years across.  As there are, perhaps, 100 billion to a trillion galaxies, there should then be from 10 to the 22nd power to 10 to the 24th power stars in the sky.

R. Brent Tully of the University of Hawaii and Helene Courtois of the University of Lyon, then went on to identify a supercluster of 100,000 galaxies, and named it Laniakea, Hawaiian for immeasurable Heaven.


The insignificance of the Laniakea Supercluster is that it represents, maybe, 0.01% to 0.001% of the observable Universe.

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Typhoon Nida is about to strike northern Philippines, and appears next headed for Hong Kong:


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