Download Astronomy Talk July 2016 - Unitarian Universalist Church of

Chalice Lighting Words
“Our seventh Principle may be our Unitarian Universalist way of
coming to fully embrace something greater than ourselves. The
interdependent web … can help us develop that social understanding
of ourselves that we and our culture so desperately need. It is a source
of meaning to which we can dedicate our lives.”
—The Rev. Forrest Gilmore, Executive Director of Shalom Community Center, Bloomington,
IN
Readings
1) The Seventh Principle
We, the Member Congregations of the Unitarian Universalist
Association, covenant to affirm and promote…Respect for the
interdependent web of all existence of which we are a part.”
2) Skeptics and True Believers by Chet Raymo. Page 47
Let this, then, be the ground of my faith: All that we know,
now and forever, all scientific knowledge that we have of this
world, or will ever have, is as an island in the sea [of
mystery]…We live in our partial knowledge as the Dutch live
on polders claimed from the sea. We dike and fill. We dredge
up soil from the bed of mystery and build ourselves room to
grow. And still the mystery surrounds us. It laps at our
shores. It permeates the land. Scratch the surface and
mystery bubbles up like a spring. And occasionally, at certain
disquieting moments in history (Aristarchus, Galileo, Planck,
Einstein), a tempest of mystery comes rolling in from the sea
and overwhelms our efforts, reclaims knowledge that has
been built up by years of patient work, and forces us to retreat
to the surest, most secure core of what we know, where we
huddle in fear and trembling until the storm subsides, and
then we start building again, throwing up dikes, pumping,
filling, extending the perimeter of our knowledge and our
security.
Knowledge is an island in a sea of mystery.
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Presentation:
The Wonders of the Universe
By Dennis Hands,
Unitarian Universalist Church of Greensboro
July 24, 2016
Thank-you Marilyn, for providing the great music for today’s service.
(Slide 1) Today I want to share a few of the recent discoveries in the
field of astronomy. I’m not an astrophysicist and I’m not a
cosmologist. I like to observe and I like to teach. I’ve been doing
astronomy since my parents bought me a telescope when I was about
10 years old.
Along with these discoveries, I also want to share some mysteries that
scientists are working on today. Scientists love mysteries. For Chet
Raymo there is a sea of mysteries. We can find these mysteries both
along the edge of our knowledge and the depth of our understanding.
(Slide 2) To that end, I’d like to share some recent discoveries and
some recently discovered mysteries. I’m not an expert in any of these
specialties, I just love teaching about them. We’ll begin with the whole
universe, shrink our way down to our galaxy, and end with our quest
for life elsewhere.
And I wish to share these in light of the Seventh UU principle, to
respect the interdependent web of existence.
But here’s my problem: it’s the word “respect.”
I think I know how to respect another person, or maybe even the Earth
but how does one respect something that’s everything? I can say “Sir”
and “Ma’am, I can recycle Styrofoam. How do I respect a collection of a
hundred billion stars almost 3 million light years away?
(Slide 3) Let’s first remember our address, where we find ourselves.
We live in the system with one star, 8 planets and some other stuff.
(Slide 4) That solar system is in the Milky Way Galaxy. (Slide 5) And
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our Galaxy is part of a cluster of about 50 galaxies bound by gravity.
There are other clusters out there, near and far. (Slide 6)
Finally there are clusters of clusters, we call them superclusters, (Slide
7) that contain many clusters of galaxies, containing many thousands
of galaxies.
(Slide 8) So here’s a computer generated image of a section of our
universe. It’s called the “cosmic web.” Doesn’t it look like a web?
The universe has about 100 billion galaxies, and they are not evenly
distributed. We see voids, with few galaxies, strands, sheets, and
walls.
Each dot in this image is a cluster of galaxies.
Dark Energy
In 1929 Edwin Hubble discovered evidence that the universe is
expanding. Yes, the universe is bigger today than it was yesterday.
(Slide 9)
There seems to be a tension between two opposing forces, 1) gravity
and 2) expansion. In a cluster, the galaxies can be relatively close
together, making the force of gravity strong between them and holding
the cluster together.
The distance between one super cluster and another super cluster can
be great and that, in turn, makes gravity so weak that instead of
gravity binding them together, the clusters are flying apart from one
another.
In 1998 astronomers, using variable stars and supernova as standard
candles, discovered that the expansion wasn’t slowing down, but was
in fact speeding up. The universe is getting bigger faster today than it
was yesterday. (Note the caption at the top right of the graphic on
slide 9.)
Discovery
In June 2016 astronomers working with the Hubble Space Telescope
observed evidence that the expansion rate is even faster than they
thought.
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The universe is expanding 45 miles of new space per second per mega
parsec. For every 20 billion-billion miles of space, expansion adds 45
miles of new space every second. This makes the distant superclusters
become even more distant.
We’ve claimed a little more knowledge about our universe. Using
Raymo’s analogy we’ve built some extra space on the island of
knowledge. But when we scratch the surface, a mystery bubbles up.
Mystery
Why is the universe accelerating in the first place? If we have an
explosion on Earth, the pieces will fly away but gravity and friction will
eventually slow the expansion and finally stop it. (Slide 10)
What’s making the expansion rate of the universe accelerate?
We don’t know. Einstein hinted at it, and we still don’t know what this
force is, but today we call it dark energy.
Black Holes
(Slide 11) Just last year Gravity Waves were detected for the first
time. The announcement described the detection of waves in the
fabric of space-time and explained that the waves were caused by the
merger of two black holes.
(Slide 12) This physics is way above my pay-grade so please let me
tell you that Gravity Waves are rooted in Einstein’s Theory of General
Relativity. Gravity Waves may provide a completely different way to
observe the universe.
From what scientists could tell, there’re two basic types of black holes.
(Slide 13) Our galaxy has gas and dusk with the stars making a disk,
and we have in the core a super massive black hole (SMBH). (Slide
14) This massive object is about 4 million times the mass of our Sun
and any star or planet that gets too close will fall in and never come
back. (Slide 15)
(Slide 16) By definition, we cannot see black holes. They have so
much matter packed so densely you would have to go faster than the
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speed of light to escape. Since nothing can go faster than the speed of
light, nothing can leave a black hole. not even light.
So how do we detect something we can’t see? We can do this by the
pull of gravity it’s mass has! Here’s an animation of six stars observed
near the center of the Milky Way Galaxy. What are they orbiting?
(Slide 17) Our SMBH is equivalent to about 4 million Suns! And we
can’t see it! Physicists are working on a couple different scenarios that
might explain how these monsters developed.
(Slide 18) The other kind of black hole has been the solar mass black
holes. These are just a few times the mass of the Sun, mostly around 5
to 10 solar masses, but sometimes up to about 20 solar masses. Black
holes are sometimes created as the final stage of a very massive star.
When a massive star runs out of fuel in the core, the very center,
exciting events begin to happen quickly. Inside the star, the outward
pressure caused by nuclear fusion stops and gravity pulls the upper
layers of the star and they fall hard onto the core. These layers then
rebound out into space in what we call a supernova explosion.
(Demonstrate with basketball and tennis ball)
Some supernova explosions obliterate the whole star, recycling all
those elements into space. And some supernova leave a lump several
times the mass of our sun that is so dense, it disappears from our
vision.
So we had solar mass black holes and SMBHs.
Putting celestial objects into categories is one of the things scientists
do. We look for similarities and differences between like objects. This
helps us understand. We’ve claimed a few more feet of island ground.
Our island of knowledge has gotten a bit larger, but still, look at the
shore and out over the sea, and we see that we’re surrounded by
mystery.
Discovery
The detection of gravity waves also ushered in another discovery. If
our understanding of physics is correct and our observations are
accurate, the two black holes that merged to cause these first gravity
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waves were a new class of object. They were each about 30 solar
masses!
(Slide 19) More massive than stellar black holes and less massive
than SMBH, these Intermediate mass black holes are an exciting
discovery.
Mystery
(Slide 20) Let’s go back to the SMBHs in the center of galaxies. It
appears every galaxy has one.
Galaxies have a collection of stars gas and dust, sometimes in a spiral
shapes, and galaxies have a SMBH.
And scientists began to wonder, which came first, the SMBH or the
stars and gas and dust?
Sort of like the chicken and the egg question, which came first? Did a
SMBH form first, and then it gathered a collection of stars and gas and
dust around it? Or did a disk of stars give birth to the SMBH? We don’t
know… Scratch the surface and we have … a mystery!
Aliens?
In 2009 NASA began the Kepler mission. Kepler is a space telescope
dedicated to finding planets in orbit around other stars in a very small
section of the sky.
Discovery
(Slide 21) Scientists working with the Kepler telescope have
confirmed 2,000 new planets and have almost 5,000 more candidates
to study.
Just yesterday (July 23, 2016) NASA announced that the planet K186f,
about 500 Light Years away, is both Earth-sized and in the habitable
zone. That means it’s massive enough to hold onto gas (an
atmosphere?) and close enough to its star to have liquid water on its
surface.
(Slide 22) One thing we’ve learned is that almost every star has at
least one planet.
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(Slide 23) Most of the new exoplanets are larger and more massive
than the Earth. Probably not good for live as we know it.
(Slide 24) Some of these planets are Earth-size. NASA Just announced
that they found that one of these Earth-size planets is in the habitable
zone, where water could exist as a liquid.
(Slide 25) In our solar system, one of the eight planets has life, maybe
intelligent life, but certainly life that has developed technology to
communicate. That’s one planet out of 8, or 12 %. Now 12% of these
2,000 confirmed Kepler-telescope planets is 240.
And the nearest of the Kepler-telescope planets is only about 12 Light
Years away. That means that any kind of electromagnetic radiation
(light, X-rays, radio waves) would take 12 years to san the distance
one-way. So right about now they should be catching the last season
of “Friends” and the first season of “House.”
If our solar system is not that unusual, there ought to be about 240
communicating civilizations among these first 2,000 confirmed
planets.
Mystery
(Slide 26) Where are they? If there are probably so many
communicating civilizations out there, why haven’t we picked up their
radio or TV shows? Why aren’t we watching their version of House?
Maybe they don’t want us to know they’re out there. If they are
picking up our radio and TV news programs, maybe they’ve had
second thoughts about revealing themselves.
Or maybe we’re looking wrong. After all, we’ve just detected gravity
waves. Maybe we are searching incorrectly. Could it be that we
haven’t developed that technology yet?
Or maybe we happen to be the first to advance this far. After all,
someone has to be first. But I doubt it. The odds are against us being
the first civilization advanced enough to make telescopes. We
probably aren’t first.
(Slide 27) The sea of mystery surrounds us. Lapping at our shore of
knowledge are mysteries. We observe and ask more questions.
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What is Dark Energy?
Which formed first in the Milky Way Galaxy, the collection of stars or
the SMBH?
And where is ET?
The structure of our universe is called the Cosmic Web. And, as Carl
Sagan said, “we are a way the universe can know itself.”
In astronomy we learn a few things and we think of more questions to
ask. So we have more mysteries. Could the detection of gravity waves
be the next “tempest of mystery” that will force us to rewrite our
paradigms, re-think our theories and rebuild our models?
Dark energy, black holes and alien life, if there is such a thing: These
are all parts of the Cosmic Web, the web of existence in our Seventh
Principle. So how do we show them respect?
Respect
I think of Sir Isaac Newton’s Third Law of Motion, that for every action
there’s an equal and opposite reaction. When that light from the
planet, star, or galaxy comes through my telescope, it will exit through
the eyepiece and touch my eye. If there’s an equal and opposite
reaction, I’m touching back.
Maybe when we look, and observe, and think about these objects we
are showing respect. When we try to understand a small part of it,
maybe we’re showing respect.
I hope you will too. Every clear Friday the Cline Observatory on the
Jamestown campus of GTCC is open to the public. I invite you to come
out and respectively touch the universe with us.
Thank-you for allowing me to share a few mysteries with you.
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Benediction
As surely as we belong to the universe
we belong together.
We join here to transcend the isolated self,
to reconnect,
to know ourselves to be at home,
here on earth, under the stars,
linked with each other
By The Rev. Margaret Ada Keip (UU minister emeritus, Carmel California)
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