HOW BIG IS THE UNIVERSE

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HOW BIG IS THE UNIVERSE?
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HOW BIG IS THE UNIVERSE?

• The universe is a pretty big place. And its
  full of empty space (empty parts of the
  universe). To try to get a better idea of what
  its like, were going to cut it down to
  sizeabout the size of a mile-wide balloon. Its
  enough to give you a headache!

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HOW BIG IS THE UNIVERSE?

• What happens if you try to breathe in space?
• You would lose consciousness from a lack of
  oxygen and would die.
• It is estimated that there are only 1 or 2
  atoms/m3 in space!

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HOW BIG IS THE UNIVERSE?

• Lets take a little stroll through the Universe,
  have a look around, and try to sort things out
  according to size. Picture, for a moment, that
  the observable Universe is like a gigantic
  balloon, some 24 billion light years across.

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HOW BIG IS THE UNIVERSE?

• Light Year the distance that light travels in
  one year
• Speed of Light 186,000 mi/sec
• So, one light year is about 6 trillion miles!

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HOW DO SPEEDS COMPARE?

• Human Walking .......... 2-4 mi/hr
• Human Running . 15 mi/hr
• Cheetah Running . 80 mi/hr
• Indy 500 Car . 200 mi/hr
• Passenger Jet . 500 mi/hr
• Speed of Sound (Mach one) . 750 mi/hr
• Space Shuttle Launching . Mach 23
• Meteorite (shooting star) . Mach 32
• Earth orbiting the Sun . Mach 90
• Speed of Light . Mach 1,000,000
• (1 million times the speed of sound)

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HOW BIG IS THE UNIVERSE?

• Suppose we could somehow suck the air out of
  that balloon. (Of course, we know there is no
  air out there what we have to remove is a lot
  of empty space). What we want to do is make that
  balloon a sphere approximately one mile in
  diameter.

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HOW BIG IS THE UNIVERSE?

• Now, put our Milky Way in the center. What would
  this do to the sizes and distances of everything
  else out there?

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SIZE OF THINGS IN SPACE (scaled down)

• Earth Basketball
• Sun Beach Ball
• Betelgeuse (giant red giant) 27x school
• Solar System 5.5 light hours to Pluto
• Galaxy (Milkyway) about 100 billion stars
• Universe (Everything) about 100 billion
  galaxies

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SIZE OF THINGS IN SPACE (scaled down)

• If the sun was 1 in diameter, the Earth would
  be at Graeters.
• Betelgeuse
• - 560 light years away
• - 700x the diameter of our sun
• - 1000 feet in diameter compared to the Earth
• - Would engulf out to the asteroid belt past
  Mars

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HOW BIG IS THE UNIVERSE?

• Well, thats a mighty interesting question. It
  turns out that given a mile wide Universe, our
  Milky Way, with its 100 billion or so stars (and
  its diameter of 81,000 light years) would be
  reduced to the size of an aspirin. (Hmmm.. A
  headache already?)
• To span the Milky Way at a speed of 25,000
  mi/hr (speed of the space shuttle), it would take
  millions of centuries to get across.

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HOW BIG IS THE UNIVERSE?

• About five or so empty inches away would be
  another aspirin the Andromeda Galaxy our
  closest galactic neighbor.

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HOW BIG IS THE UNIVERSE?

• The Milky Way and Andromeda actually belong to a
  rather small cluster of 40 galaxies. Astronomers
  humbly call it The Local Group. The nearest
  cluster is more than two feet away.

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HOW BIG IS THE UNIVERSE?

• At about 10 feet from our aspirin, things would
  start to get really interesting. Wed arrive at
  the Virgo Cluster of some 200 galaxies (er,
  aspirins, that is) in a volume the size of a
  soccerball. Each galaxy has about 500 billion
  stars!

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HOW BIG IS THE UNIVERSE?

• Our Local Group is gravitationally bound
  (attracted) to the Virgo Cluster, which is
  actually some 50 million light years away. A
  short stroll of 65 ½ feet, and wed come to the
  Coma Cluster, containing not hundreds, but
  thousands of galaxies.

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HOW BIG IS THE UNIVERSE?

• At a distance of about 148 feet, we would find
  the powerful radio-emitting galaxy Cygnus-A. It
  occupies a spot right smack in the middle of a
  constellation we call the Northern Cross.

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HOW BIG IS THE UNIVERSE?

• Could Cygnus-A have a black hole an object so
  dense not even light can escape from it? Maybe.
  Theory says black holes can give off radio noise
  as matter is pulled into them.

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HOW BIG IS THE UNIVERSE?

• Farther out, wed find more and more galactic
  clusters some even larger than the Coma Cluster
  separated by immense empty gulfs. The most
  distant objects known to us are the quasars.

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HOW BIG IS THE UNIVERSE?

• The brightest one, called by the incredibly
  uninspired name 3C273, would find us only 426 ½
  feet from the Milky Way. The farthest quasar we
  know about would be nearly a quarter of a mile
  away.

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HOW BIG IS THE UNIVERSE?

• And this is as far as weve gotten. The rest of
  the Universe, over half of it, is still a
  mystery. If the Universe were a mile wide, wed
  only have direct knowledge of a half-mile of it.
  Scientists think the Universe will expand forever.

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HOW BIG IS THE UNIVERSE?

• There you have it then. Not much of a stroll.
  On that scale, the Solar System would be smaller
  than an atom, and the nearest star to us about 10
  millionths of an inch away.

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HOW BIG IS THE UNIVERSE?

• On the real scale of things, 10 millionths of an
  inch is equal to about ¼th of a micron. A micron
  is approximately 5000 atoms lined up shoulder to
  shoulder.

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HOW BIG IS THE UNIVERSE?

• At the United States Naval Observatory, we have a
  star-platemeasuring machine that can measure the
  position of stars to within a quarter of a
  micron. STARSCAN is what we call it. This
  machine is used with our Transit Circle
  Telescopes, which tell us a stars latitude and
  longitude in the heavens.

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HOW BIG IS THE UNIVERSE?

• Together, they are so good at measuring star
  positions, that we could, at least in theory,
  travel to the star Alpha Centauri (distance 25.3
  trillion miles) and not have to make a single
  navigational instrument correction on the entire
  journey. We could just sit back and enjoy the
  ride.

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HOW BIG IS THE UNIVERSE?

• Now, thats pretty good measuring, considering
  the size of things out there, dont you think?
• Written by Gail S. Cleere
• U.S. Naval Observatory