Known Universe
(Top Posts - Science - 021509)

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Broadcast on the National Geographic Channel tonight, 
February 15, 2009, at the following times (Central times): 

7:00 PM -- Known Unitverse, The Fastest, examining 
the fabric of space and time. 

8:00 PM -- Known Universe, The Biggest and Smallest, 
the vastness of the universe is discussed. 

9:00 PM -- Known Universe, The Most Explosive, 
deconstructing the biggest explosions in the universe, 
including asteroid impacts, supernovas, and the big 
bang. 

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Space-Time Facts 
  http://channel.nationalgeographic.com/series/known-universe#tab-the-fastest-facts
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Complete article: 

NEED FOR SPEED 

In space, light and time act differently than here on Earth, and 
speed is a different concept when time can theoretically be 
stopped in its tracks. 

THE SPEED DEMON OF THE UNIVERSE 

  a.. Traveling at 100 miles per hour, it would take 14 weeks 
  to get to the moon, 50 years to get to Mars, and about 
  3,100 years to reach the outermost planet Neptune 

  b.. The speed of light is 186,000 miles per second, or 
  approximately 670 million miles per hour. 

  c.. No matter how fast you are moving when you observe 
  it, the speed of light will always be 186,000 miles per 
  second. 

  d.. Nothing in the universe travels faster than light. 

  e.. At the speed of light, time stops. 

WHAT IF AN HOUR COULD BE A MINUTE? 

  a.. Time is relative to the person observing it and time may 
  change depending on how fast the observer is moving. 

  b.. Time passes more slowly for satellites in orbit when 
  compared to time on Earth because those satellites are 
  moving. 

  c.. Satellites used for the Global Positioning System are 
  launched with their clocks running faster so that when 
  they reach orbit they mark time the same as Earth- 
  based clocks. 

  d.. Because time passes more slowly in orbit around Earth, 
  astronauts arrive home a little younger than if they had 
  spent the same amount of time on Earth. 

  e.. If you were to travel near the speed of light for what 
  seems to be 20 years, you would return to Earth thou- 
  sands of years in the future. 

PLAYING WITH SPACE-TIME 

  a.. In physics, the three dimensions of space and the fourth, 
  separate dimension of time combine to form a single con- 
  struct throughout the cosmos called space-time. Using 
  space-time, scientists can measure both the place and 
  time something occurs in one mathematical unit. 

  b.. Gravity is the result of massive objects weighing down 
  the fabric of space-time, much as a heavy ball would 
  warp a rubber sheet. 

  c.. Wormholes are theoretical tunnels through the fabric 
  of space-time that could allow travelers to navigate 
  tremendous distances instantaneously. 

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Big & Small Facts 
  http://channel.nationalgeographic.com/series/known-universe#tab-size-matters-facts
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Complete article: 

SIZE MATTERS 

BIG THINGS IN SPACE 

  a.. More than 99% of our solar system's mass is the sun. 

  b.. More than one million earths could fit comfortably inside 
  the sun. 

  c.. In 2006, the discovery of Eris, which is larger than Pluto, 
  demoted the latter's status from a planet to a dwarf planet. 
  In May of 2008, the International Astronomical Union 
  changed both dwarf planets' status to plutoids. 

  d.. Earth is in what's known as the "Goldilocks" zone: not 
  too hot and not too cold. That's because it is 93 million 
  miles away, the perfect distance from the sun. If it was 
  5% closer, searing heat would wipe the surface clean. 
  Make it 10% further away and the planet would turn into 
  a frozen wasteland covered with glaciers miles thick. 

  e.. Eighty years ago, we thought the entire universe consisted 
  of what we now know as the Milky Way galaxy. In reality, 
  our galaxy is just one of hundreds of billions of others. 

  f.. Space is extremely vast. Each galaxy is home to around 
  200 billion stars. This is more stars than there are grains 
  of sand on all the beaches of planet Earth. 

  g.. Our Milky Way galaxy has a diameter of 100,000 light 
  years. If you could take a flashlight and beam it across 
  the galaxy, it would take the light 100,000 years to reach 
  the other side. 

  h.. Back in the 1990s, we hadn't discovered any planets 
  around other stars outside our solar system. As of today, 
  we've discovered over three hundred. 

  i.. The Kepler telescope, scheduled to launch in February 
  2009, will look for other Earth-like planets around other 
  sun-like stars. 

SMALL THINGS ON EARTH 

  a.. The human hair is about the thinnest thing you can see 
  with your naked eye. That hair is about 300,000 atoms 
  wide. 

  b.. The atom is 99.9999999999% empty space. 

  c.. If an atom was expanded to the size of a large cathedral, 
  the nucleus would be the size of a housefly, and that 
  housefly would be heavier than the entire cathedral itself. 

  d.. Life on Earth was made possible by the death of stars. 
  The debris of exploding stars in the Big Bang manufac- 
  tured the atoms of which the human body is composed, 
  which means we are all made of 'star stuff!' 

  f.. When you take a glass of water and you drink oxygen 
  atoms, what you're really drinking is the remnants of a 
  star explosion. 

  g.. There are 92 chemical elements in the natural world, 
  and with the exception of the six noble gases, they inter- 
  mingle in some astounding ways. For example, from the 
  marriage of a corrosive solid (sodium) and a toxic gas 
  (chlorine), we get salt. Another instance is with two of 
  nature's most explosive elements, hydrogen and oxygen. 
  They combine rather ironically to form our life source, 
  water. 

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Explosive Facts 
  http://channel.nationalgeographic.com/series/known-universe#tab-the-most-explosive-facts
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Complete article: 

BLOWING UP THE UNIVERSE 

Our planet is vulnerable to a surprisingly varied number of 
roads to destruction. Let's hope we can avoid demolition for 
at least the next couple of thousand years. 

MAN'S CONTRIBUTION 

  a.. The largest nuclear weapon ever detonated was a 
  50-megaton hydrogen bomb dubbed the Tsar Bomba. 
  The weapon was detonated in northern Siberia by the 
  Soviet Union in 1961. 

  b.. The 2004 earthquake in Indonesia that spawned a 
  devastating tsunami had the power of roughly 32 giga- 
  tons of TNT - 650 times more powerful than our most 
  powerful nuclear detonation. 

THE SUN - AN EVENTUAL THREAT? 

  a.. The temperature of the sun's core is 27 million degrees. 

  b.. The sun is powered by nuclear fusion. Every second it 
  fuses hundreds of millions of tons of hydrogen into helium. 

  c.. It can take a particle of light created at the sun's core 
  1 million years to find its way to the surface. 

  d.. Sunlight takes eight minutes to travel from the sun to 
  Earth. 

  e.. Near the end of its life, the sun will swell into a red giant 
  and could swallow Earth. 

SUPERNOVAE AND ASTEROIDS 
AND GAMMA RAYS, OH MY! 

  a.. When a star explodes, it is called a supernova. 

  b.. In an average galaxy, supernovae occur on average 
  twice a century. 

  c.. A typical supernova will emit more energy than our 
  sun will during its entire 10- billion-year lifespan. 

  d.. Supernovae are so bright they can outshine every 
  other star in the galaxy. 

  e.. Supernovae only occur in large stars at least nine 
  times as massive as our sun. 

  f.. On average, about every 100 million years all organ- 
  isms weighing more than 50 pounds die due to a large 
  asteroid impact. 

  g.. Scientists believe that 65 million years ago, an asteroid 
  measuring 6 miles in diameter struck Earth off the coast 
  of the present-day Yucatan Peninsula, killing the dino- 
  saurs. 

  h.. Every day Earth is pelted with 25 tons of sand- and 
  dust-sized particles coming in from space. 

  i.. About once a year a meteor the size of a car enters 
  the Earth's atmosphere. 

  j.. About every 100 years a space rock the size of the 
  Statue of Liberty impacts Earth. 

  k.. The most powerful explosions ever witnessed in the 
  universe are gamma-ray bursts, which are mega- 
  supernovae that shoot jets of deadly high-energy 
  radiation, or gamma rays. 

  l.. A gamma-ray burst is trillions of times brighter than 
  our sun. 

  m.. If a gamma-ray burst occurred within 6,000 light 
  years of Earth, it could wreak havoc on the planet. 

THE BIGGEST BANG OF THEM ALL 

  a.. The most powerful explosion in history was the 
  explosion that created the universe. We call it the 
  big bang. 

  b.. The big bang was not an explosion of matter into 
  an empty space, but an explosion of space and 
  of time, which were both created by the event. 

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When watching the 2nd episode of the Known
Universe, I discovered some info on the launch
of the Kepler space telescope on March 5, an
adventure that will likely discover some of the
multitude of likely earthlike planets in the coming
years:

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February 15, 2009 
Earth-like planet could be 
discovered within three years 
  http://www.guardian.co.uk/science/2009/feb/15/earth-galaxy-planet-life 
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Excerpts: 

Galaxy has billions of planets that support life forms, 
says leading astronomer 

A planet similar to Earth could be discovered in a 
distant solar system within three years, according 
to a leading astronomer. 

Planets that support life forms could be common in 
the universe, and about 100 billion of them may exist 
in our own galaxy, said Dr Alan Boss, a researcher 
at the Carnegie Institute for Science in Washington. 

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[insert -- With over 200 billion galaxies, if Boss is 
correct that would equate to over 100 billion times 
200 billion earthlike planets in the known universe. 
That's 20,000,000,000,000,000,000,000 which 
is 20 sextillion earthlike planets in the known uni- 
verse. -- end excerpt] 
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... 

The US space agency, Nasa, is due to launch a 
space telescope, called Kepler, dedicated to 
searching for planets that are similar to, or smaller 
than Earth. 

... 

The Kepler telescope will gaze continuously at 
100,000 stars in two constellations known as 
Cygnus and Lyra for more than three years. 

"Within three to four years from now, these tele- 
scopes will tell us just how frequently Earths 
occur. It's an exciting time to be alive," Boss 
said. 

... 

"If we find that Earth-like planets are as common 
as I'm claiming, we'll make a very strong case that 
not only are they probably habitable, they are also 
going to be inhabited, but that will be up to the 
next generation of space telescopes to prove," 
Boss said. 

... 

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