According to a Greek legend, the sea god Poseidon placed the figure of <a href="/the_universe/Constellations/circumpolar/cassiopeia.html&edu=high&dev=1">Cassiopeia</a> among the stars. It is said that Cassiopeia has a ridiculous upside-down position to punish her for having been pretentious.<p><small><em>Image courtesy of 1995 Visual Language (c). All rights reserved.</em></small></p>According to <a href="http://www.jpl.nasa.gov/news/news.php?release=2013-277">NASA scientists</a>, the Voyager 1 spacecraft entered interstellar space in August 2012, becoming the first spacecraft to leave the <a href="/our_solar_system/solar_system.html&edu=high&dev=1">solar system</a>. The space probe is about 19 billion km from the <a href="/sun/sun.html&edu=high&dev=1">Sun</a>.  <a href="/space_missions/voyager.html&edu=high&dev=1">Voyager 1 and 2</a> were launched in 1977 on a <a href="/space_missions/voyager.html&edu=high&dev=1">mission</a> that flew them both by <a href="/jupiter/jupiter.html&edu=high&dev=1">Jupiter</a> and <a href="/saturn/saturn.html&edu=high&dev=1">Saturn</a>, with Voyager 2 continuing to <a href="/uranus/uranus.html&edu=high&dev=1">Uranus</a> and <a href="/neptune/neptune.html&edu=high&dev=1">Neptune</a>. Voyager 2 is the longest continuously operated spacecraft. It is about 15 billion km away from the <a href="/sun/sun.html&edu=high&dev=1">Sun</a>.<p><small><em>Image courtesy of NASA</em></small></p>How did life evolve on <a href="/earth/earth.html&edu=high&dev=1">Earth</a> during the <a href="/earth/past/Archean.html&edu=high&dev=1">Archean</a>, when the <a href="/sun/sun.html&edu=high&dev=1">Sun</a> was about 25% weaker than today?  The Earth should have been <a href="/earth/polar/cryosphere_glacier1.html&edu=high&dev=1">glaciated</a>, if <a href="/earth/climate/earth_greenhouse.html&edu=high&dev=1">greenhouse</a> gas concentration was the same as today.  <a href="http://www.manchester.ac.uk/aboutus/news/display/?id=10798">Researchers</a> studying the <a href="/physical_science/physics/atom_particle/isotope.html&edu=high&dev=1">isotopic</a> signatures of Earth's early atmosphere in <a href="/earth/geology/rocks_intro.html&edu=high&dev=1">rocks</a> from Northern Australia have ruled out high levels of <a href="/physical_science/chemistry/nitrogen_molecular.html&edu=high&dev=1">nitrogen</a> as a possible way to increase warming from <a href="/earth/Atmosphere/overview.html&edu=high&dev=1">atmospheric</a> <a href="/physical_science/chemistry/carbon_dioxide.html&edu=high&dev=1">carbon dioxide</a>.<p><small><em>Image courtesy of Manchester University</em></small></p>The spinning vortex of <a href="https://www.windows2universe.org/saturn/saturn.html">Saturn</a>'s north polar storm resembles a giant deep red rose surrounded by green foliage in this false-color <a href="http://www.nasa.gov/mission_pages/cassini/multimedia/pia14944.html">image</a> from NASA's <a href="https://www.windows2universe.org/missions/cassini.html">Cassini spacecraft</a>. The eye is 2,000 kilometers across with cloud speeds as fast as 150 meters per second.
It is not known how long this newly discovered north-polar <a href="https://www.windows2universe.org/earth/Atmosphere/hurricane/hurricane.html">hurricane</a> has been active.
The view was acquired at a distance of approximately 419,000 kilometers from Saturn.<p><small><em>NASA/JPL-Caltech/SSI</em></small></p>A group of
  Emperor penguins wait their turn to dive into the ocean near <a
  href="/people/postcards/jean_pennycook_11_29_0.html&edu=high&dev=1">Ross
  Island, Antarctica</a>
  on November 3, 2004.
Emperor penguins routinely dive to 500 meters in
  search of food. Scientists are interested in understanding how they can
  endure the stress of these dives in such an <a
  href="/earth/extreme_environments.html&edu=high&dev=1">extreme
  environment</a>.<p><small><em> Image courtesy of Emily Stone,   National Science Foundation</em></small></p>A near-Earth <a href="/our_solar_system/asteroids.html&edu=high&dev=1">asteroid</a> - named 2012 DA14 by astronomers - passed within 17,200 miles from Earth on February 15, 2013. On closest approach at about 1:25 p.m. CST on February 15, although it was within the orbit of the <a href="/earth/moons_and_rings.html&edu=high&dev=1">Moon</a> and even geosynchronous <a href="/space_missions/satellites.html&edu=high&dev=1">satellites</a>, it didn't strike Earth!  Find out more from <a href="http://www.nasa.gov/mission_pages/asteroids/news/asteroid20130201315144.html">NASA</a>! Fragments of a meteorite hit Chelyabinsk, Russia on 2/15/2013 <a href="http://www.reuters.com/article/2013/02/15/us-russia-meteorite-idUSBRE91E05Z20130215">injuring over 500</a>. Learn about <a href="http://www.windows2universe.org/our_solar_system/meteors/meteors.html">meteors and meteorites</a>.<p><small><em>NASA/JPL-CalTech</em></small></p>

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