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&dev=">solar system</a>. The space probe is about 19 billion km from the <a href="/sun/sun.html&dev=">Sun</a>.  <a href="/space_missions/voyager.html&dev=">Voyager 1 and 2</a> were launched in 1977 on a <a href="/space_missions/voyager.html&dev=">mission</a> that flew them both by <a href="/jupiter/jupiter.html&dev=">Jupiter</a> and <a href="/saturn/saturn.html&dev=">Saturn</a>, with Voyager 2 continuing to <a href="/uranus/uranus.html&dev=">Uranus</a> and <a href="/neptune/neptune.html&dev=">Neptune</a>. Voyager 2 is the longest continuously operated spacecraft. It is about 15 billion km away from the <a href="/sun/sun.html&dev=">Sun</a>.<p><small><em>Image courtesy of NASA</em></small></p>On May 20, 2013, a massive EF5 <a href="http://www.windows2universe.org/earth/Atmosphere/tornado.html">tornado</a> hit Moore, Oklahoma, devastating communities and lives.  The tornado, on the ground for 40 minutes, took a path through a subdivision of homes, destroying block after block of homes, and hitting two elementary schools just as school was ending as well as a hospital. Hundreds of people were injured, and 24 were killed.<p><small><em>Image courtesy of Ks0stm, Creative Commons Attribution-Share Alike 3.0 Unported license</em></small></p>Greenland's <a href="http://www.windows2universe.org/earth/polar/cryosphere_glacier1.html">ice sheet</a> saw a record <a href="http://www.windows2universe.org/headline_universe/olpa/greenland_10dec07.html">melt</a> in July 2012.  Scientists studying this event have found that this melting event was triggered by an influx of unusually warm air and amplified by the presence of a blanket of thin low-level <a href="http://www.windows2universe.org/earth/Atmosphere/cloud.html">clouds</a> which pushed temperatures up above freezing.  For more information see the <a href="http://www.news.wisc.edu/21638">press release</a> from the University of Wisconsin Madison.<p><small><em>Image courtesy of University of Wisconsin-Madison</em></small></p>New observations by the MESSENGER spacecraft provide  support for the hypothesis that Mercury harbors abundant water ice and other frozen volatile materials in its permanently shadowed (shown in red) polar craters. Areas where polar deposits of ice imaged by Earth-based radar are shown in yellow.<p><small><em>Image courtesy of NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington/National Astronomy and Ionosphere Center, Arecibo Observatory</em></small></p>Sinkholes are <a href="/teacher_resources/main/frameworks/esl_bi8.html&dev=">natural hazards</a> in many places around the world. They are formed when water dissolves underlying <a href="/earth/Water/carbonates.html&dev=">limestone</a>, leading to collapse of the surface.  Hydrologic conditions such as a lack of rainfall, lowered water levels, or excessive rainfall can all contribute to sinkhole development. On 2/28/2013, a sinkhole suddenly developed under the house outside of Tampa, Florida, leading to the tragic death of its occupant, Jeff Bush.<p><small><em>Image courtesy of Southwest Florida Water Management District</em></small></p>Stars don't last forever. Occasionally, a star bigger than our Sun will end its life in a huge explosion, called a <a href="/the_universe/supernova.html&dev=">supernova</a>. The center of the star collapses in less than a second, blowing away the outer layers of the star.  There are many beautiful images of supernova remnants, the expanding shell of gas made up of the outer layers of the original star. This image is the Vela Supernova Remnant.<p><small><em>Image courtesy of the Anglo-Australian Observatory/Royal Observatory Edinburgh</em></small></p>

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