                        Astronomy Picture of the Day

    Discover the cosmos! Each day a different image or photograph of our
      fascinating universe is featured, along with a brief explanation
                    written by a professional astronomer.

                                 2026 May 4

                          Superplumes Inside Earth
         Image Credit & License: Sanne Cottaar via Wikimedia Commons

   Explanation: Why are there huge, unusual masses inside the Earth? No
   one is sure. By noting how earthquakes rumble through our planet's
   interior, humanity has discovered two deep structures that appear to
   have unusual temperatures and/or chemical compositions. One hypothesis
   holds that the superplumes are sunken debris left over from the
   Earth-shattering collision that created Earth's Moon about 4.5 billion
   years ago. A competing hypothesis is that they are graveyards for old
   tectonic plates that slowly slid under each other over the past few
   billion years. No matter their origin, the superplumes are thought to
   affect Earth’s surface volcanism, possibly creating, for example,
   island chains such as Hawaii. Also known as large low-shear-velocity
   provinces (LLSVPs), Earth's superplumes are visualized in the featured
   animation.

                     Tomorrow's picture: orionic volcano
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
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                      A service of: ASD at NASA / GSFC,
                           NASA Science Activation
                             & Michigan Tech. U.

