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.

                               2020 January 9

                           Perihelion to Aphelion
            Image Credit & Copyright: Ian Griffin (Otago Museum)

   Explanation: Perihelion for 2020, the point in Earth's elliptical orbit
   when it is closest to the Sun, occurred on January 5th. The distance
   from the Sun doesn't determine the seasons, though. Those are governed
   by the tilt of Earth's axis of rotation, so January is still winter in
   the north and summer in southern hemisphere. But it does mean that on
   January 5 the Sun was at its largest apparent size. This composite
   neatly compares two pictures of the Sun, both taken from planet Earth
   with the same telescope and camera. The left half was captured on the
   date of the 2020 perihelion. The right was recorded only a week before
   the July 4 date of the 2019 aphelion, the farthest point in Earth's
   orbit. Otherwise difficult to notice, the change in the Sun's apparent
   diameter between perihelion and aphelion amounts to a little over 3
   percent. The 2020 perihelion and the preceding 2019 aphelion correspond
   to the closest and farthest perihelion and aphelion of the 21st
   century.

                   Tomorrow's picture: clouds like pearls
     __________________________________________________________________

      > Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
                NASA Web Privacy Policy and Important Notices
                      A service of: ASD at NASA / GSFC
                             & Michigan Tech. U.

--- hpt/lnx 1.9.0