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Name: Milky Way @
Watson's Way
The Milky Way is the galaxy that contains our Solar System.
Its name "milky" is derived from its appearance as a dim
glowing band arching across the night sky whose individual stars cannot
be distinguished by the naked eye. From Earth the Milky Way
appears as a band because its disk-shaped structure is viewed from
within. Galileo Galilei first resolved the band of light
into individual stars with his telescope in 1610. Until the early 1920s
most astronomers thought that the Milky Way contained all the stars in
the Universe. Following the 1920 Great Debate between the astronomers
Harlow Shapley and Heber Curtis, observations by Edwin Hubble showed
that the Milky Way is just one of many galaxies now known to number in
the billions.
The band of colours in the
sky was caused by phenomenon called the Mesospheric Bore. This
occurs at ~90km in height and is associated with the hydraulic jump of
the airglow layer. Scientists speculate that this phenomenon
is caused by atmospheric gravity waves trapped inside a temperature
inversion layer. Undular bores are usually formed when two air masses of different temperatures collide. When a low level boundary such as a cold front or outflow boundary approaches a layer of cold, stable air, it creates a disturbance in the atmosphere producing a wave-like motion, known as a gravity wave. Although the undular bore waves appear as bands of clouds across the sky, they are transverse waves, and are propelled by the transfer of energy from an oncoming storm and are shaped by gravity.
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