People
travel miles and spend thousands to see Sunset – a beautiful spectre. As we know, the Sun, the Moon, the planets, and the stars all
rise in the East and set in the West. That is
because Earth spins -- toward the east.
According
to Science data, Sunset typically occurs around 6:19 pm at Triplicane Chennai,
with the sun setting in the west. The
daylight time in Chennai is from 6:15 am
to 6:18 pm.
Sunset (or sundown)
is the disappearance of the Sun at the end of the Sun path, below the horizon
of the Earth (or any other astronomical object in the Solar System) due to its
rotation. As viewed from everywhere on Earth, it is a phenomenon that happens
approximately once every 24 hours, except in areas close to the poles. The
equinox Sun sets due west at the moment of both the spring and autumn
equinoxes.
The sunset is defined
in astronomy the moment the upper limb of the Sun disappears below the horizon.
Near the horizon, atmospheric refraction causes sunlight rays to be distorted
to such an extent that geometrically the solar disk is already about one
diameter below the horizon when a sunset is observed.
Sun
"rises in the east and sets in the west" is what we have read and
understood. However, most people don't realize that is a generalization.
Actually, the Sun only rises due east and sets due west on 2 days of the year
-- the spring and fall equinoxes! On other days, the Sun rises either north or
south of "due east" and sets north or south of "due west. Each
day the rising and setting points change slightly. At the summer solstice, the
Sun rises as far to the northeast as it ever does, and sets as far to the
northwest. Every day after that, the Sun rises a tiny bit further south.
Away,
Nasa recently released the first
high-definition images of a sunset on the Moon, two striking photographs taken
by the private lander Blue Ghost that could offer scientists further clues to
the mysterious phenomenon known as lunar horizon glow. The agency presented the
images to a press conference at Houston’s
Johnson Space Center, marking the conclusion of a 14-day mission conducted in
partnership with Texas company Firefly Aerospace. The commercial lander, which
touched down on 2 March near Mons Latreille, a volcanic formation in Mare
Crisium on the moon’s north-eastern near side, is part of a $2.6bn investment
by Nasa in commercial payload operators aiming to cut costs and support
Artemis, the program scheduled to return humans to the moon in 2027.
Sunset on the Moon - NASA image
Lunar
horizon glow was first documented by the astronaut Eugene Cernan, one of the
last two men to set foot on the moon during the Apollo 17 mission in 1972.
Subsequent observations concluded that the phenomenon was due to tiny dust
particles in the moon’s thin atmosphere glowing at lunar sunrise and sunset, while
some theories suggest the particles levitated. Blue Ghost also captured
high-definition imagery of a total eclipse on 14 March, when the Earth blocked
the sun from the moon’s horizon.
A SpaceX
Falcon rocket launched the lander, which is about the size of a hippopotamus,
on a 2.8m-mile journey on 15 January. Blue Ghost was carrying an array of
scientific experiments, including a lunar soil analyzer, a radiation-tolerant
computer and an experiment testing the feasibility of using the existing global
satellite navigation system to navigate the moon.
Interesting
! ~ first three pics are of Sunset at Triplicane captured by me today.
Regards – S
Sampathkumar
25.3.2025
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