Don’t be scared if you can’t find your shadow at noon tomorrow
TIMES NEWS NETWORK
Chennai:23.04.2019
Step out in the Sun on Wednesday around noon and find your shadow right under you, as it is Zero Shadow Day, a phenomenon that happens twice a year in the city. The shadow cast will be almost zero at around 12.07pm when the Sun crosses the local meridien, an imaginary line connecting north, south and overhead.
This year, a group of 60 city students will get together to measure the longest and shortest shadow. They will gather at the Tamil Nadu Science and Technology Centre (TNSTC) at Kottupuram, which houses the Birla Planetarium.
S Soundarajaperumal, executive director (incharge), TNSTC, said experts would be present to help the students interpret the measurements they would take, which includes studying the radius of the earth, its linear rotational velocity, which varies at different latitudes, and the axial tilt. For interpretation, measurements taken in other cities such as Bengaluru and Mangaluruwill also be taken into account.
“When the sun has its declination equal to the latitude of the place, then the Sun is at its zenith because of the tilt of the Earth’s axis. On April 24, the Sun’s declination will be at 13 degrees and cities such as Chennai, Bengaluru and Mangaluru are at 13 degree latitude. So, these cities can see zero shadow,” he said.
Every location on earth between the Tropics of Cancer and Capricorn will witness this phenomenon twice a year. In India, this happens between April and September.
Soundarajaperumal said students would assemble at the Birla Planetariums in Bengaluru andMangalurutootoconduct similar measurements. However, the time at which the shadow may be shortest will not be the same as in Chennai. “For one degree rotation, the earth takes four minutes. So, after Chennai sees shortest shadow, it will be followed by Bengaluru, which may take 10 minutes or so and then Mangaluru. ” he said.
Jump to see the shadow right under or a pipe or pole couldbeerected perpendicular to the ground, say experts.
TIMES NEWS NETWORK
Chennai:23.04.2019
Step out in the Sun on Wednesday around noon and find your shadow right under you, as it is Zero Shadow Day, a phenomenon that happens twice a year in the city. The shadow cast will be almost zero at around 12.07pm when the Sun crosses the local meridien, an imaginary line connecting north, south and overhead.
This year, a group of 60 city students will get together to measure the longest and shortest shadow. They will gather at the Tamil Nadu Science and Technology Centre (TNSTC) at Kottupuram, which houses the Birla Planetarium.
S Soundarajaperumal, executive director (incharge), TNSTC, said experts would be present to help the students interpret the measurements they would take, which includes studying the radius of the earth, its linear rotational velocity, which varies at different latitudes, and the axial tilt. For interpretation, measurements taken in other cities such as Bengaluru and Mangaluruwill also be taken into account.
“When the sun has its declination equal to the latitude of the place, then the Sun is at its zenith because of the tilt of the Earth’s axis. On April 24, the Sun’s declination will be at 13 degrees and cities such as Chennai, Bengaluru and Mangaluru are at 13 degree latitude. So, these cities can see zero shadow,” he said.
Every location on earth between the Tropics of Cancer and Capricorn will witness this phenomenon twice a year. In India, this happens between April and September.
Soundarajaperumal said students would assemble at the Birla Planetariums in Bengaluru andMangalurutootoconduct similar measurements. However, the time at which the shadow may be shortest will not be the same as in Chennai. “For one degree rotation, the earth takes four minutes. So, after Chennai sees shortest shadow, it will be followed by Bengaluru, which may take 10 minutes or so and then Mangaluru. ” he said.
Jump to see the shadow right under or a pipe or pole couldbeerected perpendicular to the ground, say experts.
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