Just as leap years keep our calendars lined up with Earth’s revolution around the sun, leap seconds adjust for Earth’s rotation. This kind of fine-tuning wasn’t much of an issue before the invention of atomic clocks, whose ticks are defined by the cycling of atoms. Cesium-based clocks, one kind of atomic clock, measure the passage of time much more precisely than those based on the rotation of our planet, so adding a leap second allows astronomical time to catch up to atomic time.
Today, the northern hemisphere is experiencing the shortest day of the year. The winter solstice marks the shortest daylight period, but it’s not the day of the latest sunrise or earliest sunset. In the mid-latitudes the earliest sunset occurs in early December, while the latest sunrise is not until early January.
The Jantar Mantar is an equinoctial sundial, consisting of a gigantic triangular gnomon with the hypotenuse parallel to the Earth’s axis. On either side of the gnomon is a quadrant of a circle, parallel to the plane of the equator. The instrument is intended to measure the time of day, correct to half a second and declination of the Sun and the other heavenly bodies.
Arguably one of the oldest victims of the digital age, telegrams were the fastest and most reliable communication method from the 19th century until the end of the 20th century. More than the Internet and email, it is the mobile phone that has led to the demise of the original character-constrained mode of communication.
Today is the winter solstice and the first day of winter in the Northern Hemisphere. It’s all due to Earth’s tilt, which ensures that the shortest day of every year falls around December 21. Some predicted that today would also mark Earth’s doomsday, thanks to a longstanding rumor that the Maya calendar ends on December 21, 2012.
A plastic-cum-tar road is 25% better than unmodified roads and is almost 200% resistant to soaking up water. The maintenance cost of the road is very low, while its durability is high. The roads reportedly need no repairing for at least five years. This is a good way to recycle the plastic and preventing further damage to the environment.
The same sites that allowed groups for communal harmony, also allowed groups that fostered communal hate. It is a free domain – and there are no rules on content. But, the society, the governments, the industry will have to take steps to curb the spread of hate messages, fake news without compromising the right to freedom of speech of the netizens. With rights, come duties.