Question

article #2: why we need to keep adding leap seconds? 1. atomic - second - how many seconds make up a standard day? 2. how many leap seconds occurred: *computer software that doesnt know about leap seconds may see time going backwards and crash. 1990 - 1999 __ 2000 - 2009 __ 3. in 100 years, how often will we have a leap second? 4. in 1,000 years, how often will we have a leap second?

Explanation:

Step1: Calculate standard day seconds

$24\times60\times60 = 86400$

Step2: Leap - second data lookup

Historical records show 7 leap - seconds from 1990 - 1999 and 2 from 2000 - 2009.

Step3: Estimate 100 - year frequency

Based on historical occurrence patterns, on average about once every 1.5 - 2 years.

Step4: Estimate 1000 - year frequency

Long - term factors like Earth's rotation changes exist, but still around once every 1.5 - 2 years on average.

Answer:

1. A standard day has 86400 seconds (24 hours 60 minutes 60 seconds).
2. 1990 - 1999: 7 leap - seconds; 2000 - 2009: 2 leap - seconds.
3. On average, about once every 1.5 to 2 years in 100 years.
4. Over 1000 years, the frequency is still approximately once every 1.5 - 2 years on average, but the long - term rate can vary due to complex Earth rotation factors.