# Quick Answer: HOW LONG WAS A DAY 4 Billion Years Ago?

## How long was a day 100 million years ago?

They indicate that 620 million years ago the day was 21 hours, says Mardling.

Since the dinosaurs lived during the Mesozoic era, from 250 million years ago to 65 million years ago, day length would have been longer than 21 hours and probably closer to 23 hours..

## How long was a day 200 million years ago?

23 hoursFor Jurassic-era stegosauruses 200 million years ago, the day was perhaps 23 hours long and each year had about 385 days. Two hundred million years from now, the daily dramas for whatever we evolve into will unfold during 25-hour days and 335-day years.

## How long will a day be in a billion years?

Assuming this quantity is conserved, the length of a day in a billion years will be between 25.5 hours (1 cm/year recession rate) and 31.7 hours (4 cm/year recession rate). A recession rate of 2 cm/year will result in a day of 27.3 hours.

## How close was the moon a billion years ago?

The Moon formed (probably as a result of a titanic collision between Earth and a Mars-size protoplanet) 4.5 billion years ago. At the time of formation it was about 4 Earth-radii distant—that is, it was orbiting about 15,000–20,000 miles away, as opposed to the current average distance of 238,000 miles.

## How much closer was the moon 2000 years ago?

Since the Moon is presently 240,000 miles from Earth, being 2000 miles closer to us in the past (about 0.8%) would not have made it perceptibly larger—let alone appearing as big as a cantaloupe! The Moon has been moving away from the Earth since its formation, which took place about four and a half billion years ago.

## How long was a day 6 billion years ago?

According to it, the first evidence of life, 3.5 billion years ago, happened when the day lasted 12 hours. The emergence of photosynthesis, 2.5 billion years ago, happened when the day lasted 18 hours.