Author Question: Why did Earth retain most of its water while Venus and Mars lost theirs? What will be an ideal ... (Read 43 times)

asan beg · **on:** Jul 27, 2018

Why did Earth retain most of its water while Venus and Mars lost theirs?

What will be an ideal response?

Question 2

When we look at an object that is 1,000 light-years away we see it

A) as it was 1,000 years ago.
B) as it was 1,000 light-years ago.
C) as it is right now, but it appears 1,000 times dimmer.
D) looking just the same as our ancestors would have seen it 1,000 years ago.

Anton · **Reply #1 on:** Jul 27, 2018

Answer to Question 1

The basic answer is that Earth was at just the right distance to retain water as liquid. Venus lost its water because it was too hot. At its closer proximity to the Sun, Venus was warm enough to keep all its water in gaseous form in the atmosphere. When the runaway greenhouse effect became prominent, Venus became even warmer and the water vapor escaped into space. Mars was far enough from the Sun that it was cold enough for the water vapor to freeze out of the atmosphere, resulting in thick polar caps.

Answer to Question 2

A