Saved Bookmarks
| 1. |
When we look at the sky in a clear night, we find the sky full of stars, filling every. portion of the sky almost uniformly. But on a very careful observation through highly sophisticated instruments, one would observe dark areas in portions of the observable universe devoid of stars. Such a region is known as a dark nebula. A dark nebula is basically a cold gas cloud in interstellar space that contains enough material to block out light from stars behind it. A typical dark nebuta is about 20 light years in diameter and contains about 50 hydrogen atoms per cubic centimeter (monatomic hydrogen, not H_2) at a temperature of about 20 K. (A light year is the distance light travels in vacuum in one year and is equal to 9.46 xx 10^(15)m). What would be the mean free time (average time between collisions) |
|
Answer» `6.4 xx 10^(8)s` |
|