英语听力:自然百科 穿越银河系的旅行 Through Milky Way—28(在线收听) |
The first stars in our Milky Way were fearsome high-octane stars, burning their hydrogen fuel at tremendous rates, rushing through their life cycle. They like the rockslides. They live fast and die young. They run out of their fuel very quickly and even after just a few million years, they will really die.
They died in some of the most violent explosions to rock the universe. Gigantic supernovae which shone brilliantly and the energy given off from the life and death of these massive stars, led to a remarkable transformation.
The first billion years of the universe history, galaxies start/ to form. The dark hydrogen fog, their light not being able to get to us, but as time / progresses and their most massive stars put out ultraviolet radiation. It's that radiation itself that changes the fog around them and the universe becomes transparent in those regions. These galaxies
are then here cleaning out the fog around them.
The blue voids where energy from the new stars is clearing the dark hydrogen fog.
But towards the billion years after the Big Bang, the entire fog has cleared we now see all the galaxies and the Dark Ages end.
As the hydrogen fog lifts, we get our first glimpse of fledgling galaxies, of which our Milky Way is one. But what does it look like?
This remarkable image is the Hubble ultra deep field, it’s the longest exposure that's ever been taken with Hubble Space Telescope. It's a truly remarkable image, probably the most famous to professional astronomers.
For over 11 days, Hubble stared at a tiny patch of the sky about the width of a penny held 75 feet away. |
原文地址:http://www.tingroom.com/lesson/zrbaike/2011/260182.html |