Visiting an Archaeological Site Lillian: Look at this! I?m going to take this home as a souvenir. Bruce: You can?t do that. That might be an artifact of some kind. It belongs to this archaeological site. Lillian: It?s just a rock. No one will miss it

发表于:2018-12-03 / 阅读(58) / 评论(0) 分类 2015年ESL之旅行交通购物

Touring Celebrity Homes and Filming Locations Tour guide: Welcome to Hollywood Tours, everybody. Im your tour guide for today, and Ill be showing you some of the most memorable locations in Hollywood history. Every seat in this double-decker bus is a

发表于:2018-12-28 / 阅读(107) / 评论(0) 分类 2013年ESL之旅行交通购物

And every faint smudge of light you are looking at is a galaxy. For Richard Ellis, it's a galactic treasure trove. So much like an archaeologist/, we piece together history by digging into deeper and deeper layers. So a cosmologist like myself, uses

发表于:2019-01-22 / 阅读(58) / 评论(0) 分类 自然百科2011年

A new galaxy is formed where, instead of the discs that the original galaxies have, where all the stars are going around more or less on a plane. Instead the stars are going every which way just like the elliptical galaxies that we see. And so we are

发表于:2019-01-22 / 阅读(56) / 评论(0) 分类 自然百科2011年

Venus is closer to the Sun, Mars is farther from the Sun. And there is a zone in between, the blazing hot furnace Venus, the frigid Mars. That zone in between we call a habitable zone and the earth lies smack in that thing where water would be in liq

发表于:2019-01-22 / 阅读(54) / 评论(0) 分类 自然百科2011年

One type of giant planet orbits very close to its star, we call them hot Jupiters because these Jupiter-like planets are so close that they are blowtorched by the intense heat from the star. The other sort of planet we have found is also bizarre. Wev

发表于:2019-01-22 / 阅读(45) / 评论(0) 分类 自然百科2011年

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 e

发表于:2019-01-22 / 阅读(60) / 评论(0) 分类 自然百科2011年

But our time traveling isnt yet over. There is still the question of how the first galaxies kindled the very first stars. We are on a journey visiting the Dark Ages, a time over 12.5 billion years ago. The sight is spectacular. The sky is ablaze with

发表于:2019-01-22 / 阅读(57) / 评论(0) 分类 自然百科2011年

What happens is that, first the dark matter forms the structure, the ordinary matter then follows the dark matter. The ordinary matter is hydrogen and helium at this stage. And the hydrogen and helium fall/ to the center of the dark matter halos that

发表于:2019-01-22 / 阅读(55) / 评论(0) 分类 自然百科2011年

Its extremely frustrating because this region, this time period holds within it, in some sense, the rose headstone of / galaxy formation. But there are clues as to what was happening inside those dense hydrogen clouds. Look back even further in time

发表于:2019-01-22 / 阅读(48) / 评论(0) 分类 自然百科2011年

But dark matter does more than simply holds galaxy like ours together. Astronomers think it binds the Milky Way into an extraordinary structure along with billions of other galaxies. To explore it, we'll take a journey to the very edge of the univers

发表于:2019-01-22 / 阅读(117) / 评论(0) 分类 自然百科2011年

Imagine the disc of our galaxy, if you just took a disc of stars and put it there, gravity would tend to make this disc collapse/ into itself and it would immediately just fall together. That is not what we see with the galaxy. Whats actually going o

发表于:2019-01-22 / 阅读(62) / 评论(0) 分类 自然百科2011年

Its a stunning location, but its also mysterious. These stars are not just close together. They are on the move at enormous speeds. Going to the heart of a galaxy might not be the similar to going to an amusement park. The rides are some similar to h

发表于:2019-01-22 / 阅读(209) / 评论(0) 分类 自然百科2011年

Each tag is whipping around the center of the galaxy, the particular, the most striking thing you will notice is the motion of SO2.So SO2 goes on an incredible roller-coaster ride. It comes whipping around and then back out. Something with tremendous

发表于:2019-01-22 / 阅读(56) / 评论(0) 分类 自然百科2011年

The glowing region is the accretion disc, star debris falling inward, would turn round in the maelstrom heated by frictions to such high temperatures that it glows white hot. So at the center of our galaxy, we do have a black hole. We now know that t

发表于:2019-01-22 / 阅读(48) / 评论(0) 分类 自然百科2011年

Like nebulae which spawn stars, it is made of gas and dust. But that's where most similarities end. For Alex Filippenko, it represents an intriguing industrial zone within our galaxy where the elements from which our world is made or manufactured. Wh

发表于:2019-01-22 / 阅读(57) / 评论(0) 分类 自然百科2011年

We are taking a ride through the Milky Way. First, we are traveling to a place where stars are born. Even at the speed of light, 196,000 miles a second, the journey lasts for 1,500 years. We've arrived at the vast glowing cloud of gas and dust, the g

发表于:2019-01-22 / 阅读(62) / 评论(0) 分类 自然百科2011年

Like nebulae which spawn stars, it is made of gas and dust. But that's where most similarities end. For Alex Filippenko, it represents an intriguing industrial zone within our galaxy where the elements from which our world is made or manufactured. Wh

发表于:2019-01-22 / 阅读(77) / 评论(0) 分类 自然百科2011年

We are at a foundry here, and they are pouring molten iron from all machinery. And they are going to make parts for new machines out of that iron, so they are recycling yet, but all that iron was created and ejected into the cosmos by gigantic stars

发表于:2019-01-22 / 阅读(70) / 评论(0) 分类 自然百科2011年

In about four or five billion years, it will grow into a much bigger star, a star called a red giant. And that outer atmosphere of gases will be held so loosely by the sun at that time that the gases will be blown away gently in what I call a cosmic

发表于:2019-01-22 / 阅读(67) / 评论(0) 分类 自然百科2011年