追踪层位

Conditions on Mars were so harsh that it was hard to imagine any life surviving there. The idea of sophisticated aliens was wiped out. We know that conditions on Mars today are not very good for life.

发表于:2018-12-07 / 阅读(260) / 评论(0) 分类 火星生命

These discoveries raised the stakes. Here was a planet similar to our own. Mars might not have cities or civilizations. But it could be home to other smaller life forms like microbes. Chris McKay is N

发表于:2018-12-07 / 阅读(286) / 评论(0) 分类 火星生命

I think it is exciting. Because it would imply that if life arose independently on Mars. The implication is that life is pervasive throughout the universe. This is why Mars has so obsessed scientists.

发表于:2018-12-07 / 阅读(272) / 评论(0) 分类 火星生命

In 2001 a new NASA probe was launched. Called Odyssey, it was sent to Mars to carry out the most detailed analysis ever of the planet’s surface. What it has discovered may be about to answer one of

发表于:2018-12-07 / 阅读(244) / 评论(0) 分类 火星生命

But even if there had been water, life doesn't start overnight. Even a simple microbe is the product of complex chemical systems that take millions of years to evolve. Had the water lasted long enough

发表于:2018-12-07 / 阅读(260) / 评论(0) 分类 火星生命

Rice had seen the same thing in Iceland, one of the few places on Earth with similarities to Mars. It too is extremely cold, and most of the water is frozen into glaciers. And also like Mars, buried u

发表于:2018-12-07 / 阅读(305) / 评论(0) 分类 火星生命

For Mars to have rivers, it must once have had streams, rain, clouds and an atmosphere, a planet just like the Earth today-if these were rivers. They had to be sure. The answers would come in 1998 wit

发表于:2018-12-07 / 阅读(290) / 评论(0) 分类 火星生命

William Boynton is professor of planetary sciences at the University of Arizona. And he's dedicated his life to looking for water on Mars. The link between life and water is very strong. Even here in

发表于:2018-12-07 / 阅读(270) / 评论(0) 分类 火星生命

Unit 1 Farm animals [00:31.66]student book page 2 [00:35.37]Let's act [00:35.44]Draw the cow on the paper [00:39.20]Draw the duck on the ground. [00:45.16]Let's talk What do you see? [00:57.88]I see a duck I see a hen I see a pig I see sheep [01:10.0

发表于:2018-12-13 / 阅读(358) / 评论(0) 分类 沪教版牛津小学英语二年级

'Deepwater Horizon' Honors The Sacrifice Without Sacrificing The Action play pause stop mute unmute max volume 00:0003:02repeat repeat off Update Required To play the media you will need to either update your browser to a recent version or update you

发表于:2018-12-18 / 阅读(231) / 评论(0) 分类 2016年NPR美国国家公共电台10月

MARY LOUISE KELLY, HOST: The phrase leave no trace is often used to describe good behavior in national parks, meaning enjoy the scenery, and then leave the park exactly as pristine as you found it. The new movie Leave No Trace is about a father and d

发表于:2018-12-18 / 阅读(240) / 评论(0) 分类 2018年NPR美国国家公共电台7月

Of course, any terraforming is still a long way off. The next few expeditions to Mars will definitely be made by machines. NASA, are sending 2 rovers, capable of travelling over 100 meters a day in se

发表于:2019-01-02 / 阅读(258) / 评论(0) 分类 火星生命

Well, hearing that Odyssey had found subsurface water on Mars was enormously exciting for somebody who is involved in planning to send humans to Mars. Water has a number of important uses for us. At t

发表于:2019-01-02 / 阅读(322) / 评论(0) 分类 火星生命

Life on Earth is basically proteins and DNA, so we can wonder if there is life on Mars will also be DNA and proteins, the same type of DNA, the same type of proteins. One might think that DNA is such

发表于:2019-01-02 / 阅读(261) / 评论(0) 分类 火星生命

But there was something even better. Odyssey may not just have found ice. There may also be liquid water, and that means, there could be living creatures there too. Right now, there might be liquid wa

发表于:2019-01-02 / 阅读(318) / 评论(0) 分类 火星生命

But they never got there. The first disappeared into deep space. Another missed its target when its coordinates were confused. One NASA control center was working in metric, the other in feet and inch

发表于:2019-01-02 / 阅读(338) / 评论(0) 分类 火星生命

The ground here is permafrost, a mixture of soil and ice frozen together. A group of Russian scientists have teamed up with NASA to drill down into it in search of microorganisms. It's work that's bee

发表于:2019-01-02 / 阅读(288) / 评论(0) 分类 火星生命

One of these wavelengths corresponds to hydrogen, another wavelength would be iron. Another wavelength would be oxygen. And so you go to the part of the spectrum you are interested in and you see you'

发表于:2019-01-02 / 阅读(290) / 评论(0) 分类 火星生命

RACHEL MARTIN, HOST: Eight years ago today, an explosion on the Deepwater Horizon drilling rig killed 11 people and led to a massive oil spill in the Gulf of Mexico. The accident prompted big changes in how the country regulates offshore drilling. No

发表于:2019-01-16 / 阅读(268) / 评论(0) 分类 2018年NPR美国国家公共电台4月

By Peter Heinlein New York City 05 October 2007 Runners on the streets of New York are commonplace this time of year. There is the marathon next month, and occasionally, other organized runs. But one annual event has skyrocketed to prominence in rece

发表于:2019-02-03 / 阅读(346) / 评论(0) 分类 2007年VOA常速英语(十月)
学英语单词
acarus folliculorum var. caninum
adrianoples
Afrikanerisms
air-refuelling
airsteps
alloiobiogenesis
analog fiber link
annuity savings deposits
at six and sevens
Ayrshire(cattle)
back-river
be busy at
Beranek scale
big cities
biological shielding
blasting bolt
blue crane
Butaritari Atoll
cape mays
charcoal adsorption process
cheald
clasp one's hands
claybord
coherent synthetic aperture imaging radar (csair)
conductance water
Crayettes
Dendrocygna
direct-indirect heating
dormifacient
egence
elopuroes
emberiza spodocephala personata
eutrophy
exit statement
Fairmount Heights
fast neutron removal collision
fl (fluid)
foam fractionation
forward breakover voltage
foxley
general layout of power plant area
genus Dasypus
Guidari
hillscape
hocs
independent utility
ink-recording
isabnormalline
j.k.
Korogen
leakage clearance
lumbar aortography
M-acid
macroscopic fission cross section
mignonette oil
neonationalist
nontherapeutic
North West Prov.
Notair
ocean thermal energy conversion
otavio
pear haw
permissive counterclaim
polarized monostable type relay
poly isobutylene
Poul
power bandwidth ratio
preliminary shearing
pulsed radar system
pyrotoxins
quando acciderint
Ribes palczewskii
rock falling
rotary valve key
safety weight
self irradiation
sexual pleasure
sheet drainage
sheweth
shinin'
short-range design
srivijaya
standard option
stereoviewer
stripper-plate mold
sub-synchronous layer
telotrochal larva
Tetramethyl-p-phenylenediamine
the town
toxicopectic
transmitter spurious meter
trichocerein
true hermaphrodite
ultraviolet transmitting filters
unbriefed
vacuum sparking
warning valve spring
welcome rain
west mark
William Ellery
workshop handicraft
wrongeld