麦克斯韦电磁场方程

SCOTT SIMON, HOST: Baseball's a game that honors tradition, like B.J. Leiderman, who writes our theme music. At Wrigley Field, which is where I believe the world champion Chicago Cubs play, that 103-year-old ballpark has a new seating and dining area

发表于:2019-01-16 / 阅读(53) / 评论(0) 分类 2017年NPR美国国家公共电台8月

The solar system is a hostile place. Earth is under attack from deadly cosmic radiation. Life here is only possible, because it's protected by the magnetosphere, an invisible force field that cocoons the planet. But new evidence reveals that this vit

发表于:2019-01-22 / 阅读(74) / 评论(0) 分类 自然百科2011年

Radiation causes damage at the most fundamental level. It mutates the blueprint of life, DNA. Earth's magnetosphere is our crucial defense. It's so fundamental to our evolution and continued existence that the race is on to understand why it's changi

发表于:2019-01-22 / 阅读(64) / 评论(0) 分类 自然百科2011年

Earth's magnetic field has reversed thousands of times since its formation 4.5 billion years ago. And scientists now believe that the next reversal is imminent. The race is on to predicting exactly when it will occur. In 2010, the European Space Agen

发表于:2019-01-22 / 阅读(49) / 评论(0) 分类 自然百科2011年

As the reversal approaches, the decay of our magnetic field will continue and cosmic radiation will get increasingly close to the Earth's surface. As the reversal approaches, the decay of our magnetic field will continue and cosmic radiation will get

发表于:2019-01-22 / 阅读(68) / 评论(0) 分类 自然百科2011年

During its magnetic cycle, the Sun undergoes periodic changes in activity. Every 11 years, it enters solar maximum. This 11 years cycle of solar activity has peaks where theres lots of solar storms. And right now where the sun is taking a little napp

发表于:2019-01-22 / 阅读(106) / 评论(0) 分类 自然百科2011年

Six years later, they come to believe these light flashes are the results of high energy, heavy cosmic rays penetrating the spacecraft and the crew members' eyes. These/ protons or electrons, just very, very high energy, ripped / part of atoms, sprin

发表于:2019-01-22 / 阅读(82) / 评论(0) 分类 自然百科2011年

Glatsmire's model shows that the magnetic poles swap places spontaneously due to / complex processes within the core. We were used to the idea that a compass points somewhere near the North Pole and hence we can use it for navigation, but there are p

发表于:2019-01-22 / 阅读(66) / 评论(0) 分类 自然百科2011年

By analyzing thousands of lava samples, geophysicists discover/ that the Earth's magnetic field has reversed over 18,000 times in the last 20 million years. On either side of these reversals is a long period of dramatically reduced field strength. Du

发表于:2019-01-22 / 阅读(65) / 评论(0) 分类 自然百科2011年

We drive them about 20 miles away to the North, and release them, and we track them as they try to fly back home. We drive them about 20 miles away to the North, and release them, and we track them as they try to fly back home. Hes up, OK. Holland wa

发表于:2019-01-22 / 阅读(78) / 评论(0) 分类 自然百科2011年

By analyzing different samples of lava, Herrero / Bervera has built up a picture of how the filed has changed since long before humans were around. They are actually the recorders of the Earth's magnetic field in hundreds of years, thousands of years

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

If we could flip a switch and just turn off the Earth's magnetic field, it will take about 15,000 years to disappear, based on the rate of decay of the field that we've seen over the last 150 years. It's currently decaying at a rate that would see an

发表于:2019-01-22 / 阅读(66) / 评论(0) 分类 自然百科2011年

In polar regions where the magnetic field is / weakest, auroras glow in the sky. These dazzling displays of colored lights form when solar particles slam into gases in our atmosphere causing them to glow. The stronger the solar wind, the more dramati

发表于:2019-01-22 / 阅读(80) / 评论(0) 分类 自然百科2011年

Scientists believe that the South Atlantic Anomaly, is a sign of a global decline in the magnetic field. Evidence of this comes from a surprising source. Dr. Mimi Hill uses pottery to uncover the secrets of earth's magnetic past. Ancient pots tell us

发表于:2019-01-22 / 阅读(71) / 评论(0) 分类 自然百科2011年

It's clear from the fact that the Martian crust is strongly magnetized, that there must have been a magnetic field on Mars in the past, that the only way we know to magnetize rocks is for them to form in the presence of magnetic field. Why did Mars l

发表于:2019-01-22 / 阅读(64) / 评论(0) 分类 自然百科2011年

The loss of the magnetic field has a catastrophic impact on the planet's evolution. Mars becomes the red planet we see today. If earths magnetic protection continues to fade, would it suffer the same fate? If it vanishes completely, the planet might

发表于:2019-01-22 / 阅读(83) / 评论(0) 分类 自然百科2011年

Easily confused by this idea, there has a big thawed iron inner core, so that I think it's just the bar magnet, just permanent magnet frozen in nad, and that's where causes all the magnetic field. But it's too hot inside the Earth, that can't happen

发表于:2019-01-22 / 阅读(74) / 评论(0) 分类 自然百科2011年

As the vast sphere reaches / maximum speed, something incredible happens. Huge lines of magnetism arc in and out of the model core. Well, we can't see the magnetic field coming out of the experiment, we can measure them, we can put many different mag

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

Larry Newitt from the Geological Survey of Canada charts the movement of the magnetic North Pole as it wanders the icy reaches of northern Canada. To determine where the magnetic pole / is, we can't rely on one single observation. What I try to do is

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

Blockson's computer model reveals that at the South Atlantic Anomaly, the magnetic field isn't just weaker than anywhere else on the planet. It's actually reversed polarity. There is a patch on the core in the South Atlantic where things are not poin

发表于:2019-01-22 / 阅读(78) / 评论(0) 分类 自然百科2011年
学英语单词
abastardized
absolute optimal function
adjacent channel selectivity
administratice chain of command
amount of physical memory
aprt
automatic-appropriate
automation with feedback control
bebed
body freedom
bowfat
cardioviruses
childe hassams
cold junction compensation
complex fractions
container load weight
duct silencer
dye-dilution
eccentric water distributor
electronic calibration laboratory
Enlund method
extension hunting
Faddeya, Zaliv
filling gun
filter parer
fire resistance rating
flappers
fluid drachm
foam mark
folk-rock
food centre
fuquas
gluier
glycerin abietate
groave
growth retardant
guiding rod
hand-offs
HeLa/fibroblast(hybrid)
heterolytic fission
hold the cards
horizontal condenser
hot isostatic compaction
idjit
jet spinner
Keith's mum
king of arms
Kos'kovo
Krestsy
laminar shear
land and sea breezes
lauric anhydride
leisure sociology
lichtenberg
managed price
marital rights
medicine shows
mid-water
model group
Murdochian
no-nation
nodal method
noncontiguous
offence of illegal infringement of citizens
operating mass
ostalgitis
paintmakers
parcelle
pavement gravel
photosensitive sealer
pike perch
pilot report
Plomer, William
pluractionality
polyvinyl phthalimide
pre-woman
principle of optimality
printed page
puttered around
queste
reference implementations
Ringarum
roll turning lathe
RPG compiler
Sageretia paucicostata
separation instrumentation
slim blade suture needle
spinoblast
standard operand format code
Statements of Standard Accounting Practice
subset construction
take a firm hold on oneself
tandem roller
thalassochemical
triaging
twist untwist method
udoes
underdefine
vellication
verta
VLF radio navigation system
Wenlock Shales