The video owner has disabled playback on external websites.
This video is no longer available on YouTube.
This video cannot be played right now.
Watch on YouTube
Cosmos - Carl Sagan - 4th Dimension
学习统计
CEFR 等级
难度
字幕 (154 片段)
in discussing the large scale structure
of the cosmos astronomers sometimes say
that space is
curved or that the universe is finite
but
unbounded whatever are they talking
about let's imagine that we are
perfectly flat I mean absolutely flat
and that we live appropriately enough in
a flat land a
land designed and named by Edwin Abbott
a Shakespearean scholar who lived in
Victoria in England everybody in
flatland is of course exceptionally flat
we have squares circles triangles and we
all Scurry about and we can go into our
houses and do our flat business now
we have width and length but no height
at at all now these little cutouts have
some little height but let's ignore that
let's imagine that these are absolutely
flat that being the case we know us
Flatlanders about left right and we know
about forward back but we have never
heard of up down let us imagine that
into flatland hovering above it comes a
strange three-dimensional creature which
oddly enough looks like an apple and the
three-dimensional creature sees an
attractive congenial looking Square
watches it enter its house and decides
完整字幕可在视频播放器中查看
评论 (0)
登录后评论互动模式
测验
正确答案：
测验
正确答案：
观看视频时会出现测验
记忆技巧
来自此视频
免费开始学语言
