彗星在圆形轨道上形成，但当它们冒险太接近行星时，就会被引力抛入现在的椭圆轨道。
Comets formed in circular orbits but were gravitationally flung into their present-day elliptical orbits when they ventured too close to planets.
在我们的太阳系中，行星的轨道几乎是圆形的，这使得科学家们预测，其他恒星周围的行星也会位于圆形轨道上。
The nearly circular orbits of planets in our solar system led scientists to expect that planets around other stars would also reside in circular orbits.
地球沿椭圆形轨道运动。
圆形轨道非常特殊。
因此，现在的，总能量比，在圆形轨道中要大。
And therefore, the total energy now is larger than the total energy that I had in my circular orbit.
Gliese 581周围的行星拥有同太阳系的行星一样类圆形轨道。
Like our solar system, the planets around Gliese 581 have nearly-circular orbits.
这颗星球每围太阳绕行一周，它的椭圆形轨道的中轴就变化一次。
The mainaxis of the planet's orbital ellipse shifts each time it goes round the sun.
我现在要进入一个椭圆形轨道，因为新的速度已经，不是圆形轨道中的速度。
I now go into an elliptical orbit because the new velocity is no longer the right velocity for a circular orbit.
月球在与赤道相对的椭圆形轨道上运行，往返于南北半球的上空。
The moon travels in an elliptical orbit in relation to the equator, swinging back and forth over the northern and southern hemispheres.
这是我们的圆形轨道,半径为r，在点，12点的位置,是我发射火箭的位置。
So this is our circular orbit X with radius r, and at location X, at 12:00, that is where I fire my rocket.
如果这是一个围绕，地球的椭圆形轨道，那么这是近地点，这是远地点。
If this is an ellipse around the Earth, then this would be perigee and this would be apogee.
同样的，第五个方程序，中的速度同样，会随时间改变，因为这是椭圆形轨道。
Also that velocity, v, in that equation number five will also change with time because it's an elliptical orbit.
沿着圆形轨道运行的，时间和沿着椭圆轨道，所花费的时间是一样的，这决非显而易见的。
So to go around this circular orbit will take the same amount of time as to go around this one, and that is by no means obvious.
首先，我想简单，复习一下我们知道的，有关于圆形轨道的知识，我在黑板上写下了，我们已有的知识。
I first want to review with you briefly what we know about circular orbits, so I wrote on the blackboard everything we know about circular orbits.
这颗膨胀的行星可以用高度椭圆形轨道来解释。高度椭圆形轨道先使它距离星很近，然后远离。
The bloated planet can be explained by a highly elliptical orbit, which brings it close to the star and then far away.
如果将围绕黑洞的轨道调至尽可能的小（即轻微拉长最内层的稳定圆形轨道），对岁差率有何改变？
What happens to the precession rate if the orbit around a black hole is made nearly as small as possible, i. e. a slight elongation of the innermost stable circular orbit?
这是一个巨大的天体，可能是褐矮星[6]，在一个与其他行星平面成一定角度的很长的椭圆形轨道上。
This is a massive astronomical object, possibly a brown dwarf6, which is on a long elliptical orbit around our own sun on an inclined plane to the rest of the planets.
提出了一个由八颗同地迹有一定倾角的地球同步圆形轨道(IGSO)卫星组成的区域导航星座方案。
A regional navigation constellation scheme composing eight IGSO satellites of ground track is presented in this paper.
因为有卫星的头衔，而且沿椭圆形轨道环绕地球运行，月亮似乎每天平均51分钟返回到天空的同一地点。
Due to the moon's titled and elliptical orbit around Earth, the moon seems to return to the same place in the sky 51 minutes later each day, on average.
这就是将要发生的-，我将要进入一个椭圆形轨道，在这里，2a肯定要，比2 R大，因为总能量增大了。
And so what's going to happen — I'm going to get an elliptical orbit like so, whereby 2a must be larger than 2r because my total energy is larger.
太阳一年内的轨迹形成这种形状是因为地球围绕着与太阳略微不同的轴旋转，而我们的地球也沿着椭圆形轨道运行。
The sun makes this shape over a year because Earth rotates on a slightly different axis than the sun, and our planet also travels on an elliptical orbit.
因此，炮弹由直线运动变成高速的环形运动，现在正沿一条椭圆形轨道绕着月亮飞行，变成了一颗真正意义上的卫星。
The rectilinear movement has thus become changed into a circular motion of extreme velocity, and it is now pursuing an elliptical orbit round the moon, of which it has become a true satellite.
选择矮行星也有不足：这就是矮行星里的恒星不按照规则的圆形轨道运动，像螺旋星系里的恒星都沿着同一方向运动那样。
The disadvantage: the stars in dwarf galaxies don't move in tidy circular orbits, traveling in the same direction the way stars in spiral galaxies do.
尽管这一太空巨石体积很大，但应该不会对地球造成太大威胁，因为该巨石沿着月球轨道之外距离较远的一个圆形轨道运行。
Despite its massive size, the cosmic rock shouldn't be too cause too much of a threat as it is on a circular path far outside the moon's orbit.
艾萨克·牛顿在其后发现彗星沿椭圆轨迹移动，处于环绕太阳的椭圆形轨道上，他还准确地预测了彗星能够一次又一次地回归。
Isaac Newton later discovered that comets move in elliptical, oval-shaped orbits around the Sun, and correctly predicted that they could return again and again.
很多人认为地球绕太阳的轨道是完美的圆形，就像手在一块制作精良的手表上移动那样平滑、有规则，但事实并非如此。
A lot of people think of earth's orbit around the sun as being perfectly circular, as smooth and as regular as, say, the way that hands move on a well-made watch, but it just doesn't work that way.
碰撞假说的一个问题是，以这种方式形成的卫星是如何在月球现在的近乎圆形的轨道上运行的。
One problem with the collision hypothesis is the question of how a satellite formed in this way could have settled into the nearly circular orbit that the Moon has today.
碰撞假说的一个问题是，以这种方式形成的卫星是如何在月球现在的近乎圆形的轨道上运行的。
One problem with the collision hypothesis is the question of how a satellite formed in this way could have settled into the nearly circular orbit that the Moon has today.
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