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If there's one thing that we all learn as kids, it's don't play with fire.
我们童年都学会的一点是：别玩儿火。
But apparently someone forgot to tell NASA, because last Sunday, they launched a billion-dollar mission to literally touch the Sun.
但美国宇航局显然不知道这点，因为上周日，他们斥资10亿美元，做与太阳近距离接触的任务。
It's called the Parker Solar Probe, or PSP, and after a couple minor hiccups with the launch, its seven-year mission has officially begun!
他们发射的是帕克太阳探测器(PSP)，在历时7年攻克了发射上的一些难关后，该任务正式开始了！
Over the course of its mission, the spacecraft will come as close as six million kilometers to the surface of Sun.
在整个任务期间，该探测器距离太阳表面最近的距离可达600万公里。
That's more than 35 million kilometers closer than any previous mission, and it will put it within the Sun's outer atmosphere, called the corona.
这是比之前最近的一次任务还要近3500万公里，可抵达太阳的外层大气，也就是日冕。
There, it will study the process that creates the solar wind, a stream of charged particles that constantly streams out of the Sun's surface in all directions.
在日冕处，该探测器将研究产生太阳风的进程。所谓太阳风，就是一股带电粒子，他们会持续不断地从太阳表面的各个方向喷薄而出。
After almost a decade of development, the probe was originally supposed to launch on July 31, but the date was pushed back to August 11 because of minor technical issues with the Delta IV Heavy rocket carrying it into space.
在经过了近10年的研发后，该探测器本来预计于7月31日发射，但又推迟到了8月11日，因为承载该探测器的三角洲四号运载火箭出现了一些小的技术问题。
Then, two minutes before liftoff on the 11th, there was a small problem with the rocket's helium pressurization system that stopped the launch.
随后，8月11日发射升空刚刚2分钟，火箭的压缩氦增压系统出了一个小故障，再次导致发射暂停。
It took longer to fix than the hour-long launch window allowed, so mission controllers had to try again the next day.
修复压缩氦增压需要的时间超过了发射期限的1小时，所以负责任务控制的工作人员不得不改日进行。
And that time, everything went smoothly!
那时候，一切进展都很顺利啊！
It's not too surprising that there were some kinks to iron out, because this was the first launch where the Delta IV Heavy had an extra third-stage booster attached.
肯定有困难要攻克，这是意料之中的，因为这是三角洲四号运载火箭第一次装载了额外的三期助推器。
The rocket needed the extra power to get the probe on the right trajectory, because it's an unusual one.
该火箭需要额外的动能才能让探测器步入正轨，因为探测器很特殊。
It might seem counterintuitive, but in many ways it's actually harder to travel towards the Sun than away from it.
看起来可能有悖于直觉，但从很多方面来看，向太阳进发比远离太阳要难的多。
Objects traveling towards the Sun are pulled faster and faster by its increasingly powerful gravity, making even the smallest course changes difficult.
向太阳移动的物体受到太阳引力的作用越来越大，移速会越来越快，所以想要改变轨道非常困难。
To help counteract this, the PSP will use flybys of Venus to help control its speed and trajectory.
为了克服太阳引力，帕克太阳探测器将通过金星的探测器来助力控制自己的速度和轨道。
Normally, planetary flybys are used to add energy to a spacecraft through what's sometimes called a “slingshot.”
正常情况下，空间探测器是用来给宇宙飞船增加动能的，方式是有时候人们口中的“弹弓”原理。
But each of PSP's seven Venus encounters will be carefully arranged so the planet's gravity actually decreases the probe's energy, causing it to fall into smaller and smaller orbits.
但帕克太阳探测器与金星的每一次相遇都会是经过精心安排的，这样金星的引力才能减少探测器的动能，让探测器落入越来越小的轨道。
And all those orbits will be highly elongated, allowing the probe to spend most of its time farther from the Sun and ensuring it doesn't spend too much time too close.
所有轨道都会进行很大程度的加长，这样探测器就能将大部分时间用于进一步与太阳拉开距离，确保不会太近。
At its closest approach to the Sun, PSP will reach speeds of up to 200 kilometers per second, making it the fastest human-made object in history.
在离太阳最近的时候，帕克太阳探测器会达到每秒200公里的速度，这是史上人造物体中速度最快的一个。
That's more than two hundred times faster than a bullet leaving a rifle.
这速度比离了枪膛的子弹还要快200多倍。
And it's good it will be going so fast, because the only thing more extreme than its speed will be its temperature.
速度如此之快是好事，因为比速度更可怕的事情是高温。
Within the corona, the Sun-facing side of the spacecraft will reach around 1400 degrees Celsius.
在日冕之内，宇宙飞船的朝阳面将达到1400摄氏度。
Which is about the melting point of steel. Protecting it from that inferno is a shield made of a super-light carbon-based material.
已经达到了钢铁的熔点。一种以碳为基础的超轻材料将成为抵挡抵挡高温的护盾。
At just 11 centimeters thick, and consisting of 97% empty space, the shield is incredibly lightweight, it contributes only 73 kilograms to the probe's 685.
这层护盾只有11厘米厚，而且97%都是真空的，所以质量很轻，只有73千克，而整个探测器是685千克。
But it's strong enough to keep the probe from melting into metal slop.
虽然如此，这层护盾足够强大，可以避免探测器融化成一滩金属液体。
Even with this protection, though, the PSP will need to spend most of its time farther from the Sun, where it's at least a little cooler.
虽然有了这层防护，帕克太阳探测器依然需要将大部分时间用于躲避太阳，这样才能保持温度相对低。
If all goes well, the mission should make its first pass by the Sun in November, but we'll have to wait until 2024 for the close approaches that will really put its shield to the test.
如果一切进展顺利，该探测器将于今年11月第一次飞过太阳，但要等2024年的时候才能近距离接近太阳，这时候是检验护盾的关键时刻。
The Parker Solar Probe may soon be the closest spacecraft to the Sun, but NASA's New Horizons mission is proving that the farthest reaches of the solar system are just as fascinating.
帕克太阳探测器可能不久后就会成为离太阳最近的宇宙飞船了，但美国宇航局的新视野号任务证明：即便离太阳很远，也别有一番滋味啊。
You may remember New Horizons for its flyby of Pluto back in 2015, but since then it's raced more than a billion kilometers farther from the Sun.
大家可能还记得2015年的时候，新视野号曾对冥王星进行过飞近探测，但从那以后，他们距离太阳的距离就又远了10亿多公里。
And in a paper published last week in the journal Geophysical Research Letters, scientists used its data to explore a mysterious glow coming from beyond the solar system.
上周，《地球物理研究通讯》上发表了一篇论文，其中科学家通过新视野号的数据探索了太阳系外的一种神秘光晕。
Filling the space between the planets is a thin fog of gas and dust astronomers call the interplanetary medium, or IPM.
各行星间的空间里有一层薄薄的气体尘雾，科学家将其称之为行星际物质(IPM)。
New Horizons sees this fog as a faint ultraviolet glow all across the sky, which comes from sunlight scattering off the IPM.
新视野号将这种雾视为天空中一种微弱的紫外线光晕，这种光晕来自于四散在行星际物质中的日光。
The light is emitted at a specific wavelength, called Lyman-alpha, produced by hydrogen atoms after they absorb energy.
这种光以特殊的莱曼α波长发出，这种波长是由吸收能量后的氢原子放出的。
But what New Horizons sees seems to be shining too brightly, so the researchers think there must be another region of hydrogen contributing to the glow.
但新视野号观测到的亮度太强了，所以研究人员认为一定有另一个氢原子区域发出了光。
One potential source is the so-called hydrogen wall at the boundary of the Sun's influence, a location called the heliopause.
可能的源头之一是太阳影响力即将消失的地方存在的氢墙，这个地方名为日球层顶。
That's where the energy of the solar wind pushing outwards is balanced by the energy of particles coming in towards the Sun from the rest of the galaxy.
在这里，太阳风向外释放的能量会被太阳系里其他部分涌入的粒子能量相抵消。
These opposing forces result in a standstill, that's the pause in heliopause, and create a place where hydrogen can pile up into a wall, or shell, around the solar system.
这种相对的力量造成了停顿的状态，也就是日球层顶的停顿，所以就产生了太阳系附近氢原子堆积成墙的情况。
This hydrogen wall would be emitting extra Lyman-alpha light, which could contaminate New Horizons's observations of the interplanetary medium.
这堵氢墙也会放射出莱曼α光，会破坏新视野号对行星际物质的观测。
There's just one catch, NASA's twin Voyager spacecraft have traveled even farther into this zone and while their measurements of the IPM match up nicely with what these researchers found, other Voyager data suggest the hydrogen wall might not be the answer.
只捕捉到了一幅图，美国宇航局的姊妹宇宙飞船旅行者号在该地区飞的更深入，而且他们对行星际物质的测量结果与研究人员的发现成果十分吻合，所以旅行者号的数据表明氢墙可能不是正解。
So what could be? The New Horizons astronomers aren't sure, but they plan to make more observations twice a year for the next decade or so to try to figure that out.
那答案是什么呢？新视野号的天文学家还不确定，但他们计划未来10年左右进行更多的观测，一年两次，以解决这个问题。
Combine that with the data we'll be getting from the Parker Solar Probe, and we might soon have our first end-to-end understanding of the Sun, from the corona to the edge of the solar system.
将我们即将可以从帕克太阳探测器获取的数据结合在一起，或许很快就可以对太阳有首次点对点的理解，无论是日冕还是太阳系的边界。
Thanks for watching this episode of SciShow Space News!
感谢收看本期的《太空科学秀》！
If you're interested in learning more about the scientific questions the Parker Solar Probe is looking to answer, you can check out a whole episode that we made about that, from back when the mission was still called Solar Probe Plus.
如果您想了解更多帕克太阳探测器可能解答疑惑的问题，有一集是专门介绍该内容的哦，那时候该任务的名字是太阳探测附加任务。
