为什么我们将旅行者1号发送到距地球17.58光年的Gliese 445,而不是距地球只有的4.22光年的Proxima Centauri? Why did we send Voyager 1 toward Gliese 445 which is 17.58 light years from Earth instead of Proxima Centauri’s much closer 4.22 light years away?

【翻译自quora】

Thanks for the ATA.

There really was no attempt to aim Voyager 1 at anything outside the Solar System. There wasn’t even a pre-planned attempt to think about doing science after it went past Saturn and Titan. Everything that Voyager 1 has done since 1980 has been part of an “extended mission” created after the primary mission was completed.

确实没有尝试将旅行者1号瞄准太阳系以外的任何物体。 在飞过土星和土卫六之后,科学家们甚至都没有预先计划过下一步该做什么。 自1980年以来,旅行者1号所做的一切都是在主要任务完成后新创建的“扩展任务”。

(An illustration of the Grand Tour — this alignment comes around about once every two centuries.)

伟大旅行插图-从地球到海王星的这种排列方式大约每两个世纪出现一次

Voyager 1 was sent on a leg of the “Grand Tour” — a chance alignment of the planets that happens once every 175 years or so, and happened to be available in the 1975–1977 launch time-frame. Point of fact, Voyager 1 missed most of the Grand Tour opportunity because it was launched at the very end of the Grand Tour window, leaving it only able to tour Jupiter and Saturn. Voyager 2 was able to tour Jupiter, Saturn, Uranus, and Neptune because it was actually launched in the closing days of the extended Grand Tour window, more than two weeks before Voyager 1 was launched.

旅行者1号是在“ 伟大旅行 ”的一个航段上发送的,这是每175年左右发生一次的行星偶然对准,并且碰巧出现在1975-1977年的发射时间范围内。 实际上,旅行者1号错过了大部分“伟大旅行”机会,因为它是在“伟大旅行”窗口的最后一刻才发射的,因此只能巡回木星和土星。 Voyager 2之所以能够游览木星,土星,天王星和海王星,是因为它实际上是在扩展“伟大旅行”窗口关闭的几天内发射的,比Voyager 1发射要早两个多星期。

The environment around Jupiter is harsh and full of radiation. They weren’t even certain that Voyager would survive passing through the Jovian system, much less making it to Saturn.

木星周围的环境恶劣且充满辐射。 他们甚至不确定旅行者号能否通过木星而幸存下来,更不用说飞过土星了。

When Voyager 1 made it past Jupiter, it was on course to Saturn, in a high-inclination approach. It was going to pass mostly under Saturn, and use its gravity to be pulled upward out of the plane of the solar system, to the position of Titan, the moon of Saturn with its own atmosphere, and the possibility of life.

当旅行者1号越过木星时,它正以高倾角方式进入土星。 它将主要经过土星下方,并利用引力弹弓被拉出太阳系水平面,到达土卫六的位置,土卫六自身具有大气层,可能有生命。

(Voyager 1 passes “below” Saturn to be sent towards Titan.)

(旅行者1号经过“土星下方”被送往土卫六。)

This encounter was so critical to the Voyager 1 mission, that, had anything gone wrong, Voyager 2 would have been re-pointed for a Titan encounter instead of going on to the other two planets.

这次经历对旅行者1号特别危险,以至于出了什么问题,旅行者2号的任务都将被重新设计为继续完成旅行者1号的任务,与土卫六相遇,而不是继续前往其他两个星球。

All the scientists cared about was Titan. They weren’t even sure Voyager would survive the environment around Saturn, or survive passing so close to Titan — if Titan had an extended atmosphere not visible from Earth, it could have actually have damaged or destroyed Voyager 1.

科学家关心的只有土卫六。 他们甚至不确定旅行者是否会在土星周围的环境中运行,或者能否在如此靠近土卫六的地方工作——如果土卫六拥有从地球上看不到的额外大气层,它实际上可能已经损坏或摧毁了旅行者1号。

They did it anyway.

他们还是这么做了。

Voyager 1 made a very successful flyby of Saturn, and hurtled past Titan, sending back enough information so that the Voyager 2 extended tour was approved.

旅行者1号成功飞越了土星,飞越了土卫六,传回了足够的信息,因此旅行者2扩展旅游得以获准。

(Titan from Voyager 1.)

With most of its maneuvering fuel expended, Voyager 1 left the Saturnian system traveling at an angle imparted by Saturn, of 35 degrees up and out of the ecliptic of the Solar System.

旅行者1的大部分机动燃料都用完了,它以土星公转的角度离开了土星系统,并以35度角向上离开了太阳系黄道。

With no other planets to encounter, it really had no way to change its course, so it kept heading out in a more or less straight line — to be totally correct, the line is curved because Voyager is on a hyperbolic orbital of the Sun — into the inky black of the outer solar system.

由于没有其他行星可以相遇,它实际上没有办法改变其航向,因此它一直以近似一条直线前进—对的,该条线是有点弯曲的,因为旅行者号位于太阳的双曲线轨道上——进入漆黑的外部太阳系。

(Voyager 1, high above the ecliptic — or the plane of the Solar System — looking back at the Sun.)

(旅行者1,在黄道上方或太阳系平面上方,回头看太阳。)

In fact, it was only after Voyager 2 completed its pass of Neptune, about 11 years after the Voyagers were launched, that someone took the time to calculate where they were going, and worked out that Voyager 1 would make a “close pass” of Gliese 445.

实际上,只有在旅行者2发射后约11年,旅行者2号已经飞过海王星,大家才计算出他们要去的地方,然后得出旅行者1将近距离通过” Gliese 445. 。

Remember, also, that the scientists and engineers only designed the probes to work for about 15 years maximum. No one dreamed they’d still be sending us data 42 years later. But there’s no way they’ll last long enough to send us any important data about their close passes to other stars in the future.

还要记住,科学家和工程师只设计了最长可使用15年的探测器。 没有人梦到他们在42年后仍会向我们发送数据。 但是,它们不可能持续足够长的时间,来向我们发送任何有关它们将近距离通过的其他恒星的重要数据。

In about 5–6 more years, the power level on Voyager 1 and 2 will drop below what’s needed for even the most basic systems that are still active, the computer will register a “PWRERROR” state, and put the system into a safe mode. Only the 60 bit per second engineering feed will make it back to Earth.

再过大约5至6年,旅行者1和旅行者2的功率水平将降至低于仍处于活动状态的最基本系统所需的功率水平,计算机也将处于“ PWRERROR”状态,并使系统进入安全模式 。 只有每秒60位的工程提要会被传返回地球。

Without the computers active, and with no continued guidance, Voyager will lose alignment of the high-gain transmitter to Earth, and we’ll lose the signal.

如果没有计算机继续休眠,并且没有持续的指导,则旅行者将失去高增益发射器与地球之间的对准,并且我们也会丢失信号。

A few years thereafter, the heaters of the instrument bay will drop below some critical level, and the computer will finally shut down entirely. Voyager will be, effectively, dead.

此后几年,仪器机架的加热器将降至某个临界水平以下,并且计算机最终将完全关闭。 旅行者将快速地,死亡。

After about 800 more years, the plutonium RTG cores will be producing less than 1% of their original heat, and the craft will drop to the temperature of deep space.

再过大约800年后, RTG磁芯产生的热量不到其原始热量的1%,并且这飞船的温度将降至与深空一样的温度。

About 39 millennia after that, Voyager 1 will pass an unimpressive 1.76 light years from Gliese 445. This is not because Voyager is travelling towards Gliese, but because Gliese is screaming towards the Solar System at 12 times the velocity of Voyager — it will actually pass the sun with over 2.5 light years distance to spare, so no special cause for alarm — while Voyager will be only about 2 light years away from Earth at that point in time.

此后大约三千年,旅行者1号将平淡地继续飞过1.76光年而越过Gliese 445。这不是因为旅行者号 正在朝Gliese 行进,而是因为 Gliese 正以旅行者12倍的速度飞向太阳系——实际上它经过太阳时,离太阳最近也有2.5光年以上的距离,所以不必太担心——而“旅行者”号此时距地球仅2个光年。

Getting to Proxima would actually take nearly 30,000 years longer because Proxima is nearing its closest approach to the Sun, and in about 10,000 years will begin moving away from us again. Even if it weren’t, then crossing the 4.22 light years would take Voyager close to 90,000 years at its current rate of travel.

到达Proxima实际上要花费将近30,000年,因为Proxima现在正在最接近太阳的地方,并且在大约10,000年后将再次远离我们。 即使不是这样,如果以目前的行进速度穿越4.22光年,旅行者号也将接近90,000年。

So, actually — totally by accident — scientists chose the star that will provide the soonest, closest encounter available in the next 100,000 years or so. Not that it will make any difference. By then, Voyager 1 will be just a lump of inert metal and plastic, serenely tumbling through the inky darkness, all alone in a shining sea of stars, humanity’s most distant and first emissary to the Milky Way.

因此,实际上——完全是偶然——科学家们选择了在未来100,000年左右的时间里,可以以最短距离最快到达的恒星恒星。 并不是因为其他的原因。 届时,旅行者1号将只是一团惰性金属和塑料,在漆黑的黑暗中安详地翻滚,独自一人在人类最遥远,银河系的最璀璨的星空中发光。

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