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Two years ago, the entire scientific community, including us, freaked out
两年前，整个科学界包括我们都吓坏了
because researchers discovered flowing liquid water on the surface of Mars.
因为研究人员发现火星表面有流动的液态水。
But now, some scientists aren't so sure.
但现在，有些科学家不那么确定了。
According to a paper published on Monday in Nature Geoscience, it might just be sand.
根据周一发表在《自然地球科学》上的一篇论文推测，它可能只是沙子。
Which is way less fun.
这就没意思了。
Y'know, sand is coarse and rough and gets everywhere.
你知道的，沙子粗糙，到处都是。
Since life on Earth relies on liquid water,
由于地球上的生命依赖液态水，
we're always searching for it in other parts of the solar system,
我们总是在太阳系的其他星球上寻找它，
in case maybe it contains alien bacteria or can teach us more about our planet.
以防它们可能包含外来细菌或告诉我们更多的行星知识。
And thanks to previous missions,
多亏之前的任务，
we've found that on Mars there is plenty of water frozen in polar ice caps or floating around as water vapor.
我们发现，在火星上有大量的水被冻结在极地冰帽中，或作为水蒸气漂浮着。
But in 2015, researchers announced that they'd found liquid water trickling down hills on Mars' surface.
但在2015年，研究人员宣布，他们发现液态水从火星表面的山上往下流。
Specifically, they found hydrated salts,
具体来说，他们发现了无机水合盐，
which are just salt molecules attached to some water molecules.
即盐分子附着在水分子上。
And these hydrated salts created dark, flowing lines on Mars' surface called recurring slope lineae, or RSLs.
这些水合盐在火星表面形成了平滑的深色线条，也就是所谓的“季节性斜坡纹线”(RSLs)
On the off-chance life was hanging out in those RSLs,
RSLs中不太可能存在生命，
we didn't want to send the Curiosity rover to check them out,
我们不想发送“好奇号”探测器去检测，
because it's contaminated with material from Earth.
因为它会被地球的物质“污染”。
But scientists have been analyzing them with satellites.
但科学家们利用卫星分析了它们。
In this new paper, they used the HiRISE satellite orbiting Mars to study the slopes of more than 150 RSLs at 10 different sites.
在这篇新论文中，他们利用绕火星旋转的HiRISE卫星研究了10个不同地点的150多个RSLs。
They found that, on average, almost all of the RSLs ended when a hill got between 28 and 35 degrees steep.
他们发现，平均而言，山体的坡度在28和35度之间时，几乎所有的RSLs都会终止。
And according to measurements of Martian sand dunes, that's about the same angle where flowing sand stops moving.
根据对火星沙丘的测量，这和流动沙子停止运动时的角度是一样的。
The scientists argue that, if the RSLs do contain liquid water,
科学家们认为，如果RSLs确实含有液态水，
some of them should flow past that roughly 30-degree mark.
其中有一些应该流过大约30度的斜坡。
Still that's not the only reason they're questioning the liquid water idea.
但这不是他们质疑液态水想法的唯一理由。
For one, if RSLs were filled with salty water,
首先，如果RSLs中充满了盐水，
they should be depositing dry salt piles when the water eventually evaporates, but scientists haven't found any yet.
当水最终蒸发时，它沉淀的干盐会堆积起来，但科学家们至今还没发现。
Also, one of the arguments for RSLs containing water is that they appear seasonally,
还有一种说法是RSLs含得水似乎是季节性出现的，
like water is freezing and melting.
比如水冻结和融化。
But this team observed that sand flows can also change seasonally, based on how dust blows around on Mars' surface.
但该研究小组发现，沙子流动的季节变化也可以根据火星表面灰尘的吹动。
Still, this definitely isn't a perfect hypothesis:
不过，这绝对不是一个完美的假设：
The researchers admitted that seasonal sand flow happens more easily on certain dunes
研究人员承认，某些沙丘更容易发生季节性的沙流，
that are constantly replenished by new sand blowing onto them.
它们不断有新沙子补充进来。
And the hills where we've seen RSLs aren't all like that.
但我们在山上看到的RSLs并不都是这样的。
And sand can't explain the hydrated salts, either.
而且沙子也不能解释水合盐。
But there are other possibilities!
但还有其他的可能性！
Previous studies, like one published last year in Geophysical Research Letters,
早期的研究，比如去年发表在《地球物理研究快报》的文章
have suggested that they could be caused by carbon dioxide frost instead,
暗示它们可能是由二氧化碳霜冻引起的，
which would form when gas condenses and freezes on the surface.
当气体在表面凝结和冻结时就会形成霜冻。
So before you throw your swimsuit into your bag and put it on your Mars rocket,
所以，在你把泳衣扔进包里并把它放到火星火箭之前，
maybe wait a little while until we know a little more.
可能要等一会儿，直到我们了解了更多信息。
But don't abandon your suitcase entirely!
但不要完全扔掉泳衣！
Because last week, astronomers announced that they've found a new, nearby exoplanet
因为上周，天文学家宣布他们发现了一颗新的近距离系外行星，
that might be one of the most welcoming yet.
它可能是最受欢迎的一颗了。
It's called Ross 128 b, and it was spotted using HARPS, an instrument attached to a telescope in Chile.
它叫Ross 128b，被高精度径向速度行星搜索器发现，后者连接在位于智利的一个望远镜上。
HARPS is one of our most successful tools for finding new worlds.
HARPS是我们寻找新世界最成功的工具之一。
It discovers planets by measuring wobbles in stars,
它通过测量恒星的晃动来发现行星，
which suggest that something like a planet is pulling on them.
也就是说行星之类的物体会牵引恒星。
And that's how we found 128 b.
这就是我们发现128b的方式。
This new planet orbits a red dwarf star only 11 light-years away,
这颗新行星围绕一颗红矮星运行，距地球仅11光年远，
making it the second closest Earth-like exoplanet we've found.
它也成为我们发现的第二近的类地行星。
Proxima Centauri b is just about 4 light-years away.
因为比邻星b仅有4光年远。
Red dwarfs are the most common stars in the universe, and they can be great exoplanet parents.
红矮星是宇宙中最常见的恒星，它们可能是伟大的系外行星创造者。
They're only half the size of the sun at most, and aren't too bright or hot.
它们最多只有太阳大小的一半,不太亮也不太热。
And, while some of them can give off the occasional violent burst of radiation,
同时，它们中有些可以偶尔释放出强烈的辐射，
the star 128 b orbits seems especially calm.
但128b围绕的主恒星似乎特别稳定。
From what we know so far, Ross 128 b doesn't seem too different from Earth.
就我们目前所知，Ross 128b看起来和地球没什么不同。
It's about the same size, and its temperature probably ranges from -60 to 20 degrees Celsius.
它和地球大小相同，温度范围在零下60℃到20℃之间。
But since its star is so small, 128 b orbits it a lot more closely than we do the sun, around 20 times closer.
但由于它的主恒星很小，128b的轨道比我们围绕太阳的轨道要近得多，大约是20倍近。
This helps it stay nice and warm, but it also means a year there lasts a little less than 10 days.
这有助于它保持温暖舒适，但也意味着它的一年时间不超过10天。
But if you don't mind, you know, a birthday cake, that's not so bad.
但如果你不介意生日蛋糕的话，也不算坏。
Right now, even though the planet seems homey,
现在，即使这颗行星似乎宜居，
we're not sure what its atmosphere is like, or if it has liquid water on its surface.
我们还不能确定它的大气层是什么样的，或者它的表面是否有液态水。
So that's the next thing to figure out.
所以这是下一步要确定的事。
But when the European Southern Observatory's Extremely Large Telescope comes online in 2024,
当欧洲南方天文台的超大望远镜在2024年上线时，
it should be able to figure out if 128 b has any oxygen in its atmosphere.
它应该能弄清楚128b的大气层中是否有氧气。
For now, it's still the most temperate planet we've ever found around such a calm star,
现在，它仍然是我们在这颗平静恒星周围发现的最温和行星，
so that's still pretty awesome.
所以相当了不起。
And we'll be learning more about it soon.
而且我们不久就会了解更多它的信息。
Plus, 128 b's star is currently cruising toward our solar system,
另外，128b的主恒星正在向我们的太阳系航行，
and in around 70,000 years, it'll be the closest star to the Earth besides the sun.
大约7万年后，它会是太阳之外离地球最近的恒星。
So if we're still around in 70,000 years, but still haven't got warp drive figured out,
所以如果我们在7万年后仍在，但还没弄清楚曲速引擎的话，
maybe the trip will be a little shorter if we do decide to go.
或许到它上面可能更近些。
Alright, exciting announcement!
好了，说一个令人兴奋的消息！
I've been telling everybody about this.
我一直在跟大家讲。
The SciShow team and I were talking about a problem that many of us have.
我和科学秀团队正讨论一个我们很多人都有的问题。
Often, people will ask us what we want for Christmas or for our birthdays
人们经常问我们圣诞节或生日想要什么，
and we won't know what to say because we don't care about stuff that much.
我们不知道说什么，因为我们不太在意这些东西。
But then I was thinking: there are things that I would like to get,
但随后我想：有些东西是我想要的，
or that I've bought for myself, or that people have given to me that I really love
或者给自己买的，或者是人们送给我喜欢的东西，
because I love the world, I love the universe, love the existence of biology...that kind of thing.
因为我爱这个世界，我爱宇宙，爱生物的存在等这样的事物。
So we put together a collection of artifacts of this universe...
所以我们收集了一些宇宙的产物，
we got a limited number of each of those things,
每个都有限，
and we have put them up at a store called SciShow Finds.
我们将它们放在SciShow Finds商店，
The SciShow Finds are curated by me, they are things that I would love to get in my stocking.
SciShow Finds是由我策划的，里面是我喜欢收藏的东西。
It's a very small list of just six cool things of varying price points.
清单很小，只有不同价位的六个酷玩意。
I did my best to only include one science book.
我奉献的只有一本科学书籍。
It's the book that I read this year that affected me the most, it's called "What is Life"
这是我今年读过的影响最大的一本书，叫做《生命是什么》，
and it makes an extremely compelling case that biology is a chemical inevitability.
它举了一个非常有说服力的例子，生物学是一种化学的必然性。
Which is a really important thought for having there be life out there in the universe.
在宇宙中有生命存在，这是一个非常重要的想法。
As time progresses, we're probably going to add some new finds.
随着时间的推移，我们可能会添加一些新发现。
And as we add new ones, they will replace the old ones,
在我们添加新东西时，它们会代替旧的，
so all of these products are only around for a limited time.
所以所有的产品都时间有限。
You're bound to have friends or family who would love some Mars Socks, trilobite fossils,
你一定会有朋友或家人喜欢一些火星袜子，三叶虫化石，
or maybe this Space Shuttle lapel pin.
或者这个航天飞机翻领针的。
And, if not, you might just want to get them for yourself
如果没有，你可能只想给自己买
or just slide the link in if anybody's like, "What do you want, man?"
如果有人问你“你想要什么”就点击链接
Just be like, "SciShowFinds.com!"
比如“SciShowFinds.com!”
And know that when you go to SciShowFinds.com or send somebody there, you're also supporting SciShow.
你登录SciShowFinds.com或发送给某人，都是在支持科学秀。
So, thank you! Thank you for doing that, in that way, and also for doing that by watching this video.
所以，感谢你，感谢您的所作所为，那样的话，观看本视频也在支持科学秀。
You're the best!
你们最棒！
