Name: 準備好了，新地平線正在接近它的下一個目標新地平線正在接近它的下一個目標 | 科學秀新聞 (Get Ready: New Horizons Is Approaching Its Next Target | SciShow News)
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In 2015, New Horizons made its famous Pluto flyby,

but once it left Pluto,  its mission wasn't over.

For the last few years, the spacecraft has been traveling toward an even more distant object

that's been frozen in time for billions of years.

The team has nicknamed it Ultima Thule, and while you're ringing in the New Year on January 1st,

Ultima Thule is a rock about the size of a city and is 6.6 billion kilometers away.

It's located in the Kuiper belt, way out past the orbit of Pluto.

And that makes it the most distant object a spacecraft has ever visited.

But you classical lit scholars out there already knew that because Ultima Thule means it's beyond the known world.

Back in August, New Horizons sent NASA a grainy postcard with its first picture of Ultima Thule,

and since then, the probe has been hurtling toward its target at about 14 kilometers per second.

That's more than 50,000 kilometers per hour!

New Horizons is going so fast that it won't be able to slow down enough to orbit the object.

Instead, it will just make a flyby, like it did with Pluto.

We don't understand Ultima Thule's orbit very well, so it's been hard to aim for,

and astronomers have had to track it constantly.

But since it's just a dim little speck in a sky full of stars, it's not easy to track, either.

We don't even know if it's a single object or two giant rocks orbiting really close together.

New Horizons is also trying to get even closer to Ultima Thule than it did to Pluto.

If all goes well, it's planning to skim just 3,500 kilometers above the surface.

Which, at 14 kilometers per second, means there's virtually no room for error.

Visiting Ultima Thule is like exploring an amazingly well preserved, 4-billion-year-old fossil.

It's an ancient rock that formed at the same time as our solar system.

And ever since then, it's been frozen solid at only a few dozen degrees Celsius above absolute zero.

So, in a way, visiting Ultima Thule is like going back in time.

We'll get to explore a snapshot taken of our neighborhood as it was being born.

Scientists are planning to look at the shape and surface features of Ultima Thule,

see whether or not it has rings, and search for clues about how it formed.

They're even going to look for an atmosphere, though they don't expect to find one.

Aside from Pluto, this is the first close-up look we'll get at an object in the Kuiper Belt,

which we didn't even know existed until 1992.

But now we understand it's like a vault full of secrets that can tell us about the origin of the solar system.

Primitive space rocks may be even more important to us than we realized, too.

Earlier this week, a team of researchers announced in Nature Communications that, in a lab,

they had made the sugar component of DNA under extraterrestrial conditions.

Meaning that it's possible that the building blocks of DNA might not have originated on Earth.

In the last several decades, we've found other sugars on a few different meteorites.

That's led scientists to suspect that the sugars that support life could have originally come to Earth on space rocks.

But we still don't understand how sugars got on meteorites in the first place.

To figure it out, researchers have been trying to create those compounds under conditions

In this paper, the team made those conditions using a process called ultraviolet irradiation.

Ironically, it's what we normally use for sterilizing things, like water.

but these scientists used it to create organic molecules from conditions that were not biological in the first place.

They started with a mixture of frozen water and methanol at -261°C.

Kind of like something you might find in a cloud in interstellar space.

Then, they shined ultraviolet light on it, like our Sun did to rocks billions of years ago.

When the light interacted with the ice, it produced a chemical reaction.

And the residue it created contained a bunch of different sugars and other compounds.

Many of them had been seen before in similar experiments.

But this time, scientists also detected a compound called 2-deoxyribose.

This is a type of sugar called a deoxy sugar, which makes up DNA.

Along with it, they found compounds that can be derived from deoxy sugars

and that we've also found on actual meteorites.

That doesn't mean those rocks used to contain deoxy sugars, we don't have evidence for that.

Either way, this study adds to a list of sugars and other organic compounds that can be created,

and have been created, in conditions a lot like the sterile environment of space.

It's the most convincing evidence yet that the sugars that gave rise to life on Earth

could have been created in totally uninhabitable worlds.

Places like comets, asteroids, and clumps of space dust,

places we don't associate with life at all.

It suggests that, as violent as it sounds,

all the meteorites that bombarded the early Earth could have helped life emerge.

One thing we really need, though, is direct evidence.

So next, scientists will be looking for these deoxy sugars on meteorites themselves.

And this study gives them a good reason to keep looking.

Thanks for watching this episode of SciShow Space News!

This will actually be our last regular news episode for 2018, but don't worry:

We have a few special things planned, and we'll be back in January.

If you don't want to miss anything, you can go to youtube.com/scishowspace and subscribe.