Name: 【TED】Carrie Nugent: Adventures of an asteroid hunter (Adventures of an asteroid hunter | Carrie Nugent)
Uploaded: 2018-02-27T08:12:29.000Z
Duration: 6 min 7 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

older than the continents and the oceans between them.

This was formed over four billion years ago

This rusty lump of nickel and iron may not appear special,

you can see that it is different from earthly metals.

This pattern reveals metallic crystals that can only form out in space

where molten metal can cool extremely slowly,

This was once part of a much larger object,

one of millions left over after the planets formed.

Asteroids are our oldest and most numerous cosmic neighbors.

This graphic shows near-Earth asteroids orbiting around the Sun,

The sizes of the Earth, Sun and asteroids have been greatly exaggerated

Teams of scientists across the globe are searching for these objects,

I think of the search for these asteroids as a giant public works project,

but instead of building a highway, we're charting outer space,

building an archive that will last for generations.

These are the 1,556 near-Earth asteroids discovered just last year.

And these are all of the known near-Earth asteroids,

and had its path around the Sun determined.

Although it varies from asteroid to asteroid,

the paths of most asteroids can be predicted for dozens of years.

And the paths of some asteroids can be predicted with incredible precision.

For example, scientists at the Jet Propulsion Laboratory

predicted where the asteroid Toutatis was going to be four years in advance

Toutatis traveled 8.5 billion kilometers.

Now, the reason I have this beautiful asteroid fragment

asteroids sometimes drop by unexpectedly.

a small asteroid exploded over the city of Chelyabinsk, Russia.

Objects of this size hit the Earth every 50 years or so.

75 percent of plant and animal species were lost,

That object was about 10 kilometers across,

and 10 kilometers is roughly the cruising altitude of a 747 jet.

snag a window seat, look out and imagine a rock so enormous

It's so wide that it takes your plane one full minute to fly past it.

That's the size of the asteroid that hit the Earth.

that asteroids have been considered a credible threat to our planet.

And since then, there's been a focused effort underway

I am lucky enough to be part of this effort.

I'm part of a team of scientists that use NASA's NEOWISE telescope.

Now, NEOWISE was not designed to find asteroids.

It was designed to orbit the earth and look far beyond our solar system

to seek out the coldest stars and the most luminous galaxies.

And it did that very well for its designed lifetime of seven months.

But today, six years later, it's still going.

We've repurposed it to discover and study asteroids.

And although it's a wonderful little space robot,

The cryogen that used to refrigerate its sensors is long gone,

so we joke that its air-conditioning is broken.

It's got 920 million miles on the odometer,

and reliably takes a photograph of the sky every 11 seconds.

It's taken 23 photos since I began speaking to you.

One of the reasons NEOWISE is so valuable

is that it sees the sky in the thermal infrared.

That means that instead of seeing the sunlight that asteroids reflect,

This is a vital capability since some asteroids are as dark as coal

and can be difficult or impossible to spot with other telescopes.

But all asteroids, light or dark, shine brightly for NEOWISE.

Astronomers are using every technique at their disposal

In 2010, a historic milestone was reached.

The community, together, discovered over 90 percent of asteroids

Subtitles ListPlay Video

【TED】Carrie Nugent: Adventures of an asteroid hunter (Adventures of an asteroid hunter | Carrie Nugent)

massive

vital

reveal

technique