The search for dark matter -- and what we've found so far | Risa Wechsler

541,514 views ・ 2020-01-27

TED


μ•„λž˜ μ˜λ¬Έμžλ§‰μ„ λ”λΈ”ν΄λ¦­ν•˜μ‹œλ©΄ μ˜μƒμ΄ μž¬μƒλ©λ‹ˆλ‹€.

λ²ˆμ—­: Miyeong Hwang κ²€ν† : Hoeun Cheong
00:12
Do you ever think about what would happen
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지ꡬ가 쑰금만 λ‹¬λžλ‹€λ©΄ 무슨 일이 생겼을지
00:14
if the world were a little bit different?
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생각해 보신 적이 μžˆμŠ΅λ‹ˆκΉŒ?
00:17
How your life would be different
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μ—¬λŸ¬λΆ„μ΄ μ§€κΈˆ 말고
00:19
if you were born 5,000 years from now
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μ•½ 5000λ…„ 후에 νƒœμ–΄λ‚¬λ‹€λ©΄
00:21
instead of today?
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μ—¬λŸ¬λΆ„μ˜ 삢은 μ–Όλ§ˆλ‚˜ λ‹¬λΌμ‘Œμ„κΉŒμš”?
00:23
How history would be different
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각 λŒ€λ₯™μ˜ μœ„λ„κ°€ 쑰금만 λ‹¬λžλ”λΌλ©΄
00:25
if the continents were at different latitudes
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역사가 λ‹¬λΌμ‘Œκ² μ£ ?
00:27
or how life in the Solar system would have developed
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ν˜Ήμ€ νƒœμ–‘μ˜ 크기가 μ§€κΈˆλ³΄λ‹€ 10%만 컸더라도
00:31
if the Sun were 10 percent larger.
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νƒœμ–‘κ³„μ˜ 생λͺ…체가 λ‹€λ₯΄κ²Œ λ°œμ „ν•˜μ§€ μ•Šμ•˜μ„κΉŒμš”?
00:35
Well, playing with these kinds of possibilities
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이런 κ°€λŠ₯성듀을 λ‹€λ£¨λŠ” 것이
00:38
is what I get to do for a living
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제 μ§μ—…μž…λ‹ˆλ‹€.
00:39
but with the entire universe.
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지ꡬ 뿐만이 μ•„λ‹Œ 전체 우주λ₯Ό λŒ€μƒμœΌλ‘œμš”.
00:43
I make model universes in a computer.
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μ €λŠ” μ»΄ν“¨ν„°λ‘œ λͺ¨ν˜• μš°μ£Όλ“€μ„ λ§Œλ“­λ‹ˆλ‹€.
00:45
Digital universes that have different starting points
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μ‹œμž‘μ μ΄ λ‹€λ₯Έ 디지털 μš°μ£Όλ“€μ€
00:48
and are made of different amounts of different kinds of material.
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λ‹€μ–‘ν•œ μ–‘μ˜ μ„œλ‘œ λ‹€λ₯Έ 물질둜 κ΅¬μ„±λ˜μ–΄ μžˆμŠ΅λ‹ˆλ‹€.
00:53
And then I compare these universes to our own
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μ €λŠ” μ΄λŸ¬ν•œ μš°μ£Όλ“€μ„ 우리 μš°μ£Όμ™€ λΉ„κ΅ν•˜μ—¬
00:56
to see what it is made of and how it evolved.
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μ–΄λ–»κ²Œ κ΅¬μ„±λ˜μ–΄ μžˆλŠ”μ§€, μ–΄λ–»κ²Œ μ§„ν™”ν•˜λŠ”μ§€λ₯Ό κ΄€μ°°ν•©λ‹ˆλ‹€.
01:02
This process of testing models with measurements of the sky
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ν•˜λŠ˜μ˜ μΈ‘μ •κ³Ό λ³‘ν–‰λ˜λŠ” λͺ¨ν˜• μ‹œν—˜ 과정은
01:06
has taught us a huge amount about our universe so far.
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μ§€κΈˆκΉŒμ§€ μš°λ¦¬μ—κ²Œ μ—„μ²­λ‚œ 것듀을 κ°€λ₯΄μ³ μ£Όμ—ˆμŠ΅λ‹ˆλ‹€.
01:10
One of the strangest things we have learned
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저희가 μ•Œμ•„λ‚Έ κ°€μž₯ μ΄μƒν–ˆλ˜ 것 쀑 ν•˜λ‚˜λŠ”
01:12
is that most of the material in the universe
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μš°μ£Όμ— μžˆλŠ” λŒ€λΆ€λΆ„μ˜ λ¬Όμ§ˆλ“€μ€
01:15
is made of something entirely different than you and me.
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저와 μ—¬λŸ¬λΆ„κ³ΌλŠ” μ™„μ „νžˆ λ‹€λ₯Έ 물질둜 κ΅¬μ„±λ˜μ–΄ μžˆλ‹€λŠ” κ²ƒμž…λ‹ˆλ‹€.
01:20
But without it,
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ν•˜μ§€λ§Œ μ΄λŸ¬ν•œ 물질 μ—†μ΄λŠ”
01:23
the universe as we know it wouldn't exist.
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μš°λ¦¬κ°€ μ•„λŠ” μš°μ£ΌλŠ” μ‘΄μž¬ν•˜μ§€ μ•Šμ„ κ²ƒμž…λ‹ˆλ‹€.
01:28
Everything we can see with telescopes
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μš°λ¦¬κ°€ 망원경을 ν†΅ν•΄μ„œ λ³΄λŠ” λͺ¨λ“  것듀은
01:32
makes up just about 15 percent of the total mass in the universe.
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우주 전체 μ§ˆλŸ‰μ˜ μ•½ 15%λ§Œμ„ μ°¨μ§€ν•˜κ³  μžˆμ„ 뿐이고
01:38
Everything else, 85 percent of it,
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κ·Έ μ™Έ 85%의 λ¬Όμ§ˆμ€
01:42
doesn't emit or absorb light.
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빛을 λ°©μΆœν•˜μ§€λ„ ν‘μˆ˜ν•˜μ§€λ„ μ•ŠμŠ΅λ‹ˆλ‹€.
01:45
We can't see it with our eyes,
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λˆˆμœΌλ‘œλŠ” κ·Έ λ¬Όμ§ˆμ„ κ΄€μ°°ν•  수 μ—†κ³ 
01:48
we can't detect it with radio waves
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μ „νŒŒλ‚˜ μ „μžνŒŒ ν˜Ήμ€ κ·Έ μ–΄λ–€ λΉ›μœΌλ‘œλ„
01:51
or microwaves or any other kind of light.
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탐지할 수 μ—†μŠ΅λ‹ˆλ‹€.
01:55
But we know it is there
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μš°λ¦¬κ°€ κ·Έ 쑴재λ₯Ό μ•Œ 수 μžˆλŠ” μ΄μœ λŠ”
01:57
because of its influence on what we can see.
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μš°λ¦¬κ°€ λ³Ό 수 μžˆλŠ” λ¬Όμ§ˆμ—κ²Œ 영ν–₯을 μ£ΌκΈ° λ•Œλ¬Έμž…λ‹ˆλ‹€.
02:01
It's a little bit like,
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이것은 마치
02:02
if you wanted to map the surface of our planet
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μš°λ¦¬κ°€ μ§€κ΅¬μ˜ ν‘œλ©΄κ³Ό κ·Έ μœ„μ— μžˆλŠ” λͺ¨λ“  것이 ν¬ν•¨λœ
02:04
and everything on it
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지도λ₯Ό λ§Œλ“ λ‹€λ©΄
02:06
using this picture of the Earth from space at night.
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μš°μ£Όμ—μ„œ 밀에 찍은 지ꡬ 사진을 μ‚¬μš©ν•˜λŠ” 것과 κ°™μŠ΅λ‹ˆλ‹€.
02:11
You get some clues from where the light is,
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빛이 μžˆλŠ” 곳의 λ‹¨μ„œλ“€μ„ 찾을 수 μžˆμ§€λ§Œ
02:14
but there's a lot that you can't see,
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μ‚¬λžŒλ“€μ—μ„œ μ‚°λ§₯κΉŒμ§€
02:16
everything from people to mountain ranges.
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보이지 μ•ŠλŠ” 뢀뢄도 λ„ˆλ¬΄ λ§ŽμŠ΅λ‹ˆλ‹€.
02:19
And you have to infer what is there from these limited clues.
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그러면 μ œν•œλœ λ‹¨μ„œλ₯Ό 가지고 무엇이 μžˆλŠ”μ§€ 좔둠을 ν•΄μ•Ό ν•©λ‹ˆλ‹€.
02:25
We call this unseen stuff "dark matter."
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μ•ˆ λ³΄μ΄λŠ” 이 λ¬Όμ§ˆμ„ 'μ•”ν‘λ¬Όμ§ˆ'이라 λΆ€λ¦…λ‹ˆλ‹€.
02:29
Now, a lot of people have heard of dark matter,
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λ§Žμ€ μ‚¬λžŒλ“€μ΄ μ•”ν‘λ¬Όμ§ˆμ΄λΌλŠ” 말을 λ“€μ–΄λ³΄μ•˜μ§€λ§Œ,
02:32
but even if you have heard of it,
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μ—¬λŸ¬λΆ„μ΄ 듀어보셨닀 ν•˜λ”λΌλ„
02:34
it probably seems abstract,
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ꡉμž₯히 좔상적인 것 κ°™κ³ 
02:38
far away, probably even irrelevant.
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μš°λ¦¬μ™€ κ΄€λ ¨ μ—†λ‹€κ³  μƒκ°ν•˜μ‹€ μˆ˜λ„ μžˆμŠ΅λ‹ˆλ‹€.
02:42
Well, the interesting thing is,
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ν₯미둜운 점은
02:45
dark matter is all around us
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μ•”ν‘λ¬Όμ§ˆμ΄ 우리 주변에 μ‘΄μž¬ν•˜κ³ 
02:48
and probably right here.
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μ•„λ§ˆλ„ μ§€κΈˆ 여기에도 μžˆμ„ κ²λ‹ˆλ‹€.
02:50
In fact, dark matter particles
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사싀, μ•”ν‘λ¬Όμ§ˆ μž…μžλ“€μ€
02:52
are probably going through your body right now
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μ§€κΈˆ μ—¬λŸ¬λΆ„μ˜ λͺΈμ„ κ΄€ν†΅ν•˜κ³  μžˆμ„μ§€λ„ λͺ¨λ¦…λ‹ˆλ‹€.
02:56
as you sit in this room.
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μ—¬λŸ¬λΆ„μ΄ μ—¬κΈ° 앉아 κ³„μ‹œλŠ” μ™€μ€‘μ—λ„μš”.
02:58
Because we are on Earth
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μ™œλƒν•˜λ©΄ μš°λ¦¬κ°€ 지ꡬ μœ„μ— 있고,
02:59
and Earth is spinning around the Sun,
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μ§€κ΅¬λŠ” νƒœμ–‘ 주변을 κ³΅μ „ν•˜λ©°,
03:01
and the Sun is hurtling through our galaxy
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νƒœμ–‘μ€ μ€ν•˜κ³„μ—μ„œ μ‹œκ°„λ‹Ή μ•½ 80만km의 μ†λ„λ‘œ
03:04
at about half a million miles per hour.
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움직이고 있기 λ•Œλ¬Έμž…λ‹ˆλ‹€.
03:07
But dark matter doesn't bump into us,
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ν•˜μ§€λ§Œ μ•”ν‘λ¬Όμ§ˆμ€ μš°λ¦¬μ™€ λΆ€λ”ͺμΉ˜μ§€λŠ” μ•Šκ³ 
03:09
it just goes right through us.
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κ·Έλƒ₯ 우리λ₯Ό 톡과해 λ²„λ¦½λ‹ˆλ‹€.
03:12
So how do we figure out more about this?
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그럼 μ–΄λ–»κ²Œ μš°λ¦¬λŠ” μ•”ν‘λ¬Όμ§ˆμ— λŒ€ν•΄
03:17
What is it,
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이것이 무엇이고,
03:18
and what does it have to do with our existence?
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우리의 μ‘΄μž¬μ™€λŠ” μ–΄λ–€ 관련성이 μžˆλŠ”μ§€ μ•Œ 수 μžˆμ„κΉŒμš”?
03:20
Well, in order to figure out how we came to be,
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μš°λ¦¬κ°€ μ–΄λ–»κ²Œ μ‘΄μž¬ν•˜κ²Œ λλŠ”μ§€ μ•Œμ•„λ‚΄κΈ° μœ„ν•΄μ„œλŠ”
03:25
we first need to understand how our galaxy came to be.
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λ¨Όμ € μ€ν•˜κ³„κ°€ μ–΄λ–»κ²Œ ν˜•μ„±λ˜μ—ˆλŠ”μ§€ 이해할 ν•„μš”κ°€ μžˆμŠ΅λ‹ˆλ‹€.
03:29
This is a picture of our galaxy, the Milky Way, today.
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이것이 ν˜„μž¬μ˜ 우리 μ€ν•˜κ³„, 즉 μ€ν•˜μˆ˜μ˜ μ‚¬μ§„μž…λ‹ˆλ‹€.
03:34
What did it look like 10 billion years in the past
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100μ–΅ λ…„ μ „ 과거에 우리 μ€ν•˜μˆ˜λŠ” μ–΄λ–€ λͺ¨μŠ΅μ΄μ—ˆμ„κΉŒμš”?
03:36
or what would it look like 10 billion years in the future?
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ν˜Ήμ€ 100μ–΅λ…„ ν›„, 미래의 우리 μ€ν•˜μˆ˜μ˜ λͺ¨μŠ΅μ€ μ–΄λ–€ λͺ¨μŠ΅μΌκΉŒμš”?
03:40
What about the stories
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μš°λ¦¬κ°€ μ‘°μ‚¬ν•΄μ„œ
03:42
of the hundreds of millions of other galaxies
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μ§€λ„λ‘œ 남긴 λ‹€λ₯Έ 수백만 개의 μ€ν•˜μˆ˜λ“€μ€ μ–΄λ–»κ²Œ λ κΉŒμš”?
03:45
that we've already mapped out with large surveys of the sky?
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03:49
How would their histories be different
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μš°μ£Όκ°€ λ­”κ°€ λ‹€λ₯Έ 물질둜 λ§Œλ“€μ–΄μ‘Œκ±°λ‚˜
03:51
if the universe was made of something else
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우주λ₯Ό κ΅¬μ„±ν•˜λŠ” 물질의 λΉ„μœ¨μ΄ λ‹¬λžλ‹€λ©΄
03:54
or if there was more or less matter in it?
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μ€ν•˜κ³„μ˜ μ—­μ‚¬λŠ” μ–΄λ–»κ²Œ λ‹¬λΌμ‘Œμ„κΉŒμš”?
03:57
So the interesting thing about these model universes
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이 λͺ¨ν˜• μš°μ£Όλ“€μ— κ΄€ν•œ ν₯미둜운 점은
04:01
is that they allow us to test these possibilities.
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μ΄λŸ¬ν•œ κ°€λŠ₯성듀을 μ‹œν—˜ν•΄ λ³Ό 수 μžˆλ„λ‘ ν•΄μ€€λ‹€λŠ” κ²ƒμž…λ‹ˆλ‹€.
04:05
Let's go back to the first moment of the universe --
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μš°μ£Όκ°€ 처음 μƒμ„±λ˜μ—ˆλ˜ κ·Έ μˆœκ°„μœΌλ‘œ κ°€λ³΄κ² μŠ΅λ‹ˆλ‹€.
04:11
just a fraction of a second after the big bang.
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빅뱅이 λ°œμƒν•œ λ°”λ‘œ κ·Έ μ§ν›„λ‘œ λ§μž…λ‹ˆλ‹€.
04:17
In this first moment,
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처음 κ·Έ μˆœκ°„μ—”
04:19
there was no matter at all.
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μ–΄λ–€ λ¬Όμ§ˆλ„ μ‘΄μž¬ν•˜μ§€ μ•Šμ•˜μŠ΅λ‹ˆλ‹€.
04:21
The universe was expanding very fast.
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μš°μ£ΌλŠ” 맀우 λΉ λ₯΄κ²Œ νŒ½μ°½ν•˜κ³  μžˆμ—ˆμŠ΅λ‹ˆλ‹€.
04:25
And quantum mechanics tells us
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μ–‘μžμ—­ν•™μ— λ”°λ₯΄λ©΄
04:28
that matter is being created and destroyed
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λ¬Όμ§ˆμ€ λŠμž„μ—†μ΄, 맀 μˆœκ°„
04:31
all the time, in every moment.
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μƒμ„±λ˜κ³  νŒŒκ΄΄λ©λ‹ˆλ‹€.
04:34
At this time, the universe was expanding so fast
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이 λ‹Ήμ‹œμ—λŠ”, 우주의 νŒ½μ°½μ†λ„κ°€ μ—„μ²­λ‚˜κ²Œ λΉ¨λžμ—ˆκ³ 
04:36
that the matter that got created couldn't get destroyed.
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μƒμ„±λ˜μ—ˆλ˜ λ¬Όμ§ˆλ“€μ€ νŒŒκ΄΄λ˜μ§€ μ•Šμ•˜μ—ˆμŠ΅λ‹ˆλ‹€.
04:40
And thus we think that all of the matter was created during this time.
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κ·Έλž˜μ„œ μš°λ¦¬λŠ” λͺ¨λ“  λ¬Όμ§ˆλ“€μ΄ 이 μ‹œκΈ°μ— μƒμ„±λ˜μ—ˆλ‹€κ³  μƒκ°ν•©λ‹ˆλ‹€.
04:45
Both the dark matter
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μ—¬λŸ¬λΆ„κ³Ό μ €λ₯Ό κ΅¬μ„±ν•˜κ³  μžˆλŠ”
04:47
and the regular matter that makes up you and me.
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μ•”ν‘λ¬Όμ§ˆμ΄λ‚˜ 일반물질 λ‘˜ λ‹€ 말이죠.
04:52
Now, let's go a little bit further
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μ΄μ œλŠ” 빅뱅이 λ°œμƒν•œ μ•½ 40λ§Œλ…„ ν›„,
04:54
to a time after the matter was created,
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μ•”ν‘λ¬Όμ§ˆμ΄ λ§Œλ“€μ–΄μ§€κ³ 
04:57
after protons and neutrons formed,
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μ–‘μ„±μžμ™€ μ€‘μ„±μž
04:59
after hydrogen formed,
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그리고 μˆ˜μ†Œκ°€ ν˜•μ„±λœ
05:01
about 400,000 years after the big bang.
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μ‹œκΈ°λ‘œ 가보도둝 ν•˜μ£ .
05:05
The universe was hot and dense and really smooth
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μš°μ£ΌλŠ” 뜨겁고 밀도가 λ†’μœΌλ©° 정말 λΆ€λ“œλŸ¬μ› μŠ΅λ‹ˆλ‹€.
05:09
but not perfectly smooth.
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κ·ΈλŸ¬λ‚˜ μ™„λ²½νžˆ λΆ€λ“œλŸ¬μ› λ˜ 것은 μ•„λ‹™λ‹ˆλ‹€.
05:12
This image, taken with a space telescope called the Planck satellite,
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'ν”Œλžœν¬ μœ„μ„±'이라 λΆˆλ¦¬λŠ” 우주 λ§μ›κ²½μœΌλ‘œ 찍은 이 μ΄λ―Έμ§€λŠ”
05:17
shows us the temperature of the universe
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μš°λ¦¬μ—κ²Œ 우주의 μ˜¨λ„λ₯Ό
05:19
in all directions.
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λͺ¨λ“  λ°©ν–₯μ—μ„œ λ³Ό 수 있게 ν•΄μ€λ‹ˆλ‹€.
05:22
And what we see
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그리고 μš°λ¦¬κ°€ λ³΄λŠ” 것은
05:23
is that there were places that were a little bit hotter
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λ‹€λ₯Έ 지역보닀 쑰금 더 뜨겁고
05:26
and denser than others.
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밀도가 높은 μ§€μ—­λ“€μž…λ‹ˆλ‹€.
05:28
The spots in this image
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이 μ΄λ―Έμ§€μ—μ„œ 점듀은
05:30
represent places where there was more or less mass in the early universe.
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초기 우주의 μ§ˆλŸ‰μ˜ 뢄포λ₯Ό λ‚˜νƒ€λƒ…λ‹ˆλ‹€.
05:37
Those spots got big because of gravity.
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μ € 점듀이 μ»€λ‹€λž€ μ΄μœ λŠ” 쀑λ ₯ λ•Œλ¬Έμž…λ‹ˆλ‹€.
05:41
The universe was expanding and getting less dense overall
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μ§€λ‚œ 138μ–΅ 년에 걸쳐 μš°μ£ΌλŠ” νŒ½μ°½ν•˜λ©΄μ„œ
05:45
over the last 13.8 billion years.
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μ „λ°˜μ μœΌλ‘œ 밀도가 μ•½ν•΄μ‘ŒμŠ΅λ‹ˆλ‹€.
05:49
But gravity worked hard in those spots
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ν•˜μ§€λ§Œ μ € μ§€μ λ“€μ˜ 쀑λ ₯은 κ°•λ ₯ν•΄μ„œ
05:52
where there was a little bit more mass
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μ•½κ°„μ˜ μ§ˆλŸ‰λ§Œμ΄ μ‘΄μž¬ν•΄λ„
05:54
and pulled more and more mass into those regions.
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점점 더 λ§Žμ€ μ§ˆλŸ‰μ„ μ € μ§€μ—­μœΌλ‘œ λŒμ–΄λ‹Ήκ²Όμ£ .
05:59
Now, all of this is a little hard to imagine,
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이것듀을 μ „λΆ€ λ¨Έλ¦Ώμ†μ—μ„œ κ·Έλ €λ‚΄κΈ΄ μ’€ μ–΄λ €μšΈ ν…Œλ‹ˆ
06:01
so let me just show you what I am talking about.
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μ œκ°€ λ§μ”€λ“œλ¦° 것을 보여 λ“œλ¦¬λ„λ‘ ν•˜κ² μŠ΅λ‹ˆλ‹€.
06:05
Those computer models I mentioned allow us to test these ideas,
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컴퓨터 λͺ¨ν˜•λ“€μ€ μ΄λŸ¬ν•œ 생각듀을 μ‹€ν—˜ν•  수 있게 ν•΄μ€λ‹ˆλ‹€.
06:08
so let's take a look at one of them.
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이 쀑 ν•˜λ‚˜λ₯Ό μ‚΄νŽ΄λ³΄λ„λ‘ ν•˜μ£ .
06:11
This movie, made by my research group,
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저희 연ꡬ κ·Έλ£Ήμ—μ„œ λ§Œλ“  이 μ˜ν™”λŠ”
06:14
shows us what happened to the universe after its earliest moments.
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탄생 초기의 μˆœκ°„μ΄ μ§€λ‚˜κ³  μš°μ£Όμ— 무슨 일이 μΌμ–΄λ‚¬λŠ”μ§€λ₯Ό λ³΄μ—¬μ€λ‹ˆλ‹€.
06:20
You see the universe started out pretty smooth,
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μ—¬λŸ¬λΆ„μ΄ λ³΄μ‹œλ‹€μ‹œν”Ό μš°μ£ΌλŠ” μƒλ‹Ήνžˆ 순쑰둭게 μ‹œμž‘λ˜μ§€λ§Œ
06:23
but there were some regions
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μ–΄λ–€ 지역듀은
06:24
where there was a little bit more material.
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λ‹€λ₯Έ 지역보닀 μ’€ 더 λ§Žμ€ λ¬Όμ§ˆλ“€μ΄ μžˆμŠ΅λ‹ˆλ‹€.
06:27
Gravity turned on and brought more and more mass
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쀑λ ₯이 μž‘μš©ν•˜λ©΄μ„œ, 점점 더 λ§Žμ€ μ§ˆλŸ‰λ“€μ΄
06:31
into those spots that started out with a little bit extra.
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μ € μ§€μ λ“€λ‘œ λŒλ €κ°€κ²Œ 되고 그둜 인해 μ’€ 더 λ§Žμ€ λ¬Όμ§ˆμ„ κ°–κ²Œ 된 것이죠.
06:36
Over time,
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μ‹œκ°„μ΄ 지남에 따라
06:37
you get enough stuff in one place
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ν•œ μž₯μ†Œμ—μ„œ μ§ˆλŸ‰μ΄ μΆ©λΆ„νžˆ μ»€μ§€λ©΄μ„œ
06:40
that the hydrogen gas,
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μ•”ν‘λ¬Όμ§ˆκ³Ό 잘 μ„žμ—¬ μžˆμ—ˆλ˜
06:41
which was initially well mixed with the dark matter,
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μˆ˜μ†Œκ°€μŠ€κ°€
06:44
starts to separate from it,
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μ•”ν‘λ¬Όμ§ˆκ³Ό λΆ„λ¦¬λ˜λ©΄μ„œ
06:46
cool down, form stars,
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μ‹ν˜€μ§€κ³ , 항성을 ν˜•μ„±ν•˜κ²Œ λ˜μ–΄
06:49
and you get a small galaxy.
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μž‘μ€ μ€ν•˜κ³„κ°€ λ©λ‹ˆλ‹€.
06:51
Over time, over billions and billions of years,
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μ‹œκ°„μ΄ 지남에 따라 수 μ‹­μ–΅ 년에 거쳐
06:54
those small galaxies crash into each other
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μ‘°κ·Έλ§ˆν•œ μ€ν•˜κ³„λ“€μ€ μ„œλ‘œ μΆ©λŒν•˜κ³ 
06:57
and merge and grow to become larger galaxies,
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합쳐지고 μ„±μž₯ν•˜λ©° 더 큰 μ€ν•˜κ³„λ“€μ΄ λ˜λŠ” κ²ƒμž…λ‹ˆλ‹€.
07:00
like our own galaxy, the Milky Way.
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우리의 μ€ν•˜κ³„μΈ, μ€ν•˜μˆ˜μ²˜λŸΌ λ§μž…λ‹ˆλ‹€.
07:03
Now, what happens if you don't have dark matter?
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그러면 λ§Œμ•½ μ•”ν‘λ¬Όμ§ˆμ΄ μ—†λ‹€λ©΄ μ–΄λ–€ 일이 μΌμ–΄λ‚ κΉŒμš”?
07:08
If you don't have dark matter,
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λ§Œμ•½ μ•”ν‘λ¬Όμ§ˆμ΄ μ—†λ‹€λ©΄,
07:10
those spots never get clumpy enough.
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μ € 점듀은 κ²°μ½” μΆ©λΆ„ν•œ μ§ˆλŸ‰μ„ κ°€μ§ˆ 수 μ—†μŠ΅λ‹ˆλ‹€.
07:14
It turns out, you need at least a million times the mass of the Sun
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'ν•­μ„±' 듀이 ν˜•μ„±λ˜λ €λ©΄ ν•˜λ‚˜μ˜ 밀집 지역에
07:19
in one dense region,
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νƒœμ–‘μ˜ 수백만 배의 μ§ˆλŸ‰μ„ ν•„μš”λ‘œ ν•©λ‹ˆλ‹€.
07:20
before you can start forming stars.
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07:23
And without dark matter,
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μ•”ν‘λ¬Όμ§ˆ μ—†μ΄λŠ”
07:25
you never get enough stuff in one place.
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ν•œ κ³³ μ—μ„œ μΆ©λΆ„ν•œ λ¬Όμ§ˆμ„ 얻을 수 μ—†μŠ΅λ‹ˆλ‹€.
07:28
So here, we're looking at two universes, side by side.
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μ—¬κΈ° 두 개의 μš°μ£Όλ“€μ„ λ‚˜λž€νžˆ 놓고 보고 κ³„μ‹ λ°μš”.
07:33
In one of them you can see
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이 쀑 ν•˜λ‚˜λŠ” λ¬Όμ§ˆλ“€μ΄ 재빨리
07:35
that things get clumpy quickly.
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뭉쳐진 것을 λ³Ό 수 μžˆμŠ΅λ‹ˆλ‹€.
07:39
In that universe,
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이 μš°μ£Όμ—μ„œλŠ”
07:40
it's really easy to form galaxies.
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μ€ν•˜κ³„λ“€μ΄ 정말 μ‰½κ²Œ ν˜•μ„±λ˜μ§€λ§Œ
07:43
In the other universe,
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λ‹€λ₯Έ μš°μ£Όμ—μ„œλŠ”
07:44
the things that start out like small clumps,
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λ¬Όμ§ˆλ“€μ΄ 정말 μž‘μ€ κ΅°μ§‘μ²΄λ‘œ μ‹œμž‘ν•©λ‹ˆλ‹€.
07:47
they just stay really small.
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그것듀은 κ·Έλƒ₯ 정말 μž‘μ€ μƒνƒœλ‘œ λ¨Έλ¬Όλ©°
07:49
Not very much happens.
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νŠΉλ³„ν•œ 사건듀이 μΌμ–΄λ‚˜μ§€ μ•ŠμŠ΅λ‹ˆλ‹€.
07:51
In that universe, you wouldn't get our galaxy.
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그런 μš°μ£Όμ—μ„œλŠ” 우리 것과 같은 μ€ν•˜λŠ” 탄생할 수 μ—†κ³ ,
07:54
Or any other galaxy.
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λ‹€λ₯Έ μ–΄λ–€ μ€ν•˜κ³„λ„ μƒμ„±λ˜μ§€ μ•ŠμŠ΅λ‹ˆλ‹€.
07:56
You wouldn't get the Milky Way,
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μ€ν•˜μˆ˜λ„ μƒμ„±λ˜μ§€ μ•Šκ³ ,
07:58
you wouldn't get the Sun,
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νƒœμ–‘λ„ μƒκ²¨λ‚˜μ§€ μ•ŠμœΌλ©°,
08:00
you wouldn't get us.
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인간도 생겨날 수 μ—†μŠ΅λ‹ˆλ‹€.
08:02
We just couldn't exist in that universe.
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μš°λ¦¬λŠ” μ € μš°μ£Όμ—μ„  μ‘΄μž¬ν•  수 μ—†μŠ΅λ‹ˆλ‹€.
08:07
OK, so this crazy stuff, dark matter,
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이런 μ—„μ²­λ‚œ 물질인 μ•”ν‘λ¬Όμ§ˆμ€
08:10
it's most of the mass in the universe,
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우주 μ§ˆλŸ‰μ˜ λŒ€λΆ€λΆ„μ„ κ΅¬μ„±ν•©λ‹ˆλ‹€.
08:12
it's going through us right now, we wouldn't be here without it.
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우리λ₯Ό κ·Έλƒ₯ ν†΅κ³Όν•˜μ§€λ§Œ, μ•”ν‘λ¬Όμ§ˆ 없이 μš°λ¦¬λŠ” μ‘΄μž¬ν•  수 μ—†λŠ” κ±°μ£ .
08:15
What is it?
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정체가 λŒ€μ²΄ λ¬΄μ—‡μΌκΉŒμš”?
08:17
Well, we have no idea.
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우린 λͺ¨λ¦…λ‹ˆλ‹€.
08:18
(Laughter)
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(μ›ƒμŒ)
08:21
But we have a lot of educated guesses,
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ν•˜μ§€λ§Œ λ§Žμ€ ꡐ윑적인 좔츑이 κ°€λŠ₯ν•˜κ³ ,
08:24
and a lot of ideas for how to find out more.
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이 λ¬Όμ§ˆμ„ μ•Œμ•„λ‚΄κΈ° μœ„ν•œ λ§Žμ€ 아이디어듀이 μžˆμŠ΅λ‹ˆλ‹€.
08:27
So, most physicists think that dark matter is a particle,
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λŒ€λΆ€λΆ„μ˜ λ¬Όλ¦¬ν•™μžλ“€μ€ μ•”ν‘λ¬Όμ§ˆμ΄ μž…μžλΌκ³  μƒκ°ν•©λ‹ˆλ‹€.
08:32
similar in many ways to the subatomic particles that we know of,
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λ§Žμ€ λ©΄μ—μ„œ μš°λ¦¬κ°€ μ•Œκ³  μžˆλŠ” μ•„μ›μž μž…μžμΈ
08:35
like protons and neutrons and electrons.
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μ–‘μ„±μž, μ€‘μ„±μž, μ „μžμ™€ μœ μ‚¬ν•˜κ±°λ“ μš”.
08:38
Whatever it is,
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μ•”ν‘λ¬Όμ§ˆμ΄ 무엇이든
08:39
it behaves very similarly with respect to gravity.
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쀑λ ₯의 μΈ‘λ©΄μ—μ„œλŠ” 맀우 μœ μ‚¬ν•œ 행동을 ν•©λ‹ˆλ‹€.
08:44
But it doesn't emit or absorb light,
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ν•˜μ§€λ§Œ 빛을 λ°©μΆœν•˜κ±°λ‚˜ ν‘μˆ˜ν•˜μ§€ μ•Šκ³ 
08:47
and it goes right through normal matter,
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μΌλ°˜λ¬Όμ§ˆμ„ ν†΅κ³Όν•΄λ²„λ¦½λ‹ˆλ‹€.
08:49
as if it wasn't even there.
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마치 μ‘΄μž¬ν•˜μ§€ μ•ŠλŠ” κ²ƒμ²˜λŸΌ 말이죠.
08:52
We'd like to know what particle it is.
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μš°λ¦¬λŠ” 이 μž…μžκ°€ 무엇인지 μ•Œκ³  μ‹Άμ—ˆμŠ΅λ‹ˆλ‹€.
08:54
For example, how heavy is it?
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μž…μžμ˜ λ¬΄κ²Œκ°€ μ–Όλ§ˆλ‚˜ λ‚˜κ°€λŠ”μ§€
08:57
Or, does anything at all happen if it interacts with normal matter?
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ν˜Ήμ€ λ³΄ν†΅λ¬Όμ§ˆκ³Ό μƒν˜Έμž‘μš©ν•˜λ©΄ μ–΄λ–€ 일이 μΌμ–΄λ‚˜λŠ”μ§€ 같은 κ²ƒλ“€μ„μš”.
09:02
Physicists have lots of great ideas for what it could be,
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λ¬Όλ¦¬ν•™μžλ“€μ€ μ•”ν‘λ¬Όμ§ˆμ΄ 무엇인지에 λŒ€ν•΄ λ§Žμ€ ν›Œλ₯­ν•œ μ˜κ²¬λ“€μ„ 가지고 μžˆλŠ”λ°
09:05
they're very creative.
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맀우 μ°½μ˜μ μž…λ‹ˆλ‹€.
09:07
But it's really hard,
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ν•˜μ§€λ§Œ μƒλ‹Ήνžˆ μ–΄λ ΅μ£ .
09:09
because those ideas span a huge range.
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κ·Έλ“€μ˜ 의견이 큰 λ²”μœ„λ₯Ό μ•„μš°λ₯΄κΈ° λ•Œλ¬Έμž…λ‹ˆλ‹€.
09:12
It could be as small as the smallest subatomic particles,
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μ•”ν‘λ¬Όμ§ˆμ€ μ•„μ›μž μž…μžλ“€κ³Ό 같이 μž‘μ„ μˆ˜λ„ 있고
09:16
or it could be as large as the mass of 100 Suns.
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100개의 νƒœμ–‘μ˜ μ§ˆλŸ‰λ§ŒνΌ κ±°λŒ€ν•  μˆ˜λ„ μžˆμŠ΅λ‹ˆλ‹€.
09:20
So, how do we figure out what it is?
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그러면 μ•”ν‘λ¬Όμ§ˆμ΄ 무엇인지 μ–΄λ–»κ²Œ μ•Œμ•„λ‚Ό 수 μžˆμ„κΉŒμš”?
09:24
Well, physicists and astronomers
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λ¬Όλ¦¬ν•™μžλ“€κ³Ό μ²œλ¬Έν•™μžλ“€μ€
09:26
have a lot of ways to look for dark matter.
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μ•”ν‘λ¬Όμ§ˆμ„ μ°ΎλŠ” λ§Žμ€ 방법듀을 μ•Œκ³  μžˆμŠ΅λ‹ˆλ‹€.
09:30
One of the things we're doing is building sensitive detectors
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κ·Έ 쀑 ν•œ 가지 방법은 λ―Όκ°ν•œ 탐지기λ₯Ό
09:34
in deep underground mines,
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μ§€ν•˜ κΉŠμˆ™ν•œ 광산에 μ„€μΉ˜ν•˜κ³ 
09:37
waiting for the possibility
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μ•”ν‘λ¬Όμ§ˆμ΄ μš°λ¦¬λ‚˜ 지ꡬλ₯Ό ν†΅κ³Όν•΄μ„œ
09:40
that a dark matter particle, which goes through us and the Earth,
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μ’€ 더 밀도 높은 λ¬Όμ§ˆμ— λΆ€λ”ͺ힐 λ•Œ
09:43
would hit a denser material
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μ§€λ‚˜μ˜¨ 곳에 흔적을 남겨 놓을
09:46
and leave behind some trace of its passage.
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κ°€λŠ₯성을 κΈ°λ‹€λ¦¬λŠ” κ²ƒμž…λ‹ˆλ‹€.
09:50
We're looking for dark matter in the sky,
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μš°λ¦¬λŠ” ν•˜λŠ˜μ—μ„œλ„ μ•”ν‘λ¬Όμ§ˆμ„ μ°Ύκ³  μžˆμŠ΅λ‹ˆλ‹€.
09:53
for the possibility that dark matter particles
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μ•”ν‘λ¬Όμ§ˆ μž…μžκ°€
09:55
would crash into each other
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μ„œλ‘œ μΆ©λŒν•΄μ„œ λ§Œλ“€μ–΄ λ‚΄λŠ”
09:56
and create high-energy light that we could see
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κ³ μ—λ„ˆμ§€μ˜ 광채λ₯Ό 특수 κ°λ§ˆμ„  λ§μ›κ²½μœΌλ‘œ
09:59
with special gamma-ray telescopes.
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κ΄€μ°°ν•  수 μžˆμŠ΅λ‹ˆλ‹€.
10:02
We're even trying to make dark matter here on Earth,
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μš°λ¦¬λŠ” μ§€κ΅¬μ—μ„œλ„ μ•”ν‘λ¬Όμ§ˆμ„ λ§Œλ“€μ–΄ λ‚΄λ €κ³  μ‹œλ„ν•˜κ³  μžˆμŠ΅λ‹ˆλ‹€.
10:06
by smashing particles together and looking for what happens,
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μŠ€μœ„μŠ€μ— μžˆλŠ” μž…μžκ°€μ†κΈ°λ₯Ό μ΄μš©ν•˜μ—¬ μ••μžλ“€μ„ μ„œλ‘œ μΆ©λŒν•˜κ²Œ ν•¨μœΌλ‘œμ¨
10:10
using the Large Hadron Collider in Switzerland.
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무슨 일이 λ°œμƒν•˜λŠ”μ§€ κ΄€μ°°ν•˜κ³  있죠.
10:15
Now, so far,
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μ§€κΈˆκΉŒμ§€
10:17
all of these experiments have taught us a lot
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μ΄λŸ¬ν•œ λͺ¨λ“  μ‹€ν—˜λ“€μ€ μš°λ¦¬μ—κ²Œ λ§Žμ€ 것을 κ°€λ₯΄μ³ μ£Όμ—ˆμŠ΅λ‹ˆλ‹€.
10:20
about what dark matter isn't
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무엇이 μ•”ν‘λ¬Όμ§ˆμ΄ μ•„λ‹Œμ§€μ— λŒ€ν•΄μ„œμš”.
10:22
(Laughter)
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(μ›ƒμŒ)
10:23
but not yet what it is.
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μ•„μ§κΉŒμ§€ μ•”ν‘λ¬Όμ§ˆμ΄ λ¬΄μ—‡μΈμ§€λŠ” μ•Œ 수 μ—†μ—ˆμŠ΅λ‹ˆλ‹€
10:25
There were really good ideas that dark matter could have been,
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μ•”ν‘λ¬Όμ§ˆμ„ 판λͺ…ν•΄ 쀄 수 μžˆλŠ” 정말 쒋은 아이디어듀이 μžˆμ—ˆκ³ 
10:29
that these experiments would have seen.
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이λ₯Ό 보여쀄 μ‹€ν—˜λ“€λ„ μžˆμ—ˆμŠ΅λ‹ˆλ‹€.
10:31
And they didn't see them yet,
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ν•˜μ§€λ§Œ 아직은 μ•Œ 수 μ—†μŠ΅λ‹ˆλ‹€.
10:32
so we have to keep looking and thinking harder.
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κ·Έλž˜μ„œ μš°λ¦¬λŠ” 계속 μ°Ύκ³  더 μ—΄μ‹¬νžˆ 생각해야 ν•©λ‹ˆλ‹€.
10:37
Now, another way to get a clue to what dark matter is
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μ•”ν‘λ¬Όμ§ˆμ΄ 무엇인지 μ•Œμ•„λ‚Ό 수 μžˆλŠ” λ‹¨μ„œλ₯Ό μ°ΎλŠ” 또 λ‹€λ₯Έ 방법은
10:42
is to study galaxies.
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μ€ν•˜κ³„λ₯Ό μ—°κ΅¬ν•˜λŠ” κ²ƒμž…λ‹ˆλ‹€.
10:44
We already talked about
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μ•žμ„œ μ΄μ•ΌκΈ°ν–ˆλ“―μ΄
10:46
how our galaxy and many other galaxies wouldn't even be here
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우리 μ€ν•˜κ³„μ™€ λ‹€λ₯Έ λ§Žμ€ μ€ν•˜κ³„λ“€μ€ μ•”ν‘λ¬Όμ§ˆ μ—†μ΄λŠ” μ‘΄μž¬ν•  μˆ˜κ°€ μ—†μŠ΅λ‹ˆλ‹€.
10:49
without dark matter.
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10:51
Those models also make predictions
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μ €λŸ° λͺ¨ν˜•μ€ λ˜ν•œ μ€ν•˜κ³„μ— λŒ€ν•œ
10:53
for many other things about galaxies:
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λ§Žμ€ 것듀 즉 뢄포 방식, μ›€μ§μž„
10:55
How they're distributed in the universe,
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μ‹œκ°„μ— 경과에 λ”°λ₯Έ
10:57
how they move,
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진화 방식 등을 예츑 κ°€λŠ₯ν•˜κ²Œ ν•΄μ€λ‹ˆλ‹€.
10:59
how they evolve over time.
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11:01
And we can test those predictions with observations of the sky.
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μš°λ¦¬λŠ” ν•˜λŠ˜μ„ κ΄€μ°°ν•¨μœΌλ‘œμ„œ μ΄λŸ¬ν•œ μ˜ˆμΈ‘μ„ 확인해 λ³Ό 수 μžˆμŠ΅λ‹ˆλ‹€.
11:06
So let me just give you two examples
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μ€ν•˜κ³„λ₯Ό 톡해 ν•  수 μžˆλŠ”
11:08
of these kinds of measurements we can make with galaxies.
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μΈ‘μ • 방식 쀑 두 κ°€μ§€μ˜ μ˜ˆμ‹œλ₯Ό λ“€μ–΄ λ“œλ¦¬κ² μŠ΅λ‹ˆλ‹€.
11:13
The first is that we can make maps of the universe with galaxies.
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λ¨Όμ €, μš°λ¦¬λŠ” μ€ν•˜κ³„λ“€μ΄ μžˆλŠ” μš°μ£Όμ§€λ„λ₯Ό λ§Œλ“€ 수 μžˆμŠ΅λ‹ˆλ‹€.
11:18
I am part of a survey called the Dark Energy Survey,
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μ €λŠ” ν˜„μ‘΄ν•˜λŠ” κ°€μž₯ 큰 μš°μ£Όμ§€λ„λ₯Ό λ§Œλ“€κ³  μžˆλŠ”
11:20
which has made the largest map of the universe so far.
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'μ•”ν‘μ—λ„ˆμ§€ 쑰사'λΌλŠ” 연ꡬ에 μ°Έμ—¬ν•˜κ³  μžˆμŠ΅λ‹ˆλ‹€.
11:25
We measured the positions and shapes of 100 million galaxies
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μš°λ¦¬λŠ” μš°λ¦¬κ°€ λ³΄λŠ” ν•˜λŠ˜μ˜ 8λΆ„μ˜ 1이 λ„˜λŠ”
11:30
over one-eighth of the sky.
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μ€ν•˜μˆ˜μ˜ μœ„μΉ˜μ™€ λͺ¨μ–‘을 μΈ‘μ •ν•΄λƒˆμŠ΅λ‹ˆλ‹€
11:34
And this map is showing us all the matter in this region of the sky,
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이 μ§€λ„λŠ” ν•˜λŠ˜μ— μžˆλŠ” κ·Έ μ§€μ—­μ˜ λͺ¨λ“  λ¬Όμ§ˆλ“€μ„ 보여주고 μžˆμŠ΅λ‹ˆλ‹€.
11:39
which is inferred by the light distorted from these 100 million galaxies.
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μ΄λŠ” 1μ–΅ 개의 μ€ν•˜κ³„λ‘œλΆ€ν„° λ°©μΆœλ˜λŠ” μ™œκ³‘λœ λΉ›μœΌλ‘œ μΆ”λ‘  κ°€λŠ₯ν•©λ‹ˆλ‹€.
11:46
The light distorted from all of the matter
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μš°λ¦¬μ™€ μ€ν•˜κ³„λ“€ μ‚¬μ΄μ—λŠ” λͺ¨λ“  λ¬Όμ§ˆλ‘œλΆ€ν„°
11:49
that was between those galaxies and us.
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λ°©μΆœλΌλŠ” μ™œκ³‘λœ 빛이 μžˆμŠ΅λ‹ˆλ‹€.
11:54
The gravity of the matter is strong enough to bend the path of light.
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이 λ¬Όμ§ˆλ“€μ˜ 쀑λ ₯은 λΉ›μ˜ 경둜λ₯Ό μ™œκ³‘μ‹œν‚¬ 만큼 μΆ©λΆ„νžˆ κ°•ν•˜κΈ° λ•Œλ¬Έμ—
11:59
And it gives us this image.
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μš°λ¦¬μ—κ²Œ μ΄λŸ¬ν•œ 이미지λ₯Ό λ³΄μ—¬μ€λ‹ˆλ‹€.
12:04
So these kinds of maps
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κ·Έλž˜μ„œ 이 같은 지도듀은
12:05
can tell us about how much dark matter there is,
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μ–Όλ§ˆλ§ŒνΌμ˜ μ•”ν‘λ¬Όμ§ˆμ΄ μ‘΄μž¬ν•˜λŠ”μ§€ 말해주고
12:08
they also tell us where it is
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그것듀이 어디에 μžˆλŠ”μ§€
12:11
and how it changes over time.
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μ‹œκ°„μ— 따라 μ–΄λ–»κ²Œ λ³€ν•˜λŠ”μ§€λ„ λ³΄μ—¬μ€λ‹ˆλ‹€.
12:14
So we're trying to learn about what the universe is made of
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μš°λ¦¬λŠ” κ±°μ‹œμ μœΌλ‘œ μš°μ£Όκ°€ μ–΄λ–»κ²Œ κ΅¬μ„±λ˜μ–΄ μžˆλŠ”μ§€
12:18
on the very largest scales.
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μ•Œμ•„λ‚΄λ €κ³  λ…Έλ ₯ν•˜κ³  μžˆμ—ˆλŠ”λ°μš”.
12:21
It turns out that the tiniest galaxies in the universe
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μš°μ£Όμ—μ„œ κ°€μž₯ μ‘°κ·Έλ§ˆν•œ μ€ν•˜κ³„κ°€ 핡심 λ‹¨μ„œλ₯Ό μ œκ³΅ν•΄ μ€€λ‹€λŠ” 것이 λ“œλŸ¬λ‚¬μŠ΅λ‹ˆλ‹€.
12:25
provide some of the best clues.
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12:29
So why is that?
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μ™œ κ·ΈλŸ΄κΉŒμš”?
12:31
Here are two example simulated universes
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μ—¬κΈ° 두 개의 λ‹€λ₯Έ μ’…λ₯˜μ˜ μ•”ν‘λ¬Όμ§ˆλ‘œ 이루어진
12:34
with two different kinds of dark matter.
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κ°€μƒμ˜ μš°μ£Όκ°€ 두 개 μžˆμŠ΅λ‹ˆλ‹€.
12:37
Both of these pictures are showing you a region
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이 두 개의 사진이 λ³΄μ—¬μ£ΌλŠ” 지역은
12:39
around a galaxy like the Milky Way.
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μ€ν•˜μˆ˜μ™€ λΉ„μŠ·ν•œ μ€ν•˜κ³„ μ£Όλ³€μž…λ‹ˆλ‹€.
12:42
And you can see that there's a lot of other material around it,
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그리고 주변에 μž‘μ€ ꡰ집체λ₯Ό 이루고 μžˆλŠ”
12:45
little small clumps.
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λ§Žμ€ λ¬Όμ§ˆλ“€μ„ λ³Ό 수 μžˆμŠ΅λ‹ˆλ‹€.
12:47
Now, in the image on the right,
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였λ₯Έμͺ½ 이미지λ₯Ό λ³΄μ‹œλ©΄,
12:49
dark matter particles are moving slower than they are in the one on the left.
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μ™Όμͺ½μ— μžˆλŠ” 것보닀 μ•”ν‘λ¬Όμ§ˆ μž…μžλ“€μ΄ 더 천천히 μ›€μ§μž…λ‹ˆλ‹€.
12:54
If those dark matter particles are moving really fast,
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λ§Œμ•½ μ € μ•”ν‘λ¬Όμ§ˆ μž…μžλ“€μ΄ 정말 λΉ λ₯΄κ²Œ 움직인닀면,
12:57
then the gravity in small clumps is not strong enough
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ꡰ집체가 λ‚΄λŠ” 쀑λ ₯이 μž…μžλ“€μ˜ 속도λ₯Ό 늦좜 만큼
13:00
to slow those fast particles down.
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κ°•ν•˜μ§€ μ•Šμ€ κ²ƒμž…λ‹ˆλ‹€.
13:03
And they keep going.
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그리고 μž…μžλ“€μ΄ κ·Έ μƒνƒœλΌλ©΄
13:04
They never collapse into these small clumps.
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그것듀이 λΆ€μ„œμ Έμ„œ μž‘μ€ ꡰ집체가 λ˜λŠ” 일은 μ—†κ²Œ 되고
13:06
So you end up with fewer of them than in the universe on the right.
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κ²°κ΅­μ—λŠ” 였λ₯Έμͺ½μ˜ μš°μ£Όλ³΄λ‹€ 더 적은 κ΅°μ§‘μ²΄μ˜ 수λ₯Ό κ°€μ§€κ²Œ 될 κ²ƒμž…λ‹ˆλ‹€.
13:11
If you don't have those small clumps,
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λ§Œμ•½ μ € μž‘μ€ ꡰ집체듀이 μ—†λ‹€λ©΄
13:13
then you get fewer small galaxies.
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μž‘μ€ μ€ν•˜κ³„μ˜ μˆ˜κ°€ 더 μ μ–΄μ§‘λ‹ˆλ‹€.
13:18
If you look up at the southern sky,
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남μͺ½ ν•˜λŠ˜μ„ λ³΄μ‹œκ²Œ 되면
13:19
you can actually see two of these small galaxies,
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μ‹€μ œλ‘œ 이 μž‘μ€ 두 개의 μ€ν•˜κ³„λ“€μ„ λ³Ό 수 μžˆμœΌμ‹ λ°μš”.
13:23
the largest of the small galaxies that are orbiting our Milky Way,
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우리 μ€ν•˜μˆ˜λ₯Ό 돌고 μžˆλŠ” μž‘μ€ μ€ν•˜κ³„ 쀑 κ°€μž₯ 큰 μ€ν•˜κ³„λ‘œ
13:26
the Large Magellanic Cloud and the Small Magellanic Cloud.
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λŒ€ λ§ˆμ €λž€μš΄κ³Ό μ†Œ λ§ˆμ €λž€μš΄μž…λ‹ˆλ‹€.
13:30
In the last several years,
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μ§€λ‚œ λͺ‡ λ…„κ°„
13:32
we have detected a whole bunch more even smaller galaxies.
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μš°λ¦¬λŠ” 훨씬 μž‘μ€ μ€ν•˜κ³„λ₯Ό λ¬΄λ”κΈ°λ‘œ λ°œκ²¬ν•˜μ˜€μŠ΅λ‹ˆλ‹€.
13:35
This is an example of one of them
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이것은 μš°λ¦¬κ°€
13:37
that we detected with the same dark energy survey
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μš°μ£Όμ§€λ„λ₯Ό λ§Œλ“€κΈ° μœ„ν•΄ μ‚¬μš©ν–ˆλ˜ μ•”ν‘μ—λ„ˆμ§€μ™€ 같은 κ²ƒμœΌλ‘œ
13:40
that we used to make maps of the universe.
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κ°μ§€λ˜μ—ˆλ˜ 것듀 쀑 ν•˜λ‚˜μ˜ μ˜ˆμž…λ‹ˆλ‹€.
13:43
These really small galaxies,
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이듀은 정말 μž‘μ€ μ€ν•˜κ³„μž…λ‹ˆλ‹€.
13:45
some of them are extremely small.
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λͺ‡λͺ‡μ€ λ„ˆλ¬΄λ‚˜λ„ μž‘μŠ΅λ‹ˆλ‹€.
13:48
Some of them have as few as a few hundred stars,
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λͺ‡λͺ‡ μ€ν•˜κ³„λŠ” κ·Έμ € λͺ‡ λ°± 개의 λ³„λ“€λ‘œ κ΅¬μ„±λ˜μ–΄ μžˆμ–΄
13:51
compared to the few hundred billion stars in our Milky Way.
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λͺ‡ μ‘° 개의 λ³„λ“€λ‘œ κ΅¬μ„±λœ μ€ν•˜μˆ˜μ™€ λΉ„κ΅ν•œλ‹€λ©΄ 정말 적은 μˆ˜μž…λ‹ˆλ‹€.
13:55
So that makes them really hard to find.
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κ·ΈλŸ¬λ‹ˆ μ΄λ ‡κ²Œ μž‘μ€ 것듀을 μ°ΎλŠ” 것은 νž˜λ“€μ£ .
13:57
But in the last decade,
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ν•˜μ§€λ§Œ μ§€λ‚œ 10λ…„κ°„
13:59
we've actually found a whole bunch more of these.
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μš°λ¦¬λŠ” 이 μž‘μ€ μ€ν•˜κ³„λ₯Ό λ¬΄λ”κΈ°λ‘œ λ°œκ²¬ν–ˆκ³ 
14:02
We now know of 60 of these tiny galaxies
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우리 μ€ν•˜μˆ˜λ₯Ό 돌고 μžˆλŠ” μž‘μ€ μ€ν•˜κ³„λ§Œ
14:05
that are orbiting our own Milky Way.
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60개λ₯Ό μ°Ύμ•„ λƒˆμŠ΅λ‹ˆλ‹€.
14:08
And these little guys are a big clue to dark matter.
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그리고, 이 μž‘μ€ μ€ν•˜κ³„λ“€μ€ μ•”ν‘λ¬Όμ§ˆμ— λŒ€ν•œ μ»€λ‹€λž€ λ‹¨μ„œμž…λ‹ˆλ‹€.
14:12
Because just the existence of these galaxies tells us
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μ™œλƒν•˜λ©΄ μ΄λŸ¬ν•œ μ€ν•˜κ³„μ˜ μ‘΄μž¬κ°€ μš°λ¦¬μ—κ²Œ λ§ν•΄μ£ΌλŠ” λ°”λŠ”
14:16
that dark matter can't be moving very fast,
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μ•”ν‘λ¬Όμ§ˆμ€ 빨리 움직이지 μ•ŠλŠ”λ‹€λŠ” κ²ƒμž…λ‹ˆλ‹€.
14:19
and not much can be happening when it runs into normal matter.
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그리고 일반물질과 μΆ©λŒν•  λ•Œλ„ νŠΉλ³„ν•œ 사건이 λ°œμƒν•˜μ§€ μ•ŠλŠ”λ‹€λŠ” 것 μž…λ‹ˆλ‹€.
14:24
In the next several years,
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μ•žμœΌλ‘œ λͺ‡ λ…„ λ™μ•ˆ
14:26
we're going to make much more precise maps of the sky.
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μš°λ¦¬λŠ” μ’€ 더 μ •ν™•ν•œ ν•˜λŠ˜ 지도듀을 λ§Œλ“€μ–΄ λ‚Ό κ²ƒμž…λ‹ˆλ‹€.
14:31
And those will help refine our movies
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그런 지도듀은 우리의 μ™„μ „ν•œ μš°μ£Όμ™€
14:33
of the whole universe and the entire galaxy.
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μ€ν•˜κ³„ 전체에 λŒ€ν•œ μ’€ 더 λ‚˜μ€ μ˜ν™”λ₯Ό λ§Œλ“œλŠ”λ° 도움을 쀄 κ²ƒμž…λ‹ˆλ‹€.
14:37
Physicists are also making new, more sensitive experiments
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λ¬Όλ¦¬ν•™μžλ“€μ€ κ·Έλ“€μ˜ μ‹€ν—˜μ‹€μ—μ„œ μ•”ν‘λ¬Όμ§ˆμ— λŒ€ν•œ λ‹¨μ„œλ₯Ό μ•Œμ•„λ‚΄κ³ μž
14:41
to try to catch some sign of dark matter in their laboratories.
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μ’€ 더 μƒˆλ‘­κ³ , μ •λ°€ν•œ μ‹€ν—˜λ“€μ„ μ‹€μ‹œν•˜κ³  μžˆμŠ΅λ‹ˆλ‹€.
14:47
Dark matter is still a huge mystery.
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μ•”ν‘λ¬Όμ§ˆμ€ μ—¬μ „νžˆ λ―ΈμŠ€ν„°λ¦¬μž…λ‹ˆλ‹€.
14:50
But it's a really exciting time to be working on it.
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ν•˜μ§€λ§Œ 그것에 λŒ€ν•΄ μ—°κ΅¬ν•˜λŠ” 것은 정말 μ¦κ²μŠ΅λ‹ˆλ‹€.
14:54
We have really clear evidence it exists.
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μš°λ¦¬λŠ” κ°€μž₯ μž‘μ€ μ€ν•˜κ³„λ‘œλΆ€ν„°
14:57
From the scale of the smallest galaxies
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전체 μš°μ£ΌκΉŒμ§€ μ•”ν‘λ¬Όμ§ˆμ΄ μ‘΄μž¬ν•œλ‹€λŠ”
14:59
to the scale of the whole universe.
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λΆ„λͺ…ν•œ 증거λ₯Ό 가지고 μžˆμŠ΅λ‹ˆλ‹€.
15:03
Will we actually find it and figure out what it is?
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μ•”ν‘λ¬Όμ§ˆμ΄ 무엇인지 μš°λ¦¬κ°€ μ‹€μ œλ‘œ λ°ν˜€λ‚Ό 수 μžˆμ„κΉŒμš”?
15:08
I have no idea.
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μ „ λͺ¨λ¦…λ‹ˆλ‹€.
15:10
But it's going to be a lot of fun to find out.
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ν•˜μ§€λ§Œ λ°œκ²¬ν•΄ λ‚Έλ‹€λ©΄ 정말 μž¬λ―Έμžˆμ„ κ²λ‹ˆλ‹€.
15:13
We have a lot of possibilities for discovery,
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μš°λ¦¬λŠ” λ°œκ²¬μ— λŒ€ν•œ λ§Žμ€ κ°€λŠ₯성듀을 가지고 있고
15:15
and we definitely will learn more about what it is doing
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μ•”ν‘λ¬Όμ§ˆμ΄ ν•˜λŠ” 일과 ν•˜μ§€ μ•ŠλŠ” 일에 λŒ€ν•΄
15:19
and about what it isn't.
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μ’€ 더 λ§Žμ€ 것을 배울 κ²ƒμž…λ‹ˆλ‹€.
15:21
Regardless of whether we find that particle anytime soon,
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μš°λ¦¬κ°€ μ–Όλ§ˆλ‚˜ 빨리 κ·Έ μž…μžλ₯Ό λ°œκ²¬ν•΄ λ‚΄λŠ”μ§€μ™€λŠ” 상관없이,
15:24
I hope I have convinced you
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이 비밀이 거의 λ°ν˜€μ‘Œλ‹€λŠ” 것을
15:26
that this mystery is actually really close to home.
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μ—¬λŸ¬λΆ„μ—κ²Œ ν™•μ‹ μ‹œμΌœ λ“œλ¦¬κ³  μ‹ΆμŠ΅λ‹ˆλ‹€.
15:30
The search for dark matter
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μ•”ν‘λ¬Όμ§ˆμ„ μ—°κ΅¬ν•˜λŠ” 것은
15:32
may just be the key to a whole new understanding of physics
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물리학과 μš°μ£Όμ—μ„œ 우리의 μœ„μΉ˜λ₯Ό μ΄ν•΄ν•˜λŠ”λ°
15:35
and our place in the universe.
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μ—΄μ‡ κ°€ λ˜μ–΄ 쀄 μˆ˜λ„ μžˆμ„ κ²ƒμž…λ‹ˆλ‹€.
15:37
Thank you.
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κ°μ‚¬ν•©λ‹ˆλ‹€.
15:38
(Applause)
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(λ°•μˆ˜)
이 μ›Ήμ‚¬μ΄νŠΈ 정보

이 μ‚¬μ΄νŠΈλŠ” μ˜μ–΄ ν•™μŠ΅μ— μœ μš©ν•œ YouTube λ™μ˜μƒμ„ μ†Œκ°œν•©λ‹ˆλ‹€. μ „ 세계 졜고의 μ„ μƒλ‹˜λ“€μ΄ κ°€λ₯΄μΉ˜λŠ” μ˜μ–΄ μˆ˜μ—…μ„ 보게 될 κ²ƒμž…λ‹ˆλ‹€. 각 λ™μ˜μƒ νŽ˜μ΄μ§€μ— ν‘œμ‹œλ˜λŠ” μ˜μ–΄ μžλ§‰μ„ 더블 ν΄λ¦­ν•˜λ©΄ κ·Έκ³³μ—μ„œ λ™μ˜μƒμ΄ μž¬μƒλ©λ‹ˆλ‹€. λΉ„λ””μ˜€ μž¬μƒμ— 맞좰 μžλ§‰μ΄ μŠ€ν¬λ‘€λ©λ‹ˆλ‹€. μ˜κ²¬μ΄λ‚˜ μš”μ²­μ΄ μžˆλŠ” 경우 이 문의 양식을 μ‚¬μš©ν•˜μ—¬ λ¬Έμ˜ν•˜μ‹­μ‹œμ˜€.

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