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What time is it on Voyager 1? 🤔 - Video học tiếng Anh
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What time is it on Voyager 1? 🤔
What time is it on Voyager 1? 🤔
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Phụ đề (59)
0:00
- What's the farthest manmade object from Earth?
0:02
It's a space probe called Voyager 1
0:05
launched by NASA in 1977.
0:07
It's zooming away at 17 kilometers per second
0:10
and is now more than 25 billion kilometers away.
0:13
But what's weird is that the clock on Voyager 1
0:15
reads a different time than ours.
0:18
That's thanks to something our friend Albert Einstein
0:20
figured out.
0:21
His theory of special relativity
0:22
showed that time passes slower for clocks
0:24
when they're moving.
0:25
It sounds crazy, but scientists have demonstrated this
0:28
effect over and over.
0:29
We actually have to account for how time passes differently
0:32
on GPS satellites orbiting the Earth
0:34
in order to track our location accurately.
0:36
Okay, so Voyager 1's been traveling
0:38
for a little over 48 years
0:40
at around 17 kilometers per second.
0:42
According to Einstein's equations for special relativity,
0:45
Voyager's clock has lost about two
0:48
and a half seconds since it launched,
0:49
but Einstein gave us another mind bending lesson
0:52
to consider, his theory of general relativity.
0:54
In addition to time being stretched for moving objects,
0:57
time is also warped by gravity.
0:59
When you're close to a massive object like a planet
1:01
or a black hole, your clock will tick a tiny bit slower
1:05
than if you're far away from it.
1:06
Our GPS satellites have to account for this effect too.
1:09
And since Voyager 1 is now more than 25 billion kilometers
1:12
from Earth, it obviously feels the gravitational pull
1:14
of our planet much less than we do.
1:16
That difference from Earth's gravity means Voyager's clock
1:18
will actually tick about a second
1:20
faster than an Earth clock.
1:21
And if you combine both of these time dilation effects,
1:24
Voyager's clock should be about a second
1:26
and a half behind ours.
1:27
But it gets even weirder
1:29
because Earth is moving really fast too.
1:31
In fact, the Earth's velocity
1:32
around the sun is even faster than Voyager
1:35
zooming through space.
1:36
Plus, we're much closer to the giant heavy sun
1:38
than Voyager is.
1:39
So our clock is slowed even further by its gravity.
1:42
If you do all these calculations relative
1:43
to a point at the center of our solar system,
1:45
factoring in the speed of Voyager,
1:47
the differences in gravity
1:48
and the speed of spaceship Earth,
1:50
the clock on Voyager is actually somewhere
1:52
around 20 seconds ahead of ours on Earth.
1:55
Woo. So what time is it really on Voyager 1?
1:59
Well, it could be the future or the past.
2:01
Just depends on where you sit.
2:03
Follow me for more cool science videos.
