WEBVTT

1
00:00:00.037 --> 00:00:04.453
Everything we know about physics could still be all turned on its head. 

2
00:00:04.855 --> 00:00:12.352
Back in September, scientists said that they discovered subatomic particles that can travel faster than light.

3
00:00:12.625 --> 00:00:16.672
Now, they've gone back to the lab, fine-tuned the experiment, and the result? 

4
00:00:16.811 --> 00:00:21.900
Well, it seems to confirm the startling finding, as Atika Shubert explains.

5
00:00:23.083 --> 00:00:24.490
Do they or don't they?

6
00:00:24.587 --> 00:00:30.963
Those pesky neutrinos are back and stubbornly refusing to obey the laws of physics and slow down.

7
00:00:31.508 --> 00:00:35.636
Remember this? In September, scientists announced some shocking results. 

8
00:00:36.020 --> 00:00:44.665
They shot a particle beam from Switzerland to Italy in 2.4 milliseconds. That's what it should take for a beam of light to cover that distance.

9
00:00:44.687 --> 00:00:51.541
But neutrinos, those tiny subatomic particles with virtually no mass and no electrical charge, 

10
00:00:51.842 --> 00:00:57.479
well, they managed to arrive 60 billionths of a second faster than light.

11
00:00:57.876 --> 00:01:00.686
Pandemonium in the world of physics, and here's why. 

12
00:01:01.294 --> 00:01:08.352
Energy equals mass times the speed of light squared. It's the bedrock of physics, Einstein's theory of relativity. 

13
00:01:08.734 --> 00:01:13.355
The fundamental principle: nothing can go faster than the speed of light.

14
00:01:13.432 --> 00:01:15.336
Without that universal speed limit, 

15
00:01:15.792 --> 00:01:22.234
physics as we know it would unravel, allowing for such mind-bending stuff as time travel.

16
00:01:22.929 --> 00:01:27.187
Of course, the problem with time travel is something called the Grandfather Paradox, 

17
00:01:27.218 --> 00:01:31.797
which means, if I've traveled back in time, and then I accidentally kill my grandfather, 

18
00:01:32.136 --> 00:01:37.380
which means, Atika, you would never have been conceived and, therefore, could not travel back in time to see yourself.

19
00:01:37.662 --> 00:01:43.568
So, you can see why scientists went back to measure and remeasure, tweak and retweak the tests. 

20
00:01:43.862 --> 00:01:50.109
And on Friday, they announced this: those speedy neutrinos are still faster than light.

21
00:01:50.764 --> 00:01:53.980
So, is Back to the Future suddenly a real possibility? 

22
00:01:54.329 --> 00:02:02.336
Scientists say two other labs in Japan and the U.S. are now conducting separate tests. But we won't get the results until next year.