WEBVTT FILE

1
00:00:00.000 --> 00:00:03.980
[Music throughout] In April 2020, astronomers

2
00:00:04.000 --> 00:00:07.980
detected an unusually bright and powerful radio signal never before

3
00:00:08.000 --> 00:00:11.980
recorded in our home galaxy. The source is a magnetar,

4
00:00:12.000 --> 00:00:15.980
a type of compact object with the strongest magnetic fields in the cosmos.

5
00:00:16.000 --> 00:00:19.980
Like pulsars and neutron stars, magnetars are the

6
00:00:20.000 --> 00:00:23.980
crushed cores left behind when a massive star explodes, but

7
00:00:24.000 --> 00:00:27.980
their superstrong magnetic fields put them in a class by themselves.

8
00:00:28.000 --> 00:00:31.980
The fields are up to a thousand times stronger than typical neutron stars

9
00:00:32.000 --> 00:00:35.980
and over 10 trillion times stronger than a refrigerator magnet.

10
00:00:36.000 --> 00:00:39.980
They can rip molecules apart from thousands of miles away, distort

11
00:00:40.000 --> 00:00:43.980
the shapes of atoms and store enormous amounts of energy.

12
00:00:44.000 --> 00:00:47.980
On April 27th, the magnetar, named SGR 1935,

13
00:00:48.000 --> 00:00:51.980
produced a rapid-fire storm of short, powerful X-ray

14
00:00:52.000 --> 00:00:55.980
bursts that lasted hours. The activity, first spotted

15
00:00:56.000 --> 00:00:59.980
by Swift, was also monitored by NASA’s Fermi Gamma-ray Space Telescope

16
00:01:00.000 --> 00:01:03.980
and the NICER X-ray telescope on the International Space Station,

17
00:01:04.000 --> 00:01:07.980
along with other space missions. As the

18
00:01:08.000 --> 00:01:11.980
storm wound down early on April 28th, NICER recorded some

19
00:01:12.000 --> 00:01:15.980
200 X-ray bursts in just 20 minutes.

20
00:01:16.000 --> 00:01:19.980
Later that day, SGR 1935 fired off another X-burst.

21
00:01:20.000 --> 00:01:23.980
This time, though, it was accompanied by something new:

22
00:01:24.000 --> 00:01:27.980
a powerful pulse of radio waves lasting a thousandth of a second.

23
00:01:28.000 --> 00:01:31.980
CHIME, a radio telescope in British Columbia

24
00:01:32.000 --> 00:01:35.980
led by several Canadian universities, discovered the signal and

25
00:01:36.000 --> 00:01:39.980
determined it came from the vicinity of SGR 1935.

26
00:01:40.000 --> 00:01:43.980
Another experiment, called STARE2 and operated by Caltech

27
00:01:44.000 --> 00:01:47.980
and NASA’s Jet Propulsion Laboratory, saw an even brighter signal at

28
00:01:48.000 --> 00:01:51.980
different radio wavelengths. Since 2007,

29
00:01:52.000 --> 00:01:55.980
astronomers have been trying to understand the sources of powerful, millisecond

30
00:01:56.000 --> 00:01:59.980
radio signals called fast radio bursts seen from other galaxies.

31
00:02:00.000 --> 00:02:03.980
Magnetars have been prominent suspects.

32
00:02:04.000 --> 00:02:07.980
The duration and energy release of SGR 1935’s radio

33
00:02:08.000 --> 00:02:11.980
signal is closer to fast radio bursts than any other source.

34
00:02:12.000 --> 00:02:15.980
For the first time, astronomers saw a magnetar in our own backyard

35
00:02:16.000 --> 00:02:19.980
produce a signal only previously seen in other galaxies.

36
00:02:20.000 --> 00:02:23.980
The discovery strengthens the case that magnetars are responsible

37
00:02:24.000 --> 00:02:27.980
for at least some fast radio bursts. Data from

38
00:02:28.000 --> 00:02:31.980
NICER and Fermi on X-ray bursts at the end of the storm show that they differed

39
00:02:32.000 --> 00:02:35.980
from the one that coincided with the radio signal. This event’s

40
00:02:36.000 --> 00:02:39.980
characteristics set it apart from the other eruptions and further study

41
00:02:40.000 --> 00:02:43.980
may provide clues about how it also powered the radio burst.

42
00:02:44.000 --> 00:02:47.980
Radio waves from normal pulsars originate high above their surfaces —

43
00:02:48.000 --> 00:02:51.980
exactly where and how, we don’t know. A big

44
00:02:52.000 --> 00:02:55.980
eruption could launch a cloud of plasma to high enough that a radio burst

45
00:02:56.000 --> 00:02:59.980
could form. Never before have astronomers seen a

46
00:03:00.000 --> 00:03:03.980
fast radio burst so close to home. It’s just one more reason

47
00:03:04.000 --> 00:03:07.980
to watch the skies — and to keep tabs on the strongest

48
00:03:08.000 --> 00:03:11.980
magnets in the universe.

49
00:03:12.000 --> 00:03:16.050
[Music]

50
00:03:16.070 --> 00:03:20.151
Drone Footage: R. Shaw/UBC/CHIME Collective All-sky image: Axel Mellinger (Central Michigan University)