WEBVTT FILE

1
00:00:01.334 --> 00:00:03.370
Almost all observations of the universe

2
00:00:03.370 --> 00:00:06.373
come by collecting
light in various wavelengths.

3
00:00:06.740 --> 00:00:09.576
This light can show variations
in brightness,

4
00:00:09.576 --> 00:00:14.347
reveal structure in cosmic objects,
and contain huge amounts of information

5
00:00:14.347 --> 00:00:17.951
in how its wavelengths are distributed
across a spectrum.

6
00:00:18.852 --> 00:00:22.689
Space isn't static, and recording data
through a given duration called

7
00:00:22.722 --> 00:00:26.893
Time-Domain Astronomy tracks
how details of an object change.

8
00:00:27.193 --> 00:00:28.428
An object can vary,

9
00:00:28.428 --> 00:00:30.864
it can move, or it can do both.

10
00:00:31.297 --> 00:00:35.235
There are three main classes
of how an object can vary in time.

11
00:00:35.301 --> 00:00:39.939
Periodic, quasiperiodic, and transient. Periodic change

12
00:00:40.040 --> 00:00:43.576
means there is a regular fixed pattern
to the change.

13
00:00:43.676 --> 00:00:47.714
Sunrise and sunset
or a blinking pulsar are examples.

14
00:00:47.814 --> 00:00:50.950
Quasiperiodic means
that there is a pattern and the change

15
00:00:51.017 --> 00:00:54.120
or event happens again and again,
but not as regularly,

16
00:00:54.220 --> 00:00:58.591
like hurricanes or flashes
from hot material around black holes.

17
00:00:58.691 --> 00:01:02.695
Transient events are less predictable
and often happen only once.

18
00:01:02.796 --> 00:01:05.532
Earthquakes and supernovas are transients.

19
00:01:05.632 --> 00:01:10.036
These are the hardest to observe because
they can be brief and start unexpectedly.

20
00:01:10.136 --> 00:01:13.673
If telescopes aren't looking in the
right place, they miss the beginning or

21
00:01:13.673 --> 00:01:15.642
even the entire event.