WEBVTT FILE

1
00:00:00.000 --> 00:00:03.970
Using NASA’s Hubble Space Telescope,

2
00:00:03.970 --> 00:00:07.674
a team of astronomers captured the clearest image to date  

3
00:00:07.674 --> 00:00:12.245
of the unexpected interstellar comet 3I/ATLAS.

4
00:00:12.245 --> 00:00:15.015
Astronomers are now able to more precisely

5
00:00:15.015 --> 00:00:19.252
estimate the size of the comet's 
solid, icy nucleus.

6
00:00:19.252 --> 00:00:24.290
Its estimated diameter is no bigger than 3.5 miles across,

7
00:00:24.290 --> 00:00:28.395

but potentially as small as 1,000 feet across. 

8
00:00:28.395 --> 00:00:30.663
Hubble captured a dust plume ejected

9
00:00:30.663 --> 00:00:32.866
from the Sun-warmed side of the comet,

10
00:00:32.866 --> 00:00:35.368
and the hint of a teardrop-shaped dust tail

11
00:00:35.368 --> 00:00:38.104
streaming away from the nucleus.

12
00:00:38.104 --> 00:00:41.207
This behavior is similar to that of previously seen

13
00:00:41.207 --> 00:00:45.011
Sun-bound comets originating within our solar system. 

14
00:00:45.011 --> 00:00:47.847
The big difference is that this mysterious visitor

15
00:00:47.847 --> 00:00:51.651
came from an ancient and unknown realm of our Milky Way,

16
00:00:51.651 --> 00:00:54.354
launching from an 
undetermined star system

17
00:00:54.354 --> 00:00:56.956
long ago and far away.

18
00:00:56.956 --> 00:01:00.560
In what may be the final chapter in its 
space odyssey,

19
00:01:00.560 --> 00:01:03.229
3I/ATLAS is plunging toward the Sun

20
00:01:03.229 --> 00:01:07.567
at a staggering 130,000 miles per 
hour.

21
00:01:07.567 --> 00:01:10.170
This is the highest velocity ever recorded

22
00:01:10.170 --> 00:01:12.572
for a solar system visitor.

23
00:01:12.572 --> 00:01:15.275

The comet's astonishing speed suggests  

24
00:01:15.275 --> 00:01:17.510
it has traversed interstellar space

25
00:01:17.510 --> 00:01:19.579
for billions of years.

26
00:01:19.579 --> 00:01:21.081
The comet gained speed

27
00:01:21.081 --> 00:01:23.483
due to the gravitational slingshot effect

28
00:01:23.483 --> 00:01:26.453
of the stars and other objects it encountered.

29
00:01:26.453 --> 00:01:29.989
The longer 3I/ATLAS traveled 
through interstellar space,

30
00:01:29.989 --> 00:01:31.991
the faster it moved.

31
00:01:31.991 --> 00:01:36.062
Hubble observations suggest that Comet 3I/ATLAS

32
00:01:36.062 --> 00:01:39.766
was likely expelled from a developing planetary system.

33
00:01:39.766 --> 00:01:42.635
This occurred as icy bodies aggregated within

34
00:01:42.635 --> 00:01:45.672
an outer disk or ring surrounding a star,

35
00:01:45.672 --> 00:01:48.541
further supporting the idea that such outer belts

36
00:01:48.541 --> 00:01:51.811
are common in planet-forming systems. 

37
00:01:51.811 --> 00:01:54.914
Another possibility is that 3I/ATLAS

38
00:01:54.914 --> 00:01:56.950
is just a fragment of a small,

39
00:01:56.950 --> 00:02:00.720
icy planet that came too close to a white dwarf star,

40
00:02:00.720 --> 00:02:03.423
disintegrated under the stress of gravity, 

41
00:02:03.423 --> 00:02:07.594
and sent its shards cannonballing back into space. 

42
00:02:07.594 --> 00:02:10.997
3I/ATLAS is an icy fossil from a time perhaps

43
00:02:10.997 --> 00:02:13.299
before Earth even existed.

44
00:02:13.299 --> 00:02:16.069
If 3I/ATLAS has wandered among the stars

45
00:02:16.069 --> 00:02:19.439
for nearly half 
of the Milky Way’s age, it could provide  

46
00:02:19.439 --> 00:02:22.075
insights into the history of our galaxy

47
00:02:22.075 --> 00:02:26.146
and the processes behind our solar system’s formation. 

48
00:02:26.146 --> 00:02:30.083
Comet 3I/ATLAS will make its closest approach to the Sun

49
00:02:30.083 --> 00:02:31.951
in October 2025,

50
00:02:31.951 --> 00:02:35.555
but don’t worry, it 
won’t be anywhere near Earth.

51
00:02:35.555 --> 00:02:38.191
NASA's assets, including Hubble,

52
00:02:38.191 --> 00:02:40.293
the James Webb Space Telescope,

53
00:02:40.293 --> 00:02:42.896
the Transiting Exoplanet Survey Satellite,

54
00:02:42.896 --> 00:02:44.831
and the Swift Observatory,

55
00:02:44.831 --> 00:02:46.699
will closely monitor the comet

56
00:02:46.699 --> 00:02:48.668
to measure its chemical composition

57
00:02:48.668 --> 00:02:52.505
as the Sun's heat further sublimates its ices.

58
00:02:52.505 --> 00:02:55.642
Should it survive the perilous journey near the Sun,

59
00:02:55.642 --> 00:02:58.645
the chances of 3I/ATLAS experiencing 
another

60
00:02:58.645 --> 00:03:02.315
close encounter with a star are incredibly remote.

61
00:03:02.315 --> 00:03:05.151
It's also possible that 3I/ATLAS,

62
00:03:05.151 --> 00:03:08.421
like many fragile comet nuclei approaching the Sun,  

63
00:03:08.421 --> 00:03:11.457
could break apart or disintegrate into dust,

64
00:03:11.457 --> 00:03:13.860
bringing its existence to an end.

65
00:03:13.860 --> 00:03:16.396
Before 3I/ATLAS entered the picture,

66
00:03:16.396 --> 00:03:19.165
we detected two other interstellar visitors:

67
00:03:19.165 --> 00:03:22.202
1I/'Oumuamua in 2017

68
00:03:22.202 --> 00:03:26.005
and comet 2I/Borisov in 2019.

69
00:03:26.005 --> 00:03:28.308
With numerous advanced observatories

70
00:03:28.308 --> 00:03:29.943
now scanning the skies,

71
00:03:29.943 --> 00:03:32.512
we should find many more interstellar objects

72
00:03:32.512 --> 00:03:34.547
visiting our solar system.

73
00:03:34.547 --> 00:03:38.117
Each new discovery offers astronomers valuable insights

74
00:03:38.117 --> 00:03:40.386
into both our 
own solar system

75
00:03:40.386 --> 00:03:47.126
and the distant universe beyond!

76
00:03:47.126 --> 00:04:00.340
Follow us on social media @NASAHubble

77
00:04:00.340 --> 00:04:05.011
NASA Meatball!!!