All About… Star Clusters — Transcript

Full transcript

1. 0:01hello everyone and Welcome to our
2. 0:03universe today we'll be talking all
3. 0:05about star
4. 0:07clusters so star clusters are groups of
5. 0:10stars which are gravitationally bound
6. 0:13together the average star distance in a
7. 0:15star cluster is much closer than the
8. 0:18average distance between stars and the
9. 0:20rest of the
10. 0:21Galaxy basically there are two types of
11. 0:24star clusters the first are globular
12. 0:27clusters these are groups of about
13. 0:2910,000
14. 0:30to several million stars these are
15. 0:33densely packed together in a spherical
16. 0:35form they consist of only old stars and
17. 0:38they are many billions of years old most
18. 0:41of the stars in the Clusters are just a
19. 0:44few hundred million years younger than
20. 0:46the universe itself meaning that
21. 0:48globular clusters can have an age
22. 0:50bracket of 12 to 13 billion years these
23. 0:54Global clusters are not part of the
24. 0:57galaxies themselves but they actually
25. 0:59orbit around them the Milky Way for
26. 1:02example is accompanied by 150 globular
27. 1:05clusters bigger galaxies like the
28. 1:08Andromeda galaxy are orbited by more
29. 1:10than 500 of these clusters and even
30. 1:13bigger galaxies like m87 can have more
31. 1:16than 10,000 of these galaxies in
32. 1:22orbit the second type of cluster is the
33. 1:25open clusters which have almost all the
34. 1:27opposite characteristics of a globular
35. 1:30cluster they contain less Stars which
36. 1:32can be fewer than 100 and they are less
37. 1:35densely packed and are very
38. 1:37young open clusters are the places where
39. 1:40new Stars Are Born basically a star
40. 1:44Factory take our son for example 4.6
41. 1:47billion years ago our star must have
42. 1:49been born from an open
43. 1:51cluster because they are less dense they
44. 1:54are less tightly gravitationally bound
45. 1:56together and this is why they disperse
46. 1:59over time
47. 2:00this has also happened to our solar
48. 2:02system which has moved from an open star
49. 2:04cluster to a relatively empty region of
50. 2:07the Milky Way since open clusters are
51. 2:11places where new Stars Are Born they are
52. 2:13often surrounded by huge gas and dust
53. 2:16clouds these are known as the emission
54. 2:23nebula so I'm going to talk about a
55. 2:25couple of examples of globular clusters
56. 2:28and open clusters so the first one is
57. 2:31M45 the pleades the pleades are also
58. 2:35known as the Seven Sisters it is an open
59. 2:38star cluster in the constellation of
60. 2:41Taurus at a distance of 450 L years it
61. 2:45is one of the closest star clusters to
62. 2:47Earth and is mostly famous for its
63. 2:49bright blue stars that are clearly
64. 2:51visible with the naked eye in the
65. 2:53northern
66. 2:54hemisphere despite its nickname the
67. 2:56Seven Sisters it actually has more than
68. 2:59just is seven bright blue stars the
69. 3:02number of confirmed Stars actually
70. 3:04exceeds over a
71. 3:06thousand the brightest blue stars are
72. 3:08very young by very young I mean that
73. 3:11they're less than 100 million years old
74. 3:14which in astronomy terms is very young
75. 3:17they burn their hydrogen at very high
76. 3:19rates and will be the next stars in the
77. 3:22cluster to end their lives with these
78. 3:24hot blue stars still existing today
79. 3:27gives us valuable information into the
80. 3:29maximum age of the star
81. 3:34cluster within the next 250 million
82. 3:37years the pleades will slowly disperse
83. 3:40due to its gravitational disturbances
84. 3:42caused by its Galactic
85. 3:45[Music]
86. 3:48neighborhood so in contrast a globular
87. 3:50cluster example would be
88. 3:52M4 it is 6,700 light years away from
89. 3:56Earth and has a mass of 67,000 solar
90. 4:00masses and a diameter of approximately
91. 4:0275 light
92. 4:04years even with the smallest telescopes
93. 4:07you can see M4 as a fuzzy ball of light
94. 4:11provided that you have very clear skies
95. 4:13and also that it's devoid of light
96. 4:16pollution if you want to experience a
97. 4:18better view of this globular cluster you
98. 4:20probably need to get a bigger telescope
99. 4:22with a bigger aperture a telescope with
100. 4:24a 6-in aperture enables you to see a lot
101. 4:27more of the detail within the cluster
102. 4:29and you might be able to observe the
103. 4:31single Stars within this massive
104. 4:33spherical
105. 4:40structure so I hope that's given you a
106. 4:42great insight into all about star
107. 4:45clusters and as always if you've enjoyed
108. 4:47the video click the like button and if
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111. 4:58watching
112. 4:59[Music]