## mayankdevnani Group Title My first TUTORIAL on BLACK HOLE- one year ago one year ago

1. mayankdevnani

$\Huge{\bf{\color{blue}{Whatis }\color{red}{Blackhole--}}}$ $\Large{\bf{\color{black}{What is }\color{red}{Blackhole==}}}$ A black hole is defined by the escape velocity that would have to be attained to escape from the gravitational pull exerted upon an object. For example, the escape velocity of earth is equal to 11 km/s. Anything that wants to escape earth's gravitational pull must go at least 11 km/s, no matter what the thing is — a rocket ship or a baseball. The escape velocity of an object depends on how compact it is; that is, the ratio of its mass to radius. A black hole is an object so compact that, within a certain distance of it, even the speed of light is not fast enough to escape. A black hole itself is invisible because no light can escape from it. In fact, when black holes were first hypothesized they were called "invisible stars." If black holes are invisible, how do we know they exist? This is exactly why it is so difficult to find a black hole in space! However, a black hole can be found indirectly by observing its effect on the stars and gas close to it. For example, consider a double-star system in which the stars are very close. If one of the stars explodes as a supernova and creates a black hole, gas and dust from the companion star might be pulled toward the black hole if the companion wanders too close. In that case, the gas and dust are pulled toward the black hole and begin to orbit around the event horizon and then orbit the black hole. The gas becomes heavily compressed and the friction that develops among the atoms converts the kinetic energy of the gas and dust into heat, and x-rays are emitted. Using the radiation coming from the orbiting material, scientists can measure its heat and speed. From the motion and heat of the circulating matter, we can infer the presence of a black hole. The hot matter swirling near the event horizon of a black hole is called an accretion disk. $\Large{\bf{\color{pink}{What does a}\color{green}{black hole look like?}}}$ John Wheeler, a prominent theorist, compared observing these double-star systems to watching women in white dresses dancing with men in black tuxedos within a dimly lit ballroom. You see only the women, but you could predict the existence of their invisible partners because of the women's' spinning and whirling motions around a central axis. Searching for stars whose motions are influenced by invisible partners is one way in which astronomers search for possible black holes.

2. mayankdevnani

@ajprincess @JOYAL @jiteshmeghwal9 @thivitaa @rahul_rajawat have a look:)

3. mayankdevnani

@ganeshie8 @hba @moongazer @Musicdude123 @Miyuru plz

4. mayankdevnani

5. rahul_rajawat

thanks the information is realy nice dear... :)

6. mayankdevnani

welcome

7. jiteshmeghwal9

` $\Huge{\color{red}{\text{What \space is \space Black \space hole ?? }}}$

8. jiteshmeghwal9

It ill give u gap

9. mayankdevnani

$\Huge{\color{red}{\text{What \space is \space Black \space hole ?? }}}$

10. jiteshmeghwal9

Well, really good concept about black hole :)

11. mayankdevnani

hey!!! don't works @jiteshmeghwal9

12. Miyuru

Wow Great tutorial. I didn't knew these facts... Thanks very much for sharing.. And for the space you don't actually need to type space.. :)

13. mayankdevnani

ok thnx... @Miyuru

14. Miyuru

No problem..

15. jiteshmeghwal9

& when the astraunauts go to space they first look at the space which is very dark & they try to escape. Black holes are made when star become much older & then there is a very great blast namely nova or supernova & then it turns to black hole. Nice stuff @mayankdevnani :)

16. jiteshmeghwal9

$\Huge{\color{red}{\text{What is Black Hole ?}}}$

17. jiteshmeghwal9

It's working in my computer :)

18. Miyuru

Great indeed @mayankdevnani

19. jiteshmeghwal9

Ok ! now write it without putting space in LaTeX

20. mayankdevnani

ok

21. Miyuru

Well is the escape velocity greater than the speed of light ? ;)

22. jiteshmeghwal9

$\Huge{\color{gold}{\star \star \star}{\color{red}{\mathbb{G}\color{blue}{\mathbb{r}\color{green}{\mathbb{e}}\color{magenta}{a}\color{purple}{t}\color{violet}{!!!}}}}}$

23. mayankdevnani

That is the very definition of a black hole: an object so massive and dense its escape velocity is greater than the speed of light. So yes. If the escape velocity was slightly less than the speed of light the object would be a neutron star. ok @Miyuru

24. hba

\Huge{\color{red}{\text{What is Black Hole ?}}}

25. Miyuru

Ohh NICE Got it Thanks again... And nice letters @jiteshmeghwal9

26. jiteshmeghwal9

Thanxx !!! XD

27. hba

@jiteshmeghwal9 Can you teach me latex ?

28. jiteshmeghwal9

yeah ! why not

29. hba

@jiteshmeghwal9 So Lets start with it in a new tab i want it from the basics

30. jiteshmeghwal9

but in LaTeX group :)

31. jiteshmeghwal9

ok !

32. Miyuru

$\color{green}{\text{I'll give you a nice idea what about posting a tutorial about LaTex..}}$ @jiteshmeghwal9

33. mayankdevnani

@Kira_Yamato @nubeer

34. mayankdevnani

35. Kira_Yamato

すごいい

36. ajprincess

$\Large\frak\color{silver}{Great~Tutorial}$ @mayankdevnani

37. mayankdevnani

thnx... @ajprincess

38. mayankdevnani

what? @Kira_Yamato

39. Miyuru

Great letters @ajprincess

40. mayankdevnani

41. Kira_Yamato

すごいい = Great, Impressive, Awesome

42. mayankdevnani

i don' think @moongazer would like my tutorial!!!

43. mayankdevnani

thnx... any medals @Kira_Yamato

44. ajprincess

welcome:) @mayankdevnani nd thanx:) @miyuru

45. mayankdevnani

@RahulZ @Calculator @FlyingBubbles

46. nubeer

it's a nice tutorial. Good Work. :)

47. mayankdevnani

thnx... @nubeer

48. jiteshmeghwal9

@Miyuru most better LaTeX tutorial has been given by @AccessDenied :)

49. mayankdevnani

@angela210793 @AccessDenied

50. Miyuru

Ohh really @jiteshmeghwal9 thnx for telling me tht .. How can i find his tutorial...:)

51. jiteshmeghwal9

wait...

52. mayankdevnani

@sirm3d

53. mayankdevnani

54. jiteshmeghwal9
55. jiteshmeghwal9

In this tutorial my bro @TheViper has a gr8 role :)

56. jiteshmeghwal9

@Miyuru :)

57. Miyuru

Ohh thnx a lot @jiteshmeghwal9 for the links I'll see them ....:)

58. jiteshmeghwal9

yw :)

I'm guessing this is the Newtonian description of a black hole. :) Nice work.

60. mayankdevnani

thnx...

61. mayankdevnani

62. mayankdevnani

@mukushla

63. mayankdevnani

@TheViper

64. mayankdevnani

@ganeshie8

65. TheViper

$Nice \quad Tutorial$

66. mayankdevnani

thnx....

67. mayankdevnani

@nincompoop

68. mayankdevnani

@Omniscience

69. mayankdevnani

hey!!! @nincompoop it's just a basic

70. mayankdevnani

what??

As a side note, the black hole must be thought in terms of General Relativity instead of Newtonian Mechanics to avoid discrepancies between "gravity". For example escape velocity of a black hole is infinite and is not subject to the radius of the black hole in GR instead but not NM. IOW, NM just don't cut it.

72. mayankdevnani

it's just a structure not a deeply study ok @nincompoop but you are said it was very imp. part of black hole.....thanks for your advice

73. mayankdevnani

74. mayankdevnani

yaa

75. mayankdevnani

@Faris_Waleed