Black Hole Munches On A Star!

[veritassemper]

I am still not well versed on matters astronomical although I do try to read as much as I can. Hence I have been away from this forum for quite some time.<br /><br />Black Holes, as they are called, do fascinate me basically due to the mysteries that they pose. Here is an article I found and I would appreciate any comments.<br /><br />http://spaceflightnow.com/news/n0612/05blackhole/<br /><br />v s<br /> <div class="Discussion_UserSignature"> </div>

 

[alokmohan]

For the last few days this story is running in many websites and it has become popular.Any black hole has event horizon and orbital deviation may have brought the poor star to its death trap.Any future space ship veturing near event horizon may face thesame fate if by chance it is having gravitational inter actio with sotmehing of massive size.Kip Thorne in his introducory chapter has drawn a picture of humans fetching black hole.Book on Black hole.There is a complete chapter on what happens when we go iside a black hole.But can you tell me if black holes really exists?

 

[veritassemper]

<b><font color="purple">ALOKMOHAN</font></b><br /><br />That is the never ending question. Even some of the best minds on cosmology hold varying views.<br /><br />I can only answer your question as answered by probably the majority view as found in the following:-<br /><br />http://blackholes.stardate.org/resources/faqs/faq.php?id=2<br /><br />What do you think?<br /><br />v s<br /> <div class="Discussion_UserSignature"> </div>

 

[weeman]

Black holes have certainly eluded our knowledge more than just about anything else in the Universe. Their physical properties make them almost impossible to observe. That is why we can thank the mathematics of physics to allow us to almost peer beyond the event horizon, and view the other side.<br /><br />I'm no astronomer, but I too have always been interested with black holes. They are so massive, that their gravity is capable of pulling in light itself. The article didn't explain this so much. It is based on a black hole's escape velocity, that is, being greater than the speed of light. Although it may not literally be faster than the speed of light, it is simply stated that way since light cannot escape it. In addition, the event horizon is merely a mathematical boundry, not a physical one. If it were a physical boundry, the event horizon might appear smooth and stationary from far away. However, from close up, you would observe the horizon to be moving at the speed of light!<br /><br />An analogy to describe this might be from a horror movie or a nightmare. In a nightmare, you might be running as fast as you can from a beast/killer, yet your destination will never get closer to you. You can run as fast as you can towards the door at the end of the hall, but it never gets closer.<br /><br />The event horizon might work in the same way. It's always moving at the speed of light, but it doesn't actually go anywhere. <br /><br />So to answer the question: "Do they really exist?" <br />I think they certainly do exist. <div class="Discussion_UserSignature"> <p> </p><p><strong><font color="#ff0000">Techies: We do it in the dark. </font></strong></p><p><font color="#0000ff"><strong>"Put your hand on a stove for a minute and it seems like an hour. Sit with that special girl for an hour and it seems like a minute. That's relativity.</strong><strong>" -Albert Einstein </strong></font></p> </div>

 

[alokmohan]

Event horizon does not move in speed of light.In case of a stellr black hole,it rotates with space speed fron which it was originally formed.On earth we have horizon beyond which we canot see.Event horizon of a blackhole is the point beyond which we cannot see.

 

[weeman]

Correct, and that is where it's stated as a mathematical boundry. Lets forget the event horizon for a second, and explain it another way. Beyond the event horizon you would essentially have to travel faster than light to break the black hole's grasp. If you were to have a space ship that was powerful enough, and you traveled to the horizon, you would have to maintain the speed of light to evade being sucked into the black hole. The speedometer on your ship would tell you that you're traveling at the speed of light, yet when you looked outside, it wouldn't appear that you're moving anywhere. I guess this is what we can apply to the analogy I was using in my previous comment. <br /><br />Can you explain your Earth event horizon to me a little more? <div class="Discussion_UserSignature"> <p> </p><p><strong><font color="#ff0000">Techies: We do it in the dark. </font></strong></p><p><font color="#0000ff"><strong>"Put your hand on a stove for a minute and it seems like an hour. Sit with that special girl for an hour and it seems like a minute. That's relativity.</strong><strong>" -Albert Einstein </strong></font></p> </div>

 

[alokmohan]

If you enter the black hole,means you cross the event horizon you will smartly get inside.Tidal pressure will increase your height.You will keep on being taller and taller and theoritically you may be onebillion km tall.But your body wil be stretched andsqueezed and you break up and become part of black hole.

 

[alokmohan]

Same case with the poor star.

 

[newtonian]

veritassemper - Hi! I'm the former paulharth6 btw.<br /><br />How are you?<br /><br />I will now check out your link and respond.

 

[newtonian]

veritassemper - Interesting article.<br /><br />What mysteries do you have in mind?<br /><br />There was a program on the Science channel recently on supermassive black holes in virtually all galaxies - it postulated that galaxy formation was strongly influenced by black holes and showed that black hole spin and also mass is mathematically related by consistent ratios in many galaxies to galaxy rotation and mass respectively.<br /><br />That is on another thread, btw.<br /><br />The point relevant to the article is that it was postulated that black holes in their initial feeding frenzy actually pushed back most of the mass of galaxies and that shock waves from these black hole feeding episodes triggered structure and star formation.<br /><br />Of course, as usual, the program ignored other factors also postulated to be involved in the formation of structure - for example: shock waves from the big bang, dubbed in Scientific American: "The Cosmic Symphony;" Also structure caused magnetic and ionizatioon influences - in effect a magnetic formation of 'seeds' for galaxies.<br /><br />My own independent question is: what is the speed limit for black hole spin, since spin increases as radius decreases?<br /><br />I will be offline for a little while (a day or 2 perhaps), but I will respond further later.

 

[alokmohan]

In a black hole all calculations are based on theory os relativity and they are differen than truths postulated by Newtonian calculations.You may see the 1st chapter of Black holes by Kip Thorne.

 

[veritassemper]

<b><font color="purple">NEWTONIAN</font></b><br /><br />Mysteries? Well there seems to be a few theories just as to what actually happens at event horizon. For example I have read elsewhere some time ago that if man were to reach that point time would stand still and he would therefore be ageless. Another is that at event horizon, the speed of light is achieved.<br /><br />As I am fascinated by black holes, basically a misnoma, as to all the theories related to them and that every galaxy seems to have so many of them that I think that without them galaxies would have an entirely different effect within the universe. Just the ramblings of a very poor amateur.<br /><br />Here is another site that might help:-<br /><br />http://www.nasa.gov/vision/universe/starsgalaxies/spinning_blackhole.html<br /><br />v s<br /> <div class="Discussion_UserSignature"> </div>

 

[alokmohan]

Time there is very slow.You age slowly.A man near event horizon may be 1 year older if he is hovering near event horizon.I am tempted to quote Kip Thorne but I have faced the post just now.But near event horizon tidal gravity will be a real problem.

 

[alokmohan]

Dont get near a black hole.You get gulped before you reach singularity.

 

[veritassemper]

<b><font color="purple">ALOKMOHAN</font></b><br /><br />Here is a question which will I suppose show my poor intelligence on black holes, fascinating as they are.<br /><br />If a black hole is spinning at the event horizon at C or as close to it as makes no difference, how does matter enter the event horizon? Nothing travels faster than light. On that basis I am getting rather silly in my understanding of the physics involved.<br /><br />I know, from many articles and from experts who are studying black holes that matter is pulled into the black hole never to reappear until the collapsed star goes supernova.<br /><br />So how does my first statement stand in such complexities?<br /><br />v s<br /> <div class="Discussion_UserSignature"> </div>

 

[veritassemper]

<b><font color="purple">EHCUOB</font></b><br /><br />Apologies. I failed to notice your thread on that very topic. Anyone who wants to see/make any replies to my last post, please go to the other thread.<br /><br />Thank you.<br /><br />v s<br /> <div class="Discussion_UserSignature"> </div>

 

[alokmohan]

Unless the collapsed star is supernova you never have a black hole.Mass of the star should be three suns and it should shrink to 18 km in dia per solar mass.

 

[nexium]

A one Earth mass black hole, if any, might spin at 0.9999999 c at the event horizon. a one solar mass black hole (we think we have found a few that small) 0.9999c. A million solar mass black hole perhaps 0.9 c.<br />A million times a million solar mass, if any, perhaps 0.01c at the event horizon. I'm guessing can someone calculate? Neil

 

[nexium]

Is the diameter of the event horizon directly proportional to the mass? One Earth mass is 18 millimeters, assuming the sun has one million Earth mass?<br />18X10 to the 12th kilometers = 1.8 light years event horizon diameter for the million times a million solar mass black hole if any have that much mass? Neil

 

[alokmohan]

It is.But always try to think of circumference only.Never dream of diameter.You may land in danger.

 

[enigma10]

When i dream of diameter, i dream of large women.<img src="/images/icons/wink.gif" /><br /> <div class="Discussion_UserSignature"> <em>"<font color="#333399">An organism at war with itself is a doomed organism." - Carl Sagan</font></em> </div>

 

[alokmohan]

but if the diameter is hundrd of billoin km and the hole thrusts you up and down,right and left and reduce you to quarks ,will you like the total chaos?