Black Holes

[cptwhite_uk]

Can I just recommend these 2 documentries if you'd like to know more. It was originally broadcast on BBC4 around 4 or 5 years ago and I think think they're the gold standard in introducing the layman to a broad overview of Cosmology and Quantum Theory. They are part history lesson and explain how different ideas evolved over time as new minds joined the debate, eventually morphing into our current theories. Hosted by Jim Al-khalili. The cinematography is also superb.

http://www.dailymotion.com/video/xuv...1-2_shortfilms
http://www.dailymotion.com/video/xuh...2-2_shortfilms

[Bagnaj97]

Didn't know about the telescopes. Exciting indeed!

If you really want your mind blown when it comes to telescopes, take a look at this for a sense of scale - http://www.eso.org/public/images/e-e...-vlt-vsosseum/ First light is planned for 2024.

http://en.wikipedia.org/wiki/List_of...lescopes#Plans

[SeriousSam]

Before I get into the question I would recommend checking out some of the other Horizon programmes on i-player. Another one that is great for bending your head is the one on Infinity. Essentially it is to mathematics what black holes are to physics. The interview with Richard Feynman is also very interesting, not least as he has (in my opinion) the right attitude towards science plus learning in general. Finally, the one titled "Secrets of the Universe: Great Scientists in their own words" is a fascinating insight into some of the greatest discoveries of the past century.

Anyway, being somewhat of an oldie my first "encounter" with black holes was the 1979 film by Disney. To someone that was already a bit of a science / space geek, even at that young age, it was a bit of a shock to think that something that powerful and destructive existed. Obviously at that point it was also a case of Since then our perspective has changed quite dramatically, not least with the discovery that they lurk at the heart of galaxies. Plus more so with the realisation that there are parallels between black holes and the origin of the universe. After all if everything came from nothing, then at some point everything was in an infinitesimal space of infinite density.

As mentioned already in this thread a telescope, well more like a network of telescopes, is being "built" to study the super massive black hole at the centre of our galaxy. The hope being that we can find some clues as to what happens as you near the extremes of gravities effect on space. The scientists involved in this find themselves in a curious position. They will either find evidence that Einstein was right or that he was wrong. Showing up any holes in General relativity would knock down one of the greatest theories of the 20th century, but at the same time giving us a glimpse of a greater truth.

Personally I think that there is an analogous situation between Einstein's theory and that of Newton's. The latter worked up to a point, until the former came along to show that at high velocities odd things start to happen. The same may be true when it comes to relativistic mechanics, i.e. once you reach higher levels of gravitational force even weirder effects occur. Perhaps another indicator is that when you try and combine general relativity with quantum mechanics, infinity rears its ugly head as a solution to some of the equations in a way that cannot be normalised. Unlike the other 3 forces.

If I was to speculate as to what we could find, I'd have to go with some insight into the nature of space itself. Part of my reasoning links to the other great question, is the universe bounded or infinite? My suspicion is that both are true depending on how you define space. That may sound rather odd but think of it this way. The universe started at a single point and then expanded outward at what is now an ever increasing rate. There aught to be an edge defined by how far matter or energy has travelled in that time, which begs the question what lies outside that. In some respects you could look at it as "potential space", seeing as in time the universe will expand into it, and this could in all likelihood be infinite.

Santa - I wouldn't worry about Andromeda (see 1) as that collision is 4Billion years away Though even if we survive that our own sun will swallow the earth once is becomes a red giant. Even after that we potentially have "the big rip" to contend with (see 2)

1. http://science.nasa.gov/science-news...may_andromeda/

2. http://en.wikipedia.org/wiki/Big_Rip

As for quasars the simplest description I can come up with is as follows;

If a super-massive black hole has an abundance* of matter to "feed" on then it will also emit gargantuan amounts of energy as a consequence. This energy release comes about due to the breakdown of atomic matter at the event horizon with photons of light (e/m radiation) being ejected in the process. Essentially it's the same sort of thing that goes on a CERN, i.e. smashing atoms / particles together, but on a galactic scale. However, rather than being emitted in all directions like a star it shoots out in two jets at the top and bottom of the black hole. Why that is so is something that I'd have to go back and check. I think it has something to do with the fact that black holes spin and so the top and bottom are its poles. In any case these jets are among the "brightest" objects in the universe.

* The largest known consumes the equivalent of 600 earths per minute

Anyway below is an artists impression.

[santa claus]

Whew, thanks all, that little lot will keep me quiet for a bit. I've watched the first of the enthralling BBC4 documentaries and can make 2 understatements: 'space' is big and advertising is annoying .

[RobbieRoy]

Personally I find Horizon a little tedious these days with the sometimes an over simplification of heavy subjects. I prefer a weekly dose of New Scientist. This is a link to one of their on-line articles which should help anyone on black holes: http://www.newscientist.com/article/...html?full=true

[santa claus]

Now there's a revelation for me: space is getting bigger all the time and at a point in the future the night sky will be totally black because the light from the stars moving away won't reach us. There'll be no 'wishing on a star' or 'starry, starry nights'. Next time I'm on my way home worse for wear, I think I'll stop and contemplate the stars; we take them for granted. I bet I get arrested .

I've also noticed in wiki that in addition to 'the Big Rip' mentioned above, there's also 'the Big Bounce', 'the Big Freeze' and 'the Big Crunch' to contend with. My lack of knowledge is of cosmic proportion and is to be referred to in the discussions of future scientific circles as 'the Dumb Santa' - a collective term for people who know bugger all and are ashamed of it

[SeriousSam]

Personally I find Horizon a little tedious these days with the sometimes an over simplification of heavy subjects. I prefer a weekly dose of New Scientist.

I don't disagree in regards to the more recent Horizon programs, the days of Jacob Bronowski and James Burke are long gone sadly. Now we have too much style and not enough substance, with the same simple point being laboured over repeatedly. In some respects it's indicative of the growing gap between scientific education levels and the boundaries that we are pushing. Plus an unwillingness to say anything contentious or ask difficult questions for fear of upsetting the convenient delusions we have built for ourselves on half truths.

To be honest I even find New Scientist somewhat "light" these days. More often than not if I read an interesting article I have to do further research to get a more in depth picture. Still some areas are covered better than others, and it is at least useful to have things brought to my attention that otherwise I might have missed.

[Phage]

For me I've found BHs facsinating, but the concept of the Heat Death of the Universe terrifyingly depressing.
Yes, the timespan makes it it all moot, but the concept that nothing matters at all....

[Saracen]

Personally I find Horizon a little tedious these days with the sometimes an over simplification of heavy subjects. I prefer a weekly dose of New Scientist. This is a link to one of their on-line articles which should help anyone on black holes: http://www.newscientist.com/article/...html?full=true

Well, true enough, perhaps.

But the audience is the general public, whose knowledge of cosmology and theoretical physics of "Big Bang? That's when the universe was created, innit?"

I'm interested to know how you can explain not just the general model, but the limitations at the extreme edges of it, and the theories if what else might be implied, and inflation, etc, in an hour, and in a way lay people will understand, without huge levels of simplification.

Any successful attempt, that doesn't go straight over their (and my) head is going to be a bit like explaining calculus to a five year old - heavily simplified.

It doesn't matter, to me or anyone else, if I understand the first few picoseconds of creation. Watching a program like horizon is, for me, equal parts education and entertainment. If you rack up the educational quotient too much, it'll be at the expense of entertainment, and then even the education element fails because I'll glaze over, mentally turn off, and change channel.

Horizon usually succeeds, for me, because it expands my general education a tad, often in areas that are of no great interest to me, in areas where I have next to no real knowledge.

Also, it's not just about the science. Those horizons were about the history of the science. About who discovered what, when, and how. It's telling a story, not just of the science itself, but of how our growing understanding, as a species, came about.

For me, they do a damn good job. Which may mean I'm in their target audience, the generally ignorant, and you're not.

[santa claus]

Which may mean I'm in their target audience, the generally ignorant, and you're not.

Fair point, that's me too. Horizon and Hexus help me to fill those black holes in my general education and as is suggested, the gap is considerable

[SeriousSam]

When I left him, I reasoned thus with myself: I am wiser than this man, for neither of us appears to know anything great and good; but he fancies he knows something, although he knows nothing; whereas I, as I do not know anything, so I do not fancy I do. In this trifling particular, then, I appear to be wiser than he, because I do not fancy I know what I do not know.

[santa claus]

Socrates...but true to my confession of ignorance, I had to google it. I have no shame .

[TheAnimus]

Ignorance shouldn't ever be a shameful thing, it's almost as if it's a fractal, the closer you look (the more you learn) the more you realise there is still to see. To the point that the more you focus and specialise, the subject matter shifts, reminiscent of this illusion


One of the worst things we do as a society, is our schools. I hope that we will before too long look back on it as child abuse. The forced national curriculum, the idiotic insistence on equality. As a result far too many children think that school is learning and that's all learning can ever be, they will never know the joy because they haven't been in an environment that is right for them.

When I was a uni student, I did some maths tutoring for money, I did some paid mentoring of disadvantaged children, and also had some parents paying me double minimum wage to ensure their child gets an A/A* at GCSE. What was interesting is I could get children switched on to things, get them wanting to learn more regardless of the kind of family the child had, but that some parents didn't like me teaching their child things that the child wanted to know, but wasn't part 'of the test'. This mentality is awful. I can (and have) explained concepts of calculus, such as differentiation to a 10 year old, it's not hard if they are interested, some people will find the idea of understanding say velocity and acceleration far better.

As an employer, someone who has done a fair bit of consultancy often helping hiring people I've yet to notice any real correlation between grades attained, and someone's ability to do a software engineering related job. Many children, hell even adults, learn things at a different pace, just because someone understood something at 8, doesn't mean they are better than the person who only understood it at 9, heck think how the year a child starts school will impact that too.

It's very sad that we kill the desire to learn in so many children. This is really important when we are heading towards an economy that has only demand for jobs that can't be automated.

[santa claus]

Ignorance shouldn't ever be a shameful thing, it's almost as if it's a fractal, the closer you look (the more you learn) the more you realise there is still to see.

Good post. Looking back to my school days, I greatly regret not taking physics (and art) and realise now this was partly because the way it was being taught did not appeal to me. I could have been Professor Santa by now. Well, ok, but you never know!

ps ooo just discovered how to 'stop' the illusion! Do I get a bafta or an oscar or something?

[TheAnimus]

Do I get a bafta or an oscar or something?

Some desire to experiment or learn more about optical illusions

I was lucky enough to attend a lecture by Prof Nutt last week (the guy who got fired for writing a report about the dangers of drugs that was based on science rather than the daily mail) it was amazing because I realised quite how many misconceptions I had about neuroscience, in particular how psychoactive substances would effect our brain.

There are some great resources for learning on YouTube available completely for free. For almost anything you could want to learn more about too.

[santa claus]

I realised quite how many misconceptions I had about neuroscience, in particular how psychoactive substances would effect our brain.

Changing your views on use and legal highs?