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Announcements & News => Astronomy & Science => Topic started by: Nickel2 on January 26, 2016, 09:24:29 AM



Title: Black Holes
Post by: Nickel2 on January 26, 2016, 09:24:29 AM
Reith Lectures starting now R4

Stephen Hawking Black Holes


Title: Re: Black Holes
Post by: gravyminer on January 26, 2016, 10:34:49 AM
Doh !

I was going to listen to this. Will have to ''listen again'

Apparently he was also talking about the need for humans to get off planet before we make it inhospitable for ourselves.
Suggesting he thinks humans are more important than planet .......


Title: Re: Black Holes
Post by: desperate on January 26, 2016, 09:58:31 PM
Bottoms I missed it too, still with the help of a black hole I will listen yesterday wackoold

Desp


Title: Re: Black Holes
Post by: Ted on January 27, 2016, 12:09:27 PM
http://www.bbc.co.uk/iplayer/search?q=hawking&search_group_id=urn:bbc:programmes:b00729d9


Title: Re: Black Holes
Post by: desperate on February 13, 2016, 02:54:36 PM
Talking of black holes, I see the LIGO scientists have just announced the detection of gravitational waves caused by the merging of two black holes a billion light years away. I wonder if with some refinement in detection techniques they might be able to "see" dark matter or even dark energy?

Desp


Title: Re: Black Holes
Post by: dan_b on February 13, 2016, 07:04:14 PM
I'm convinced dark matter / energy as a mysterious new thing is cobblers it's just normal matter we've not seen yet.  I vividly recall a documentary about the Hubble telescope where they pointed it at the darkest most empty piece of the sky astronomers could find, expecting to see overt little, and Hubble revealed the most extraordinary number of previously unseen galaxies...


Title: Re: Black Holes
Post by: biff on February 13, 2016, 07:45:17 PM
 Ah !  "Black holes" says he,
                       He was sitting at the kitchen table cutting squares of newspaper for the outside toilet,
    " Dam,d right" says he,"They are impossible to see,"
   .
                                                       Biff


Title: Re: Black Holes
Post by: djs63 on February 13, 2016, 07:49:15 PM
To dan_b
There is plenty of other evidence for dark matter within nearby galaxies never mind in the unimaginably distant universe.


Title: Re: Black Holes
Post by: Stuart Ian Naylor on February 13, 2016, 07:54:47 PM
I am not sure about the main evidence of dark matter.

"Things are not acting like we expect, so it must be something else"

Maybe what we are expecting is wrong.


Title: Re: Black Holes
Post by: desperate on February 13, 2016, 08:07:11 PM
I think there is a bit more to it than that Stuart, as I understand it (which is not much) the standard model makes predictions that constrain the ratios and amounts of Hydrogen, Helium and Lithium produced in the first few minutes on nucleosynthesis after the big bang, these ratios are indeed seen throughout the universe wherever we look. Also the acceleration of the expansion of the universe has in the last 15 years been observed, it was predicted by General relativity a hundred years ago. It is very hard to see why it should accelerate unless there is some kind of unseen force pushing it.

Who knows??

Desp


Title: Re: Black Holes
Post by: Stuart Ian Naylor on February 13, 2016, 09:28:52 PM
If the Higgs wasn't found then scientists where going to state the standard model is wrong and its back to the drawing board.

They did find it but there are still loads of questions with supersymmetry, even the speed of light has new queries.

"Things are not acting like we expect, so it must be something else", sort if sums it up to me and neatly ties up the problem in a Douglas Adams "Somebody else's, problem field" style.

Humanity is always right at the time, whilst the future has repeatedly shown that we were wrong. Interesting stuff if you're a scientist and way beyond me.

Dark matter, might not be and the standard model could just be like Newtonian physics and the real underlying physics could be something else entirely.

The Higgs answered a question, but the LHC has opened a load more new ones.

To be honest I wouldn't be any more surprised that dark matter doesn't exist, than by them actually proving it does.



 


Title: Re: Black Holes
Post by: desperate on February 13, 2016, 10:21:46 PM
Quote
Insert Quote
If the Higgs wasn't found then scientists where going to state the standard model is wrong and its back to the drawing board.

I disagree with that,

 even before the Higgs was discovered there was a lot of good evidence for the standard model, not least the Microwave backgroound. This was predicted years before the COBE sattelite by the theories and when COBE was finally launched the background radiation was seen, although we could not see the irregularities.  Years later when the observations were refined,  the irregularities were observed to within one part in ten thousand of the predictions.

Even if the Higgs were not discovered it wouldn't be back to the drawing board, sure it could mean some refinements are needed but basically the model would still work. In the same way as Newtonian laws worked for gravity, well almost, but it took general relativity to finally clear up the tiny discrepancy, we didn't need to dump Newtonian physics merely refine it a bit. Probably that would be the case with C, although there aren't many who doubt it isn't a universal constant as far as I know.

The standard model has made too many predictions that have subsequently been confirmed by observation to be wildly inaccurate, but sure there are many many questions that still need answers.

Mind you, never say never...............

Desp


Title: Re: Black Holes
Post by: Stuart Ian Naylor on February 14, 2016, 02:27:42 AM
I really don't know Desp, I read and watch a few science articles and my memory isn't great. I seem to remember quite a few scientists said not finding the Higgs would be more exciting.
The Higgs boson and Higgs field is the base fundamental particle in the standard model, but they found it anyway. But at the time many were not sure if the LHC would solidify or break the standard model.

Standard model is still shaky but to be honest I thought a bottom quark was caused by a dodgy curry, so aint a clue.



 


Title: Re: Black Holes
Post by: Ivan on February 14, 2016, 02:53:45 AM
I read today in New Scientist, that the gravitational waves detected were probably caused by two black holes spiraling into each other, and in doing so, they would lose around 3 'suns' worth of mass in about 0.2seconds - briefly outshining the entire rest of the universe.


Title: Re: Black Holes
Post by: Nickel2 on February 14, 2016, 09:06:41 AM
The wonderful thing about scientific discoveries is that they lead to further theorising and the search for more scientific discoveries. The latest scientific discovery?  Ancient cures to the fore:

Take ye onions, wine, garlic, leaks, and cow-bile, Chop ye ingredients well, mix and let stand for nine days and nights. Strain ye the liquor and use to kill 90% of MRSA in ye wounds.

http://www.bbc.co.uk/news/health-35550165

I love it. Perhaps we are not doomed after all.

N2


Title: Re: Black Holes
Post by: desperate on February 14, 2016, 03:50:12 PM
I read today in New Scientist, that the gravitational waves detected were probably caused by two black holes spiraling into each other, and in doing so, they would lose around 3 'suns' worth of mass in about 0.2seconds - briefly outshining the entire rest of the universe.

Wow those numbers really are astronomical, what happens to the mass that is "lost" is it converted to energy? 3 solar masses in .2 of a second is going to be a lot of power horror: sh*tfan:

Desp


Title: Re: Black Holes
Post by: desperate on February 14, 2016, 04:05:02 PM
Oh dear what a saddo I am, I just couldn't leave it alone........... tumble:

in Joules it works out at 5.97^30*3*10^8*3*10^8 ............liberated in .2 of a second so if you multiply that by 3600*5 and then divide by 3,600,000 that I think would give you the energy in kWhr.................. sh*tfan: sh*tfan: sh*tfan: sh*tfan: sh*tfan: sh*tfan: give or take a brazzzillion or ten.


someone else care to crunch that,? even I ain't that sad whistle whistle

I love astronomy, it's just so astronomical ralph:

Desp


Title: Re: Black Holes
Post by: Countrypaul on February 14, 2016, 04:20:36 PM
I think that should be 5.97*10^30*3*10^8*3*10^8 though google shows the mass of the sun as 1.989 rather than 5.97

Yes I'm that sad as well.


Title: Re: Black Holes
Post by: todthedog on February 14, 2016, 04:27:18 PM
Quite a big number then! surrender: surrender:


Title: Re: Black Holes
Post by: biff on February 14, 2016, 05:43:20 PM
I don,t mind if you are a few point out,
                I forgive ya all and I am happy to just look up from time to time and see a star our two. I only need one star and the moon. The rest only complicate things.
    When my daughter was very small, she used to ask all kinds of questions about stars and galaxies. It was terrible. I heard about bears and ploughs and milky ways but I had,nt a notion you see, then she got a book on astronomy when she was six and that was my ignorance exposed. It was terrible, it was. Just imagine being preached to by a 6 year old.
  Then she grew up an d became an engineer and her kids are into everything. So they ask me a question and I pull their leg because I don,t know the answer to the question and then she starts on me," Now do you see what I had to put up with" (to the kids) Hands on hips.
 The kids look at me ,with a certain understanding, I have a look of a rabbit caught in the headlight of a car. It is tricky being a grandpa,especially if you forget to keep quiet.
  Modern kids are a very serious lot.When I was a kid, I would be sent to the shop for a long stand. So I would stand there with my hands in my short trouser pockets and the old lady would ask me, "was that long enough" and I would go Eh,!?. Then she would feel sorry for me and give me a gobstopper, one of the ones with that red dye that used to run all over your chin, like blood. Half way down the road i would swop the rest of the gobstopper for a marble, some gobstoppers had hollow centres and you had to ditch them before the hole appeared or you would get nothing for them. There was a lot of sucking and slurping in half a solid gobstopper and well worth a marble any day. Then if I was really bored,with nothing to do and no dough, I would go to the shop myself and say that I had been sent for a long stand. It did not work every time but it was worth the effort. Random success is 10 times the excitement.
  Half the time we carried all kinds of exotic extras, ringworm was a big scorer. mumps, Measels, chicken pox and of course big green snotty noses. There was a gang of about 20 of us. No creche would allow us in the door nowaday. There was not a single playstsation of PC to be heard of and we still had to discover TV,, You could just see the action through the snow. It was different back then.
  Twinkle twinkle little star, When I grow up I,ll buy a car, Up and down the road I.ll fly.and 50ty verses after that.
   Errr were wuz i,,,,,,,,,,? Ah Black holes.. yes, Calcutta has a big one.
                                                                     Biff


Title: Re: Black Holes
Post by: desperate on February 14, 2016, 09:31:50 PM
I think that should be 5.97*10^30*3*10^8*3*10^8 though google shows the mass of the sun as 1.989 rather than 5.97

Yes I'm that sad as well.

You're right of course, I ommited the ten, and one solar mass is 1.989*10^30kg but I multiplied by three as Ivan quoted three solar masses were destroyed, but hey what's a coupla solar masses between friends ;D

Desp


Title: Re: Black Holes
Post by: desperate on February 14, 2016, 09:35:22 PM
I know exactly what you mean Biff, kids have a knack of asking the most penetrating questions in all innocense, sometimes we have quite a struggle with a public viewing night at the astronomical society.

Desp