This is the Message Centre for Galaxy Babe - eclectic editor

Prof Michael Merrifield

Post 21

Gnomon - time to move on

Do you feel an entry coming on?


Prof Michael Merrifield

Post 22

AlsoRan80

Hi GB.

I do hope that you enjoyed the talk and met some nice people.

go well,

Christiane
AR80

Thursday 5th November 2009 5.40 GMT


Prof Michael Merrifield

Post 23

IctoanAWEWawi

"I've been learning about the centre of our galaxy."
Was it a holey experience?
Or did the speaker manage to shine some light on it?


Prof Michael Merrifield

Post 24

Gnomon - time to move on

Is it true that galaxies form because of the supermassive black holes at the centre?

Does anybody yet know where the supermassive black holes come from?

Are they left over from before the Big Bang as some scientists think?


Prof Michael Merrifield

Post 25

Galaxy Babe - eclectic editor

Same sort of questions as were asked after the talk. There's a correlation between the mass of the black hole, and the size of the galaxy. Which suggests they are related some way, but as the Prof said, it's the "chicken and egg syndrome" no-one knows which came first.


Prof Michael Merrifield

Post 26

A Super Furry Animal

>> it's the "chicken and egg syndrome" no-one knows which came first. <<

I thought we'd settled that one: http://www.snorgtees.com/images/WhichCameFirst_Fullpic_1.gif

RFsmiley - evilgrin


Prof Michael Merrifield

Post 27

IctoanAWEWawi

"Is it true that galaxies form because of the supermassive black holes at the centre?"
As GB said - could be, could also be that they form due to the collapse of supermassive stars at the galactic centre (one theory of their origins). I suspect it might not be an either/or case though. I suspect the SMBH and galaxy might actually be two sides of the same thing.

"Does anybody yet know where the supermassive black holes come from?"
See above but also theorised just a normal black hole that has grown (although would have to start as a supermassive star) Or due to the collapse of a whole star cluster.

"Are they left over from before the Big Bang as some scientists think?"
*before* the big bang? There isn't any *before* with the big bang. Whatever they are, they came out of the energies released in the big bang.

Key to helping us find out is LISA - http://lisa.nasa.gov/ - which will be looking for gravity waves which should be emitted by supermassive black holes (and by SMBH twins). If, of course, such waves exist.
And if SMBHs emit them.


Prof Michael Merrifield

Post 28

Gnomon - time to move on

I think you're a bit behind the times there Ictoan. Scientists no longer believe the supermassive black holes are formed by stars collapsing and clumping together, as there hasn't been enough time since the Big Bang.

And the "before the Big Bang" theory was proposed quite seriously in the last two or three weeks. So I'd like to see what the professional astronomer said.


Prof Michael Merrifield

Post 29

IctoanAWEWawi

"I think you're a bit behind the times there Ictoan. Scientists no longer believe the supermassive black holes are formed by stars collapsing and clumping together, as there hasn't been enough time since the Big Bang."

Not stars Gnomon, *supermassive* stars - such as the first sequence ones. And there has been enough time, according to a paper I was reading t'other day - shall see if I can find it. Makes a load of caveats, of course, but then you'd expect that with such leading edge research.

"And the "before the Big Bang" theory was proposed quite seriously in the last two or three weeks."
Well maybe so, but so was the LHC damaging itself from the future. But since was created in the big bang, you can't have a before. It's fairly simple. I suspect they didn't mean 'before' or are using a different concept of the big bang - wasn't a cyclic universe theory was it?



Prof Michael Merrifield

Post 30

IctoanAWEWawi

Found it!

an interesting white paper for next year.
http://www.stsci.edu/~marel/decadal/sc/296.pdf
"THE NUCLEI OF LOW-MASS GALAXIES AND THE SEARCH
FOR THE SMALLEST MASSIVE BLACK HOLES"

gives a good overview of the three theories currently in consideration and their problems, plus what we don't know. And yes, stellar collapse of supermassive stars is in there as is global collapse. Although both have problems.

Another paper (but from 2006/2007 IAU) is
http://journals.cambridge.org/download.php?file=%2FIAU%2FIAU2_S238%2FS1743921307005376a.pdf&code=94f2bf41496de5a9b38b329bcd41b762

which indicates that for their given method an IMBH can grow by accretion into an SMBH within 0.8 Gyrs.

course, they're only theories and the actual truth of the matter is likely a)different and b)more complicated. But they are still current theories.


Prof Michael Merrifield

Post 31

IctoanAWEWawi

global? Globular I meant!


Prof Michael Merrifield

Post 32

Gnomon - time to move on

smiley - ok


Prof Michael Merrifield

Post 33

Galaxy Babe - eclectic editor

The Prof did explain Hawking radiation in a way that I understood it, using his fists as props smiley - biggrin


Prof Michael Merrifield

Post 34

pailaway - (an utterly gratuitous link in the evolutionary chain)


smiley - huh are you sure he wasn't just using his fists to ward off questions?

(no, seriously, it's great when you get a speaker that can explain things well smiley - ok)


Prof Michael Merrifield

Post 35

Galaxy Babe - eclectic editor

His fists were the particlessmiley - biggrin


Prof Michael Merrifield

Post 36

IctoanAWEWawi

that'd be interesting - I hope he remembered to keep his fists apart so they didn't annihilate themselves!


Prof Michael Merrifield

Post 37

Galaxy Babe - eclectic editor

He did that until he demonstrated how one went into the black hole, and the other was an anomily, which was the Hawking radiation. I did grasp it, although, I wonder where it is nowsmiley - silly


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