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I'm a cosmologist ask me anything

grazorblade

grazorblade

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G&G Podcast
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Oct 17, 2024
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Not sure how many on this forum are curious about physics, but happy to answer any questions
 
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grazorblade said:
I guess that's more a philosophical question

what makes you think we are insignificant?
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You did say "ask me anything" 😂 I could've asked what's your favourite breakfast?

But seriously, what's your opinion? I know it doesn't mean you're an expert on the matter.
 
Very cool.

Have a long running interest in all things space and the cosmos.

I have Simon Singh's book the Big Bang which is excellent. (Plus a bunch of others.)

Never ceases to amaze me that the calcium in our bones, the gold in the ground, the iron in the dirt came from exploding stars.
 
HappyGuus said:
You did say "ask me anything" 😂 I could've asked what's your favourite breakfast?

But seriously, what's your opinion? I know it doesn't mean you're an expert on the matter.
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haha my favourite breakfast is those absolute feasts you get in german hotels :D

I guess some people think because the Universe is big that might indicate we are insignificant. I never understood that intuition - size doesn't seem correlated with significance (if humans grew to 100 ft tall I don't think that would make us more valuable). As for why we are here, I'm a Christian so I tend to get answers about purpose from that
 
Sometimes I have thoughts of 'what if we just had an immediate big bang or blackout?' I mean anything is possible but the idea that the entire universe could just pop like a grape and be gone. Then again, we wouldn't know as it may be one's own sudden death.

The thought of that, immediate disintegration, no one to witness or study it, is mind blowing. Wiped off the face of the universe.

I'm interested in the concept of tine and existence. Sometimes I'll sit and daze and then just think 'I'm physically here now and my mind is on but what's the absolute opposite alternative to living things?' purely existing and thinking this is me is something else. Out of body feelings develop then.
 
JS96 said:
Sometimes I have thoughts of 'what if we just had an immediate big bang or blackout?' I mean anything is possible but the idea that the entire universe could just pop like a grape and be gone. Then again, we wouldn't know as it may be one's own sudden death.

The thought of that, immediate disintegration, no one to witness or study it, is mind blowing. Wiped off the face of the universe.

I'm interested in the concept of tine and existence. Sometimes I'll sit and daze and then just think 'I'm physically here now and my mind is on but what's the absolute opposite alternative to living things?' purely existing and thinking this is me is something else. Out of body feelings develop then.
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existence is mind blowing. Science can't explain (at least in any future I concieve) why there is something rather than nothing, why the Universe continues to bother to exist and why there are laws which the universe cares a lot about to obey for some reason.
Those are all interesting and open questions in philosophy :)
 
I never had much time or belief in horoscopes and the like...

But seriously - I love it on unreality TV when some says "I'm a cosmologist" and the other person says "Oh cool. I'm a Sagittarius".

Brian Cox is a legend. He is classed as a cosmologist isn't he?
 
grazorblade said:
haha my favourite breakfast is those absolute feasts you get in german hotels :D

I guess some people think because the Universe is big that might indicate we are insignificant. I never understood that intuition - size doesn't seem correlated with significance (if humans grew to 100 ft tall I don't think that would make us more valuable). As for why we are here, I'm a Christian so I tend to get answers about purpose from that
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Core memory unlocked, European breakfasts!! Yeah they were something else. I'm glad I was in good shape because I certainly took advantage of those buffets hehehe.

I suppose I say we're insignificant because I lean towards "we're not alone". Seems over the last few years that it's more acceptable to think there's intelligent life other than the norm, here and out there. And we've achieved sweet FA in comparison, but that's ok if we're millions or billions of years behind other life. Maybe we're the aliens? DNA and RNA in meteorites, panspermia and all that.
 
Is the universe continually expanding? If so, what is it expanding into, that is, what is outside the boundaries of the universe?
 
Are meteors and other large space objects actually flying that fast towards us or are we moving faster from the centre of the big bang towards them making them appear to be the moving body?

Are meteors actually closer to stationary objects we are expanding towards?
 
HappyGuus said:
Core memory unlocked, European breakfasts!! Yeah they were something else. I'm glad I was in good shape because I certainly took advantage of those buffets hehehe.

I suppose I say we're insignificant because I lean towards "we're not alone". Seems over the last few years that it's more acceptable to think there's intelligent life other than the norm, here and out there. And we've achieved sweet FA in comparison, but that's ok if we're millions or billions of years behind other life. Maybe we're the aliens? DNA and RNA in meteorites, panspermia and all that.
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yeah I think if aliens existed that wouldn't impact our significance -to make an analogy, the first Australians are just as significant before and after the first europeans make contact and I'd view us as just as significant if aliens appeared tomorrow
 
Keeper66 said:
Is the universe continually expanding? If so, what is it expanding into, that is, what is outside the boundaries of the universe?
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so the second question is actually a question that even some cosmologists will answer wrong!

So on the first question - yes and the rate of expansion is accelerating.

For the first question it depends on features of the Universe we cannot observe. We can tell looking at the first light from the Big Bang that the Universe has to be at least 400 times bigger than what we see. But there is no way to tell whether it is bigger than that because light hasn't had time to get to us to tell us about it.
If the Universe is finite in size and 400 times what we see, rewind the clock and the big bang was a hot dense state roughly the size of an orange expanding into empty space

There are more exotic possibilities, in pop science you often see the Universe compared to ants on an expanding balloon. As the balloon blows up, the ants don't need to move to end up further apart because the space between them is expanding.
The truth is we don't know

We also don't know if there is anything outside the Universe or if it has a boundary
 
RIMB said:
Are meteors and other large space objects actually flying that fast towards us or are we moving faster from the centre of the big bang towards them making them appear to be the moving body?

Are meteors actually closer to stationary objects we are expanding towards?
Click to expand...
If you have a meteor within a galaxy, then it's motion has little to do with the big bang and more to do with the evolution of our galaxy and the history of that particular meteor

The sun goes around the center of the galaxy at around 200 km per second. The galaxy is a bit of a washing machine with stuff flying everywhere, including meteorites!
 
Keeper66 said:
Is the universe continually expanding? If so, what is it expanding into, that is, what is outside the boundaries of the universe?
Click to expand...
That's the question for me.

The human mind cannot understand/grasp the concept of infinity as I understand it (I know I can't) and yet we also cannot accept that the universe is not infinite at the same time. If we imagine there must be a boundary - even if the boundary is a mobius strip - we then have to ask what is outside that mobius strip.

I do not think it will ever be possible to find out - no matter how long we exist for or who comes to tell us about it. Not a problem for me - I just find it interesting to casually think about.

I suspect I will not be given clarity in my lifetime... ;)
 
grazorblade said:
If you have a meteor within a galaxy, then it's motion has little to do with the big bang and more to do with the evolution of our galaxy and the history of that particular meteor

The sun goes around the center of the galaxy at around 200 km per second. The galaxy is a bit of a washing machine with stuff flying everywhere, including meteorites!
Click to expand...
So it is unlikely any objects we encounter have travelled from other galaxies?
 
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