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Enjoy galaxy season while it lasts?


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Here is a subject I don't often think about these days. Youtube recommended this for me. They must have known the weather has turned...

 

 

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Just had a thought.

This expansion means that we should be able to detect density change in observed galaxies as we look further away?

Space is expanding and galaxies were earlier closer than they are now. As we look further away - we are also looking back in time.

If we assume homogeneity of universe - and there is expansion of universe - well, when we look at distant galaxies - they should be much more bunched up than we would assume from density of near by galaxies.

Is this so?

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8 minutes ago, vlaiv said:

If we assume homogeneity of universe - and there is expansion of universe - well, when we look at distant galaxies - they should be much more bunched up than we would assume from density of near by galaxies.

Pretty sure that’s correct Vlaiv, although someone with far more knowledge than me would have to confirm.

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Posted (edited)

I think it is what we see - think of the Hubble Deep Field and Ultra Deep Field  - it's like every available parking space has been taken by a Galaxy .  Having said that there will also be the factor of the timeline for the rate of Galaxy formation - no doubt some complicated maths will describe the interplay there. I love this video - music fits perfectly (Shine On Crazy Diamond) .  Oh ignore the hack partway through - Ill try find a better one. 

Jim 

 

Edited by saac
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Posted (edited)

Here's a question - can we actually compare galaxy density , any spatial measurement really, between back then and now?  What I'm getting at is given that spacetime was/is expanding then are we able to compare a standard unit of spatial measurement across the universe's evolutionary epochs (don't know if that is right word) ?  Are these measurements invariant in that way ? 

Jim

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I don’t believe a word of it! Solid state universe, zero expansion. Existence makes so much sense this way. Why complicate things with a Big Bang?

Just think how many problems could be solved if all the people trying to find dark matter looked for real stuff😁

Marv

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5 hours ago, Marvin Jenkins said:

I don’t believe a word of it! Solid state universe

 

And before it was a solid state universe, it was a valve universe.

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On 05/05/2021 at 22:59, saac said:

Here's a question - can we actually compare galaxy density , any spatial measurement really, between back then and now?  What I'm getting at is given that spacetime was/is expanding then are we able to compare a standard unit of spatial measurement across the universe's evolutionary epochs (don't know if that is right word) ?  Are these measurements invariant in that way ? 

Jim

Yes but they will be model dependant . Currently the best accepted model is the LCDM one.

Regards Andrew 

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18 hours ago, George Jones said:

And before it was a solid state universe, it was a valve universe.

And before that acoustic.

Regards Andrew 

 

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Now I did think how can I blame my solid state comment on spell check but realised that my mistake from Solid State which should have been Steady State is actually a very funny gag.

I can see Fred Hoyle holding his head in his hands. Valve Universe, might be a breakthrough.

Laughing with you all,

Marv

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  • 3 weeks later...

Why is it called Galaxy season anyway? It never gets astro dark here at this time of the year so so point in dragging the gear outside during the summer.  So  what's up there now, only Galaxies, no nebulas?

Just curious!

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18 hours ago, Viktiste said:

Why is it called Galaxy season anyway?

Because this time of the year and in autumn, the Milky Way is reasonably out of the way. This means a less obscured view out of our galaxy, and fewer nebulae (which are in our galaxy). Galaxies are visible all year round, as are nebulae, but they're not always in the best position. Here up North, we miss much of what's going on between Hercules and Cygnus, almost up to Pegasus. It is possible to image in those constellations, but we miss their best positions. Otoh, we get that back during winter, with targets near Orion.

C'est la vie.

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On 02/06/2021 at 00:03, Viktiste said:

Why is it called Galaxy season anyway? It never gets astro dark here at this time of the year so so point in dragging the gear outside during the summer.  So  what's up there now, only Galaxies, no nebulas?

Just curious!

This isn't called galaxy season. Not by me anyway. Galaxy season is over, for me, by the month of June. That's at Lat 44.

Olly

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Hmmm. You I learn something new every now and then. I never realized it was because of the milky way being 'less in the way'. Now I know. Thanks for the enlightenment.  👍

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I see it a bit the other way around - galaxy season in the spring is becasue there is less Milky Way nebula to aim at, so we are mainly left with galaxies. But there is always plenty of galaxies around, also when the Milky Way is up there with all its glory. However, if you get hold of a light bucket like a RASA or Tak Epsilon, then you can always have IFN season unless you are up here in bright-summer-night Scandinavia where we have a no-AP season right now😣

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  • 2 weeks later...
On 07/05/2021 at 01:46, George Jones said:

And before it was a solid state universe, it was a valve universe.

I assume. You mean steam valves 

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On 07/05/2021 at 01:46, George Jones said:

And before it was a solid state universe, it was a valve universe.

And before that it was just relays and lamps and it was a lot bigger.

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On 09/05/2021 at 21:23, Paul M said:

In a solid state universe we'd be a Silicon based life form.. :)

 

Life but now as we know it.

Turn it around and us carbon based are life unknown to the rest of the silicon based aliens 

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21 hours ago, Paul M said:

And before that it was just relays and lamps and it was a lot bigger.

And occasional hot big bangs I assume

Edited by Gfamily
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