Understanding through Discussion


Welcome! You are not logged in. [ Login ]
EvC Forum active members: 112 (8734 total)
Current session began: 
Page Loaded: 03-30-2017 4:31 PM
423 online now:
14174dm, CosmicChimp, Coyote, kjsimons, NoNukes, nwr, ooh-child, PaulK, Percy (Admin) (9 members, 414 visitors)
Chatting now:  Chat room empty
Newest Member: timtak
Post Volume:
Total: 802,243 Year: 6,849/21,208 Month: 2,610/2,634 Week: 273/525 Day: 32/74 Hour: 3/4


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
Prev1
...
45678
9
Author Topic:   How is the Universe here?
cavediver
Member (Idle past 998 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 121 of 131 (502640)
03-12-2009 4:00 PM
Reply to: Message 116 by Dr Jack
03-12-2009 10:49 AM


Re: 13.7 billion years ago? By who's reference?
you say time is relative, so there is no universal timeframe.

No, *I* don't say that :) It may be true in Special Relativity, but not always in General Relativity. The standard cosmological solutions admit a preferred rest-frame: the "comoving" rest-frame. You can say that it is the expansion of the Universe that provides the basis for this rest-frame. We clearly see it in the CMBR, and we have to subtract a doppler component from our observations of the CMBR based on our own peculiar motion wrt this rest-frame. Essentially, the 13.7 Ga age of the Universe is the *maximum* possible age of a test particle emitted at the Big Bang.


This message is a reply to:
 Message 116 by Dr Jack, posted 03-12-2009 10:49 AM Dr Jack has responded

Replies to this message:
 Message 122 by Dr Jack, posted 03-12-2009 4:01 PM cavediver has not yet responded

  
Dr Jack
Member
Posts: 3500
From: Leicester, England
Joined: 07-14-2003


Message 122 of 131 (502641)
03-12-2009 4:01 PM
Reply to: Message 121 by cavediver
03-12-2009 4:00 PM


Re: 13.7 billion years ago? By who's reference?
Ah, that makes sense. Ta.
This message is a reply to:
 Message 121 by cavediver, posted 03-12-2009 4:00 PM cavediver has not yet responded

  
AustinG
Member (Idle past 2523 days)
Posts: 36
Joined: 04-06-2009


Message 123 of 131 (505871)
04-18-2009 8:35 PM


Time as dimension
I read over the posts that described how time is different for each oberserver; how a man on mercury would see a solar flare before we do on earth. I get that. What I don't get is how it relates to time. If the solar flare happend at 4:00 p.m. on the sun than it still happend a 4:00 p.m. for observers on earth, they just havn't observed it yet.

If my friend, who livers 30 minutes away, leaves his house at 4:00 and arrives ay my place at 4:30, I wouldn't say he left his house at 4:30 and also arived at 4:30. I would know he left at 4:00 and it took him 30 minutes to get here. Isn't this the same thing as the sun example?

Or am I being totally close minded? Can anyone elaborate more for me?


Replies to this message:
 Message 124 by lyx2no, posted 04-19-2009 12:54 AM AustinG has responded

    
lyx2no
Member (Idle past 2071 days)
Posts: 1277
From: A vast, undifferentiated plane.
Joined: 02-28-2008


(1)
Message 124 of 131 (505878)
04-19-2009 12:54 AM
Reply to: Message 123 by AustinG
04-18-2009 8:35 PM


Re: Time as dimension
Welcome AustinG

You're correct in your example. If observers on the Sun, Mercury and Earth each had a synchronized Timex then a solar flare happening at four o'clock on the Sun observers watch would be seen to happen at 4:03 on the Mercury observers watch and at 4:08 on the Earth observers watch. And each would know at what time it happened on the other observers watches. No big deal.

But now lets give them all super accurate atomic clocks synchronized At Venus' north pole. The Sun observer would have to include a correction for his clock being slow due to the Sun's enormous gravitational field. The Mercury observer would have to include a correction for his clock being fast due to Mercury's rapid orbit. The Earth observer has to account for his gravity changing over the course of the day as the Moon changes position in the sky. More to the point, they each have to take into account on their very accurate clocks every acceleration they don't share in common. Accelerations warp space-time.


Genesis 2
17 But of the ponderosa pine, thou shalt not eat of it; for in the day that thou shinniest thereof thou shalt sorely learn of thy nakedness.
18 And we all live happily ever after.
This message is a reply to:
 Message 123 by AustinG, posted 04-18-2009 8:35 PM AustinG has responded

Replies to this message:
 Message 125 by AustinG, posted 04-20-2009 1:01 AM lyx2no has responded

  
AustinG
Member (Idle past 2523 days)
Posts: 36
Joined: 04-06-2009


Message 125 of 131 (505915)
04-20-2009 1:01 AM
Reply to: Message 124 by lyx2no
04-19-2009 12:54 AM


Re: Time as dimension
Yes, but how does one know if time actually slows down because of velocity/gravitational fields? What if only the clock is slowed down?

How would you know either way?


This message is a reply to:
 Message 124 by lyx2no, posted 04-19-2009 12:54 AM lyx2no has responded

Replies to this message:
 Message 126 by lyx2no, posted 04-20-2009 10:23 AM AustinG has not yet responded

    
lyx2no
Member (Idle past 2071 days)
Posts: 1277
From: A vast, undifferentiated plane.
Joined: 02-28-2008


Message 126 of 131 (505940)
04-20-2009 10:23 AM
Reply to: Message 125 by AustinG
04-20-2009 1:01 AM


Habits
Because there is nothing particularly special about a clock. A clock is merely a device for accounting a sequence of events in time. As a person of habit can be used to set ones watch by, cesium atoms are only of a more stringent habit.

Cosmic ray particles slamming into our upper atmosphere produce daughter particles that should decay before making it to the surface of the Earth. So how is it that they make it down here where we can measure them. By theory, if a daughter particle were moving at 87% of the speed of light — a real slow poke — it should "live" twice as long as we would expect if its time were the same as our own. And this is what is seen.

Are we measuring a changing habit of a particle or a habit of space-time? Take your pick. Either all particles and events without exception behave exactly as if time has changed for reasons only beknowst to themselves or time is not the same to all observers.

AbE: cavediver, I'm not really sure this is on topic or not because I'm not really sure I (come anywhere close?) understand what the topic is. There is something I vaguely recall about "Why is there something instead of nothing?" I don't know where that comes from… so why haven't I Googled it already? Let me Google it and get back to you with something worth the time (no pun intended). Thanks, I always like reading your stuff.

Edited by lyx2no, : Hit the topic somewhere.

Edited by lyx2no, : No reason given.


Genesis 2
17 But of the ponderosa pine, thou shalt not eat of it; for in the day that thou shinniest thereof thou shalt sorely learn of thy nakedness.
18 And we all live happily ever after.
This message is a reply to:
 Message 125 by AustinG, posted 04-20-2009 1:01 AM AustinG has not yet responded

  
Lurkey
Junior Member (Idle past 1442 days)
Posts: 11
Joined: 11-03-2012


(2)
Message 127 of 131 (678456)
11-08-2012 7:55 AM
Reply to: Message 85 by cavediver
11-09-2008 10:19 AM


Re: Back again, and let's first dispense with this nonsense...
and for them to feel pleasure at having learned something complex about the Universe.

There sure is. If you ever read this - thanks for everything you’ve done on this site cavediver. You're some teacher.

Oh, only a few billion times In a one-on-one, it is much more simple as you can gauge their ability to understand, and present accordingly.

The problem is that this always leads to them passing it on to others, and very quickly the message becomes hopelessly corrupted in the inevitable Chinese Whispers. That is why there are so many horrible misconceptions floating around that actually started with professionals. I guess I should only present this stuff on the condition that the audience promises never to repeat it Anway, presenting at EvC is much more difficult because you have so little feel as to where to pitch the material.

Purely personal, but i have to disagree. There is something about this site that works and I reckon the passing on has a lot to do with it.

Like the idea gets marched all the way down the line to a point where I can understand. Then when I finally do get it, the path back up is right there for me to follow.

And if one person makes a mistake, others point it out.

Tbh, i didn't understand most of the physics here, but still i'm spewing it got jacked. A golden resource lost.

Not into bashing, but what the jackers did here was immoral....evil...criminal...like defacing an antiquity.


This message is a reply to:
 Message 85 by cavediver, posted 11-09-2008 10:19 AM cavediver has responded

Replies to this message:
 Message 128 by cavediver, posted 11-08-2012 5:13 PM Lurkey has not yet responded

  
cavediver
Member (Idle past 998 days)
Posts: 4129
From: UK
Joined: 06-16-2005


(5)
Message 128 of 131 (678499)
11-08-2012 5:13 PM
Reply to: Message 127 by Lurkey
11-08-2012 7:55 AM


Re: Back again, and let's first dispense with this nonsense...
Oh, I'm here And thanks - that means a great deal to me.

I'm always lurking but I have so little time these days to contribute much. When I joined EvC in 2005, I was working for myself, and a master of my own time. Now I'm a slave to running my company

I guess I should only present this stuff on the condition that the audience promises never to repeat it
Purely personal, but i have to disagree. There is something about this site that works and I reckon the passing on has a lot to do with it.

Yep, you're right. EvC is rather special, and some of the folks here have more than excelled themselves. That's one reason why I don't feel I'm letting the side down too much - for example, Catholic Scientist's cosmology explanations have become first rate.


This message is a reply to:
 Message 127 by Lurkey, posted 11-08-2012 7:55 AM Lurkey has not yet responded

Replies to this message:
 Message 129 by Stile, posted 11-09-2012 8:28 AM cavediver has not yet responded

  
Stile
Member
Posts: 2851
From: Ontario, Canada
Joined: 12-02-2004
Member Rating: 1.8


Message 129 of 131 (678585)
11-09-2012 8:28 AM
Reply to: Message 128 by cavediver
11-08-2012 5:13 PM


Re: Back again, and let's first dispense with this nonsense...
cavediver writes:

Yep, you're right. EvC is rather special, and some of the folks here have more than excelled themselves.

"Oooooooooohhhhh.... for he's a jolly good fell..."

...no? Anybody? Just me, then?
I don't care what anybody else says about you, cavediver, I think you're a good guy

And maybe one day, sometime, you'll be able to continue this thread.


This message is a reply to:
 Message 128 by cavediver, posted 11-08-2012 5:13 PM cavediver has not yet responded

    
kofh2u
Member (Idle past 1175 days)
Posts: 1162
From: phila., PA
Joined: 04-05-2004


Message 130 of 131 (678591)
11-09-2012 9:02 AM
Reply to: Message 106 by Agobot
12-12-2008 2:14 PM


Re: Back again, and let's first dispense with this nonsense...
Agobot:
When almost everything about this mass/energy comes from virtual particles, the article concludes in:

The Higgs field is also thought to make a small contribution, giving mass to individual quarks as well as to electrons and some other particles. The Higgs field creates mass out of the quantum vacuum too, in the form of virtual Higgs bosons. So if the LHC confirms that the Higgs exists, it will mean all reality is virtual.

If you think hard enough about E=m.c^2, you'll see what they meant with the above quote.

Kofh2u:

Interesting confirmation of the Copenhagen Interpretation which infers the virtual reality become concrete for us when we observe it???

Truth is also virtual, in that it is an ideal that corresponds to a Reality tp which it is congruent.
Truth is thought or spirit of mind, too, for man,'Man can fill his mind with the spirit of Truth or the spirit of lies.

.
.
.
1 John 4:6
We are of God: he that knoweth God heareth us; he that is not of God heareth not us. Hereby know we the spirit of truth, and the spirit of error.

"God" apparently is the ever unfolding reality which sane people conceive mentally and chosse to accept for their own salvation, isn't it?


This message is a reply to:
 Message 106 by Agobot, posted 12-12-2008 2:14 PM Agobot has not yet responded

Replies to this message:
 Message 131 by Eli, posted 11-10-2012 10:12 AM kofh2u has not yet responded

    
Eli
Member (Idle past 846 days)
Posts: 274
Joined: 08-24-2012


(1)
Message 131 of 131 (678777)
11-10-2012 10:12 AM
Reply to: Message 130 by kofh2u
11-09-2012 9:02 AM


Re: Back again, and let's first dispense with this nonsense...
That's not the Copenhagen Interpretation.
This message is a reply to:
 Message 130 by kofh2u, posted 11-09-2012 9:02 AM kofh2u has not yet responded

  
Prev1
...
45678
9
Newer Topic | Older Topic
Jump to:


Copyright 2001-2015 by EvC Forum, All Rights Reserved

™ Version 4.0 Beta
Innovative software from Qwixotic © 2017